Stellarium 25.4 User Guide

Georg Zotti, Alexander Wolf (editors)

2025

STELLARIUM.ORG

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU

Free Documentation License, Version 1.3 or any later version published by the Free Software

Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of

the license is included in the appendix G entitled “GNU Free Documentation License”.

All trademarks, third party brands, product names, trade names, corporate names and company names

mentioned may be trademarks of their respective owners or registered trademarks of other companies and

are used for purposes of explanation and to the readers’ beneﬁt, without implying a violation of copyright law.

Version 25.4-1, December 29, 2025

Contents

Basic Use

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 Historical notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 Version Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.3 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.4 Scientiﬁc use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.5 About this User Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1 System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1.1 Minimum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1.2 Recommended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2 Downloading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3.1 Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3.2 macOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3.3 Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3.4 *BSD/Solaris/OpenIndiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3.5 Haiku . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4 Running Stellarium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4.1 Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4.2 macOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4.3 Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4.4 *BSD/Solaris/OpenIndiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4.5 Haiku . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.5 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 A First Tour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 Time Travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.2 Moving Around the Sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3 The Main Tool Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.4 Taking Screenshots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.5 Observing Lists (Bookmarks) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.6 Custom Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.7 Copy Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.8 Speech Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4 The User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.1 Setting the Date and Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.2 Setting Your Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2.1 Time Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.2.2 Geographical Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.2.3 Observers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.3 The Conﬁguration Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.3.1 The Main Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.3.2 The Information Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.3.3 The Extras Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.3.4 The Time Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.3.5 The Tools Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.3.6 The Speech Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.3.7 The Scripts Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.3.8 The Plugins Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.4 The View Settings Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.4.1 The Sky Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.4.2 The Solar System Objects (SSO) Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.4.3 The Deep-Sky Objects (DSO) Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.4.4 The Markings Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.4.5 The Landscape Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

4.4.6 The Sky Culture Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4.7 The Surveys Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.5 The Search Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.5.1 The Object tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4.5.2 The SIMBAD tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.5.3 The Position tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.5.4 The Lists tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.5.5 The Options tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.6 The Astronomical Calculations Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.6.1 The Positions Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.6.2 The Ephemeris Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.6.3 The “Risings, Transits, and Settings” (RTS) Ta b . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.6.4 The Phenomena Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.6.5 The Graphs Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

4.6.6 The “What’s Up Tonight” (WUT) Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.6.7 The “Planetary Calculator” (PC) Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.6.8 The Eclipses Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4.6.9 The Almanac Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

4.7 The Help Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.7.1 The Help Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.7.2 The About Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.7.3 The Log Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.7.4 The Conﬁg Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.8 Editing Keyboard Shortcuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

4.8.1 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Advanced Use

5 Files and Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5.1 Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5.1.1 Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5.1.2 macOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.1.3 Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.1.4 *BSD/Solaris/OpenIndiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.1.5 Haiku . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.1.6 Customized Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.2 Directory Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

5.3 The Logﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.4 The Main Conﬁguration File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.5 Getting Extra Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.5.1 More Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.5.2 More Deep-Sky Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

5.5.3 Alternative Planet Ephemerides: DE430, DE431, DE440, DE441 . . . . . . . . . . . . . 60

5.5.4 GPS Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

5.5.5 Modernized MESA3D libraries (Software OpenGL on Windows) . . . . . . . . . . . . 62

6 Advanced Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.1 Command Line Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.1.1 Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.2 Environment Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.2.1 Logﬁle tweaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.3 GUI Customizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.3.1 Panel transparency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.3.2 Button brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.3.3 Text shadow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.3.4 User interface colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.4 Spout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.5 Spherical Mirror Mode for Planetarium Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

7 Landscapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

7.1 Stellarium Landscapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

7.1.1 Location information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

7.1.2 Polygonal landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

7.1.3 Spherical landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

7.1.4 High resolution (“Old Style”) landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

7.1.5 Fisheye landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

7.1.6 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

7.1.7 Gazetteer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

7.1.8 Packing and Publishing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

7.2 Creating Panorama Photographs for Stellarium . . . . . . . . . . . . . . . . . . . . . . . . 80

7.2.1 Panorama Photography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

7.2.2 Hugin Panorama Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

7.2.3 Regular creation of panoramas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

7.3 Panorama Postprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

7.3.1 The GIMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

7.3.2 ImageMagick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

7.3.3 Final Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

7.3.4 Artiﬁcial Panoramas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

7.3.5 Nightscape Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

7.4 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7.5 Other recommended software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7.5.1 IrfanView . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7.5.2 FSPViewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7.5.3 Clink and GNUWin32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

7.5.4 WSL – Windows Subsystem for Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

8 Deep-Sky Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

8.1 Stellarium DSO Catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

8.1.1 Modifying catalog.dat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.1.2 Modifying names.dat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.1.3 Modifying textures.json . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

8.1.4 Modifying outlines.dat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

8.2 Adding Extra Nebula Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8.2.1 Image requirements for inclusion in Stellarium . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8.2.2 Processing requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

8.2.3 Manual processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

8.2.4 Automated processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

8.2.5 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

9 Adding Sky Cultures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9.1 Text description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9.1.1 Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

9.1.2 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

9.1.3 License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

9.1.4 Technical Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

9.2 Technical data: index.json . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

9.2.1 Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

9.2.2 Classiﬁcation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

9.2.3 Constellation boundaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

9.2.4 Constellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

9.2.5 Asterisms and help rays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

9.2.6 Culture Relevant Coordinate Systems: Zodiac and Lunar Systems . . . . . . . . . 117

9.2.7 Names of Stars, Planets and Nonstellar Objects . . . . . . . . . . . . . . . . . . . . . . . 119

9.2.8 Deep-Sky Objects Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

9.2.9 User Settings for the Skycultures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

9.3 The Skyculture Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

9.4 Publish Your Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

10 Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.2 Hipslist ﬁle and default surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.3 Solar system HiPS survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10.4 Digitized Sky Survey 2 (TOAST Survey) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10.4.1 Local Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

11 Stellarium’s Skylight Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

11.2 The Skylight Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

11.2.1 Legacy Mode: The Preetham Skylight Model . . . . . . . . . . . . . . . . . . . . . . . . . 127

11.2.2 Advanced Mode: The ShowMySky Skylight Model . . . . . . . . . . . . . . . . . . . . . 128

11.3 Light Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

11.4 Tone Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

III

Extending Stellarium

12 Plugins: An Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

12.1 Enabling plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

12.2 Data for plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

13 Interface Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

13.1 Angle Measure Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

13.2 Equation of Time Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

13.2.1 Section



EquationOfTime



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

13.3 Pointer Coordinates Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

13.3.1 Section



PointerCoordinates



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . 138

13.4 Text User Interface Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

13.4.1 Using the Text User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

13.4.2 TUI Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

13.4.3 Section



tui



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

13.5 Remote Control Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

13.5.1 Using the plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

13.5.2 Remote Control Web Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

13.5.3 Remote Control API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

13.5.4 Developer information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

13.5.5 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

13.6 Remote Sync Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

13.6.1 Developer notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

13.6.2 Finetuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

13.7 OnlineQueries Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

13.7.1 Section



OnlineQueries



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

13.8 Solar System Editor Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

13.9 Nebula Textures Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

13.9.1 Online Solving and Texture Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

13.9.2 Manual Texture Addition) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

13.9.3 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

13.10 Calendars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.10.2 The Calendars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

13.10.3 Scripting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

13.10.4 Conﬁguration Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

13.10.5 Further development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

13.10.6 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

14 Object Catalog Plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

14.1 Bright Novae Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

14.1.1 Section



Novae



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

14.1.2 Format of bright novae catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

14.1.3 Light curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

14.2 Historical Super novae Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

14.2.1 List of supernovae in default catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

14.2.2 Light curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

14.2.3 Section



Supernovae



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

14.2.4 Format of historical supernovae catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

14.3 Exoplanets Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

14.3.1 Potential habitable exoplanets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

14.3.2 Proper names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

14.3.3 Section



Exoplanets



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

14.3.4 Format of exoplanets catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

14.4 Pulsars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

14.4.1 Section



Pulsars



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

14.4.2 Format of pulsars catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

14.5 Quasars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.5.1 Section



Quasars



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.5.2 Format of quasars catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.6 Meteor Showers Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

14.6.1 Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

14.6.2 Section



MeteorShowers



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

14.6.3 Format of Meteor Showers catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

14.6.4 Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

14.6.5 Further Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

14.7 Navigational Stars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

14.7.1 Section



NavigationalStars



in conﬁg.ini ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

14.8 Satellites Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

14.8.1 Satellite Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

14.8.2 Satellite Catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

14.8.3 Conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

14.8.4 The approximated visual magnitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

14.8.5 Sources for TLE data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

14.9 ArchaeoLines Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

14.9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

14.9.2 Characteristic Declinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

14.9.3 Geographical Targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

14.9.4 Custom Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

14.9.5 Conﬁguration Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192

14.9.6 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

15 Scenery3d – 3D Landscapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

15.2 Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

15.3 Hardware Requirements & Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

15.3.1 Performance notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

15.4 Model Conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

15.4.1 Exporting OBJ from Sketchup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

15.4.2 Notes on OBJ ﬁle format limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

15.4.3 Conﬁguring OBJ for Scenery3d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

15.4.4 Concatenating OBJ ﬁles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

15.4.5 Beyond 3D: Temporally evolving Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

15.4.6 Working with non-georeferenced OBJ ﬁles . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

15.4.7 Rotating OBJs with recognized survey points . . . . . . . . . . . . . . . . . . . . . . . . . 203

15.5 Predeﬁned views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

15.6 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

15.7 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

16 Stellarium at the Telescope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

16.1 Oculars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

16.1.1 Using the Ocular plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

16.1.2 Conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

16.1.3 Scaling the eyepiece view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

16.2 TelescopeControl Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

16.2.1 Abilities and limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

16.2.2 Using this plug-in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

16.2.3 Main window (’Telescopes’) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

16.2.4 Telescope conﬁguration window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

16.2.5 Supported devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

16.2.6 RTS2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

16.2.7 INDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

16.2.8 ASCOM 7 (Windows only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

16.2.9 StellariumScope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

16.2.10 Other telescope servers and Stellarium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

16.3 Observability Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228

16.4 Mosaic Camera Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

16.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

16.4.2 Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

16.4.3 Cameras . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

16.4.4 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

17 Scripting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

17.2 The Script Console . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.2.1 The Tabs in the Console . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.2.2 The Menu Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.2.3 German Keyboards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.3 Includes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.4 Minimal Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.5 Critical Scripting Differences introduced with version 1.0 . . . . . . . . . . . . . . . . 235

17.5.1 Pause/Resume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

17.5.2 The Vec3f problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

17.6 Example: Retrograde motion of Mars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

17.6.1 Script header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

17.6.2 A body of script . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

17.7 More Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

Practical Astronomy

18 Astronomical Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

18.1 The Celestial Sphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

18.2 Coordinate Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

18.2.1 Altitude/Azimuth Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

18.2.2 Right Ascension/Declination Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

18.2.3 Fixed Equatorial Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

18.2.4 Ecliptical Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

18.2.5 Galactic Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

18.2.6 Planet Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

18.3 Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

18.4 Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

18.4.1 Sidereal Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

18.4.2 Julian Day Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

18.4.3 Delta T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250

18.5 Angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

18.5.1 Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

18.5.2 Handy Angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

18.6 The Magnitude Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

18.7 Luminosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

18.8 Precession . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

18.9 Parallax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

18.9.1 Geocentric and Topocentric Observations . . . . . . . . . . . . . . . . . . . . . . . . . . 257

18.9.2 Stellar Parallax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

18.10 Aberration of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

18.11 Proper Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

18.11.1 Binary Star s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

19 Astronomical Phenomena . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

19.1 The Sun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

19.1.1 Twilight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

19.2 Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

19.2.1 Multiple Star Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

19.2.2 Constellations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

19.2.3 Star Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

19.2.4 Spectral Type & Luminosity Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

19.2.5 Variable Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

19.3 Our Moon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

19.3.1 Phases of the Moon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

19.3.2 The Lunar Magnitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

19.4 The Major Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

19.4.1 Terrestrial Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

19.4.2 Jovian Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

19.4.3 Apparent Magnitudes of the Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

19.5 The Minor Bodies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

19.5.1 Asteroids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

19.5.2 Comets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

19.6 Meteoroids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268

19.7 Zodiacal Light and Gegenschein . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

19.8 The Milky Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

19.9 Nebulae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

19.9.1 The Messier Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

19.9.2 The Caldwell catalogue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

19.10 Galaxies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

19.11 Eclipses and Transits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

19.11.1 Solar Eclipses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270

19.11.2 Lunar Eclipses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

19.11.3 Transits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

19.11.4 Contact Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

19.12 Observing Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

19.13 Atmospheric effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

19.13.1 Atmospheric Extinction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

19.13.2 Atmospheric Refraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

19.13.3 Light Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

20 A Little Sky Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

20.1 Dubhe and Merak, The Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

20.2 M31, Messier 31, The Andromeda Galaxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

20.3 The Garnet Star,

µ Cephei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

20.4 4 and 5 Lyrae,

ε Lyrae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

20.5 M13, Hercules Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

20.6 M45, The Pleiades, The Seven Sisters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

20.7 C41, The Hyades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

20.8 Algol, The Demon Star,

β Persei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

20.9 Sirius,

α Canis Majoris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

20.10 M44, The Beehive, Praesepe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

20.11 27 Cephei,

δ Cephei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

20.12 Betelgeuse,

α Orionis, 58 Orionis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

20.13 M42, The Great Orion Nebula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

20.14 La Superba, Y Canum Venaticorum, HIP 62223 . . . . . . . . . . . . . . . . . . . . . . . . 279

20.15 52 and 53 Bootis, ν

and

Bootis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

20.16 Almach,

γ Andromedae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

20.17 Algieba,

γ Leonis, 41 Leonis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

20.18 Castor, α Geminorum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

20.19 PZ Cas, HIP 117078 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

20.20 VV Cephei, HIP 108317 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

20.21 AH Scorpii, HIP 84071 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

20.22 Albireo,

β Cygni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

20.23 31 and 32 Cygni, o

and o

Cygni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

20.24 The Coathanger, Brocchi’s Cluster, Cr 399 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

20.25 Kemble’s Cascade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

20.26 The Double Cluster, χ and h Persei, NGC 884 and NGC 869 . . . . . . . . . . . . . . 282

20.27 Large Magellanic Cloud, PGC 17223 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

20.28 Tarantula Nebula, C 103, NGC 2070 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282

20.29 Small Magellanic Cloud, NGC 292, PGC 3085 . . . . . . . . . . . . . . . . . . . . . . . . . 283

20.30

ω Centauri cluster, C 80, NGC 5139 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

20.31 47 Tucanae, C 106, NGC 104 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

20.32 The Coalsack Nebula, C 99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

20.33 Mira, o Ceti, 68 Cet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

20.34

α Persei Cluster, Cr 39, Mel 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

20.35 M7, The Ptolemy Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

20.36 M22, NGC 6656, The Great Sagittarius Cluster . . . . . . . . . . . . . . . . . . . . . . . . . 285

20.37 M24, The Sagittarius Star Cloud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

20.38 IC 4665, The Summer Beehive Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

20.39 The E Nebula, Barnard 142 and 143 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286

21 Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

21.1 Find M31 in Binoculars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

21.1.1 Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

21.1.2 For Real . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

21.2 Handy Angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

21.3 Find a Lunar Eclipse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

21.4 Find a Solar Eclipse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

21.5 Find a retrograde motion of Mars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

21.6 Analemma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

21.7 Transit of Venus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

21.8 Transit of Mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

21.9 Triple shadows on Jupiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

21.10 Jupiter without satellites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

21.11 Mutual occultations of planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

21.12 The proper motion of stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

Appendices

A Default Hotkeys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

A.1 Mouse actions with combination of the keyboard keys . . . . . . . . . . . . . . . . . 293

A.2 Display Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

A.3 Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

A.4 Movement and Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

A.5 Date and Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

A.6 Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

A.7 Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

A.8 Plugins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.1 Angle Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.2 ArchaeoLines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.3 Calendars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.4 Equation of Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.5 Exoplanets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.6 Meteor Showers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.7 Oculars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.8 Pulsars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

A.8.9 Quasars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

A.8.10 Satellites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

A.8.11 Scenery3d: 3D landscapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

A.8.12 Solar System Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

A.8.13 Telescope Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298

A.8.14 Text User Interface (TUI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

A.9 Special local keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

B The Bortle Scale of Light Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

B.1 Excellent dark sky site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

B.2 Typical truly dark site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

B.3 Rural sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

B.4 Rural/suburban transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

B.5 Suburban sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

B.6 Bright suburban sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

B.7 Suburban/urban transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

B.8 City sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

B.9 Inner-city sky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

C Star Catalogues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

C.1 Stellarium’s Sky Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

C.1.1 Zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

C.2 Star Catalogue File Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

C.2.1 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

C.2.2 File Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306

C.2.3 Record Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307

C.3 Variable Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

C.3.1 Variable Star Catalog File Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

C.3.2 GCVS Variability Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

C.4 Double Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320

C.4.1 Double Star Catalog File Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320

C.4.2 Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320

C.5 Cross-Identiﬁcation Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331

C.5.1 Cross-Identiﬁcation Catalog File Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331

C.6 Binary Star System Orbital Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331

C.6.1 Binary Star System Orbital Parameters Catalog File Format . . . . . . . . . . . . . . 331

D Conﬁguration Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

D.1 Program Conﬁguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

D.1.1



astro



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

D.1.2



astrocalc



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336

D.1.3



audio



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

D.1.4



color



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

D.1.5



custom_selected_info



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340

D.1.6



custom_time_correction



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

D.1.7



devel



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

D.1.8



dso_catalog_ﬁlters



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

D.1.9



dso_type_ﬁlters



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

D.1.10



fov



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

D.1.11



gui



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

D.1.12



init_location



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344

D.1.13



landscape



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344

D.1.14



localization



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

D.1.15



main



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

D.1.16



navigation



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346

D.1.17



plugins_load_at_startup



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347

D.1.18



projection



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347

D.1.19



proxy



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

D.1.20



scripts



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

D.1.21





. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

D.1.22



spheric_mirror



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

D.1.23



stars



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

D.1.24



tui



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

D.1.25



video



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350

D.1.26



viewing



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351

D.1.27



DialogPositions



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

D.1.28



DialogSizes



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

D.1.29



hips



. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

D.2 Solar System Conﬁguration Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354

D.2.1 File ssystem_major.ini . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354

D.2.2 File ssystem_minor.ini . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357

D.2.3 JPL Horizons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361

E Planetary nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365

E.1 Format of nomenclature data ﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366

E.2 Planetary Coordinate Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366

E.3 How names are approved by the IAU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367

E.4 IAU rules and conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367

E.5 Naming conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

E.6 Descriptor terms (feature types) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370

E.6.1 Chart of landform types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371

F Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

F.1 Date Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

F.2 Stellar Astrometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376

F.3 Planetary Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376

F.4 Minor Bodies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

F.5 Precession and Nutation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

F.6 Planet Axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

F.7 Eclipses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

F.8 The Calendar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

F.9 Comparison to Reference Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378

G GNU Free Documentation License . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385

G.1 PREAMBLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385

G.2 APPLICABILITY AND DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385

G.3 VERBATIM COPYING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386

G.4 COPYING IN QUANTITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387

G.5 MODIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387

G.6 COMBINING DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388

G.7 COLLECTIONS OF DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

G.8 AGGREGATION WITH INDEPENDENT WORKS . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

G.9 TRANSLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

G.10 TERMINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

G.11 FUTURE REVISIONS OF THIS LICENSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390

G.12 RELICENSING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390

H Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391

H.1 Contributors to this User Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391

H.2 Developers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391

H.2.1 Developers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391

H.2.2 Former Developers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392

H.2.3 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392

H.3 How you can help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393

H.4 Technical Articles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393

H.5 Included Source Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394

H.6 Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394

H.7 Graphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395

H.7.1 Full credits for “earthmap” texture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405

H.7.2 License for the JPL planets images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405

H.7.3 DSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407

Index

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417

Foreword for Stellarium 25.2

Only a few months ago, in the previous foreword, we could announce big updates with the new Gaia-based

star catalog and the new ﬁle format for Skycultures. But there are more surprises!

Just as we prepared version 24.4 last December and had ﬁrst trials with the new star catalog, a new

contributor presented his plugin. Josh Meyers has developed a Stellarium plugin for his commissioning work

at the new Vera C. Rubin observatory’s Simonyi Survey Telescope

Some messages have to be read more than once to sink in. Stellarium is used during commissioning of

the survey telescope at the Vera C. Rubin observatory. This is doubtlessly one of the most jaw-dropping

astronomical instruments to become operational in this decade, capturing repeated surveys of the whole sky

that take only 3 days with its gigantic 3.2 Gigapixel sensor array, and scheduled to producing 20 Terabytes

of data. Per night! Josh’s plugin just didn’t make it into 25.1, but is now integrated in version 25.2 (see 16.4),

just in time as ﬁrst-light images have been announced for the week after our June 2025 solstice release. It is

great to see that Stellarium is used in the control room of this magniﬁcent telescope!

You may not run your own survey telescope, but with this plugin you can display several preconﬁgured

sensor areas, and even conﬁgure your own dream system. I can imagine it can help in outreach, when the

ﬁelds of view for professional telescopes can be demonstrated in Stellarium’s sky rendition.

Another new plugin that certainly more of you have been waiting for: Wang Siliang has made integrating

your own astrophotos into Stellarium so much easier! In his NebulaTextures plugin (see 13.9), just upload an

image to Astrometry.net and receive its accurate location within seconds, then display and ﬁnetune, and store

in your private collection for running in future Stellarium sessions. You can also manually adjust positions,

which might be useful to integrate your sketches and paintings (which Astrometry.net may not like). We

would like to see a collection of sketches that more represent what observers can see to use as alternative to

the ever more stunning photos.

While these new plugins will certainly ﬁnd friends soon, the core team and our tireless translators were

busy in continuing what was ﬁrst visible in version 25.1. Stellarium has become the de-facto most relevant

simulation environment for cultural astronomy, be it archaeoastronomical simulation of old standing stone

rows under simulated skies of yesteryear, or explaining the constellations and how they can be used in the

lives of the many cultures living on our planet.

The new skyculture ﬁle format has grown far, closing the deﬁciencies of the old system that we and some

of you had identiﬁed in the last years. Stellarium can now display multiple linguistic variants of constellation

and star labels, can show “single star constellations” and “dark constellations” formed by dust clouds in

the Milky Way, can properly identify Morning and Evening star, and for those cultures where it is relevant,

illustrate the zodiac and lunar stations or lunar mansions in various culture-dependent versions, and some

more. All details of the new format can be found in chapter 9.

If something about star names is not found in a skyculture description, chances are such data are or will

soon be available in a new online project by Susanne M. Hoffmann, the All Skies Encyclopaedia (ASE).

Stellarium’s OnlineQueries plugin (13.7) can now retrieve data for stars and constellations from ASE into its

Wording clariﬁed since the 25.2 User Guide.

integrated web browser.

So, Stellarium is going strong as we approach the 25th anniversary of this project! Twenty-ﬁve years

ago, in summer of 2000, Fabien Chéreau typed the ﬁrst lines of code of this desktop planetarium to try

something with astronomy and computer graphics. What has grown from these ﬁrst lines is just awesome.

However, developing and maintaining a project of this size needs dedication, especially when done as

unpaid side occupation. Large progress needs funding which is sometimes hard to ﬁnd. We want to thank

all sponsors and backers of the project as meanwhile we had collected substantial funds to support this

development also in work hours. We like working on this project, but also must pay our bills, so please keep

up your kind support!

In the name of all prior and current developers we wish you much enjoyment with this and future

versions of the Stellarium desktop planetarium!

Georg Zotti and Alexander Wolf, June 2025

. . . and on to V25.3. . .

Over the summer we have further reﬁned many details around skycultures. Contributors have provided and

updated many details especially in Arab, Chinese and even Mesopotamian skycultures. Don’t imagine, just

see Cuneiform labels in the sky!

We have also updated the DSO catalog and further enhanced the AstroCalc module. And we dare to

increase the maximum range of dates to

±200.000

years to observe stellar proper motion. (Please note that

planet positions by far cannot be modelled in that long time range!)

Clear skies!

Georg Zotti and Alexander Wolf, September 2025

. . . and V25.4

Our reﬁnements around skycultures continued. Our skyculture researcher, Susanne M. Hoffmann, and her

international peers and students have created no less than 4 new skycultures and reﬁned several more. One

is a remarkable Chinese adaptation of the standard IAU constellations which replaces the internationally

known constellations by characters from the Journey to the West, a well-known story from classical Chinese

literature. While we cannot provide the whole story and surely all of us not familiar with the story will miss

a lot, the cute artwork alone, together with the standard names available in the “Byname” labels, may bring a

fresh view to the old ﬁgures.

Some time ago, a user asked why our speech output was so bad. To be honest, I was not even aware of

the current state of operating system support to output audibly whatever text is shown in the user interface.

But indeed there are places where speech output may be helpful even for users without visibility problems.

When you have selected a constellation, you may now hear whatever the skyculture author had to say about it.

Spoken Information is also available for stars, planets and deep-sky objects. Also the introductory sections

of skycultures, and landscape descriptions can be read out. Of course this needs texts translated to your user

language, so our thanks again go to our team of translators, we know the amount of text in the sky cultures

is quite a challenge. It also needs support of your language by the speech engines, this is out of our hands.

Some details may still sound a bit rough, we are also still learning here, so further improvements are likely.

And: If you are expert in the ﬁeld of accessibility and want to redesign and extend this to become fully

functional, we welcome your support!

You may also see this User Guide has fewer pages than the last. We have slightly redesigned the

appearance and reduced font size, but the actual content has again grown.

Clear skies!

Georg Zotti and Alexander Wolf, December 2025

Basic Use

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 Historical notes . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 Version Numbers . . . . . . . . . . . . . . . . . . . . . . . . 5

1.3 Acknowledgements . . . . . . . . . . . . . . . . . . . . . 5

1.4 Scientiﬁc use . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.5 About this User Guide . . . . . . . . . . . . . . . . . . . . 6

2 Getting Started . . . . . . . . . . . . . . . . . . . . . . . 7

2.1 System Requirements . . . . . . . . . . . . . . . . . . . . . 7

2.2 Downloading . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Running Stellarium . . . . . . . . . . . . . . . . . . . . . . . 9

2.5 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . 10

3 A First Tour . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 Time Travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.2 Moving Around the Sky . . . . . . . . . . . . . . . . . . 13

3.3 The Main Tool Bar . . . . . . . . . . . . . . . . . . . . . . . . 14

3.4 Taking Screenshots . . . . . . . . . . . . . . . . . . . . . . 16

3.5 Observing Lists (Bookmarks) . . . . . . . . . . . . . . . 16

3.6 Custom Markers . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.7 Copy Information . . . . . . . . . . . . . . . . . . . . . . . . 17

3.8 Speech Output . . . . . . . . . . . . . . . . . . . . . . . . . 17

4 The User Interface . . . . . . . . . . . . . . . . . . . 19

4.1 Setting the Date and Time . . . . . . . . . . . . . . . . 19

4.2 Setting Your Location . . . . . . . . . . . . . . . . . . . . 20

4.3 The Conﬁguration Window . . . . . . . . . . . . . . . . 21

4.4 The View Settings Window . . . . . . . . . . . . . . . . . 27

4.5 The Search Window . . . . . . . . . . . . . . . . . . . . . 36

4.6 The Astronomical Calculations Window . . . . . 40

4.7 The Help Window . . . . . . . . . . . . . . . . . . . . . . . 52

4.8 Editing Keyboard Shortcuts . . . . . . . . . . . . . . . . 54

1. Introduction

Stellarium is a software project that allows people to use their home computer as a virtual planetarium.

It calculates the positions of the Sun and Moon, planets and stars, and draws how the sky would look to

an observer depending on their location and the time. It can also draw the constellations and simulate

astronomical phenomena such as meteor showers or comets, and solar or lunar eclipses.

Stellarium may be used as an educational tool for teaching about the night sky, as an observational aid for

amateur astronomers wishing to plan a night’s observing or even drive their telescopes to observing targets,

or simply as a curiosity (it’s fun!). Because of the high quality of the graphics that Stellarium produces, it is

used in some real planetarium projector products and museum projection setups. Some amateur astronomy

groups use it to create sky maps for describing regions of the sky in articles for newsletters and magazines,

and the exchangeable sky cultures feature invites its use in the ﬁeld of Cultural Astronomy research and

outreach.

Stellarium is under continuous development, and by the time you read this guide, a newer version may

have been released with even more features than those documented here. Check for updates to Stellarium at

the Stellarium website

If you have questions and/or comments about this guide, or about Stellarium itself, visit the Stellarium

site at GitHub

or our Google Groups forum

1.1 Historical notes

Fabien Chéreau started the project during the summer 2000, and throughout the years found continuous

support by a small team of enthusiastic developers.

Here is a list of past and present major contributors sorted roughly by date of arrival on the project:

https://stellarium.org

https://github.com/Stellarium/stellarium

https://groups.google.com/forum/#!forum/stellarium

4 Chapter 1. Introduction

Fabien Chéreau original creator, maintainer, general development

Matthew Gates maintainer, original user guide, user support, general development

Johannes Gajdosik astronomical computations, large star catalogs support

Johan Meuris GUI design, website creation, drawings of our 88 Western constellations

Nigel Kerr Mac OSX port

Rob Spearman funding for planetarium support

Barry Gerdes

user support, tester, Windows support. Barry passed away in October 2014 at age 80. He was

a major contributor on the forums, wiki pages and mailing list where his good will and enthusiasm is

strongly missed. RIP Barry.

Timothy Reaves ocular plugin

Bogdan Marinov GUI, telescope control, other plugins

Diego Marcos SVMT plugin

Guillaume Chéreau display, optimization, Qt upgrades, HiPS surveys

Alexander Wolf maintainer, DSO catalogs, AstroCalc module, user guide, general development

Georg Zotti

astronomical computations, Scenery 3D plugin, ArchaeoLines and Calendars plugins, general

development, user guide, user support

Marcos Cardinot MeteorShowers plugin

Florian Schaukowitsch

Scenery 3D plugin, Remote Control plugin, RemoteSync plugin, OBJ rendering,

Qt/OpenGL internals

Teresa Huertas Roldán Planetary nomenclature

Jocelyn Girod Observing Lists

Ruslan Kabatsayev ShowMySky Skylight model (based on Bruneton’s model)

Worachate Boonplod Eclipse computations

Unfortunately time is evolving, and most members of the original development team are no longer able

to devote most of their spare time to the project (some are still available for limited work which requires

speciﬁc knowledge about the project).

As of 2017, the project’s maintainer is Alexander Wolf, doing most maintenance and regular releases.

He has also introduced the AstroCalc module. Other new features are contributed mostly by Georg Zotti and

his team focusing on extensions of Stellarium’s applicability in the ﬁelds of historical and cultural astronomy

research (which means Stellarium is getting more accurate) and outreach (making it usable for museum

installations), but also on graphic items like comet tails, light pollution artwork or the Zodiacal Light.

A detailed track of development can be found in the

ChangeLog

ﬁle in the installation folder. A few

important milestones for the project:

2000 ﬁrst lines of code for the project

2001-06

ﬁrst public mention (and user feedbacks!) of the software on a French amateur astronomy news-

group

2003-01 Stellarium reviewed by Astronomy magazine

2003-07 funding for developing planetarium features (ﬁsheye projection and other features)

2005-12 use accurate (and fast) planetary model

2006-05 Stellarium “Project Of the Month” on SourceForge

2006-08 large stars catalogs

2007-01 funding by ESO for development of professional astronomy extensions (VirGO)

2007-04 developers’ meeting near Munich, Germany

2007-05 switch to the Qt4 library as main GUI and general purpose library

2009-09 plugin system, enabling a lot of new development

2010-07 Stellarium ported on Maemo mobile device

2010-11 artiﬁcial satellites plugin

2014-06 high quality satellites and Saturn rings shadows, normal mapping for moon craters

2014-07

v0.13.0: adapt to OpenGL evolutions in the Qt5 framework, now requires more modern graphic

hardware than earlier versions

2015-04 v0.13.3: Scenery 3D plugin

2015-10 v0.14.0: Accurate precession

2016-07 v0.15.0: Remote Control plugin

2016-12 v0.15.1: DE430&DE431, AstroCalc, DSS layer, and Stellarium acting as SpoutSender

https://groups.google.com/d/topic/fr.sci.astronomie.amateur/OT7K8yogRlI/discussion

1.2 Version Numbers 5

2017-06 v0.16.0: Remote Sync plugin, polygonal OBJ models for minor bodies, RTS2 telescope support

2017-09 v0.16.1: Standard and extended DSO catalog, new subcatalogues for DSO

2017-12 v0.17.0: Nomenclature labels for planets and moons, INDI telescope support

2018-03 v0.18.0: Multiple image surveys

2019-12 v0.19.3: ASCOM telescope support

2020-09 v0.20.3: Accurate seasons’ beginnings

2021-03 v0.21.0: Accurate planet rotation (Libration, central meridians, subsolar points, . . . )

2021-09 v0.21.2: Annual aberration, DE440&441. Accuracy goals reached.

2022-10 Stellarium 1.0: Switch to Qt6, ShowMySky skylight model, Eclipse details.

2025-03 v25.1: New star catalog, parallax and revolving binary stars, new Skyculture ﬁle format.

1.2 Version Numbers

Since its inception, Stellarium’s version number had started with 0 to indicate “work in progress”. The

numbers after that have followed a year.release convention with approximately seasonal releases since 2018.

(For example, 0.18.2 was the third release in 2018 which appeared around autumn equinox, after 0.18.0 and

0.18.1.) If needed urgently, there can be additional releases which however break the simple season count.

A software version number of 1.0 signiﬁes a milestone of some sort, like completion of a particular

original feature set, usability, or stability. With the completion of the original accuracy issues in 2021 we felt

it was time to ﬁnally change version number to 1. However, a major technical update in the underlying Qt

framework also forced some technical changes upon us to ensure Stellarium will remain working in the later

2020s, and therefore we decided to base the 1.* series on the new version of Qt.

Qt6 does not support old hardware, particularly 32-bit systems will not be able to run 1.* versions.

Therefore, we are going to keep both series alive for those with older hardware. Thanks to only minor

differences in the underlying frameworks, both series should retain feature equivalence. The only notable

difference for now lied in the Scripting functionality (see chapter 17). Our “internal” version numbers

therefore indicated which version of Qt was used: series 0.* continued to be based on Qt5, and series 1.*

was based on Qt6.

In 2023 we’ve changed the numbering scheme again to avoid new misunderstandings. Our “internal”

version has a standard of 3 components

, where the ﬁrst indicates the two last digits of the year of release,

the second is the release within that year (0 is used before ﬁrst release, from January to March) and the last

one can be 0 for releases, or the day number of the current year for snapshots. Our short (“public”) version

has 2 components: year and number of the release. Example: the ﬁrst release in year 2023 has version 23.1.0

and short (public) version 23.1, the series has number 23.0.

In addition to the version number we are adding the name component

qtX

, where

respectively

and marks the major version of Qt which is used as the base for the package.

1.3 Acknowledgements

Stellarium has been kindly supported by ESA in their Summer of Code in Space initiatives, which so far

has resulted in better planetary rendering (2012), the Meteor Showers plugin (2013), the web-based remote

control and an alternative solution for planetary positions based on the DE430/DE431 ephemeris (2015), the

RemoteSync plugin and OBJ models (2016), and the planet nomenclature labels (2017). Some of Georg’s

work of 2015–2023 was supported by the Ludwig Boltzmann Institute for Archaeological Prospection and

Virtual Archaeology, Vienna, Austria.

Stellarium receives funding on OpenCollective. We thank all our sponsors and backers who help us

maintaining the software and expanding it with yet more features to come.

1.4 Scientiﬁc use

Stellarium has gained wide popularity in the research areas of cultural astronomy. Please note limitations

of Stellarium mentioned in Appendix F. If you used Stellarium in scientiﬁc work, please cite our overview

paper (Zotti, S. Hoffmann, et al., 2021) or those mentioned in the respective feature descriptions.

On Windows it has 4 components, where the last one is always 0.

6 Chapter 1. Introduction

1.5 About this User Guide

This guide is based on the user guide written by Matthew Gates for version 0.10 around 2008. The guide

was then ported to the Stellarium wiki and continuously updated by Barry Gerdes and Alexander Wolf up to

version 0.12. Unfortunately, some new features were not properly documented in the wiki, and generally,

without Barry the wiki started to fall out of sync with the actual program. In late 2015 we (Alexander and

Georg) started porting the texts back to L

X and updated and added information where necessary, or wrote

new chapters for the features which were introduced in the last years. We feel that a single book is the better

format for ofﬂine reading. The PDF version of this guide has a clickable table of contents and clickable

hyperlinks.

These new editions of the Guide (since v0.15) do not contain notes about using earlier versions than 0.13

or using very outdated hardware. Some references to previous versions may still be made for completeness,

but if you are using earlier versions of Stellarium for particular reasons, please use the older guides.

2. Getting Started

2.1 System Requirements

Stellarium has been seen to run on most systems where Qt5 is available, from tiny ARM computers like the

Raspberry Pi 2/3/4 or Odroid C1 to big museum installations with multiple projectors and planetaria with

ﬁsh-eye projectors. The most important hardware requirement is a contemporary graphics subsystem.

2.1.1 Minimum

•

Linux/Unix; Windows 7 and later; macOS 10.15 and later

•

3D graphics capabilities which support OpenGL 3.0 (2008 GeForce 8xxx and later, ATI/AMD Radeon

HD-2xxx and later; Intel HD graphics (Core-i 2xxx and later)) or OpenGL ES 2.0 (e.g., ARM SBCs

like Raspberry Pi 2/3/4). On Windows, some older cards may be supported via ANGLE when they

support DirectX9.

•

Screen resolution 1024× 768

•

512 MB RAM

•

250 MB free on disk

•

Keyboard

2.1.2 Recommended

•

Linux/Unix; Windows 10 and later; macOS 11.0 and later

•

3D graphics card which supports OpenGL 3.3 or higher

•

FullHD (1920× 1080 or 1920× 1200) or larger screen.

•

1 GB RAM or more

•

1.5 GB free on disk (About 3GB extra required for the optional DE430/DE431 ﬁles).

•

Keyboard and mouse or equivalent device (e.g. touchpad)

•

A dark room for realistic rendering — details like the Milky Way, Zodiacal Light or star twinkling

can’t be seen in a bright room.

Windows 10 and macOS 11.0 is minimal for Qt6-based Stellarium.

On Linux, an 800 × 600 screen can still be used by scaling the desktop e.g. to 1200× 900:

xrandr -- output HDMI -1 -- scale 1.5 x1 .5

To reset after running Stellarium, run

xrandr -- output HDMI -1 -- scale 1 x1

HiDPI screens may work, but show occasional platform-dependent issues.

8 Chapter 2. Getting Started

2.2 Downloading

Download the correct package for your operating system directly from the main page,

https://stellarium.org

. An archive of all available versions is available at our GitHub page —

https://github.com/Stellarium/stellarium/releases.

2.3 Installation

2.3.1 Windows

1. Double click on the installer ﬁle you downloaded:

•

stellarium-25.4-qt6-win64.exe for 64-bit Windows 10 and later.

•

stellarium-25.4-qt6-arm64.exe for Windows 10 and later on ARM64 device.

•

stellarium-25.4-qt5-win64.exe for 64-bit Windows 7 and later.

2. Follow the on-screen instructions.

2.3.1.1 Unattended Install/Uninstall

The installation program allows for unattended installation (e.g., for lab setups) following ofﬁcial documen-

tation

You can uninstall the program like any other program from the Applications list in the system control

panel. The uninstaller asks if you want to remove (delete) all your Stellarium user data. Be sure to answer

NO when you plan to re-use landscapes, 3D sceneries and the like. For unattended uninstallation in larger

setups, also the uninstaller can be called with additional options, which will keep the user data.

"C :\ Progra m File s [ ( x86 )]\ Stellarium \ un i n s000 . exe " / VERYSILENT / S U P P R E S S M S GB O X ES

2.3.2 macOS

Locate the downloaded

Stellarium

ﬁle in Finder (Stellarium will be automatic unpack from archive

by operating system after downloading).

2. Drag Stellarium to the Applications folder.

2.3.3 Linux

Check if your distribution has a package for Stellarium already — if so you’re probably best off using it. If

not, you can download and build the source.

For Ubuntu Linux we provide a package repository with the latest stable releases. Open a terminal and

type:

sudo add -apt - repository ppa : stellarium / stellarium - releases

sudo apt -get update

sudo apt -get insta ll stellarium

You can also download and run universal binary packages for linux systems: ﬂat

or snap

2.3.3.1 Raspberry Pi 2/3/4

These tiny ARM-based computers are very popular for small and energy-efﬁcient applications like controlling

push-to Dobsonians. Stellarium requires Mesa 17 or later, available in the current Raspbian OS. To set up a

Raspberry Pi 2 or 3 with Raspbian Buster for use with Stellarium, activate the OpenGL driver in raspi-conﬁg.

The latest Raspberry Pi 4 comes with this driver by default and can even drive two HiDPI screens.

You must build Stellarium from sources. Please follow instructions from the wiki

For Ubuntu 16.04 LTS, follow instructions

Note that as of December 2019 the 3D planets do not work on Raspberry Pi 2/3, and DSS or HiPS

surveys seem to cause issues after a while.

https://documentation.help/Inno-Setup/topic_setupcmdline.htm

https://flathub.org/apps/details/org.stellarium.Stellarium

https://snapcraft.io/stellarium-daily

https://github.com/Stellarium/stellarium/wiki/Raspberry-Pi

https://ubuntu-mate.community/t/tutorial-activate-opengl-driver-for-ubuntu-mate-16-0

4/7094

2.4 Running Stellarium 9

2.3.4 *BSD/Solaris/OpenIndiana

Check if your operating system has a package or port for Stellarium already — if so you’re probably best off

using it. If not, you can download and build the source.

2.3.5 Haiku

Please use HaikuDepot or open Terminal and type:

pkgman install stellarium

to install the Stellarium.

2.4 Running Stellarium

2.4.1 Windows

The Stellarium installer creates a whole list of items in the Start Menu under the Programs/Stellarium

section. The list evolves over time, not all entries listed here may be installed on your system. Select one of

these to run Stellarium:

Stellarium

OpenGL version. This is the most efﬁcient for modern PCs and should be used when you

have installed appropriate OpenGL drivers. Note that some graphics cards are “blacklisted” by Qt

to immediately run via ANGLE (Direct3D), you cannot force OpenGL in this case. This should not

bother you.

Stellarium (ANGLE mode)

Uses Direct3D translation of the OpenGL rendering via ANGLE library.

Forces Direct3D version 9.

Stellarium (ANGLE WARP mode)

Uses DirectX3D 11 software rendering via ANGLE library. This

should work on any PC without dedicated graphics card.

Stellarium (MESA mode)

Uses software rendering via MESA library. This should work on any PC without

dedicated graphics card.

Stellarium (200%)

On some systems with 4k screens, Stellarium appears too small. This link forces an

upscaling.

If for some reason Stellarium’s dialogs and buttons appear too large, and you want to scale them

down, edit the link and change the scaling parameter.

On startup, a diagnostic check is performed to test whether the graphics hardware is capable of running. If

all is ﬁne, you will see nothing of it. Else you may see an error panel informing you that your computer

is not capable of running Stellarium (“No OpenGL 2 found”), or a warning that there is only OpenGL 2.1

support. The latter means you will be able to see some graphics, but depending on the type of issue you will

have some bad graphics. For example, on an Intel GMA4500 there is only a minor issue in Night Mode,

while on other systems we had reports of missing planets or even crashes as soon as a planet comes into

view. If you see this, try running in Direct3D 9 or MESA mode, or upgrade your system. The warning, once

ignored, will not show again.

When you have found a mode that works on your system, you can delete the other links.

2.4.2 macOS

Double click on the Stellarium application. Add it to your Dock for quick access.

2.4.3 Linux

If your distribution had a package you’ll probably already have an item in the GNOME or KDE application

menus. If not, just open a terminal and type stellarium.

2.4.4 *BSD/Solaris/OpenIndiana

If your operating system had a package or port you’ll probably already have an item in the GNOME or

KDE application menus. If not, just open a terminal and type stellarium.

2.4.5 Haiku

If you had installed a package you’ll already have an item in the Applications menus.

Stellarium series 0.* and Qt5-based builds only

10 Chapter 2. Getting Started

2.5 Troubleshooting

Stellarium writes startup and other diagnostic messages into a logﬁle. Please see section 5.3 where this ﬁle is

located on your system. This ﬁle is essential in case when you feel you need to report a problem with your

system which has not been found before.

At startup also a few pop-up windows may appear with information about possible troubles or warnings

to make those messages more visible for users.

On some Intel UHD systems users may see the screen blanking when Stellarium is working — the

startup of the program with --single-buffer parameter can help here. The same option also helps when on an

Nvidia system tooltips don’t appear in fullscreen mode.

On some older or weak systems, the option --low-graphics may be required. This forcefully disables

advanced graphics features of OpenGL 3.3 which otherwise would slow down or cause other issues on such

systems.

If you don’t succeed in running Stellarium, please see the online forum

. It includes FAQ (Frequently

Asked Questions, also Frequently Answered Questions) and a general question section which may include

further hints. Please make sure you have read and understood the FAQ before asking the same questions

again.

https://github.com/Stellarium/stellarium

3. A First Tour

Figure 3.1: Stellarium main view. (Combination of day and night views.)

When Stellarium ﬁrst starts, we see a green meadow under a sky. Depending on the time of day, it is either

a day or night scene. If you are connected to the Internet, an automatic lookup will attempt to detect your

approximate position.

At the bottom left of the screen, you can see the status bar. This shows the current observer location,

vertical ﬁeld of view (FOV), graphics performance in frames per second (FPS) and the current simulation

date and time. If you move the mouse over the status bar, it will move up to reveal a tool bar which gives

quick control over the program.

The rest of the view is devoted to rendering a realistic scene including a panoramic landscape and the

sky. If the simulation time and observer location are such that it is night time, you will see stars, planets and

See section 4.2 if you want to switch this off.

12 Chapter 3. A First Tour

the moon in the sky, all in the correct positions.

You can drag with the mouse on the sky to look around or use the cursor keys. You can zoom with the

mouse wheel or the

Page

keys.

Much of Stellarium can be controlled very intuitively with the mouse. Many settings can additionally be

switched with shortcut keys (hotkeys). Advanced users will learn to use these shortcut keys. Sometimes

a key combination will be used. For example, you can quit Stellarium by pressing

Ctrl

on Windows

and Linux, and

on Mac OS X. For simplicity, we will show only the Windows/Linux version. We

will present the default hotkeys in this guide. However, almost all hotkeys can be reconﬁgured to match

your taste. Note that some listed shortkeys are only available as key combinations on international keyboard

layouts, e.g., keys which require pressing

AltGr

on a German keyboard. These must be reconﬁgured, please

see 4.8 for details.

The way Stellarium is shown on the screen is primarily governed by the menus. These are accessed by

dragging the mouse to the left or bottom edge of the screen, where the menus will slide out. In case you

want to see the menu bars permanently, you can press the small buttons right in the lower left corner to keep

them visible.

3.1 Time Travel

When Stellarium starts up, it sets its clock to the same time and date as the system clock. However,

Stellarium’s clock is not ﬁxed to the same time and date as the system clock, or indeed to the same speed.

We may tell Stellarium to change how fast time should pass, and even make time go backwards! So the

ﬁrst thing we shall do is to travel into the future! Let’s take a look at the time control buttons on the right

hand ride of the tool-bar. If you hover the mouse cursor over the buttons, a short description of the button’s

purpose and keyboard shortcut will appear.

Button Shortcut key Description

Decrease the rate at which time passes

Make time pass as normal

Increase the rate at which time passes

Return to the current time & date

Table 3.1: Time Travel

OK, so lets go see the future! Click the mouse once on the increase time speed button . Not a

whole lot seems to happen. However, take a look at the clock in the status bar. You should see the time going

by faster than a normal clock! Click the button a second time. Now the time is going by faster than before. If

it’s night time, you might also notice that the stars have started to move slightly across the sky. If it’s daytime

you might be able to see the sun moving (but it’s less apparent than the movement of the stars). Increase the

rate at which time passes again by clicking on the button a third time. Now time is really ﬂying!

Let time move on at this fast speed for a little while. Notice how the stars move across the sky. If you

wait a little while, you’ll see the Sun rising and setting. It’s a bit like a time-lapse movie.

Stellarium not only allows for moving forward through time – you can go backwards too! Click on the

real time speed button . The stars and/or the Sun should stop scooting across the sky. Now press the

decrease time speed button once. Look at the clock. Time has stopped. Click the decrease time speed

button four or ﬁve more times. Now we’re falling back through time at quite a rate (about one day every ten

seconds!).

3.2 Moving Around the Sky 13

Time Dragging, Time Scrolling

Another way to quickly change time is time dragging. Press

Ctrl

, press the left mouse button, and slide the

mouse along the direction of daily motion to go forward, or to the other direction to go backward.

Similarly, pressing

Ctrl

and scrolling the mouse wheel will advance time by minutes, pressing

Ctrl

and scrolling the mouse wheel will advance time by hours,

Ctrl

Alt

by days, and ﬁnally

Ctrl

Alt

by calendar years.

Enough time travel for now. Wait until it’s night time, and then click the real time speed button . If

all works as intended you will now be looking at the night sky.

3.2 Moving Around the Sky

Key Description

Cursor keys Pan the view left, right, up and down

Page

Ctrl

Zoom in and out

Left mouse button Select an object in the sky

Right mouse button,

Ctrl

Clear selected object

Centre mouse button (wheel press) Centre selected object and start tracking

Mouse wheel Zoom in and out

Centre view on selected object

Forward-slash (

) Auto-zoom in to selected object

Backslash (

) Auto-zoom out to original ﬁeld of view

Look towards North (keep altitude)

Look towards East (keep altitude)

Look towards South (keep altitude)

Look towards West (keep altitude)

Look towards Zenith (south down)

Alt

Look towards North Celestial Pole

Alt

Look towards South Celestial Pole

Table 3.2: Moving Around the Sky

As well as travelling through time, Stellarium lets you look around the sky freely, and zoom in and out.

There are several ways to accomplish this, listed in table 3.2.

Let’s try it. Use the cursors to move around left, right, up and down. Zoom in a little using the

Page

key, and back out again using the

Page

. Press the

key and see how Stellarium returns to the original

ﬁeld of view (how “zoomed in” the view is), and direction of view.

If you prefer stepwise zooming to ﬁxed values for ﬁeld of view, table 3.3 lists the keys to reach a certain

ﬁeld of view.

Most users prefer to move around using the mouse. If you left-click and drag somewhere on the sky, you

can pull the view around.

Hotkey Field of view Hotkey Field of view

Ctrl

Alt

180°

Ctrl

Alt

10°

Ctrl

Alt

90°

Ctrl

Alt

5°

Ctrl

Alt

60°

Ctrl

Alt

2°

Ctrl

Alt

45°

Ctrl

Alt

1°

Ctrl

Alt

20°

Ctrl

Alt

0.5°

Table 3.3: Hotkeys to set ﬁxed vertical ﬁelds of view

14 Chapter 3. A First Tour

Another method of moving is to select some object in the sky (left-click on the object), and press the

Space

key to centre the view on that object. Similarly, selecting an object and pressing the forward-slash

key

will centre on the object and zoom right in on it.

The forward-slash

and backslash

keys auto-zoom in and out to different zoom levels depending

on what is selected. If the object selected is a planet or moon in a sub-system with a lot of moons (e.g.

Jupiter), the initial zoom in will go to an intermediate level where the whole sub-system should be visible.

A second zoom will go to the full zoom level on the selected object. Similarly, if you are fully zoomed in

on a moon of Jupiter, the ﬁrst auto-zoom out will go to the sub-system zoom level. Subsequent auto-zoom

out will fully zoom out and return the initial direction of view. For objects that are not part of a sub-system,

the initial auto-zoom in will zoom right in on the selected object (the exact ﬁeld of view depending on the

size/type of the selected object), and the initial auto-zoom out will return to the initial FOV and direction of

view.

If you have a touch screen, you can even use one ﬁnger directly to drag the sky around and select objects,

and two ﬁngers to zoom. The support for touch screens is incomplete though, and more advanced use of the

program requires the classical operation with keyboard and mouse.

3.3 The Main Tool Bar

Figure 3.2: Night scene with constellation artwork and moon.

Stellarium can do a whole lot more than just draw the stars. Figure 3.2 shows some of Stellarium’s visual

effects including constellation line and boundary drawing, constellation art, planet hints, and atmospheric

halo around the bright Moon. The controls in the main tool bar provide a mechanism for turning on and off

the visual effects.

When the mouse is moved to the bottom left of the screen, a second tool bar becomes visible. All the

buttons in this side tool bar open and close dialog boxes which contain controls for further conﬁguration of

the program. The dialogs will be described in the next chapter.

Table 3.4 describes the operations of buttons on the main tool bar and the side tool bar, and gives their

default keyboard shortcuts.

3.3 The Main Tool Bar 15

Feature Button Hotkey Description

Constellations

Draw constellations as “stick ﬁgures”

Constellation Names

Draw name of the constellations

Constellation Art

Superimpose artistic representations of

the constellations

Constellation Boundaries

Draw boundaries of the constellations

Asterisms

Draw asterism “stick ﬁgures”

Asterism Names

Draw name of the asterisms

Equatorial Grid

Draw grid lines for the equatorial coor-

dinate system of date (RA/Dec)

Azimuth Grid

Draw grid lines for the horizontal coor-

dinate system (Alt/Azi)

Galactic Grid

Draw grid lines for the galactic coordi-

nate system (Long/Lat)

Equatorial J2000 Grid

Draw grid lines for the equatorial

coordinate system at standard epoch

J2000.0 (RA/Dec)

Ecliptic Grid

Draw grid lines for the ecliptic coordi-

nate system of date (Long/Lat)

Toggle Ground

Toggle drawing of the ground. Turn

this off to see objects that are below the

horizon.

Toggle Cardinal Points

Toggle marking of the North, South,

East and West points on the horizon.

Toggle Compass Marks

Toggle degree marks along the horizon.

Toggle Atmosphere

Toggle atmospheric effects. Most no-

tably makes the stars visible in the day-

time.

Deep-Sky Objects

Toggle marking the positions of Deep-

Sky Objects.

Planet Hints

Toggle indicators to show the position

of planets.

Nebula images

Toggle “nebula images”.

Digitized Sky Survey

Toggle “Digitized Sky Survey”

(TOAST).

Hierarchical Progressive

Surveys

Ctrl

Alt

Toggle “Hierarchical Progressive Sur-

veys”.

Coordinate System

Ctrl

Toggle between horizontal (Alt/Azi)

& equatorial (RA/Dec) coordinate sys-

tems.

This button must be enabled ﬁrst, see section 4.3.5

16 Chapter 3. A First Tour

Feature Button Hotkey Description

Center Center the view on the selected object

Night Mode

Ctrl

Toggle “night mode”, which applies a

red-only ﬁlter to the view to be easier

on the dark-adapted eye.

Full Screen Mode

F11

Toggle full screen mode.

Bookmarks

Alt

Toggle bookmarks window.

Flip view (horizontal)

Ctrl

Flip the image in the horizontal plane.

Flip view (vertical)

Ctrl

Flip the image in the vertical plane.

Quit Stellarium

Ctrl

Close Stellarium.

Help Window

Show the help window, with key bind-

ings and other useful information

Conﬁguration Window

Show the conﬁguration window

Search Window

Ctrl

Show the object search window

View Window

Show the view window

Time Window

Show the time window

Location Window

Show the observer location window

(map)

AstroCalc Window

F10

Show the astronomical calculations

window

Table 3.4: Stellarium’s standard menu buttons. Those marked

must be

enabled ﬁrst, see section 4.3.5.

3.4 Taking Screenshots

You can save what is on the screen to a ﬁle by pressing

Ctrl

. Screenshots are taken in PNG format,

and have ﬁlenames like

stellarium-000.png

stellarium-001.png

(the number increments to prevent

overwriting existing ﬁles).

The screenshots are stored to a directory depending on your operating system, see section 5.1 Files and

Directories. See also section 4.3.5 for more screenshot options.

3.5 Observing Lists (Bookmarks)

You can store your favourite objects or views in observing lists. Press

Alt

or to call up the

dialog. A bookmarks ﬁle from previous versions will be imported and converted to the new format. You can

however create an arbitrary number of lists.

The list display shows all entries from the current list. A double click on an entry selects the object.

To add/remove an object to/from the list, press

Edit list

. This changes the view. Highlight (select) your

object in the sky and press

Add object

. To remove an object from a list, select its entry in the list and press

Remove object

3.6 Custom Markers 17

Sometimes storing the object alone is not enough. Interesting views like planet conjunctions or eclipses

require at least a time entry, if not a particular location. Likewise, the displayed landscape may be nice to

restore. Additionally, the ﬁeld of view may be relevant. To store these data and later retrieve them, use the

respective checkboxes.

You can also export the current list or all lists with the according button, or import such an exported list

on another system. To export the current list, keep the default

.sol

ﬁle type in the ﬁlename dialog. To export

all your lists, use the

.ol

ﬁle type in the ﬁlename dialog. Lists are identiﬁed with an Universally Unique

Identiﬁer (UUID) which we call OLUD (Observing List Unique Identiﬁer). On importing a list, existing lists

with the same OLUD may be replaced after a warning. During editing, storing a list with an existing name is

prevented. The list import may however import a list with an existing name as long as the OLUD is different.

You may want to change one of the duplicate list names after import. To transfer all your lists to another

system, export them as

.ol

ﬁle, or copy, rename and import (or just copy, to replace the existing) the full ﬁle

observingLists.json from the data/ subdirectory of your user directory (see section 5.1).

3.6 Custom Markers

You can set temporary markers anywhere in the screen. These may be useful for various purposes but cannot

be stored.

Actions Description

Shift

& left click Add custom marker

Shift

& right click Delete the one closest marker to mouse cursor

Alt

& right click Delete all custom markers

3.7 Copy Information

If you have selected an object and want to use the displayed information elsewhere, you may want to copy

it to the system clipboard with

Ctrl

. In case you want to use its numbers elsewhere, please see

Appendix F for known accuracy limitations.

3.8 Speech Output

Sometimes you may have dimmed down your ﬁeld laptop or the font may be too small. Object information

v 25.4

can also be output audibly by a Text-to-Speech engine. After object selection, press

Shift

to let a voice

read ot to you. See section 4.3.6 for details and conﬁguration.

4. The User Interface

This chapter describes the dialog windows which can be accessed from the left menu bar.

Most of Stellarium’s settings can be changed using the view window (press or

) and the

conﬁguration window (

). Most settings have short labels. To learn more about some settings,

more information is available as tooltips, small text boxes which appear when you hover the mouse cursor

over a button.

You can drag the windows around, and the position will be used again when you restart Stellarium. If

this would mean the window is off-screen (because you start in windowed mode, or with a different screen),

the window will be moved so that at least a part is visible.

Some options are really rarely changed and therefore may only be conﬁgured by editing the conﬁguration

ﬁle. See 5.4 The Main Conﬁguration File for more details.

4.1 Setting the Date and Time

Figure 4.1: Date and Time dialog

In addition to the time rate control buttons on the main toolbar, you can use the date and time window

(open with the button or

) to set the simulation time. The values for year, month, day, hour, minutes

and seconds may be modiﬁed by typing new values, by clicking the up and down arrows above and below

the values, and by using the mouse wheel.

The other tab in this window allows you to see or set Julian Day and/or Modiﬁed Julian Day numbers

(see 18.4.2).

20 Chapter 4. The User Interface

Figure 4.2: Location window

4.2 Setting Your Location

The positions of the stars in the sky is dependent on your location on Earth (or other planet) as well as the

time and date. For Stellarium to show accurately what is (or will be/was) in the sky, you must tell it where

you are. You only need to do this once – Stellarium can save your location so you won’t need to set it again

until you move.

After installation, Stellarium uses an online service which tries to ﬁnd your approximate location based

on the IP address you are using. This seems very practical, but if you feel this causes privacy issues, you

may want to switch this feature off. You should also consider switching it off on a computer which does not

move, to save network bandwidth.

To set your location more accurately, or if the lookup service fails, press

to open the location window

(Fig. 4.2). There are a few ways you can set your location in this dialog:

1. Just click on the map.

Search for a city where you live using the search edit box at the top right of the window, and select

the right city from the list.

Click on the map to ﬁlter the list of cities in the vicinity of your click, then choose from the shortlist.

4. Enter a new location using the longitude, latitude and other data.

Click on

Get Location from GPS

if you have a GPS receiver. You activate a periodic request for GPS

ﬁxes. After a few seconds, the button should change color and give a textual feedback. Green indicates

a good location ﬁx, yellow indicates a 2D-ﬁx only, which means altitudes are not available. (Leave the

GPS device running for a few minutes and/or search a place with better sky view.) You could leave it

running if you are operating a fast-moving observatory platform, but rather switch it off when you see

a good ﬁx, so that other programs can use the serial GPS connection. Red signals an error, and further

positions are not retrieved but the button is reset. You may press the button again to start over.

Sometimes you have to try several times or let it run for a while to get a green button indicating a

valid 3D ﬁx including altitude. See section 5.5.4 for conﬁguration details.

On Windows, if there is no GPS device, a system location service will be queried as fallback.v 1.0

If you want to use the current location permanently, click on the “use as default” checkbox, disable “Get

location from Network”, and close the location window.

Two settings may inﬂuence the landscape when changing locations:

Auto select landscapes

When changing the planet, a ﬁtting landscape panorama will be shown when

available. Also, when clicking on the earth map, a zero-altitude landscape is displayed in the

v 23.2

Unfortunately, on Windows 7 and later, with some Nvidia and AMD GPUs in OpenGL mode, these tooltips

sometimes do not work. Sometimes it is enough to leave fullscreen mode to see them.

4.3 The Conﬁguration Window 21

approximate color of that location (taken from the map).

Auto-enable atmosphere

When changing planet during location change, the atmosphere will be switched

as required.

As a reverse functionality, loading landscapes may also change location. See section 4.4.5.

4.2.1 Time Zones

Locations in Stellarium’s location database include their respective time zone. When you click on a location

in the list, the time should be shown in the respective time zone. If daylight time rules exist and you have

selected “Enable daylight saving time”, also this abomination of modern civilisation is respected. Most users

will require to have this setting active.

When you select “Use custom time zone”, you can select other time zones. Those that start with UTC

have no daylight time rules.

Time zones were introduced in the 19th century, originally for purposes of railway trafﬁc synchronization.

The ﬁrst such action was taken in 1847, and therefore Stellarium by default will present Local Mean Solar

Time (LMST) for dates before 1847, and ignore all conﬁgured time zones unless you deliberately activate

“Use custom time zone”. The history of time zones and their rules is very complicated, though, and Stellarium

should not be expected to ﬁnd the exact date when time zone use was introduced at a certain location or

country. Just be sure to use LMST when replaying historical observations before the 20th century.

For even earlier observations, you can also set Local True Solar Time (LTST), which is the time given

by sundials. Here, 12 o’clock is the time when the sun transits the meridian, strictly, daily. The difference

between LMST and LTST is called equation of time. See section 13.2 for more information.

When you click on the map to set your location, Stellarium has currently no way to guess the timezone of

the coordinate pair. In this case, Local Mean Solar Time is presented, which only depends on longitude and

was the “normal” time before the development of time zones. Either select a city from the list or manually

select a time zone.

4.2.2 Geographical Regions

The world is split into political entities called “countries”. Humans have an unappealing tendency of

ﬁghting over the question to which country some territories should be counted. Stellarium is an astronomy

program which labels coordinates of locations like cities with a name. Earlier editions of Stellarium used

countries as further superordinate entities to locations for identiﬁcation purposes. In consequence to much

unnecessary and unfriendly discussion we decided to completely drop the petty-minded assignment of

political country names to locations in favour of geographical regions. There is only one known habitable

planet, one humankind, and one sky. Stellarium users should overcome borders!

For the “region” classiﬁcation of sky cultures we use the same regions (see 9.2.1), and we follow the

UN M49 geoscheme

with extensions for other planets.

4.2.3 Observers

In the list of Planets you can ﬁnd entries called Solar System Observer, Jupiter Observer and similar for

each major planet that has moons: Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. These are specialized

locations. When switching to them, you will ﬁnd yourself looking onto the respective observed object (Sun,

Jupiter, . . . ) from somewhat above the plane of the Solar system. By pressing

Alt

you can

rotate around a vertical axis through the observed object. Likewise, by pressing

Alt

you can

change the latitude of observation. Finally, with

Alt

Home

Alt

End

you can change the distance from

the observed object.

4.3 The Conﬁguration Window

The conﬁguration window contains general program settings, and many other settings which do not concern

speciﬁc display options. Press the tool button or

to open.

4.3.1 The Main Tab

The Main tab in the conﬁguration window (Fig. 4.3) provides control for changing the program language.

The next setting group allows to enable using DE430/DE431 and DE440/DE441 ephemeris ﬁles. These

ﬁles have to be installed separately. Most users do not require this. See section 5.5.3 if you are interested.

https://unstats.un.org/unsd/methodology/m49/

22 Chapter 4. The User Interface

Figure 4.3: Conﬁguration Window: Main Tab

The tab also provides the buttons for saving the current view direction as default for the next startup, and

for saving the program conﬁguration: most display settings have to be explicitly stored to make a setting

change permanent. If you prefer, you can activate

Immediate Save

. Then all settings changes will be stored

v 24.4

immediately and the program will use them the next time you launch it. Language and font settings have

to be stored explicitly with the buttons next to their settings to protect you from unwanted surprises. To

permanently set this mode, use

Save settings

a ﬁnal time.

4.3.2 The Information Tab

Figure 4.4: Conﬁguration Window: Information Tab

The Information tab (Fig. 4.4) allows you to set the type and amount of information displayed (left column)

or output by speech (right column; see 4.3.6) about a selected object. The Radio buttons on the top of the

v 25.4

dialog allow quick selection of some useful conﬁgurations for display.

4.3 The Conﬁguration Window 23

4.3.3 The Extras Tab

Figure 4.5: Conﬁguration Window: Extras Tab

The Extras tab (Fig. 4.5) allows you to customize information displayed about a selected object, download

more star catalogs and also allows to hide or show additional buttons in the lower button bar.

4.3.3.1 Customization of information displays

The information display can be tweaked a bit with the options found in the GUI section “Additional

information settings”.

Use mag/arcsecˆ2 for surface brightness instead of mag/arcminˆ2.

Short notation for units of surface brightness symbolic abbreviation.

Designations for celestial coordinate systems Use symbols like

α, δ instead of textual labels.

Tabular output for coordinates and time uses a more eye-friendly layout.

Use decimal degrees You can toggle usage of decimal degree format for coordinates.

Azimuth from South Some users may be used to counting azimuth from south.

Allow negative hour angles Count hour angles −12h. . . 12h instead of 0h. . . 24h. v 25.4

Polar distance, not declination Used by some telescopes. Using label p or PD instead of

δ. v 25.4

4.3.3.2 Customization of button visibility on bottom toolbar

If your screen is too narrow to show all buttons or you simply don’t need them because you prefer the

keyboard shortcuts, you can choose your optimal setup. The selection of buttons is stored immediately.

Constellation boundaries You can toggle display of constellation boundaries with this button.

Asterism lines You can toggle display of asterism lines with this button.

Asterism labels You can toggle display of asterism labels with this button.

Ecliptic grid You can toggle display of ecliptic coordinate grid with this button.

ICRS grid

You can toggle display of the International Coordinate Reference System (equatorial J2000

coordinate grid) with this button.

Galactic grid You can toggle display of galactic coordinate grid with this button.

Cardinal points You can toggle display of the “Cardinal points” button.

Compass marks You can toggle display of the “Compass marks” button.

Night mode You can toggle display of the nightmode button.

Centering button You can toggle display of the “Center on selected object” button.

Fullscreen button You can toggle display of the fullscreen button.

Quit button You can toggle display of the button to quit Stellarium.

Nebula background You can toggle display of DSO photographs with this button.

Flip buttons

When enabled, two buttons will be added to the main tool bar which allow the main view to

be mirrored in the vertical and horizontal directions. This is useful when observing through telecopes

which may cause the image to be mirrored.

24 Chapter 4. The User Interface

DSS survey You can toggle display of Digitized Sky Survey with this button (see section 10.4).

HiPS Surveys

You can toggle display of Hierarchical Progressive Surveys with this button (see section

4.4.7).

Bookmarks You can enable display of Bookmarks (Observing Lists) dialog with this button.

Use buttons background Applies a gray background under the buttons on the bottom bar.

4.3.3.3 Download more star catalogs

Stellarium comes with enough stars for casual stargazing with the unaided eye or binoculars. If you have a

telescope and want to see more stars, here you can download more catalogs. (See Appendix C)

4.3.4 The Time Tab

Figure 4.6: Conﬁguration Window: Time Tab

The Time tab (Fig. 4.6) allows to specify what simulation time should be used when the program starts:

System date and time Stellarium will start with the simulation time equal to the operating system clock.

System date at

Stellarium will start with the same date as the operating system clock, but the time will be

ﬁxed at the speciﬁed value. This is a useful setting for those people who use Stellarium during the day

to plan observing sessions for the upcoming evening.

Other some ﬁxed time can be chosen which will be used every time Stellarium starts.

The middle ﬁeld allows specify display formats for date and time on bottom toolbar:

JD Stellarium will display Julian Days (JD).

Date and time Stellarium will display date and time in selected format.

The lowest ﬁeld allows selection of the correction model for the time correction

∆T

(see section 18.4.3).

Default is “Modiﬁed Espenak and Meeus (2006, 2014, 2023)”. Please use other values only if you know

what you are doing.

4.3.5 The Tools Tab

The Tools tab (Fig. 4.7) contains planetarium options (like enabling/disabling of keyboard shortcuts for

panning and zooming the main view) and options for screenshots.

Spheric mirror distortion

This option pre-warps the main view such that it may be projected onto a

spherical mirror using a projector. The resulting image will be reﬂected up from the spherical mirror

in such a way that it may shine onto a small planetarium dome (or even just the ceiling of your dining

room), making a cheap planetarium projection system.

Disc viewport

This option masks the main view producing the effect of a telescope eyepiece. It is also

useful when projecting Stellarium’s output with a ﬁsh-eye lens planetarium projector.

4.3 The Conﬁguration Window 25

Figure 4.7: Conﬁguration Window: Tools Tab

Gravity labels

This option makes labels of objects in the main view align with the nearest horizon. This

means that labels projected onto a dome are always aligned properly.

Auto zoom out returns to initial direction of view

When enabled, this option changes the behavior of the

zoom out key

so that it resets the initial direction of view in addition to the ﬁeld of view.

Enable keyboard navigation

, i.e. moving the view with cursor keys. The tool button calls the keyboard

conﬁguration panel. (See section 4.8.)

Enable mouse navigation , i.e. mouse dragging.

Enable mouse zooming use mouse wheel to zoom ﬁeld of view.

Mouse cursor timeout

You can decide whether, and when, the mouse cursor should disappear from view

when not moved.

Include Topocentric coordinates

If you require planetocentric coordinates, you may switch this off.

Usually it should be enabled. (See 18.9.1)

Nutation

Compute the slight wobble of earth’s axis. This feature is active only about 500 years

around J2000.0.

Aberration

Add effect of annual aberration of light to the object’s position (see 18.10). Note:

This also inﬂuences the displayed position in the J2000 frame! For didactic purposes you can

exaggerate the effect by up to 5×.

Overwrite text color

— enabling this option will ignore the color settings for each celestial object and

enable one color for text on the info panel for all celestial objects. By default Stellarium uses white

color for this option, but you may re-deﬁne it through a color chooser.

Set keyboard focus to day input

— you may use this option to force setting the keyboard focus on the day

input ﬁeld in the Date and Time dialog.

Important note: the focus in the sky will be lost when you open the Date and Time dialog after

enabling this option.

Use kinetic scrolling

Text ﬁelds in dialogs can either be moved on sidebar handles (with this switch

disabled) or by dragging the text itself (enabled), as it is known from touch-enabled devices like

smartphones.

Dithering options to allow select better simulation of sky on different hardware.

Indication for mount mode

You can activate the short display of a message when switching type of used

mount.

Info text color at daylight

— this is a color chooser for deﬁning the text color for the info panel at daylight

to increase the contrast of the text. By default Stellarium use black color.

Multithreading

For every frame, the positions of all planets and minor bodies of the Solar system are computed. Most of the

other time between frame updates is needed for the actual frame drawing, and waiting for the next frame

26 Chapter 4. The User Interface

cycle if you have deliberately set a low frame rate (useful to conserve energy; see below). If you have many

thousands of solar system objects and a moderately new computer, you may feel that Stellarium becomes

slow (few frames/second) but see that mostly only one core of your CPU seems to be busy. You can try to

v 24.3

distribute the computation of solar system bodies to more CPU cores. But take note, thread synchronization

(combining all results ahead of drawing) takes its time, so it pays off only when your solar system is really

large. With more than 1000 objects, we recommend starting with 1 additional thread. Even with 25.000

objects, assigning more than 4 additional threads on a 20-core CPU does not show any further gain. Frame

drawing is still performed by the main thread, and too many objects still slow down the program. Just try out

what works best on your system.

Framerate intent

The pace of screen updates (frames per second, FPS) depends on several factors: CPU speed, graphics card

speed, screen size, number of displayed objects and grids, etc. As is common for interactive programs,

the main program thread runs on a single core also on a multicore system. For running Stellarium, a CPU

with few but fast cores will appear faster in total than a multicore system at slower CPU cycles. High-end

systems may deliver needlessly high framerates, at cost of energy consumption. The maximum FPS setting

limits the frame rate when Stellarium is interactively operated (zoomed, panned, settings switched, etc.)

After a few seconds, when Stellarium is not interactively operated, it falls back to a minimum FPS setting

to conserve energy. Of course, when the system cannot even reach this FPS, the factual FPS will be lower

and the system may be overloaded. Keep in mind that the minimum setting also applies to running scripts

(non-interactively).

Font size and font selection

You can change the font sizes for on-screen text and GUI dialogs separately. For some purposes like

presentations it may be helpful to enlarge screen font size while keeping GUI font regular, or vice versa. It

also depends on your screen size whether all the object info ﬁts on screen. This may also depend on the

writing system and installed font. If you are using a non-Western character system and the default font

looks bad, you can select another system font. For this, edit

config.ini

(see chapter 5.1): locate the

[gui]

section and set the key

flag_font_selection=true

. On next start of Stellarium, you will ﬁnd two

elements for font selection: one allows you to pre-select a writing system, the other will then allow selection

of a font installed in your system that includes the characters used in the selected writing system. When you

have found the best font, store your settings here or on the Main tab (see section 4.3.1), and you may edit

config.ini again to disable the font selection switches.

Screenshots

You can set the directory where screenshots will be stored, and also whether you want screenshots sized

like Stellarium’s window or some other, likely larger size. The maximum possible size depends on your

hardware.

4096× 4096

should be possible on most PCs, others may even create

16384× 16384

images. The

vertical ﬁeld of view will be the same as in the current view.

You can also set the ﬁle format. The exact selection depends on platform and version of the underlying

Qt framework. Notable formats are PNG (lossless), JPG (lossy), JPEG (higher quality JPG), BMP (Windows

Bitmap), WEBP, TIF (LZW compressed), TIFF (uncompressed), PBM, PGM, PPM, XBM, XPM, and ICO

(thumbnails).

Some printing workﬂows require particular DPI (dots per inch) settings stored in the screenshots. You

can conﬁgure DPI which will be stored in the image metadata. The intended print size in

is shown in

the tooltip of the dpi spinner.

4.3.6 The Speech Tab

The Speech tab (Fig. 4.8) allows conﬁguring speech output.

You can select some speech engine, then

v 25.4

(hopefully) a list of voices for your user language becomes available from which you can choose. You can

inﬂuence pitch and speed (Rate) and balance volume against your system volume. Then test the content of

the text box with the

▶ Say

, or cut this off via

∎ Stop

Speech output is available for data of the currently selected object. In the Information tab (see 4.3.2), the

right checkbox colums let you select those information bits which should be output by voice. Most users

will keep coordinate readings off, but some physical or morphological data may be interesting to listen to.

The default hotkey for speech output is

Shift

. Pressing it another time will cut off narration.

This fully depends on capabilities of the operating system and is not available for builds/platforms with Qt version

less than 6.4.

4.4 The View Settings Window 27

Figure 4.8: Conﬁguration Window: Speech Tab

Also the long texts in the Landscape (see 4.4.5) and Skyculture (4.4.6) tabs of the View Settings dialog

can be narrated with the

▶ Read text

∎ Stop

buttons near the respective text boxes.

4.3.7 The Scripts Tab

The Scripts tab (Fig. 4.9) allows the selection of pre-assembled scripts bundled with Stellarium that can be

run (See chapter 17 for an introduction to the scripting capabilities and language). This list can be expanded

with your own scripts as required. See section 5.2 where to store your own scripts.

When a script is selected it can be run by pressing the arrow button and stopped with the stop button.

With some scripts the stop button is inhibited until the script is ﬁnished.

Scripts that use sound or embedded videos will need a version of Stellarium conﬁgured at compile time

with multimedia support enabled. It must be pointed out here that sound or video codecs available depends

on the sound and video capabilities of you computer platform and may not work.

4.3.8 The Plugins Tab

Plugins (see chapter 12 for an introduction) can be enabled here (Fig. 4.10) to be loaded the next time you

start Stellarium. When loaded, many plugins allow additional conﬁguration which is available by pressing

the

conﬁgure

button on this tab.

4.4 The View Settings Window

The View settings window controls many display features of Stellarium which are not available via the main

toolbar.

4.4.1 The Sky Tab

The Sky tab of the View window (Fig. 4.11) contains settings for changing the general appearance of the

main sky view and projections. Some highlights of sky ﬁeld:

28 Chapter 4. The User Interface

Figure 4.9: Conﬁguration Window: Scripts Tab

Figure 4.10: Conﬁguration Window: Plugins Tab

4.4 The View Settings Window 29

Figure 4.11: View Settings Window: Sky Tab

Dynamic eye adaptation

When enabled this feature reduces the brightness of faint objects when a bright

object is in the ﬁeld of view. This simulates how the eye can be dazzled by a bright object such as the

moon, making it harder to see faint stars and galaxies.

Light pollution

In urban and suburban areas, the sky is brightened by terrestrial light pollution reﬂected in

the atmosphere. Stellarium simulates light pollution and lets the user conﬁgure how bright the night

sky is. There are several ways to set it up:

Automatic from locations database

option makes Stellarium ﬁnd sky brightness from its locations

database and simulate light pollution without any further user input.

Manual

mode lets the user choose the amount of light pollution by moving a slider. To make it easier

to orient in the resulting amount of light pollution, a tooltip will show the classiﬁcation of the

sky according to the Bortle Dark Sky Scale (See Appendix B for more information), as well as

the naked-eye limiting magnitude.

Manual from SQM

mode lets one enter the reading of a Sky Quality Meter. Stellarium can accept it

in several units: physical (

cdm

mcdm

µcdm

) as well as astronomical,

magarcsec

. To

enter a value, ﬁrst choose the unit, and then type the number into the spinbox.

Solar altitude for Twilight Finder

You can conﬁgure shortcut keys to go to the time when the sun reaches

this altitude below the mathematical horizon. See section 4.8.1.

Shooting stars

Stellarium has a simple meteor simulation option. This setting controls how many shooting

stars will be shown. Note that shooting stars are only visible when the time rate is 1, and might not

be visible at some times of the day. Meteor showers can be simulated using a dedicated plugin (see

section 14.6).

Some highlights of the stars ﬁeld:

Absolute scale

is the size of stars as rendered by Stellarium. If you increase this value, all stars will appear

larger than before.

Relative scale

determines the difference in size of bright stars compared to faint stars. Values higher than

1.00 will make the brightest stars appear much larger than they do in the sky. This is useful for creating

star charts, or when learning the basic constellations.

Twinkle

controls how much the stars twinkle when atmosphere is enabled (scintillation, see section 19.13.2.1).

Since v0.15.0, the twinkling is reduced in higher altitudes, where the star light passes the atmosphere

in a steeper angle and is less distorted.

Limit magnitude

Inhibits automatic addition of fainter stars when zooming in. This may be helpful if you

are interested in naked eye stars only.

Labels and markers

you can independently change the amount of labels displayed for stars. The further to

the right the sliders are set, the more labels you will see. Note that more labels will also appear as you

zoom in.

Use designations for screen labels

— when this option is enabled you will see in the sky (on-screen labels)

only scientiﬁc designations (catalog numbers) of the stars instead of their common names. To

30 Chapter 4. The User Interface

customize the on-screen labels we added 3 additional options

— Dbl. stars, Var. stars and HIP

— which will show, in this sequence of preference, the ﬁrst available occurrence of the traditional

designations of double stars, variable stars or HIP numbers, respectively.

4.4.1.1 The Projections ﬁeld

Selecting items in this list changes the projection method which Stellarium uses to draw the sky (Snyder,

1987). Options are:

Perspective

Perspective projection maps the horizon and other great circles like equator, ecliptic, hour lines,

etc. into straight lines. The maximum ﬁeld of view is 150°. The mathematical name for this projection

method is gnomonic projection.

Stereographic

Stereographic projection has been known since antiquity and was originally known as the

planisphere projection. It preserves the angles at which curves cross each other but it does not preserve

area. Else it is similar to ﬁsh-eye projection mode. The maximum ﬁeld of view in this mode is 235°.

Fish-Eye

Stellarium draws the sky using azimuthal equidistant projection. In ﬁsh-eye projection, straight

lines become curves when they appear a large angular distance from the center of the ﬁeld of view

(like the distortions seen with very wide angle camera lenses). This is more pronounced as the user

zooms out. The maximum ﬁeld of view in this mode is 180°.

Orthographic

Orthographic projection is related to perspective projection, but the point of perspective is

set to an inﬁnite distance. The maximum ﬁeld of view is 180°.

Equal Area

The full name of this projection method is Lambert azimuthal equal-area projection. It

preserves the area but not the angle. The maximum ﬁeld of view is 360°.

Hammer-Aitoff

The Hammer projection is an equal-area map projection, described by ERNST VON

HAMMER (1858–1925) in 1892 and directly inspired by the Aitoff projection. The maximum ﬁeld of

view in this mode is 360°.

Mollweide

The Mollweide projection is a pseudocylindrical equal

area map projection, widely used for

whole

sky displays; it preserves relative areas across the sphere while trading off shape and angular

ﬁdelity, especially near the poles. The maximum ﬁeld of view in this mode is 360°.

Sinusoidal

The sinusoidal projection is a pseudocylindrical equal-area map projection, sometimes called

the Sanson–Flamsteed or the Mercator equal-area projection. Meridians are mapped to sine curves.

Mercator

Mercator projection is a cylindrical projection developed by GERARDUS MERCATOR (1512–

1594) which preserves the angles between objects, and the scale around an object is the same in all

directions. The poles are mapped to inﬁnity. The maximum ﬁeld of view in this mode is 233°.

Miller cylindrical

The Miller cylindrical projection is a modiﬁed Mercator projection, proposed by OS-

BORN MAITLAND MILLER (1897–1979) in 1942. The poles are no longer mapped to inﬁnity.

Cylinder

The full name of this simple projection mode is cylindrical equidistant projection or Plate Carrée.

The maximum ﬁeld of view in this mode is 233°.

Two more settings allow ﬁnetuning:

Vertical viewport offset

If you have a wide screen or like wide-angle views, you may feel that too much of

screen space lies below the horizon. This setting can shift the view up or down.

Custom FoV limit

Some projections allow very wide views, like 180° which covers a complete celestial

hemisphere (e.g. the entire skydome) or even more. In some cases like if you are running a planetarium,

you may want to limit the vertical ﬁeld of view so that you won’t ever zoom out too far.

4.4.1.2 Atmosphere settings

An auxiliary dialog opens when you select and contains detail settings for the atmosphere. Here you can

choose visual model of atmosphere, set atmospheric pressure and temperature which inﬂuence refraction (see

section 19.13.2) and the opacity factor k

for extinction, magnitude loss per airmass (see section 19.13.1).

There are two visual models for the atmosphere available:

Preetham

This is the legacy model (see section 11.2.1), fallback for the cases when the other one doesn’t

work.

ShowMySky

This model is the more realistic visual model of the atmosphere colors (see section 11.2.2). It

relies on a precomputed dataset that can be chosen in the user interface after the ShowMySky model

is enabled.

4.4.2 The Solar System Objects (SSO) Tab

The Solar System Objects tab of the View window (Fig. 4.12) contains settings for changing the general

appearance of the view of Solar system objects. Some highlights:

These options are only used if the star does not have Bayer/Flamsted designations.

4.4 The View Settings Window 31

Figure 4.12: View Settings Window: SSO Tab

Simulate light speed

will give more precise positions for planetary bodies which move rapidly against

background stars (e.g. the moons of Jupiter).

Scale will increase the apparent size of the selected class of objects:

Moon

will increase the apparent size of the Moon in the sky, which can be nice for wide ﬁeld of view

shots.

Minor bodies

will increase the apparent size of minor bodies: planet satellites, all kinds of asteroids,

and comets. Forsome of these 3D models are available, which will be better discernible if

enlarged.

Sun

will increase the apparent size of the Sun in the sky, which can be nice for didactic purposes or

demonstrations.

Planets will increase the apparent size of major planets.

Mark minor bodies

Show a little circle at the location of every minor body (comet, asteroid, . . . ), down to

v 24.3

the conﬁgured visual magnitude. The marks are shown regardless of sky brightness, even in daytime.

Also, in this mode, markers for objects with highly outdated orbital elements are still plotted (see 13.8

and Appendix D.2.2). This is useful to show the distribution of asteroids and comets on the sky, or

especially when viewed from the Solar System Observer (see 4.2.3).

From the “Observer” viewpoints, the visual magnitude for minor bodies is computed as seen from the

Sun, so that objects in inferior conjunction ae not dimmed down and ﬁltered away by effects of phase

angle, and comet tails are better visible.

Show orbits

adds a rendition of the orbit or trajectory of an SSO. For efﬁciency, orbits are not displayed

when the object is not inside the screen, unless you set the “permanently” option. You can further

ﬁne-tune the selection and appearance (width and colors) of orbits with the additional settings.

Show trails plots the apparent path of SSO among the stars as seen from the current planet.

Show planetary nomenclature

displays positions and names of surface features ofﬁcially named by the

IAU (See Appendix E). When the sun is below the horizon at the location of the feature, the label is

attenuated. A few special markers show Centre, North and South poles, east and west points along the

equator, and the subsolar point (where the sun is at the zenith as seen from that feature). Features like

craters are best visible when they are illuminated by a low sun. You can therefore limit the display to

v 1.2

items along the terminator (the border between light and dark on the surface). You can also mark

v 23.3

craters and lunar maria (the dark “seas”) with circles.

GRS details. . .

: The Great Red Spot (GRS) is slowly drifting along Jupiter’s System II coordinate system.

This button opens a new dialog in which you can adjust the longitude (Jupiter system II) and annual

drift rate of this feature at a particular epoch. To help you, another button in this dialog opens a

website with relevant data. The central meridian data given in the object information on screen still

shows System II longitude.

Labels and markers

you can independently change the amount of labels displayed for Solar system objects.

The further to the right the sliders are set, the more labels you will see. Note that more labels will also

appear as you zoom in.

32 Chapter 4. The User Interface

Planet magnitude algorithm

several ways to compute planet magnitudes have been made available from

the literature. Data by Müller (1893) provide visual magnitudes. The other models provide instrumen-

tal (Johnson V) magnitudes.

Earth shadow enlargement after Danjon

Earth’s shadow is enlarged by the atmosphere. You can select

whether the 2% enlargement used by the Astronomical Almanac should be applied (default), or the

formulation of DANJON (see section 19.11.2).

4.4.3 The Deep-Sky Objects (DSO) Tab

Deep-sky objects or DSO are extended objects which are external to the solar system, and are not point

sources like stars. DSO include galaxies, planetary nebulae and star clusters. These objects may or may

not have images associated with them. Stellarium comes with a catalog of over 90,000 extended objects

containing the combined data from many catalogs, with 500+ images.

The DSO tab (Fig. 4.13) allows you to specify which catalogs or which object types you are interested

in. This selection will also be respected in other parts of the program, most notably Search (section 4.5) and

AstroCalc/WUT (section 4.6.6) will not ﬁnd objects from catalogs which you have not selected here.

See chapter 8 for details about the catalog, and how to extend it with your own photographs.

4.4.4 The Markings Tab

The Markings tab of the View window (Fig. 4.14) controls plotting various grids and lines on the celestial

sphere. Colors for grids, lines and points can be adjusted by clicking on the corresponding colored square.

The central column governs lines like equator, ecliptic, meridian etc., where each can optionally be ﬁne-tuned

to show partition marks and labels. Color settings are stored immediately, all other ﬂags need explicit saving

of the settings (see section 4.3.1).

4.4.5 The Landscape Tab

The Landscape tab of the View window (Fig. 4.15) controls the landscape graphics (the horizon which

surrounds you). To change the landscape graphics, select a landscape from the list on the left side of the

window. A description of the landscape will be shown on the right.

Note that while a landscape can include information about where the landscape graphics were taken

(planet, longitude, latitude and altitude), this location does not have to be the same as the location selected in

the Location window, although you can set up Stellarium such that selection of a new landscape will alter the

location for you.

The controls at the bottom right of the window operate as follows:

Use this landscape as default

Selecting this option will save the landscape into the program conﬁguration

ﬁle so that the current landscape will be the one used when Stellarium starts.

Show ground This turns on and off landscape rendering (same as the button

in the main tool bar).

Show fog

This turns on and off rendering of a band of fog/haze along the horizon, when available in this

landscape.

Show illumination

to reﬂect the ugly developments of our civilisation, landscapes can be conﬁgured with a

layer of light pollution, e.g., streetlamps, bright windows, or the sky glow of a nearby city. This layer,

if present, will be mixed in when it is dark enough.

Show landscape labels

Landscapes can be conﬁgured with a gazetteer of interesting points, e.g., mountain

peaks, which can be labeled with this option. Color and font size can also be conﬁgured.

Location from landscape

When enabled, selecting a new landscape will automatically update the observer

location. Use this if the landscape is not just decoration, but a true representation of a particular site

you wish to visit in the simulation.

Minimal brightness

Moonless night on very dark locations may appear too dark on your screen. You may

want to conﬁgure some minimal brightness here.

from landscape, if given

Landscape authors may decide to provide such a minimal brightness value

in the landscape.ini ﬁle.

Draw only polygon

If a polygonal horizon line has been deﬁned for the landscape, only draw this with the

given thickness and color.

Transparency Allow peeking below the horizon. Note that this may show graphical errors.v 23.3

Using the button

Add/remove landscapes. . .

, you can also install new landscapes from ZIP ﬁles which you

can download e.g. from the Stellarium website

or create yourself (see ch. 7 Landscapes), or remove these

custom landscapes.

https://stellarium.org/landscapes.html

4.4 The View Settings Window 33

Figure 4.13: View Settings Window: DSO Tab

Figure 4.14: View Settings Window: Markings Tab

Figure 4.15: View Settings Window: Landscape Tab

34 Chapter 4. The User Interface

Loading large landscapes may take several seconds. If you like to switch rapidly between several

landscapes and have enough memory, you can increase the default cache size to keep more landscapes loaded

previously available in memory. Note that a large landscape can take up 200MB or more! See section D.1.13.

4.4.6 The Sky Culture Tab

Figure 4.16: World map showing Stellarium’s built-in set of sky cultures. To avoid overcrowding,

smaller European sky cultures which are mostly derivatives or relatives of the “Modern” sky culture

are not shown. (Image: S. M. Hoffmann)

If you want to explore humankind’s cultural history, you could also switch to the viewpoint of ancient or

other contemporary peoples. Constellations are deﬁned as patterns in the sky shaped from ﬁxed celestial

objects, often serving to set calendar marks and to navigate while travelling on Earth. Which patterns are

seen depends on the natural environment and the cultural habits of the people, i.e., the Inuit in the arctic

area might have seen an Elk where the Chinese have seen a huge spoon or dipper. There cannot be any

astrological inﬂuence from these patterns as they had been seen differently and, thus, are a product of

human’s imagination. So, pointing out these cultural differences might have an educational function, too.

Caution

Some of our native peoples’ constellations have been contributed for noncommercial use only. Please

respect their heritage holders and check-out the CC licence version in the description before you use sky

cultures for broadcasting! See section 9.1.3 for details.

The Sky Culture tab of the View window (Fig. 4.17) controls which culture’s constellations and bright

star names will be used in the main display. Some cultures have constellation art (e.g., Modern or Inuit), and

the rest do not. Conﬁgurable options include

Use this sky culture as default Activate this option to load this sky culture when Stellarium starts.

Info and screen label styles

The new skyculture system has introduced a plethora of new name elements,

v 25.2

the complete set of which is not required to exist. There are name components that may come in

the skyculture’s original (native) language. If such a culture uses non-Latin glyphs in its writing,

non-native users need a transliteration that also helps pronunciation, which even depends on user

language. Then there are scientiﬁc transliteration systems for some cases. Finally, a pronunciation

aid can be given using the International Phonetic Alphabet (IPA). And, for reference, you may want

to add the commonly used modern name to an object.

There are two sets of settings, for the screen label and for the label used in the information area in the

top-left. The currently conﬁgured settings are immediately stored per-skyculture and retrieved when

you load another skyculture, so that you can adapt the system to your knowledge of languages and

character systems. See 9.2.9 for more.

Abbreviated names

To provide a less cluttered screen in case constellation names are long, you can

4.4 The View Settings Window 35

Figure 4.17: View Settings Window: Sky Culture Tab

show abbreviations. The Modern skycultures use the 3-letter codes given by the IAU, for the other

skycultures we depend on our skyculture authors to deﬁne unique short labels that help memorizing.

Some skycultures still just show numbers.

Select single constellation/Isolated See section 4.4.6.1 for details.

Constellation labels Activate display of constellation labels, like

Constellation lines

Activate display of stick ﬁgures, like or

, and you can conﬁgure constellation

line thickness in the right spinbox.

Constellation art

Activate display of constellation art (if available), like or

. You can also select

the brightness here.

Constellation boundaries

Activate display of constellation boundaries, like

. Currently, boundaries

have been deﬁned only for “Modern” sky cultures.

Asterism labels Activate display of asterism labels, like

Alt

Asterism lines

Activate display of asterism stick ﬁgures (like the shortcut

Alt

), and you can conﬁgure

asterism line thickness as well.

Ray helpers

Activate display of special navigational lines which connect stars often from different constel-

lations (like the shortcut

Alt

), and you can conﬁgure thickness of those lines as well.

Constellation areas optional, advanced research feature. See page 115 for details.

Zodiac

If this skyculture has a concept of Zodiac (usually a region around the ecliptic split into 12 equal-

sized parts), you can enable it here.

Lunar Stations

If this skyculture has a concept of Lunar stations or mansions, you can enable them here.

For example, Indian skycultures observe 27 nakshatras along the ecliptic, and Chinese skycultures

have 28 Lunar mansions of unequal width in equatorial coordinates deﬁned by particular stars.

4.4.6.1 Select single constellations

Some presenters may want to explain a particular storyline about the constellations of a sky culture, which

includes showing single constellations or showing a sequence of appearing constellations. To achieve this,

ﬁrst activate “Select single constellation” mode (see ﬁg 4.17). Then, click on a star which is part of a

constellation line set. Click another star which is part of another constellation to show that one in addition. If

you really only want to show a single constellation, also add the “Isolated” option.

If you explain a sky culture where constellations also have borders deﬁned, a click anywhere in the

constellation area is enough. For other sky cultures, clicking onto a star which is not member of a constellation

line will display all constellations.

Press

to remove all but the last selected constellation. If you had deleted selection (right mouse

click) before pressing

, all constellations are hidden. Press

again to also hide the single displayed

one, or click another star to select the next constellation. If you need to keep the single constellation visible,

select the currently selected star again to select it again. Press

Alt

to show all constellations.

With a little training, you will be able to give inspiring constellation tours.

36 Chapter 4. The User Interface

4.4.7 The Surveys Tab

Figure 4.18: View Settings Window: Surveys Tab

The Surveys tab (Fig. 4.18) allows to toggle the visibility of online sky or solar system surveys (see

chapter 10 for description of the surveys format). Currently, only HiPS surveys are supported.

On the left side of the window we see the list of available surveys from the conﬁgured sources (See

section D.1.29 for how to change the default sources). On the right side a description of the selected survey

and its properties are displayed.

Surveys are grouped by types. The top combobox allows to ﬁlter the listed surveys according to a given

type (Deep Sky or Solar System).

You can toggle the visibility of a survey by checking the box on the left of the survey name in the list.

(Note that as of v0.18.0, only a single deep sky survey can be rendered at a time, so it makes no sense to

select more than one in the list!) Once a survey is visible you should be able to see its loading status in the

loading bar area of the sky view.

Deep sky surveys will be rendered aligned with the sky view, while solar system surveys automatically

map on the proper body.

4.5 The Search Window

4.5.1 The Object tab

The Object tab of the Search window provides a convenient way to locate objects in the sky. Simply type in

the name of an object to ﬁnd, and press . Stellarium will point you at that object in the sky.

As you type, Stellarium will make a list of objects which contains what you have typed so far. The ﬁrst

of the list of matching objects will be highlighted. If you press the or key, the selection will change

to the next item in the list. Pressing the key will bring you to the previous item. Hitting the key will

center on the currently highlighted object and close the Search window.

For example, suppose we want to locate Saturn’s moon Mimas (SI). Open the Search window ( ,

, or

Ctrl

). Type the ﬁrst letter of the name, m, to see a list of objects whose name contains m:

Miranda (UV)

Psamathe (NX)

Umbriel (UII)

. . .

You may want at this point to have Stellarium rather propose object names which start with the string

you enter. Do that in the Options tab of this panel (see section 4.5.5). The search result should update

automatically when you navigate back to the Object tab. Now the list is shorter and contains only objects

which start with m:

4.5 The Search Window 37

Figure 4.19: The Search Window: Object

Figure 4.20: The Search Window: Object (Recent Searches)

Figure 4.21: The Search Window: SIMBAD

38 Chapter 4. The User Interface

Figure 4.22: The Search Window: Position

Figure 4.23: The Search Window: Lists

Figure 4.24: The Search Window: Options

4.5 The Search Window 39

Mago

Maia

Mars

. . .

The ﬁrst item in this list, Mago, is highlighted. Pressing now would go to Mago, but we want Mimas

(SI). We can either press or a few times to highlight Mimas (SI) and then hit , or we can continue

to type the name until it is the ﬁrst/only object in the list.

After you searched for an object, the next time the Search window opens, your most recently searched

object(s) will automatically appear in the search result of the Object tab. For instance, continuing with our

example, re-open the Search window’s Object tab. Mimas (SI) should already be populated and highlighted:

Mimas (SI)

The Object tab’s search result will now prioritize your most recent searches (which will be shown in bold).

To modify the search results, see section 4.5.5. From our earlier example, re-enter m into the Object tab.

Doing so will generate a slightly different list than before. In this case, Mimas (SI) will appear ﬁrst, as shown

in Figure 4.20:

Mimas (SI)

Mago

Maia

Mars

. . .

4.5.2 The SIMBAD tab

The SIMBAD tab (Fig. 4.21) provides a convenient way to fetch and show a set of information for selected

object from the astronomical online database SIMBAD (Wenger et al., 2000). If some object is only visible

in a survey or DSS background (see section 10) and not in Stellarium’s catalogs, you can also set a custom

marker (see section 3.6), select it and query SIMBAD “tell me what’s known about objects at this location”.

4.5.3 The Position tab

The Position tab (Fig. 4.22) provides a convenient way to enter a set of coordinates.

4.5.4 The Lists tab

The Lists tab (Fig. 4.23) allows selection of an object from predeﬁned sets. The number of choices is

governed by the loaded DSO catalogs and plug-ins. Scroll down the ﬁrst window to select the type. Click on

the name and Stellarium will center on that object.

4.5.5 The Options tab

The Options tab (Fig. 4.24) provides a few settings to ﬁne-tune your search experience.

Use SIMBAD

When the name of an object to ﬁnd is typed in the Object tab and you are connected to the

internet and “Use SIMBAD” is ticked, Stellarium will search the SIMBAD on-line databases for its

coordinates. You can then click the button or press . Stellarium will point you at that object

in the sky even if there is no object displayed on the screen. The SIMBAD server being used can be

selected from the scroll window.

Server: for server selection

Search Options group allows for changes in the search result behaviour.

Use autoﬁll only from the beginning of words

when checked, will search for object names that

begins with the same letters as your input. Example provided in section 4.5.1.

Lock position when coordinates are used

Show FOV center marker when position is search

Recent Searches

group allows modiﬁcation to your recent search data. Any changes here will automatically

update the search results displayed in the Object tab. Example provided in section 4.5.1.

Max items to display amount of recent searches that can appear in the search result

button deletes your recent search history

40 Chapter 4. The User Interface

4.6 The Astronomical Calculations Window

This window provides advanced functionality, some of which is still under development. You can call it by

pressing

F10

or the button on the left menu bar. The Astronomical Calculations window shows eight

tabs with different functionality.

Most tabs allow exporting computed data to XLSX (Excel) ﬁles in addition to CSV ﬁles, and graphs

can be exported as PNG ﬁles.

4.6.1 The Positions Tab

This tab shows equatorial J2000.0 or horizontal positions, magnitudes and additional parameters (e.g. surface

brightness for deep-sky objects or angular separation for double stars) for various lists of celestial objects

above the horizon at the simulated time, ﬁltered by magnitude. Double-clicking on an entry brings the object

into focus (Fig. 4.25). You may also export the list of positions into an XLSX or CSV ﬁle.

Figure 4.25: Astronomical Calculations (AstroCalc): Celestial positions / Seen now

This tab is split into 2 subtabs: “Seen now” and “Major planets”. The “Major planets” subtab (Fig. 4.26)

shows a table with heliocentric ecliptic positions of the major planets and a graphical representation of these

positions (in polar coordinates). You may also export the list of positions into an XLSX or CSV ﬁle.

Figure 4.26: Astronomical Calculations (AstroCalc): Celestial positions / Major Planets

4.6 The Astronomical Calculations Window 41

4.6.2 The Ephemeris Tab

Select an object, start and end time, and compute an ephemeris (list of positions and magnitudes evolving

over time) for that object. The positions are marked in the sky with yellow disks (Fig. 4.27).

When you click on a date, an orange disk indicates this date and/or magnitude. Double-clicking sets the

respective date and brings the object to focus. Dates and/or magnitudes will show up near position markers

when Show dates and/or Show magnitudes checkboxes are active. To show a line between markers please

tick checkbox Show line. You may customize the format of displayed data near markers and their frequency

in the Extra options window (Fig. 4.28). You can also deﬁne the color of markers and enable display markers

for all naked-eye visible planets.

You can export the calculated ephemeris into an XLSX or CSV ﬁle.

Another interesting option in this tool: using horizontal coordinates for plotting traces of the Solar

system objects. In this mode, the circle marks are not linked to the sky, but to the horizontal coordinate

system. For example, you can get an analemma of the Sun for any location (Fig. 4.29 and 4.30), or observe

the visibility of Mercury, Venus or a comet in the twilight sky.

You can draw an ephemeris of two objects at the same time and deﬁne custom time step for the

ephemeris (Fig. 4.31).

Note: The ephemeris is computed with the current settings for atmosphere, topocentric correction etc. In

consequence, e.g. magnitudes may be affected by atmospheric absorption and may show unexpected values.

Remember to switch off atmosphere etc. to create extinction free geocentric mean positions as found in

almanachs.

4.6.3 The “Risings, Transits, and Settings” (RTS) Tab

This tab allows you to compute meridian transits and rising and setting times of selected celestial object

(except unnamed stars and artiﬁcial satellites) for a speciﬁc date range. The tool is useful for planning

observations, and it suggests the best time and conditions for visual observations or astrophotography

(Fig. 4.32).

You may also export the list of transits into an XLSX or CSV ﬁle.

4.6.4 The Phenomena Tab

This tab allows you to compute phenomena like conjunctions, oppositions, occultations and eclipses (in

special cases) between planetary objects (Fig. 4.33). In addition, it provides computation of greatest

elongations for the inner planets and stationary points for all planets, and, for all Solar system bodies except

the moons, we also compute perihelia and aphelia.

You can export the calculated phenomena into an XLSX or CSV ﬁle.

Four columns in the table may be helpful for planning observation of phenomena:

solar elongation angular distance from the Sun

lunar elongation angular distance from the Moon

mag. 1 magnitude of ﬁrst object

mag. 2 magnitude of second object

4.6.5 The Graphs Tab

This tab provides on several sub-tabs graphs which are helpful for monthly observation planning of deep-sky

objects and analysis of changes between objects or changes of their positions. Clicking in the graph sets the

time at that point, and setting the mouse onto a graph displays values at this point. However, most graphs are

intended for a rapid overview and are plotted using an interpolating spline through sparse samples, so do not

expect highest accuracy.

4.6.5.1 The “Altitude vs. Time” Subtab

On this subtab (the ﬁrst subtab and default view in the Graphs tab) you can compute the geometrical altitude

of the currently selected object on the currently set date and draw it as a graph (Fig. 4.34).

Optional graphs for the Sun (with lines for civil, nautical and astronomical twilight) and the Moon

(dashed) are also available.

4.6.5.2 The “Azimuth vs. Time” Subtab

On this subtab you can compute the geometrical azimuth of the currently selected object on the currently set

date and draw it as a graph (Fig. 4.35).

4.6.5.3 The “Monthly Elevation” Subtab

This subtab can show a “Monthly Elevation” graph for the current year at the selected time. This tool was

introduced for planning yearly observations (Fig. 4.36).

42 Chapter 4. The User Interface

Figure 4.27: Astronomical Calculations (AstroCalc): Plot trace of planet

Figure 4.28: Astronomical Calculations (AstroCalc): Extra options for ephemeris

Figure 4.29: Astronomical Calculations (AstroCalc): Analemma on the Earth

4.6 The Astronomical Calculations Window 43

Figure 4.30: Astronomical Calculations (AstroCalc): Analemma on Mars

Figure 4.31: Astronomical Calculations (AstroCalc): Two asteroids nearby to one place

Figure 4.32: Astronomical Calculations (AstroCalc): Risings, transits, and settings of selected

celestial object

44 Chapter 4. The User Interface

Figure 4.33: Astronomical Calculations (AstroCalc): Phenomena

Figure 4.34: Astronomical Calculations (AstroCalc): Graphs / Altitude vs. Time

Figure 4.35: Astronomical Calculations (AstroCalc): Graphs / Azimuth vs. Time

4.6 The Astronomical Calculations Window 45

4.6.5.4 The “Graphs” Subtab

This subtab can show two functions over time for the current month or for up to 30 years and draw graphs

for them in one screen (Fig. 4.37). You can select from

•

Magnitude vs. Time

•

Phase vs. Time

•

Distance vs. Time

•

Elongation vs. Time

•

Angular size vs. Time

•

Phase angle vs. Time

•

Heliocentric distance vs. Time

•

Transit altitude vs. Time

•

Right ascension vs. Time

•

Declination vs. Time

This tool may be very helpful for educational and statistics purposes.

For example, the magnitude curve

for Jupiter’s moons shows occasional dips where the moon is in Jupiter’s shadow. However, while for most

graphs a sampling interval of 24 hours should be sufﬁcient (i.e., 1 value per day), for this graph you may

want to reduce the sampling interval to 1 or 2 hours to avoid missing those eclipses by undersampling. Of

course, such high density takes much longer to compute, so you should avoid plotting this curve for many

years, or expect a long delay where the program may seem unresponsive.

4.6.5.5 The “Lunar Elongation” Subtab

This subtab (Fig. 4.38) can show a “Lunar Elongation” graph — the angular distance between the Moon and

the selected object (for example some deep-sky object) for the nearest 30 days. This tool was introduced for

planning monthly observations.

4.6.6 The “What’s Up Tonight” (WUT) Tab

The “What’s Up Tonight” (WUT) tool

displays a list of objects that will be visible at night for the current

date and location.

The objects are organized into type categories. Select an object type in the box labeled Select a Category,

and all objects of that type which are above the horizon on the selected night will be displayed in the box

labeled Matching Objects. For example, in the screenshot, the Planets category has been selected, and three

planets which are up in the selected night are displayed (Jupiter, Mars and Mercury).

By default, the WUT will display objects which are above the horizon between sunset and midnight (i.e.

in the evening). You can choose to show objects which are up between midnight and dawn (in the morning),

around midnight, or any time between dusk and dawn (any time tonight) using the combobox near the top

of the window. You can also choose to see only those objects that are brighter than a certain magnitude by

setting a minimum magnitude using the Show objects brighter than magnitude spinbox. You may center an

object from the right list in the sky map just by selecting it.

Note that only DSO from catalogs which you have selected in the DSO panel (section 4.4.3) will be

found.

In version 0.18.3 this tool has been refactored: the tool for searching items from list of Matching Objects

was removed, the ﬁlter for magnitudes was moved to the right, and we added a new ﬁlter here to limit the

range of acceptable angular sizes of matched objects. In addition to the names we added 5 new sortable

columns: magnitude, rising time, transit time, setting time and angular size of object.

4.6.7 The “Planetary Calculator” (PC) Tab

The “Planetary Calculator” (PC) tool has been added after user requests. It computes the relations between

two Solar system bodies for the current date and location — linear and angular distances, orbital resonances

and orbital velocities.

The Graphs tab (Fig. 4.41) shows the change in the linear and angular distances between selected

celestial bodies over a range of 600 days (centered on the current date) as graphs.

4.6.8 The Eclipses Tab

The Eclipses tool has four subtabs: “All Solar Eclipses”, “Local Solar Eclipses”, “Lunar Eclipses” and

“Planetary Transits”.

You can export the calculated eclipses and transits into an XLSX or CSV ﬁle.

The idea for this tool has been obtained from SkytechX: http://www.skytechx.eu/

This tool has been partially ported from the KStars planetarium: https://edu.kde.org/kstars/

46 Chapter 4. The User Interface

Figure 4.36: Astronomical Calculations (AstroCalc): Graphs / Monthly Elevation

Figure 4.37: Astronomical Calculations (AstroCalc): Graphs

Figure 4.38: Astronomical Calculations (AstroCalc): Graphs / Lunar Elongation

4.6 The Astronomical Calculations Window 47

Figure 4.39: Astronomical Calculations (AstroCalc): What’s Up Tonight (WUT)

Figure 4.40: Astronomical Calculations (AstroCalc): Planetary Calculator (PC), Data Tab

Figure 4.41: Astronomical Calculations (AstroCalc): Planetary Calculator (PC), Graphs Tab

48 Chapter 4. The User Interface

Caution

Predicting eclipses and transits, and in particular local circumstances, over thousands of years in the past and

future is not reliable due to the principal unpredictability of

∆T

, caused by ﬂuctuations of Earth’s rotation.

(See section 18.4.3 for details.)

4.6.8.1 The “All Solar Eclipses” Subtab

This subtab (Fig. 4.42) contains data for all solar eclipses on the Earth in the selected time range. Double

click on a line in the table will set location and time of greatest eclipse. Click on the table row will show

circumstances of selected eclipse in the lower table.

The quantity Gamma is the minimum distance of the lunar shadow cone axis to the center of the Earth,

in units of Earth’s equatorial radius. This distance is positive or negative, depending on whether the axis of

the shadow cone passes north or south of the Earth’s center.

Click the

Export KML. . .

button to create a KML ﬁle of the selected eclipse. KML is a ﬁle format used to

display geographic data in Earth browsers, such as Marble, Google Earth or Google Maps. The ﬁle can be

opened in applications that support KML version 2.2. A description of the lines for solar eclipses is shown

in Fig. 4.43. Different colors are used to draw path of central eclipse. Red = total eclipse, blue = annular

eclipse, and purple = hybrid eclipse. Limits of penumbral or partial eclipse are green.

4.6.8.2 The “Local Solar Eclipses” Subta b

This subtab (Fig. 4.44) contains data for solar eclipses for the current location (on the Earth!) in deﬁned time

range.

Double click on a line in the table will set the time of greatest eclipse.

4.6.8.3 The “Lunar Eclipses” Subtab

This subtab (Fig. 4.45) contains data for all lunar eclipses on the Earth in deﬁned time range. Double click

on the table row will set time of greatest eclipse. Click on the table row will show circumstances of selected

eclipse in the lower table.

The quantity gamma is the minimum distance from the center of the Moon to the axis of Earth’s umbral

shadow cone, in units of Earth’s equatorial radius. This distance is positive or negative, depending on whether

the Moon passes north or south of the shadow cone axis.

The visibility conditions are based on the altitude of the Moon at greatest eclipse:

Invisible — the greatest eclipse is invisible at the current location (altitude is negative);

Not obs.

— not observable eclipse. Our rule of thumb is that a partial penumbral eclipse is detectable with

the unaided eye if penumbral magnitude > 0.7;

Bad — bad visibility conditions for current location (altitude range is 0—30°);

Good

— good visibility conditions for current location (altitude range is 30—45°; i.e., “photometric

altitude”);

Perfect — perfect visibility conditions for current location (altitude range is 45—90°).

4.6.8.4 The “Planetary Transits” Subtab

This subtab (Fig. 4.46) contains data for all transits of Mercury and Venus across the Sun as seen from Earth

(see 19.11.3) in the deﬁned time range. If an event is not observable because the Sun/planet is below the

horizon, its time will be shown in brackets and greyed-out. Further columns show the total duration of the

event, and the observable duration at the current location, which takes rising and setting times into account.

Double click on the table row will set time of mid-transit.

4.6.9 The Almanac Tab

The Almanac tool has one subtab: “Speciﬁc Time”.v 25.1

4.6.9.1 The “Speciﬁc Time” Subtab

This subtab (Fig. 4.47) contains data for speciﬁc time moments in this year (starring and duration seasons)

and at today — time for setting and rising the Sun and Moon, time and duration of twilights, and duration of

the daytime and astronomical night. You can use buttons to quick set these speciﬁc time moments. All dates

and times are selectable.

4.6 The Astronomical Calculations Window 49

Figure 4.42: Astronomical Calculations (AstroCalc): Eclipses / All Solar Eclipses

Northern limit of penumbra (partial eclipse)

Total Solar Eclipse 2027 August 2

Southern limit of penumbra (partial eclipse)

Outline of umbra

plotted every 10 minutes

Point of greatest eclipse

Path of total eclipse

Southern limit

Northern limit

Center line

Eclipse begins at sunrise

Maximum eclipse at sunrise

Eclipse ends at sunrise

Eclipse begins at sunset

Maximum eclipse at sunset

Eclipse ends at sunset

Figure 4.43: Key to solar eclipse map

50 Chapter 4. The User Interface

Figure 4.44: Astronomical Calculations (AstroCalc): Eclipses / Local Solar Eclipses

Figure 4.45: Astronomical Calculations (AstroCalc): Eclipses / Lunar Eclipses

Figure 4.46: Astronomical Calculations (AstroCalc): Eclipses / Planetary Transits

4.6 The Astronomical Calculations Window 51

Figure 4.47: Astronomical Calculations (AstroCalc): Almanac / Speciﬁc Time

52 Chapter 4. The User Interface

4.7 The Help Window

4.7.1 The Help Tab

Figure 4.48: Help Window

The Help Tab lists all of Stellarium’s keystrokes. Note that some features are only available as keystrokes, so

it’s a good idea to have a browse of the information in this window.

4.7.2 The About Tab

The About Tab (Fig. 4.49) shows version and licensing information, and a list of people who helped to

produce the program. This tab also provides a tool to check for updates of Stellarium.

4.7.3 The Log Tab

The Log Tab (Fig. 4.50) shows messages like the loading conﬁrmations carried out when Stellarium runs. It

is useful to locate the ﬁles that Stellarium writes to your computer. The same information is written to the

ﬁle log.txt that you will ﬁnd in your user data directory (see 5.1).

4.7.4 The Conﬁg Tab

The Conﬁg Tab (Fig. 4.51) shows conﬁguration data of the Stellarium. It is useful to locate the ﬁles that

Stellarium writes to your computer. The same information is written to the ﬁle

config.ini

that you will

ﬁnd in your user data directory (see 5.1).

4.7 The Help Window 53

Figure 4.49: Help Window: About

Figure 4.50: Help Window: Logﬁle

Figure 4.51: Help Window: Conﬁg ﬁle

54 Chapter 4. The User Interface

4.8 Editing Keyboard Shortcuts

Figure 4.52: Keyboard Shortcuts

You can edit the shortcut keys here. Each available function can be conﬁgured with up to two key

combinations. You may want to reconﬁgure keys for example if you have a non-English keyboard layout and

some keys either do not work at all, or feel unintuitive for you, or if you are familiar with other software and

want to use the same hotkeys for similar functions. Simply select the function and click with the mouse into

the edit ﬁeld, then press your key of choice. If the key has been taken already, a message will tell you.

This tool is available through the Help Tab of the Help window (see section 4.7.1) and the Tools Tab of

the Conﬁguration window (see section 4.3.5).

4.8.1 Example

If you want to follow the sky view each evening with the Sun at the same depth below the horizon, so

that the twilight is of equal darkness, you may want to assign some actions to intuitive shortcut keys. In

the Keyboard Shortcut editor (Fig. 4.52), ﬁnd the Date and Time group and assign, e.g., the keys on your

numeric keypad:

Previous evening twilight Ctrl+9

Previous morning twilight Ctrl+7

Next evening twilight Ctrl+3

Next morning twilight Ctrl+1

Today’s evening twilight Ctrl+6

Today’s morning twilight Ctrl+4

Advanced Use

5 Files and Directories . . . . . . . . . . . . . . . . . 57

5.1 Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5.2 Directory Structure . . . . . . . . . . . . . . . . . . . . . . 58

5.3 The Logﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

5.4 The Main Conﬁguration File . . . . . . . . . . . . . . . 59

5.5 Getting Extra Data . . . . . . . . . . . . . . . . . . . . . . 59

6 Advanced Options . . . . . . . . . . . . . . . . . . 63

6.1 Command Line Options . . . . . . . . . . . . . . . . . 63

6.2 Environment Variables . . . . . . . . . . . . . . . . . . . 65

6.3 GUI Customizations . . . . . . . . . . . . . . . . . . . . . 66

6.4 Spout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.5 Spherical Mirror Mode for Planetarium Use . . . . 67

7 Landscapes . . . . . . . . . . . . . . . . . . . . . . . . . 71

7.1 Stellarium Landscapes . . . . . . . . . . . . . . . . . . . . 71

7.2 Creating Panorama Photographs for Stellarium 80

7.3 Panorama Postprocessing . . . . . . . . . . . . . . . . 85

7.4 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . 90

7.5 Other recommended software . . . . . . . . . . . . 90

8 Deep-Sky Objects . . . . . . . . . . . . . . . . . . . 93

8.1 Stellarium DSO Catalog . . . . . . . . . . . . . . . . . . 93

8.2 Adding Extra Nebula Images . . . . . . . . . . . . . . 99

9 Adding Sky Cultures . . . . . . . . . . . . . . . . 105

9.1 Text description . . . . . . . . . . . . . . . . . . . . . . . . 105

9.2 Technical data: index.json . . . . . . . . . . . . . . . . 108

9.3 The Skyculture Converter . . . . . . . . . . . . . . . . . 122

9.4 Publish Your Work . . . . . . . . . . . . . . . . . . . . . . . 123

10 Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

10.2 Hipslist ﬁle and default surveys . . . . . . . . . . . . . 125

10.3 Solar system HiPS survey . . . . . . . . . . . . . . . . . . 126

10.4 Digitized Sky Survey 2 (TOAST Survey) . . . . . . . 126

11 Stellarium’s Skylight Models . . . . . . . . . 127

11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

11.2 The Skylight Models . . . . . . . . . . . . . . . . . . . . . 127

11.3 Light Pollution . . . . . . . . . . . . . . . . . . . . . . . . . . 129

11.4 Tone Mapping . . . . . . . . . . . . . . . . . . . . . . . . . 129

5. Files and Directories

5.1 Directories

Stellarium has many data ﬁles containing such things as star catalogue data, nebula images, button icons,

font ﬁles and conﬁguration ﬁles. When Stellarium looks for a ﬁle, it looks in two places. First, it looks in

the user directory

for the account which is running Stellarium. If the ﬁle is not found there, Stellarium

looks in the installation directory

. Thus it is possible for Stellarium to be installed by an administrative user

and yet have a writable conﬁguration ﬁle for non-administrative users. Another beneﬁt of this method is on

multi-user systems: Stellarium can be installed by the administrator, and different users can maintain their

own conﬁguration and other ﬁles in their personal user accounts.

In addition to the main search path, Stellarium saves some ﬁles in other locations, for example screens

shots and recorded scripts.

The locations of the user directory, installation directory, screenshot save directory and script save

directory vary according to the operating system and installation options used. The following sections

describe the locations for various operating systems.

5.1.1 Windows

installation directory

By default this is

C:\Program Files\Stellarium\

, although this can be adjusted

during the installation process.

user directory

This is the Stellarium sub-folder in the Application Data folder for the user account which is

used to run Stellarium. Depending on the version of Windows and its conﬁguration, this could be any

of the following (each of these is tried, if it fails, the next in the list if tried).

% APPDAT A %\ S te ll ar ium \

% USERPROFIL E %\ Stellarium \

% HOMEDRI VE %\% HOMEPATH %\ Stellarium \

% HOME %\ Stellarium \

Stellarium ’s installatio n dir ec tory

Thus, on a typical Windows Vista/7/10 system with user “Bob Dobbs”, the user directory will be:

C :\ Users \ Bob Dobbs \ AppDa ta \ Roaming \ St el la ri um \

The user data directory is unfortunately hidden by default. To make it accessible in the Windows ﬁle

explorer, open an Explorer window and select

Organize... Folder and search options

. Make sure

folders marked as hidden are now displayed. Also, deselect the checkbox to “hide known ﬁle name

endings”.

also called user data directory

The installation directory was referred to as the conﬁg root directory in previous versions of this guide

This is a very confusing default setting and in fact a security risk: Consider you receive an email with some ﬁle

58 Chapter 5. Files and Directories

screenshot save directory

Screenshots will be saved to the

Pictures/Stellarium

directory, although

this can be changed in the GUI (see section 4.3.5) or with a command line option (see section 6.1).

5.1.2 macOS

installation directory

This is found inside the application bundle,

Stellarium.app

. See The Anatomy of

macOS App Bundles

or Bundle Programming Guide

for more information.

user directory

This is the sub-directory

~/Library/Application Support/Stellarium

of the user’s

home directory.

screenshot save directory Screenshots are saved to the user’s Desktop.

5.1.3 Linux

installation directory

This is in the

share/stellarium

sub-directory of the installation preﬁx, i.e., usu-

ally /usr/share/stellarium.

user directory

This is the

.stellarium

sub-directory of user’s home directory, i.e.,

~/.stellarium/

This is a hidden folder, so if you are using a graphical ﬁle browser, you may want to change its settings

to “display hidden folders”.

screenshot save directory Screenshots are saved to the user’s home directory.

5.1.4 *BSD/Solaris/OpenIndiana

installation directory

This is in the

share/stellarium

sub-directory of the installation preﬁx, i.e., usu-

ally /usr/local/share/stellarium/.

user directory

This is the

.stellarium

sub-directory of user’s home directory, i.e.,

~/.stellarium/

This is a hidden folder, so if you are using a graphical ﬁle browser, you may want to change its settings

to “display hidden folders”.

screenshot save directory Screenshots are saved to the user’s home directory.

5.1.5 Haiku

installation directory This is in the /boot/system/data/stellarium/ sub-directory.

user directory

This is in the user’s home directory, i.e.,

~/config/settings/Stellarium/

or the sub-

directory /boot/home/config/settings/Stellarium/.

screenshot save directory Screenshots are saved to the user’s home directory.

5.1.6 Customized Location

Some users may prefer non-standard locations for their own data, for example when the Windows

drive

(which usually contains user data), or the Linux

/home

partition has become too small to hold tens of

high-resolution landscapes or detailed 3D sceneries. You can move the entire directory elsewhere and use an

environment variable STEL_USERDIR that contains the pathname.

5.2 Directory Structure

Within the installation directory and user directory deﬁned in section 5.1, ﬁles are arranged in the following

sub-directories.

landscapes/

contains data ﬁles and textures used for Stellarium’s various landscapes. Each landscape has

its own sub-directory. The name of this sub-directory is called the landscape ID, which is used to

specify the default landscape in the main conﬁguration ﬁle, or in script commands.

skycultures/

contains constellations, common star names and constellation artwork for Stellarium’s

many sky cultures. Each culture has its own sub-directory in the skycultures directory.

scripts/ contains your own scripts. These can be used to create complex demonstrations (see ch. 17).

nebulae/

contains data and image ﬁles for nebula textures. In the future Stellarium may be able to support

multiple sets of nebula images and switch between them at runtime. This feature is not implemented

for version 25.4, although the directory structure is in place – each set of nebula textures has its own

sub-directory in the nebulae directory.

funny.png.exe

attached. Your explorer displays this as

funny.png

. You double-click it, expecting to open some

image browser with a funny image. However, you start some unknown program instead, and running this

.exe

executable

program may turn out to be anything but funny!

https://www.maketecheasier.com/anatomy-macos-app-bundles/

https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CF

Bundles/Introduction/Introduction.html

5.3 The Logﬁle 59

stars/

contains Stellarium’s star catalogues. In the future Stellarium may be able to support multiple star

catalogues and switch between them at runtime. This feature is not implemented for version 25.4,

although the directory structure is in place – each star catalogue has its own sub-directory in the stars

directory.

data/ contains miscellaneous data ﬁles including fonts, solar system data, city locations, etc.

textures/

contains miscellaneous texture ﬁles, such as the graphics for the toolbar buttons, planet texture

maps, etc.

ephem/

(optional) may contain data ﬁles for planetary ephemerides DE430, DE431, DE440 and DE441

(see 5.5.3).

If any ﬁle exists in both the installation directory and user directory, the version in the user directory will

be used. Thus it is possible to override settings which are part of the main Stellarium installation by copying

the relevant ﬁle to the user area and modifying it there.

It is recommended to add new landscapes or sky cultures by creating the relevant ﬁles and directories

within the user directory, leaving the installation directory unchanged. In this manner different users on a

multi-user system can customise Stellarium without affecting the other users, and updating Stellarium will

not risk the loss of your own data.

5.3 The Logﬁle

Stellarium reports various events and conﬁrmations to a logﬁle,

log.txt

, in the user directory. This has

the same content as you can see on the console on Linux when you start Stellarium on the command line.

Normally you don’t need to bother with its contents, however, if Stellarium behaves unexpectedly, crashes,

or shows other problems, a quick look into this ﬁle may help to identify the problem. Also when you report a

problem to the developers in the hope that they (we) can ’ﬁx’ anything, this logﬁle is an essential ingredient

to your report. The logﬁle can also be displayed within the program: press

to call the help panel, and

select the Logﬁle tab.

5.4 The Main Conﬁguration File

The main conﬁguration ﬁle is read each time Stellarium starts, and settings such as the observer’s location

and display preferences are taken from it. Ideally this mechanism should be totally transparent to the user

– anything that is conﬁgurable should be conﬁgured “in” the program GUI. However, at time of writing

Stellarium isn’t quite complete in this respect, despite improvements in each version. Some settings, esp.

color values for some lines, grids, etc. can only be changed by directly editing the conﬁguration ﬁle.

This

section describes some of the settings a user may wish to modify in this way, and how to do it.

The name of the conﬁguration ﬁle is

config.ini

. If the conﬁguration ﬁle does not exist in the user

directory when Stellarium is started (e.g., the ﬁrst time the user starts the program), one will be created with

default values for all settings (refer to section 5 Files and Directories for the location of the user directory on

your operating system).

The conﬁguration ﬁle is a regular text ﬁle, so all you need to edit it is a text editor like Notepad on

Windows, Text Edit on the Mac, or nano/vi/gedit/emacs/leafpad etc. on Linux.

A complete list of conﬁguration ﬁle options and values may be found in appendix D.1.

5.5 Getting Extra Data

5.5.1 More Stars

Stellarium is packaged with over 600 thousand stars in the normal program download, but much larger star

catalogues may be downloaded in the Tools tab of the Conﬁguration dialog (

Color values can be edited interactively by the Text User Interface plugin (see 13.4).

It is possible to specify a different name for the main conﬁguration ﬁle using the

--config-file

command line

option. See section 6.1 Command Line Options for details.

60 Chapter 5. Files and Directories

5.5.2 More Deep-Sky Objects

Stellarium is packaged with over 94 thousand deep-sky objects

in the normal program download (the

standard edition of Stellarium DSO catalog

, see section 8.1), but an extended edition of DSO catalog with

over one million objects (up to

20.0

for galaxies) may be downloaded from Stellarium’s Github website

Version; Edition Filename MD5 hash Size

3.22; extended catalog-3.22.dat c4820d050791046baf1460b186fa23c6 28MB

The ﬁle can be placed in a folder named nebulae/default inside the user directory (see section 5.2).

5.5.3 Alternative Planet Ephemerides: DE430, DE431, DE440, DE441

By default, Stellarium uses the VSOP87 planetary theory, an analytical solution which is able to deliver

planetary positions for any input date (P. Bretagnon and Francou, 1988). However, its use is recommended

only for the year range

−4000. . . + 8000

. Outside this range, it seems to be usable for a few more millennia

without too great errors, but with degrading accuracy. Likewise for the moon, Stellarium by default uses

ELP 2000-82B (Chapront-Touze, 1982; Chapront-Touzé and Chapront, 1983; Chapront-Touzé and Chapront,

1988b).

Since v0.15.0 you can install extra data ﬁles which allow access to the numerical integration runs DE430

and DE431 (Folkner et al., 2014), and meanwhile also DE440 and DE441 (Park et al., 2021), from NASA’s

Jet Propulsion Laboratory (JPL). The data ﬁles have to be downloaded separately, and most users will likely

not need them. DE430 and DE440 provide highly accurate data for the years

+1550. . . + 2650

, while DE431

and DE441 covers years

−13000. . . + 17000

, which allows e.g. archaeoastronomical research on Mesolithic

landscapes. (But see Appendix F!) Outside these year ranges, positional computation falls back to VSOP87.

Some current approximations may still lead to numerical data which differ slightly from best possible

ephemerides. Please at least compare with JPL Horizons

for dependable results.

To enable use of these data, download the ﬁles from JPL

Ephemeris Filename MD5 hash Size

DE430 linux_p1550p2650.430 707c4262533d52d59abaaaa5e69c5738 97.5 MB

DE431 lnxm13000p17000.431 fad0f432ae18c330f9e14915fbf8960a 2.59 GB

DE440 linux_p1550p2650.440 9dc8a9cefd32b0090002407847e718ba 97.5 MB

DE441 linux_m13000p17000.441 4e3b924463d17b68ec9c4a18240300cd 2.59 GB

The ﬁles can be placed in a folder named

ephem

inside either the installation directory or the user

directory (see 5.2). Alternatively, if you have them already stored elsewhere, you may add the path to

config.ini like:

[ astro ]

de430_path = C :/ Ast ro data / JPL_ DE43x / li nu x_p15 50p26 50 .430

de431_path = C :/ Ast ro data / JPL_ DE43x / ln xm 13000 p1 7000 .431

de440_path = C :/ Ast ro data / JPL_ DE44x / li nu x_p15 50p26 50 .440

de441_path = C :/ Ast ro data / JPL_ DE44x / li nux_m 13000 p17 00 0 .441

For fast access avoid storing them on a network drive or USB pendrive!

You activate use of either ephemeris in the Conﬁguration panel (

). If you activate more than one,

preference will be given for DE440 over DE441 if the simulation time allows it. Only if DE44x are not

enabled, DE430 is given preference over DE431 if simulation time allows it. Outside of the valid times,

VSOP87 will always be used.

Acknowledgement

The optional use of DE430/431 has been supported by the ESA Summer of Code in Space 2015 initiative.

Over 83 thousand deep-sky objects in version 0.16.0.

The ﬁrst number in the version of Stellarium DSO catalog means version of catalog structure, and the second

number means version of data.

https://github.com/Stellarium/stellarium-data/releases/tag/dso-3.22

https://ssd.jpl.nasa.gov/horizons.cgi

https://ssd.jpl.nasa.gov/ftp/eph/planets/Linux/

(Also download from this directory if you are not

running Linux!)

5.5 Getting Extra Data 61

5.5.4 GPS Position

In the Location panel (see section 4.2) you can receive your location from a GPS device. The exact way to

receive GPS location depends on your operating system.

5.5.4.1 GPSD (Linux, Mac OS X only)

On Linux, Mac-OS X and other Unixoid platforms, Stellarium preferably should not connect directly to a

GPS USB device, serial device, bluetooth device, etc., but use a connection to the gpsd daemon running on

a computer in your network which provides GPS services concurrently for any interested application. In

most cases, this will be a gpsd running on your localhost, receiving data from some GPS device plugged in

via USB. Please follow instructions by the gpsd authors

to properly conﬁgure this system daemon. A few

hints:

•

On Ubuntu 16.04 and likely other systems, USB hotplug devices are handled by the udev daemon

which detects newly plugged-in devices and creates device ﬁles in the

/dev

directory. Unfortunately,

most GPS devices use the Proliﬁc 2303 chipset in their serial-to-USB converter and are identiﬁed as

such, without other unique information like serial numbers. This chipset is also used in other Serial-

to-USB converter cables, and to avoid conﬂicts the according rule has been disabled by the release

managers of Ubuntu. In /lib/udev/60-gpsd.rules, ﬁnd the commented line and re-activate it.

•

If you have such an USB GPS mouse and USB-to-serial converters for other purposes like for your

telescope control, you must solve the “udev crisis” in some other way to get gpsd running. You may

be able to ﬁnd some property in your device to uniquely identify this device and write an udev rule to

create the symlink in /dev/gps0 to which gpsd can then connect.

•

You can also connect to another computer which runs gpsd. This could be a little Raspberry Pi

computer which happens to be in your WiFi to allow localisation and time service. To conﬁgure this,

you must manually edit config.ini. Find the [gui] section and edit

[ gui ]

# These values are used on non - Windows systems

# supporting GPSD

gp sd _h ostname = localhost

gpsd_port = 2947

Also, gpsd must be started with the -G parameter to enable this.

•

Even your smartphone can be used as GPS data source

: Apps like BlueNMEA can provide these

data for gpsd, but you must make sure to conﬁgure hostname/IP Address and port number correctly,

for example

sudo gpsd -n - D8 -S 1001 tcp :/ /19 2.168 .1. 101:4 352

which means

-n to start without a device connection

-D8 maximum debug level. When it works, use what suits you

-S 1001 provide service on port 1001

tcp

Use this address:port combination to receive data from (IP of your smartphone, port shown on

BlueNMEA screen).

•

In case you really don’t want to use the gpsd, you can use a directly connected device, see below.

This is however not recommended when you have gpsd available.

5.5.4.2 NMEA Device

This mode is primarily for Windows users, but also for Linux and Mac users who don’t want to use gpsd.

Virtually all GPS receivers are able to emit the standardized NMEA-0183 messages which encode time,

position, speed, satellite information and other data. The standard originally required connection settings of

4800 baud, 8 bit, no parity, one stop bit (8N1), however some devices come with faster transfer.

Compatible devices today are connected on a “virtual COM port” via USB. Unfortunately the COM

number seems to depend on the USB plug where you attach the receiver. You can identify the port name

(COM3, COM4, . . . ) in the Windows system conﬁguration (Device Manager) or with the software that came

with your device.

https://gpsd.gitlab.io/gpsd/index.html

Thanks to user Caysho for this hint.

On Linux, this may read /dev/ttyUSB0, /dev/gps0 or similar.

62 Chapter 5. Files and Directories

If this is the only serial device, Stellarium should automatically connect to it regardless of conﬁguration

entries. If you have a device with non-standard baudrate or several serial devices on serial ports (e.g., your

telescope?), you must ﬁnd out which serial port is used by the GPS device and manually edit

config.ini

Find the [gui] section and edit

[ gui ]

# These values are used on Windows prima ri ly .

gp s_ in terface = COM3

gps_ ba ud rate = 4800

From now on, always use the same USB plug conﬁguration to connect GPS and telescope.

If GPS lookup fails, see section 6.2.1 to enable more diagnostic messages in the logﬁle.

Bluetooth GPS

Most smartphones provide GPS and Bluetooth hardware. You can install a virtual COM port in your

Windows Bluetooth settings and use a smartphone app like Share GPS

to provide the NMEA strings.

Windows location service

On Windows devices, you can get your location using the Windows location service. The result depends on

available hardware and other settings, e.g. real GPS sensor or network and WiFi detection.

5.5.5 Modernized MESA3D libraries (Software OpenGL on Windows)

Stellarium uses hardware-accelerated OpenGL for rendering. On very old Windows systems without

dedicated graphics hardware, or in special circumstances like virtual machines, hardware accelerated

graphics may not be available, and the Mesa3D software implementation of OpenGL is used. This can also

be forced by the command-line option

--mesa-mode

. Rendering the graphics without hardware acceleration

is of course much slower than accelerated graphics, but it’s surely better than nothing.

Qt’s default Mesa library (Mesa 11) provides support for OpenGL 3.0 only. This prevents users of all

versions from applying dithering in Mesa mode. Also the ShowMySky skylight model (see section 11.2.2) is

then not available.

We have replaced this by a version of Mesa 20 compiled by Federico Dossena

which appears to be

v 23.4

even a bit faster.

The Mesa3D project

meanwhile (2023) provides at least OpenGL 4.5. If you wish to use more “up to

date” precompiled binaries and have Administrator privileges on your Windows system, you can replace

this library using the following steps to install unofﬁcial builds

. Note however that after this upgrade, the

program runs with considerably (

≈

35%?) lower framerate. You must decide whether this is really beneﬁcial

in your situation. The libraries don’t provide any additional graphics features that Stellarium makes use of.

•

Download the latest “release-msvc” package as you need from

https://github.com/pal1000/m

esa-dist-win/releases and unpack it somewhere.

•

Copy

(x86|x64)/libglapi.dll,libgallium_wgl.dll,opengl32.dll

to where the executable

stellarium.exe is.

•

Delete the existing opengl32sw.dll

•

Rename the just-copied opengl32.dll to opengl32sw.dll.

Now running Stellarium in Mesa mode (with link from program menu or command line) should report to

provide OpenGL 4.5.

Again, for Linux the port number is deﬁned in order of hotplugging by udev. You should develop an udev rule

which adds a unique name and use this. In this case, you may also need to add your user to the

dialout

group (or

whichever group owns your serial port). Better yet, use gpsd (see above).

https://play.google.com/store/apps/details?id=com.jillybunch.shareGPS

https://support.microsoft.com/en-us/windows/windows-location-service-and-privacy-3a8

eee0a-5b0b-dc07-eede-2a5ca1c49088

https://fdossena.com/?p=mesa/index.frag

https://www.mesa3d.org/

https://github.com/pal1000/mesa-dist-win/

6. Advanced Options

6.1 Command Line Options

Stellarium’s behaviour can be modiﬁed by providing parameters to the program when it is called via the

command line. See table for a full list:

Option Option Parameter Description

--help or -h [none]

Print a quick command line help message, and

exit.

--version or -v [none]

Print the program name and version information,

and exit.

--conﬁg-ﬁle or -c conﬁg ﬁle name

Specify the conﬁguration ﬁle name. The default

value is config.ini.

The parameter can be a full path (which will be

used verbatim) or a partial path.

Partial paths will be searched for inside the reg-

ular search paths unless they start with a “

”,

which may be used to explicitly specify a ﬁle in

the current directory or similar.

For example, using the option

-c

my_config.ini

would resolve to the ﬁle

<user directory>/my_config.ini

whereas

-c ./my_config.ini

can be used to explicitly

point to the ﬁle

my_config.ini

in the current

working directory.

--log-ﬁle or -l

log ﬁle name

Specify the log ﬁle name. The default value is

log.txt.

The value of parameter can be a simple ﬁlename

or absolute path to the log ﬁle.

When a path is speciﬁed like

-l

my_log.txt

, the ﬁle will be written to

<user

directory>/my_log.txt

. When a path is spec-

iﬁed like

-l /home/user/stellarium.log

/home/user/stellarium.log

64 Chapter 6. Advanced Options

--restore-defaults [none]

Stellarium will start with the default conﬁgura-

tion. Note: The old conﬁguration ﬁle will be

overwritten.

--user-dir path Specify the user data directory.

--screenshot-dir

path

Specify the directory to which screenshots will

be saved.

--full-screen yes or no

Overrides the full screen setting in the conﬁg ﬁle.

--home-planet planet Specify observer planet (English name).

--latitude

latitude Specify latitude, e.g. 41.1 or +53d58’16.6"

--longitude

longitude Specify longitude, e.g. 16.2 or -1d4’27.48"

--altitude

altitude Specify observer altitude in meters.

--list-landscapes [none] Print a list of available landscape IDs and exit.

--landscape

landscape ID

Start using landscape whose ID matches the

passed parameter (dir name of landscape).

--sky-date date The initial date in yyyymmdd format.

--sky-time

time The initial time in hh:mm:ss format.

--startup-script script name

The name of a script to run after the program has

started. [startup.ssc]

--fov angle (degrees) The initial vertical ﬁeld of view in degrees.

--scale-gui scale factor Scaling the GUI according to scale factor

--gui-css style

name Use name.css to deﬁne GUI style

--projection-type ptype The initial projection type: one of

ProjectionPerspective

ProjectionEqualArea

ProjectionStereographic

ProjectionFisheye

ProjectionCylinder

ProjectionCylinderFill

ProjectionMercator ProjectionMiller

ProjectionOrthographic

ProjectionHammer

ProjectionSinusoidal

--spout or -S all or sky Act as Spout sender (See section 6.4).

2,3

--spout-name

name

Use

name

as name of the Spout sender. Default

name: Stellarium.

--dump-opengl-details or -d [none]

Dump information about OpenGL support to log-

ﬁle. Use this is you have graphics problems and

want to send a bug report.

--angle-mode or -a [none]

Use ANGLE as OpenGL ES2 rendering engine

(autodetect Direct3D version).

2,4

--angle-d3d9 or -9

[none]

Force use Direct3D 9 for ANGLE OpenGL ES2

rendering engine.

2,4

--angle-d3d11

[none]

Force use Direct3D 11 for ANGLE OpenGL ES2

rendering engine.

2,4

--angle-warp

[none]

Force use the Direct3D 11 software rasterizer for

ANGLE OpenGL ES2 rendering engine.

2,4

You may have to escape the minute/second characters, like +53d58\’16.6\"

On Windows only

This function requires running in OpenGL mode.

Qt5-based Stellarium versions only

6.2 Environment Variables 65

--mesa-mode or -m [none]

Use MESA as software OpenGL rendering en-

gine.

--single-buffer

[none]

Use single-buffering. This reportedly avoids

screen blanking problems with some Intel GPUs.

--opengl-compat or -C [none]

Request OpenGL 3.3 Compatibility Proﬁle.

Might ﬁx graphics problems in some driver con-

ﬁgurations.

--low-graphics or -L

[none]

Force low-graphics mode. May be useful on old

GPUs that do support OpenGL 3.3 but perform

too slowly.

--no-audio [none]

Disable sound output (avoids initialisation prob-

lems on Virtual Machines or special builds).

--no-screensaver [none]

Disable screensaver and auto-sleep when in

fullscreen mode (Windows only).

If you want to avoid adding the same switch every time when you start Stellarium from the command line,

you can also set an environment variable STEL_OPTS with your default options.

Calling the respective options on the command line overrides settings from environment variables (apart

from STEL_OPTS).

6.1.1 Examples

•

To start Stellarium using the conﬁguration ﬁle

configuration_one.ini

situated in the user direc-

tory (use either of these):

stellarium -- config - file = c onf ig ura ti on_on e . ini

stellarium -c con figur ation _one . ini

•

To list the available landscapes, and then start using the landscape with the ID “ocean”

stellarium -- list - landscape s

stellarium -- land sc ape = ocean

Note that console output (like --list-landscapes) may not be possible on some Windows systems.

6.2 Environment Variables

Some command-line options or settings can be set permanently by storing them into environment variables.

How to set them depends on the respective operating system.

Windows

Press the start menu, search for “environment variable”. Use the command to change user

variables. After setting, you can call Stellarium via its menu entry or desktop links.

This may be especially helpful on Windows systems with older graphics cards which may not

fully be compatible with OpenGL. Here we recommend you either use the program links using the

ANGLE-related options, or you can set the environment variable once and forget about the problems.

Linux, macOS

You will usually set such variables at the end of your

~/.bashrc

ﬁle. Open this with a text

editor and add, near the end,

export STEL_OPTS =" - platfor m xcb -- single - buffer "

This forces use of the X11 platform plugin which may work better than wayland on older systems.

These environment variables are important:

STEL_OPTS

may contain a default commandline with options in the syntax of the table above. Also some

Qt settings can only be tweaked with this. For example, Windows users of international keyboards

with

Alt Gr

key may want to use

STE L _ O PTS = - platform wi n dows : altgr , fo n t e ngine = f r eetype -- single - b uffer

The

-platform

parameter is part of Qt. Its second argument,

fontengine

, selects a different font

engine (i.e., some fonts may look better with it). The other argument,

- -single-buffer

, is a setting

that inﬂuences Stellarium (see table above).

STEL_USERDIR

may contain the path to a user data directory deviating from the default (see section 5.1).

66 Chapter 6. Advanced Options

QT_OPENGL

May be one of

desktop

(native OpenGL for your GPU, recommended),

angle

software

. The last activates pure software rendering using the MESA OpenGL library. Note that

command line options take precedence over this environment variable.

QT_ANGLE_PLATFORM

2,4

May be one of

d3d9

(DirectX 9) or

d3d11

(DirectX 11), or

warp

for

another software-only solution. Note that command line options take precedence over this environment

variable.

6.2.1 Logﬁle tweaks

Qt based programs can write log ﬁles where status messages of varying severity can be written

. There

are categories

debug

(usually only of developer interest),

info

(informational),

warning

(something unex-

pected),

critical

(usually connected to some real failure) and

fatal

(program fails (usually exits) here).

The amount of logging messages can be tuned by setting the environment variable

QT_LOGGING_RULES

. For

example, to remove all

debug

messages, set it to

*.debug=false;

. To remove even the

info

messages,

add

*.info=false;

. (Close each rule, also the last, with semicolon!) If you experience operating trouble,

make sure you allow all messages, i.e., set these entries shown here to true (or delete the variable).

Some modules can be individually ﬁnetuned with respect to the amount of logging. Most users won’t

v 25.4

ever want to see the ugly details, so debug is deactivated by default for:

stel.GPS GPS related issues.

stel.LocIP IP-based location queries.

stel.Texture Texture handling.

stel.Atmosphere Atmosphere related messages.

stel.Scripting scripting related messages.

stel.Media Multimedia related messages.

stel.HiPS HiPS related messages.

stel.Properties StelProperty related messages.

If you suspect issues with some features on your computer, add those entries as shown above, e.g., to

hunt down issues with a GPS device:

QT _LOGG IN G_RUL ES =*. debug = false ; stel . GPS . debug = true ;

or if you are developing scripts and videos don’t play, try if this helps:

QT _LOGG IN G_RUL ES =*. debug = false ; stel . Media . debug = true ;

6.3 GUI Customizations

Some users have difﬁculties to read Stellarium’s rather dark user interface. Some screens may be too dark, or

environments too bright.

6.3.1 Panel transparency

The GUI panels are semitransparent by design. If this impedes your ability to read them, you can make them

fully opaque with an entry to config.ini.

[ gui ]

fl ag_ use _wi ndo w_t ran spa ren cy = false

6.3.2 Button brightness

If you only want a bit brighter buttons, these can be tweaked separately in config.ini.v 24.4

[ gui ]

pi xmaps _brig htn es s =1.25

The value is clamped to [1. . . 1.8] to avoid making active and inactive buttons equally bright.

6.4 Spout 67

6.3.3 Text shadow

Some users complain the infotext is badly visible when there are trees or the Milky Way in the background.

v 24.4

This can also be mitigated in config.ini.

[ gui ]

fl ag_in fo _shad ow = true

6.3.4 User interface color s

Others users still ﬁnd the GUI too bright, and they would prefer a real “dark mode”. To allow this, you can

create and load your own alternative style ﬁles.

The appearance of the windows, buttons etc. is governed by a CSS (Cascaded Style Sheet) ﬁle. It

certainly requires some knowledge and guessing to edit your own, but there is enough general help on CSS

available online. You can ﬁnd the CSS ﬁles in Stellarium’s Github site

Copy them into your user directory and rename to e.g.

myOwnGreatStyle.css

. Edit numbers, but do

not change the item names! Then you can either launch Stellarium with the added command line option like

stellarium -- gui - css myOwnG reatS ty le

or you could also use the scripting option (see chapter 17):

core.setGuiStyle("MyOwnGreatStyle ");

To go back to Stellarium’s default, just use

core.setGuiStyle("default ");

If link colors in text panels are now difﬁcult to read, copy

normalHtml.css

from Github to your own

MyOwnGreatStyleHtml.css and modify to your taste.

Note that, as Stellarium evolves, these ﬁles also may change from version to version. We cannot give any

guarantees that one customized ﬁle will work without adaptation on later or earlier versions of Stellarium.

6.4 Spout

Apart from stand-alone use, Stellarium can be used as multimedia source in larger installations, in museums

or science exhibitions. Spout

is a technology which enables use of Stellarium’s output window as texture in

DirectX applications on Windows. Simply start Stellarium with the

--spout=sky

command line option.

(Currently Spout output is limited to the main window without GUI panels, but this may change in future

versions.) Your master application must obviously embed a Spout receiver. The default name of the Spout

sender is

Stellarium

. If you need more than one instance of Stellarium acting as source, you can use

option

--spout-name=StelSpout2

in addition to create another Spout sender without a name conﬂict. In

such cases, it may be useful to also have separate user data directories and use option --user-dir.

This mode does not work in ANGLE mode and requires reasonably modern graphics hardware with the

WGL_NV_DX_interop

driver extension running in OpenGL mode. Some Nvidia GPUs work without this

extension listed explicitly. On a notebook with Nvidia Optimus technology, make sure to launch Stellarium

and SpoutReceiver (or your target application) on the Nvidia hardware. For permanent setting, use the

Nvidia conﬁguration dialog to conﬁgure Stellarium and the target application explicitly to run always on the

Nvidia card.

Note that Spout use disables any multisampling setting (see Appendix D.1.25).

6.5 Spherical Mirror Mode for Planetarium Use

IMMERSIVE-THEATRES.COM

With Stellarium it’s very easy to project the sky on a dome and create your own planetarium.

https://doc.qt.io/qt-6/qloggingcategory.html, https://doc.qt.io/qt-6/debug.html

https://github.com/Stellarium/stellarium/blob/stellarium-stable/data/gui/normalStyle.c

and

https://github.com/Stellarium/stellarium/blob/stellarium-stable/data/gui/normalHtml.

css

https://spout.zeal.co/

68 Chapter 6. Advanced Options

6.5.0.1 360° Projection

You can use either a very expensive ﬁsheye lens projector – or a standard projector with a spherical mirror.

Not only is spherical mirror projection less expensive, but it produces a higher resolution image on the

dome

, and it’s very easy to upgrade the projector.

A planetarium spherical mirror is curved like a security mirror (convex safety mirror) – with the

important difference that its ‘ﬁrst surface’, i.e., the reﬂective silver, is not protected by a transparent acrylic or

polycarbonate layer. This allows light to be reﬂected without being refracted. Spherical mirrors are therefore

very delicate and should never be touched with ﬁngers or wiped with a cloth. A powerful dust blower is all

you need to keep it clean.

There are two types of spherical mirror projection boxes: compact ‘Newtonians’ (spherical mirror with

an additional small mirror)

; or full-length boxes (spherical mirror only)

. The former take up less space in

the planetarium (but a little less light reaches the dome); whereas the latter produce a slightly brighter image

(but require more space in the planetarium).

Although commercial projection boxes are quite expensive (mainly due to the cost of the ﬁrst-surface

spherical mirror); it’s quite easy to build your own

– and you can use a cheap convex safety mirror for

testing before investing in a ﬁrst-surface mirror.

6.5.0.2 Projector Speciﬁcations

A major challenge with digital planetariums (360° cinemas) is the cross-reﬂection of light on the dome. This

is why projector contrast ratio and colour saturation are more important than brightness (lumens). Light

‘bouncing’ around the dome causes the planetarium image to ‘wash out’ (lose colour) – so the higher the

projector colour saturation, the better. Similarly, the higher the contrast ratio, the sharper and crisper the

planetarium image will be, especially the night sky.

4K projectors are now very affordable, allowing you to deliver the same high-quality visuals in your

small dome as large planetariums!

6.5.0.3 Computer Conﬁguration

The best way to operate a planetarium is with a dual display arrangement, i.e., computer screen as the primary

(main) display, and projector as the secondary (extended) display.

This way the Stellarium remote control window, desktop shortcuts, other applications, etc., will only be

visible to you. The audience will only see what you want them to see. To ensure there’s always something

nice on the dome (even with no application open), use a high-resolution image of stars as your desktop

wallpaper.

To function as a planetarium, Stellarium should be conﬁgured to open in full screen mode on the

extended display (see below).

6.5.0.4 System Conﬁguration

To minimise image distortion at the back of the dome, it’s worth carrying out the slightly complex Meshmap-

per conﬁguration

. This creates a custom distortion ﬁle for your speciﬁc system (i.e., your dome diameter,

stand height, spherical mirror dimensions); and the image improvement will be remarkable

. This custom

distortion ﬁle (‘warp mesh data ﬁle’) can then be used with dome applications like Stellarium.

6.5.0.5 Stellarium Conﬁguration

To enable planetarium spherical mirror projection, the config.ini ﬁle needs to include the following:

[ navigation ]

init_ fov = 180

[ projection ]

type = Pr oje ct ion Fi sheye

au to_ zoo m_o ut_ res ets _di r ect ion = true

[ video ]

fullscreen = true

vi ew port_ effect = sph ericM irr orD is tor ter

https://domeclub.com/#PxComp

https://www.eplanetarium.com/projector_newtonian.php

https://myplanetarium.com/projection-dome-system

https://docs.worldwidetelescope.org/diy-planetarium-dome/1/dome/#setting-up-the-proje

ctor-and-mirrors

https://paulbourke.net/dome/meshmapper

https://domeclub.com/images/Meshmapper-1152w.jpg

6.5 Spherical Mirror Mode for Planetarium Use 69

sc re en _number = 1

[ sp he ric_m ir ror ]

di stort er_ma x_fov = 180

dome_rad iu s = 5.0 ( note : re gardless of your actual dome radius )

im age _di sta nce _div_ hei ght = 2.67

mi rror_ posit ion_x = 0

mi rror_ posit ion_y = 5

mi rror_ posit ion_z = 0

mi rr or _radius = 0.37 ( regardless of your actual mirror radius )

Stellarium also has built-in options to help you project the best possible planetarium night sky. In a

planetarium, removing the Stellarium atmosphere results in a much darker (and more beautiful) night sky.

Yet without the atmosphere, the stars stop twinkling and meteors (shooting stars) disappear – which is correct

for the real sky, but not what you may desire in the planetarium. To maintain twinkling and meteors even

without the atmosphere, manually add the following lines to the config.ini ﬁle:

[ stars ]

fl ag_ fo rce d_twi nkl e = true

[ astro ]

fl ag_ for ced _me teo r_a cti vit y = true

Another useful conﬁguration for planetariums is to completely hide the vertical and horizontal toolbars

on the dome:

[ gui ]

fl ag _s how_gui = false

The following are also recommended (adjust the values to your preference):

[ viewing ]

fl ag_mo on _scal ed = true

moon_scale = 8.00

[ astro ]

meteor_zhr = 3000

[ landsca pe ]

flag_ fog = false

[ stars ]

ab so lute_ sc ale = 6.00

fl ag_st ar_tw inkle = 1.00

fl ag _star _spiky = false

re la tive_ sc ale = 0.70

st ar_ tw ink le_am oun t = 0.50

6.5.0.6 Further notes

This feature is rarely used by the current developers and cannot be tested on standard hardware. See ongoing

discussion on Github

and get involved.

https://github.com/Stellarium/stellarium/issues/1914 and

https://github.com/Stellarium/stellarium/issues/3535

7. Landscapes

GEORG ZOTTI

Landscapes are one of the key features that make Stellarium popular. Originally just used for decoration,

since version 10.6 they can be conﬁgured accurately for research and demonstration in “skyscape astronomy”,

a term which describes the connection of landscape, the sky above, and the observer (D. Brown, 2015).

Conﬁgured properly, they can act as reliable proxies of the real landscapes, so that you can take e.g.

measurements of sunrise or stellar alignments (Zotti and Neubauer, 2015), or prepare your next moonrise

photograph, as though you were on-site.

In this chapter you can ﬁnd relevant information required to accurately conﬁgure Stellarium landscapes,

using panoramas created from photographs taken on-site, optionally supported by horizon measurements

with a theodolite.

Creating an accurate panorama requires some experience with photography and image processing.

However, great open-source tools have been developed to help you on the job. If you already know other

tools, you should be able to easily transfer the presented concepts to those other tools.

While you are editing a landscape, you may want to reload it frequently. Turn off caching by editing the

config.ini:

[ landsca pe ]

ca ch e_ size_mb = 0

7.1 Stellarium Landscapes

As of version 0.15, the available landscape types are:

polygonal

A point list of measured azimuth/altitude pairs, used to deﬁne a sharp horizon polygon. The area

below the horizon line is colored in a single color (Section 7.1.2).

spherical

The simple form to conﬁgure a photo-based panorama: A single image is used as texture map for

the horizon (Section 7.1.3).

old_style

The original photo panorama. This is the most difﬁcult to conﬁgure, but allows highest resolution

by using several texture maps (Section 7.1.4).

ﬁsheye

Another 1-texture approach, utilizing an image made with a ﬁsheye lens. This landscape suffers

from calibration uncertainties and can only be recommended for decoration (Section 7.1.5).

A landscape consists of a

landscape.ini

plus the data ﬁles that are referenced from there, like a

coordinate list or the textures. Those reside in a subdirectory of the

landscape

folder inside the Stellarium

program directory, or, for own work, in a subdirectory of the

landscape

folder inside your Stellarium user

data directory (see section 5.1).

72 Chapter 7. Landscapes

Let us assume we want to create a landscape for a place called Rosenburg. The location for the ﬁles of

our new custom landscape Rosenburg depends on the operating system (see 5.1). Create a new subdirectory,

and for maximum compatibility, use small letters and no spaces:

Windows C:/Users/YOU/AppData/Roaming/Stellarium/landscapes/rosenburg

Linux ~/.stellarium/landscapes/rosenburg

Mac $HOME/Library/Application Support/Stellarium/landscapes/rosenburg

7.1.1 Location information

This optional section in

landscape.ini

allows automatic loading of site coordinates if this option is

activated in the program GUI (see 4.4.5). For our purposes we should consider especially the coordinates in

the location section mandatory!

[ loc ation ]

planet = Earth

country = A ustria

name = KGA Rosenburg

latit ude = +48 d38 ’ 3.3"

longitude = +15 d38 ’ 2.8 "

altit ude = 266

timez one = Europe / Vienna

li gh t_pol lution = 1

at mos p her ic_ ext inc tio n_c oef f ici ent = 0.2

display_ fo g = 0

at mos phe ric_t emp era tur e = 10.0

at mos pheri c_p re ssu re = 1013.0

Where:

planet Is the English name of the solar system body for the landscape.

latitude

Is the latitude of site of the landscape in degrees, minutes and seconds. Positive values represent

North of the equator, negative values South of the equator.

longitude

Is the longitude of site of the landscape. Positive values represent East of the Greenwich

Meridian on Earth (or equivalent on other bodies), Negative values represent Western longitude.

altitude Is the altitude of the site of the landscape in meters.

country (optional) Name of the country the location is in.

state (optional) Name of the state the location is in.

timezone (optional) IANA Timezone code

name

(optional) Name of the location. This may contain spaces, but keep it short to have it fully visible in

the selection box.

Since v0.11.0, there are a few more optional parameters that can be loaded if the according switch is active

in the landscape selection panel. If they are missing, the parameters do not change to defaults.

light_pollution

(optional) Light pollution of the site, given on the Bortle Scale (1: none . . . 9: metropoli-

tan; see Appendix B). If negative or absent, no change will be made.

atmospheric_extinction_coefficient

(optional, no change if absent.) Extinction coefﬁcient (mag/air-

mass) for this site.

atmospheric_temperature

(optional, no change if absent.) Surface air temperature (Degrees Celsius).

Used for refraction. Set to -1000 to explicitly declare “no change”.

atmospheric_pressure

(optional, no change if absent.) Surface air pressure (mbar; would be 1013 for

“normal” sea-level conditions). Used for refraction. Set to -2 to declare “no change”, or -1 to compute

from altitude.

display_fog

(optional, -1/0/1, default=-1) You may want to preconﬁgure setting 0 for a landscape on the

Moon. Set -1 to declare “no change”.

7.1.2 Polygonal landscape

This landscape type has been added to allow the use of measured horizons. Users of Cartes du Ciel

will be

happy to hear that the format of the list of measurements is mostly compatible.

SkyChart / Cartes du Ciel planetarium: https://www.ap-i.net/skychart/en/start

7.1 Stellarium Landscapes 73

This is the technically simplest of the landscapes, but may be used to describe accurately measured

horizon proﬁles. The ﬁle that encodes horizon altitudes can also be used in all other landscape types. If

present there, it will be used to deﬁne object visibility (instead of the opacity of the landscape photo textures)

and, if horizon_line_color is deﬁned, will be plotted.

There are a few little caveats:

•

If you create a polygonal line with vertex azimuths 0, 90, 180, 270 (exactly), the horizon may not

show up at all. Add a tiny nonzero value to the global rotation, like

po lyg ona l_ang le_ rot ate z = 0.0000001

•

Sometimes, there may appear vertical lines from some corners towards the zenith or the mathematical

horizon, e.g. if there is a vertex including azimuth 0 or 180. If this irritates you, just offset this azimuth

minimally (e.g., 180.00001).

•

As technical requirement, the zenith is always assumed to remain free and uncovered. It is not possible

to deﬁne a “dome cutout” or similar restricted views out of a window. Such effect can be achieved

with a Spherical Landscape (see section 7.1.3).

The

landscape.ini

ﬁle for a polygonal type landscape looks like this (this example is based on the

Geneve landscape which was borrowed from Cartes du Ciel and comes with Stellarium):

[ landsca pe ]

name = Geneve

type = polygonal

author = Georg Zotti ; Horizon definiti on by Patri ck Chevalley

descript io n = H orizon line of Geneve .

Demo ns tr ates com patibil it y with

horizon descri pt io ns from Cartes du Ciel .

po lyg onal_ hor izo n_lis t = hor iz on_Ge ne ve . txt

po lyg ona l_ang le_ rot ate z = 0

grou nd _c olor = .15 ,.45 ,.45

Where:

name appears in the landscape tab of the conﬁguration window.

type identiﬁes the method used for this landscape. polygonal in this case.

author lists the author(s) responsible for images and composition.

description

gives a short description visible in the selection panel. The text can be superseded by optional

description.<lang>.utf8 ﬁles.

polygonal_horizon_list is the name of the horizon data ﬁle for this landscape.

polygonal_horizon_list_mode

(optional) the two ﬁrst columns in the list are numbers: azimuth and

altitude or zenith distance, in either degrees or radians or gradians(gon). The value must be one of

azDeg_altDeg

azDeg_zdDeg

azRad_altRad

azRad_zdRad

azGrad_altGrad

azGrad_zdGrad

Default: azDeg_altDeg

polygonal_angle_rotatez

(optional, default=0) Angle (degrees) to adjust azimuth. This may be used

to apply a (usually) small offset rotation, e.g. when you have measured the horizon in a grid-based

coordinate system like UTM and have to compensate for the meridian convergence.

ground_color

(optional, default=

0,0,0

, i.e., black) Color for the area below the horizon line. Each R,G,B

component is a ﬂoat within 0..1.

minimal_brightness

(optional) Some minimum brightness to keep landscape visible. Default=-1, i.e.,

use minimal_brightness from the [landscape] section in the global config.ini.

minimal_altitude

(optional, default=-2) Some sky elements, e.g. stars, are not drawn below this altitude

to increase performance. Under certain circumstances you may want to specify something else here.

(since v0.14.0)

polygonal_horizon_inverted

(optional, default=false; only required in v0.15.0–0.20.2) In rare cases

like horizon lines for high mountain peaks with many negative horizon values this should be set to

true.

No longer used:

horizon_line_color

(optional, default: invisible) used to draw a polygonal horizon line. This is now a

v 24.4

global setting, config.ini:landscape/polygon_color.

74 Chapter 7. Landscapes

7.1.2.1 Artiﬁcial Polygonal Panoramas

The online service HeyWhatsThat

allows an SRTM-based analysis of the viewshed (the visible topographic

area) for an observing location which also gives names for the mountain peaks visible at a given location. In

summer of 2020 a dedicated landscape download option for Stellarium was added (see upper-right corner),

so that you can install a custom landscape. Its package/directory name is

stellarium-landscape

. If you

create more than one, you must rename the directory. You may also want to extend the scene description in

landscape.ini.

A data download option provides users inclined to do some programming with the necessary data to

create a polygonal landscape for Stellarium. From this, BRIAN DOYLE has created another online service,

horiZONE

, which does just this work for you.

When your viewshed analysis has been created in HeyWhatsThat, enter the “all panoramas” tab, and

on the map click the marker associated with the panorama. Select “make public”.

Then, take the landscape key given to you by HeyWhatsThat

, add a few lines of description and

other details that will become visible and used in Stellarium, and you receive a ZIP ﬁle ready for

installation in Stellarium (see section 4.4.5).

A similar web service, PeakFinder

, meanwhile also allows downloading the horizon polygon as instal-

lable landscape for Stellarium. A great feature of this service is the excellent gazetteer (peak identiﬁcation)

also visible on the website.

7.1.3 Spherical landscape

This method uses a more usual type of panorama – the kind which is produced directly from software such

as autostitch or Hugin

. The Moon landscape which comes with Stellarium provides a minimal example of

a landscape.ini ﬁle for a spherical type landscape:

[ landsca pe ]

name = Moon

type = spherical

maptex = ap ollo17 . png

A more elaborate example is found with the Grossmugl landscape:

[ landsca pe ]

name = Grossmugl

type = spherical

author = Gu enther Wuchterl , Kuffner - Sternwarte . at ;

Lightscape : Georg Zotti

descript io n = Field near Leeberg , Grossm ugl ( Riese nt umulus ),

Austria - Primary Obs er ving Spot of the Grossmug l

Starlight Oasis - http :// st arlight oa sis . org

maptex = g ros smugl _le ebe rg_ cro p11 .25. png

maptex_top =11.25

maptex_fog = g ros smu gl_ leeberg_fog _cr op2 2 .5. png

ma pt ex_fo g_ top = 22.5

ma ptex_ fog_b ottom = -22.5

mapt ex _i llum = gr oss mug l_l eeb erg _il lum _cr op0 .png

ma pte x_ ill um_bo tto m = 0

an gl e_ rotatez = -89.1

mi nimal _brig htn es s = 0.0075

po lyg onal_ hor izo n_lis t = h or izon_ gross mugl . txt

po lyg ona l_ang le_ rot ate z =0

mi nimal _a ltitu de = -1

https://www.heywhatsthat.com/

https://briandoylegit.github.io/horiZONE/

in the line https://www.heywhatsthat.com/?view=N15ABXY

https://www.peakfinder.com

http://hugin.sourceforge.net/

7.1 Stellarium Landscapes 75

Where:

name appears in the landscape tab of the conﬁguration window. This name may be translated.

type identiﬁes the method used for this landscape. spherical in this case.

author lists the author(s) responsible for images and composition.

description

gives a short description visible in the selection panel. The text will be superseded by

optional description.<lang>.utf8 ﬁles.

maptex is the name of the image ﬁle for this landscape.

maptex_top (optional; default=90) is the altitude angle of the top edge.

maptex_bottom

(optional; default=-90) is the altitude angle of the bottom edge. Usually you will not

require this, or else there will be a hole at your feet, unless you also specify

bottom_cap_color

(optional; default=

-1.0,0.0,0.0

to signal “no color”). If set, this is used to close

any hole in the nadir area (if maptex_bottom higher than -90).

maptex_fog (optional; default: no fog) is the name of the fog image ﬁle for this landscape.

maptex_fog_top

(optional; default=90) is the altitude angle of the top edge of the fog texture. Useful to

crop away parts of the image to conserve texture memory.

maptex_fog_bottom (optional; default=-90) is the altitude angle of the bottom edge.

maptex_illum

(optional; default: no illumination layer) is the name of the nocturnal illumination/light

pollution image ﬁle for this landscape.

maptex_illum_top

(optional; default=90) is the altitude angle of the top edge, if you have light pollution

only close to the horizon.

maptex_illum_bottom (optional; default=-90) is the altitude angle of the bottom edge.

angle_rotatez

(optional, default=0) Angle (degrees) to adjust azimuth. If 0, the left/right edge is due

east.

tesselate_rows

(optional, default=20) This is the number of rows for the maptex. If straight vertical

edges in your landscape appear broken, try increasing this value, but higher values require more

computing power. Fog and illumination textures will have a similar vertical resolution.

tesselate_cols

(optional, default=40) If straight horizontal edges in your landscape appear broken, try

increasing.

polygonal_horizon_list

(optional) is the name of the (measured) horizon data ﬁle for this landscape.

Can be used to deﬁne the exact position of the horizon. If missing, the texture can be queried for

horizon transparency (for accurate object rising/setting times)

polygonal_horizon_list_mode (optional) see 7.1.2

polygonal_angle_rotatez (optional, default=0) see 7.1.2

minimal_brightness see 7.1.2

minimal_altitude

(optional, default=-2) Some sky elements, e.g. stars, are not drawn below this altitude

for efﬁciency. Under certain circumstances (e.g. for space station panoramas where you may have sky

below your feet, or for deep valleys/high mountains, you may want to specify something else here.

To save texture memory, you can trim away the transparent sky and deﬁne the angle

maptex_top

. Like-

wise,

fogtex_top

fogtex_bottom

maptex_illum_top

and

maptex_illum_bottom

. You should then

stretch the texture to a full power of 2 for maximum compatibility, like

4096× 1024

(but note that some

hardware is even limited to 2048 pixels). The easiest method to create perfectly aligned fog and illumination

layers is with an image editor that supports layers like the GIMP or Photoshop. Fog and Light images should

have black background.

7.1.4 High resolution (“Old Style”) landscape

The

old_style

or multiple image method works by having the 360°panorama of the horizon (without

wasting too much texture memory with the sky) split into a number of reasonably small side textures, and a

separate ground texture. This has the advantage over the single-image method that the detail level of the

horizon can be increased without ending up with a single very large image ﬁle, so this is usable for either

very high-resolution panoramas or for older hardware with limited capabilities. The ground texture can be a

different resolution than the side textures. Memory usage may be more efﬁcient because there are no unused

texture parts like the corners of the texture ﬁle in the ﬁsh-eye method. It is even possible to repeat the horizon

several times (for purely decorative purpose). The side textures are mapped onto curved (spherical ring or

cylinder) walls (Fig. 7.1).

On the negative side, it is more difﬁcult to create this type of landscape – merging the ground texture

with the side textures can prove tricky. (Hugin can be used to create also this ﬁle, though. And on the

other hand, you can replace this by something else like a site map.) The contents of the

landscape.ini

76 Chapter 7. Landscapes

Figure 7.1: Old_style landscape: eight parts delivering a high-resolution panorama. The bottom

(ground) texture, drawn on a ﬂat plane, is not shown here.

ﬁle for this landscape type is also somewhat more complicated than for other landscape types. Here is the

landscape.ini ﬁle which describes our Rosenburg landscape

[ landsca pe ]

name = KGA Rosenburg

author = Georg Zotti , VIAS / A STROSIM

descript io n = KGA R osenburg

type = old_style

nbsidetex = 8

tex0 = Horiz -0. png

tex1 = Horiz -1. png

tex2 = Horiz -2. png

tex3 = Horiz -3. png

tex4 = Horiz -4. png

tex5 = Horiz -5. png

tex6 = Horiz -6. png

tex7 = Horiz -7. png

nbside = 8

side0 = tex0 :0:0:1:1

side1 = tex1 :0:0:1:1

side2 = tex2 :0:0:1:1

side3 = tex3 :0:0:1:1

side4 = tex4 :0:0:1:1

side5 = tex5 :0:0:1:1

side6 = tex6 :0:0:1:1

side7 = tex7 :0:0:1:1

groundtex = gra ss gr ou nd . png

ground = grou nd tex :0: 0:1:1

nb _d ecor_ repeat = 1

de co r_alt _angle = 82

de cor_a ngle_ shift = -62

; Rotatez devia tes from -90 by the Meri dian Converge nc e .

the groundtex grassground.png mentioned here has been taken from the Guereins landscape.

7.1 Stellarium Landscapes 77

; The original landscap e pano is grid - aligned ,

; not north - aligned !

de cor _a ngl e_rot ate z = -90.525837223

gr ound_ angle _sh if t = -62

gr oun d_ang le_ ro tat ez = 44.4741 62 77 7

dr aw_gr ound_ first = 1

fogtex = fog . png

fo g_ al t_angle = 20

fo g_ angle _shift = -3

fog = fogtex :0:0:1:1

calibrated = true

[ loc ation ]

planet = Earth

latit ude = +48 d38 ’ 3.3"

longitude = +15 d38 ’ 2.8 "

altit ude = 266

li gh t_pol lution = 1

at mos p her ic_ ext inc tio n_c oef f ici ent = 0.2

display_ fo g = 0

at mos phe ric_t emp era tur e = 10.0

at mos pheri c_p re ssu re = 1013.0

Where:

name is the name that will appear in the landscape tab of the conﬁguration window for this landscape

type should be old_style for the multiple image method.

author lists the author(s) responsible for images and composition.

description

gives a short description visible in the selection panel. The text will be superseded by

optional description.<lang>.utf8 ﬁles.

nbsidetex is the number of side textures for the landscape.

tex0 ... tex<nbsidetex-1>

are the side texture ﬁle names. These should exist in the

textures /

landscapes / landscape directory in PNG format.

light0 ... light<nbsidetex-1>

are optional textures. If they exist, they are used as overlays on top

of the respective

tex<...>

ﬁles and represent nocturnal illumination, e.g. street lamps, lit windows,

red dots on towers, sky glow by city light pollution, . .. Empty (black) panels can be omitted. They are

rendered exactly over the

tex<...>

ﬁles even when the PNG ﬁles have different size. If you need

your light pollution higher in the sky, you must use a spherical or ﬁsheye landscape.

nbside is the number of side textures

side0 ...side<nbside-1>

are the descriptions of how the side textures should be arranged in the

program. Each description contains ﬁve ﬁelds separated by colon characters (

). The ﬁrst ﬁeld is the

ID of the texture (e.g.

tex0

), the remaining ﬁelds are the texture coordinates (

x0:y0:x1:y1

) used to

place the texture in the scene. If you want to use all of the image, this will just be 0:0:1:1.

groundtex

is the name of the ground texture ﬁle. (This could also be a diagram e.g. indicating the mountain

peaks!)

fogtex

is the name of the texture ﬁle for fog in this landscape. Fog is mapped onto a simple cylinder.

Note

that for this landscape, accurate overlay of fog and landscape is only guaranteed if

calibrated=true

and tan_mode=true.

nb_decor_repeat

is the number of times to repeat the side textures in the 360 panorama. (Useful photo

panoramas should have 1 here)

decor_alt_angle

(degrees) is the vertical angular extent of the textures (i.e. how many degrees of the full

altitude range they span).

decor_angle_shift

(degrees) vertical angular offset of the scenery textures, at which height the bottom

line of the side textures is placed.

decor_angle_rotatez

(degrees) angular rotation of the panorama around the vertical axis. This is handy

for rotating the landscape so North is in the correct direction. Note that for historical reasons, a

landscape with this value set to zero degrees has its leftmost edge pointing towards east.

In very wide-angle views, the fog cylinder may become visible in the corners.

78 Chapter 7. Landscapes

ground_angle_shift

(degrees) vertical angular offset of the ground texture, at which height the ground

texture is placed. Values above -10 are not recommended for non-photographic content (e.g., a map)

due to high distortion.

ground_angle_rotatez

(degrees) angular rotation of the ground texture around the vertical axis. When

the sides are rotated, the ground texture may need to be rotated as well to match up with the

sides. If 0, east is up. if North is up in your image, set this to 90. Note that adjustments of

decor_angle_rotatez require adjustments of this angle in the opposite direction!

fog_alt_angle

(degrees) vertical angular size of the fog cylinder - how fog looks. Accurate vertical size

requires calibrated=true.

fog_angle_shift

(degrees) vertical angular offset of the fog texture - at what height is it drawn. Accurate

vertical placement requires calibrated=true.

draw_ground_first

true

the ground is drawn in front of the scenery, i.e. the side textures will

overlap over the ground texture if ground_angle_shift > decor_angle_shift.

calibrated

(optional). Only if true,

decor_alt_angle

etc. really work as documented above. The

(buggy) old code was left to work with the landscapes already existing. Note that with “uncalibrated”

landscapes, sunrise computations and similar functionality which requires an accurate horizon line

will not work.

tan_mode

(optional, not used in this ﬁle). If true, the panorama image must be in in cylindrical, not

equirectangular projection. Finding

decor_alt_angle

and

decor_angle_shift

may be a bit

more difﬁcult with this, but now (v0.13.0) works also with calibrated. A fog image created as overlay

on the pano will be perfectly placed.

polygonal_horizon_list (optional) see 7.1.3

polygonal_horizon_list_mode (optional) see 7.1.2

polygonal_angle_rotatez (optional, default=0) see 7.1.2

minimal_brightness (optional) see 7.1.2

minimal_altitude (optional) see 7.1.2

7.1.5 Fisheye landscape

The Trees landscape that is provided with Stellarium is an example of the single ﬁsh-eye method, and

provides a good illustration. The centre of the image is the spot directly above the observer (the zenith). The

point below the observer (the nadir) becomes a circle that just touches the edges of the image. The remaining

areas of the image (the corners outside the circle) are not used.

The image ﬁle (Fig. 7.2) should be saved in PNG format with alpha transparency. Wherever the image is

transparent Stellarium will render the sky.

The

landscape.ini

ﬁle for a ﬁsh-eye type landscape looks like this (this example is based on the Trees

landscape which comes with Stellarium):

[ landsca pe ]

name = Trees

type = fisheye

author = Robert Spea rman . Light pol lu tion image : Georg Zotti

descript io n = Trees in Gr eenlake Park , Seattle

maptex = tree s_ 512 . png

mapt ex _i llum = t rees_ il lum_5 12 .png

maptex_fog = trees _f og_512 . png

texturefov = 210

an gl e_ rotatez = 17

te ss elate _r ows = 28

te ss elate _c ols = 60

Where:

name appears in the landscape tab of the conﬁguration window.

type identiﬁes the method used for this landscape. fisheye in this case.

author lists the author(s) responsible for images and composition.

description

gives a short description visible in the selection panel. The text will be superseded by

optional description.<lang>.utf8 ﬁles.

Boolean values true|false preferred since V0.19.3, but 0|1 are still accepted.

7.1 Stellarium Landscapes 79

Figure 7.2: Texture for the Trees Fisheye landscape.

maptex is the name of the image ﬁle for this landscape.

maptex_fog (optional) is the name of the fog image ﬁle for this landscape.

maptex_illum

(optional) is the name of the nocturnal illumination/light pollution image ﬁle for this

landscape.

texturefov is the ﬁeld of view that the image covers in degrees.

angle_rotatez (optional) Angle (degrees) to adjust azimuth.

tesselate_rows (optional, default=20) If straight edges in your landscape appear broken, try increasing.

tesselate_cols (optional, default=40) If straight edges in your landscape appear broken, try increasing.

polygonal_horizon_list (optional) see 7.1.3

polygonal_horizon_list_mode (optional) see 7.1.2

polygonal_angle_rotatez (optional, default=0) see 7.1.2

minimal_brightness (optional) see 7.1.2

minimal_altitude (optional) see 7.1.2

7.1.6 Description

The short

description

entry in

landscape.ini

will be replaced by the contents of an optional ﬁle

description.<LANG>.utf8

<LANG>

is the ISO 639-1 language code, or its extension which contains

language and country code, like

pt_BR

for Brazilian Portuguese. The long description requires the ﬁle

80 Chapter 7. Landscapes

description.en.utf8

, this is

en=english

text with optional HTML tags for sections, tables, etc. You

can also have embedded images in the HTML (Views of sacred landscapes, other informative images, . . . ?),

just make them PNG format please. The length of the description texts is not limited, you have room for a

good description, links to external resources, whatever seems suitable.

If you can provide other languages supported by Stellarium, you can provide translations yourself, else

Stellarium translators may translate the English version for you. (It may take years though.) The ﬁle ending

.utf8

indicates that for special characters like ÄÖÜßáé you should use UTF8 encoding. If you write only

English/ASCII, this may not be relevant.

7.1.7 Gazetteer

An optional feature for landscapes is a gazetteer function, i.e., labels for landscape features. The Grossmugl

landscape demonstrates an example and should be self-explanatory. This is again multilingual, so the ﬁles

are called gazetteer.<LANG>.utf8.

# demo g a zetteer for Grossmugl la ndscape .

# Can be used to bette r d escribe the landscape ,

# i. e . show labe ls on l a ndscape feat u r es .

# Fie lds must be se parated by v ertical line ,

# la bel m ust not have such a verti c a l line .

# Comm e n ts have this ha sh mark in first colu mn .

# coordinates in degree s from true North .

# line t owards z enit h draws a singl e line str i c tly upw ard .

# la bel is cent e r ed on line endpo i nt .

# Azi m uth | A ltitude | de g rees | azi m uth | label

# | | tow a rds zen ith | shift |

11 3.66 | 5.5 | 4 | -6 | Le eberg

35 | 1.5 | 2.5 | 0 | G r o ssmugl

335 | 2 | 2 | 0 | Ste i n a b r u n n

305 | 2 | 1 | 0 | Ri n g e n d orf

180 | 2 | 2 | 0 | Vienna (30 km )

135 | 2 | 0.5 | 0 | Wind pow er pl ant St r a s shof

7.1.8 Packing and Publishing

You likely have developed your landscape already in your own Stellarium user data directory, but when you

are happy with your work, you may consider sharing it with other users. For easy distribution and installation

via Stellarium’s GUI (see section 4.4.5), you should create a ZIP ﬁle. This must contain

landscape.ini

and any textures and auxiliary ﬁles described above (

description.en.utf8

gazetteer.en.utf8

and

their translations, horizon ﬁles, images for the description . . . ) used by your landscape. If you want to release

the landscape for download, consider adding a

README.txt

clarifying license and usage conditions. It does

not matter whether the ZIP ﬁle contains a directory name inside the ZIP. If not, the directory name (ID) of

the landscape will be taken from the ZIP ﬁle name.

7.2 Creating Panorama Photographs for Stellarium

7.2.1 Panorama Photography

Traditional ﬁlm-based panorama photography required dedicated cameras with curved ﬁlm holders and

specialized lenses (Figure 7.3).

Digital photography has brought a revolution also in this ﬁeld, and it has become quite easy to create

panoramas simply by taking a series of photographs with a regular camera on the same spot and combining

them with dedicated software.

A complete panorama photo visually encloses the observer like the mental image that astronomers

have been using for millennia: the celestial sphere. If we want to document the view, say, in a big hall

like a church, optimal results will be gained with a camera on a tripod with a specialized panorama head

(Figure 7.4) which assures the camera rotates around the entrance pupil

of the lens in order to avoid errors

by the parallax shift observed on photographs taken on adjacent but separate positions.

In many references you will ﬁnd “Nodal Point” mentioned here. But see these:

https://en.wikipedia.org/wik

i/Cardinal_point_%28optics%29#Nodal_points

http://web.archive.org/web/20060513074042/http:

//doug.kerr.home.att.net/pumpkin/Pivot_Point.pdf

http://www.janrik.net/PanoPostings/NoPara

llaxPoint/TheoryOfTheNoParallaxPoint.pdf

7.2 Creating Panorama Photographs for Stellarium 81

Figure 7.3: Zenit “Horizon 202” panorama camera with rotating lens for 35mm ﬁlm. (Source:

Wikipedia, “Horizon202” by BillC - Own Work. Licensed under CC BY-SA 3.0 via Wikimedia Commons -

https:

//commons.wikimedia.org/wiki/File:Horizon202.jpg)

Figure 7.4: Automated panorama head. (Source: Wikipedia

https://commons.wikimedia.org/wiki/Fil

e:Rodeon_vr_head_01.jpg)

82 Chapter 7. Landscapes

Often however, both the upper half of the observer’s environment (the sky) and the ground the photogra-

pher is standing on, are regarded of lesser importance, and only a series of laterally adjacent photographs is

taken and combined into a cylindrical or spherical ring that shows the landscape horizon, i.e., where ground

and sky meet. If the closest object of interest is farther away that a few metres, requirements on parallax

avoidance are far less critical, and the author has taken lots of landscape panoramas with a camera on the

usual tripod screw, and even more entirely without a tripod. However, any visible errors that are caused by a

shifted camera will require more effort in postprocessing.

When you have no tripod, note that you must not rotate the camera on your outstretched arm! Rather,

the camera’s entrance pupil must be rotated, so you should appear to dance around the camera!

The images should match in brightness and white balance. If you can shoot in RAW, do so to be able to

change white balance later. If the camera can only create JPG, ensure you have set the camera to a suitable

white balance before taking the photos and not to “auto”, because this may ﬁnd different settings and thus

give colour mismatches. Exposure brightness differences can be largely removed during stitching, but good,

well-exposed original shots always give better results.

As a general recommendation, the images of a panorama should be taken from left to right, else please

accordingly invert some of the instructions given below.

There are several panorama making programs. Often they are included in the software that comes with a

digital camera and allow the creation of simple panoramas. Other software titles are available for purchase.

However, there is one cost-free open-source program that does everything we need for our task, and much

7.2.2 Hugin Panorama Software

Hugin

, named after one of the ravens that sits on Odin’s shoulder and tells him about the world, is a

user-friendly catch-all package with graphical user interface that allows creating panoramas with a single

application. Actually, Hugin is a GUI application which calls several specialized sub-programs with ﬁtting

parameters. The instructions are based on Hugin V2014.0 and 2015.0.

Typically digital images come in JPG format with information about camera, lens, and settings stored in

invisible metadata in the EXIF format. When Hugin reads such images, it can automatically derive focal

length, ﬁeld of view, and exposure differences (exposure time, aperture, color balance) to create panoramas

as easily as possible.

After starting Hugin for the ﬁrst time, select

Interface Expert

to release several options not visible to

“beginners”. In the Preferences dialog (

Files Preferences

), edit number of CPU to match the number of

cores in your computer and allow parallel processing. E.g., if you have an Intel Core-i7, you usually can set

up to 8 cores (4 cores with hyperthreading; but maybe leave one core for your other tasks while you wait for

a processing job?). If your PC is equipped with a modern programmable graphics card, you can enable its

use in the

Programs

tab with activating “Use GPU for remapping”.

After that, we are ready for creating our panoramas.

7.2.3 Regular creation of panoramas

The graphical user interface (GUI) consists of a main menu, symbols, and 4 tabs. We start on the tab Photos.

•

Add images. . .

Opens a ﬁle browser. Select the images which you want to stitch. Usually, lens data

(focal length, horizontal ﬁeld of view

, . . . ) are read from the EXIF data. If those are not available

(e.g. cheap cameras, images scanned from ﬁlm), you can enter those data on loading or later. The

images are now listed in the ﬁle list, and you can edit image parameters by marking one or more, and

then choosing from the context menu which you get from pressing the right mouse button. In case

you have used different lenses (or inadvertently used different focal lengths of a zoom lens), you can

assign separate lenses to the images.

Caveat: If you have resized the images, or produced copied on your RAW converter with non-native

resolution, the horizontal Field of View (FoV) in Hugin may be misidentiﬁed. You must edit lens

parameters and ﬁll in the ﬁeld of view from a full-size image. Else the ﬁrst round of optimisation will

run into unsolvable trouble.

•

Select one image as position anchor (usually the center image), and one as exposure anchor (this can

be the same image). For our purpose, the anchor image should face south.

http://hugin.sourceforge.net/

contrary to Stellarium, ﬁeld of view (FoV) in Hugin means the horizontal extent in degrees.

7.2 Creating Panorama Photographs for Stellarium 83

•

Next, we must ﬁnd common feature points. The next ﬁeld below provides the required settings. It

is recommended to use the CPFind command. To avoid ﬁnding control points in (moving) clouds,

select setting

Hugin’s CPFind + Celeste

. Then press

Create control points

. This opens a dialog box

in which you can see output of the selected feature point extractor. It should ﬁnish with a box telling

you the number of identiﬁed points. In rare cases some images cannot be linked to others, you will

have to manually add or edit feature points in those cases.

•

Now it’s time to start optimisations. On the

Geometric Optimimisation

combo, start with the button

Positions, incremental from anchor

, and press

Calculate

. Moments later, a ﬁrst rough match is

available for inspection.

•

First open the Preview window (press

Ctrl

or click the blue icon). Assumed your images cover

the full horizon, the window shows an equirectangular area (360 degrees along the horizon and 180

degrees from zenith to nadir). The anchor image should be close to the image center, and the other

images should be already well-aligned to both sides. You can set the exact center point by clicking it

in the image. If the horizon appears badly warped, use the right mouse key and click on the horizon

roughly near −90 or +90 degrees (halfway to the left or right).

•

Open the OpenGL preview window (press

Ctrl

Shift

or click the blue icon with GL inside).

This panel provides several important views:

–

The

Preview

tab is similar to the non-OpenGL preview. You can display an overlay of the

control points, which are colored according to match quality. Also, with button

Identify

activated, you see the overlapping image frames when you move the mouse over the image.

– The

Layout

tab helps ﬁnding links between images.

– The

Move/Drag

dialog may help to interactively adjust a panorama.

Sometimes the preview image may however be distorted and unusable.

•

Open the Control Points Table dialog (press

or click the “table” button). Here you see the points

listed which link two images. Clicking a column label sorts by this column. It is recommended that

only neighboring overlapping images should be included here. If you have very large overlap, it is

possible that points are found between two images which are not directly adjacent. In the OpenGL

preview window, you can use the

Preview

or the

Layout

tabs to identify those image pairs. Such

points should be deleted. In the point table, click on columns “Right Img.”, then “Left Img.”, and then

ﬁnd pairs like 0/2, 1/3, 2/4 etc. Mark those lines, and delete the points.

•

To re-run the optimisation, press the double-arrow icon or the

calculate

button in the Optimise/Geo-

metric area.

7.2.3.1 Preliminary Geometric Optimisation

Now the (usually) longest part begins: Iterative optimisation of the photo matchpoints. If your images were

taken on a panorama tripod head, there should only be very few bad matchpoints, e.g. those found on persons

or clouds

which have moved between photos. For handheld photos, the following considerations should be

observed.

The most important line which we want to create in all perfection is the visible horizon, where sky and

earth meet. The foreground, usually grassy or rocky, is of lesser interest, and stitching errors in those areas

may not even be relevant.

Therefore, matchpoints with large errors in the foreground can be safely removed, while, if necessary,

points on the horizon should be added manually. Use the

Control Points

tab, select adjacent images (start

with 0 on the left and 1 on the right side), and delete the worst-ﬁtting matchpoints closest to the camera (near

the bottom of the images). We now start a long phase of re-optimizing and deletion of ill-matching points as

long as those are far from the horizon. When all near matchpoints are deleted, the result should already look

not too bad.

For continued optimisation, the number of parameters to optimize can be extended. To begin, I

recommend

Positions and View (y, p, r, v)

, which may ﬁnd a new focal length slightly different from the data

in the EXIF tags. Again, delete further foreground points. If after a few rounds you still have bad point

distances, try

Positions and Barrel Distortion (y, p, r, b)

to balance distortion by bad optics, or even go up to

Everything without translation

. Optimisation can only reach perfect results if you did not move between

exposures. Else, ﬁnd a solution which shows the least error.

In case you took your photos not on a tripod and moved too much, you may even want to play with the

translation options, but errors will be increasingly hard to avoid.

If you forget this, you can remove cloud points by calling Celeste in the control point editor later

You should have created control points with the Celeste option!

84 Chapter 7. Landscapes

Using Straight Edges as Guides

If the panorama contains straight lines like vertical edges of buildings, these can be used to automatically

get a correctly leveled horizon: Vertical lines are mapped to vertical lines in equirectangular panos! In the

Control Points

tab, select the image with the vertical edge in both subframes, and mark points on the vertical

edge. (switch off auto-estimate!). Likewise, horizontal lines may help, but make sure lines like rooves are

perpendicular to your line of view, else the perspective effect causes an inclination.

Multi-ring Panoramas

If you are trying to create a panorama with several rings (horizon, one or two rings below, and nadir area),

you must try to create/keep control points that best give a result without visible seams. In this case, and esp.

if you have only used a regular tripod or even dared to go for a free-handed panorama, you may observe that

it is best to remove control points in neighboring photos in the lower rings, but keep only the “vertical” links

between images with similar azimuth.

In total, and if the foreground is not important but only grassy or sandy, the rule of thumb is that the

horizon images must be strongly linked with good quality (small errors), while images in the lower rings

should be linked mostly to their respective upper photos, but not necessarily to the images to its sides. The

resulting panorama will then show a good horizon line, while stitching artifacts in a grassy or otherwise only

decorative ground will usually be acceptable and can, if needed, be camouﬂaged in post-processing.

This optimization and editing of control points is likely a longish iterative process, and these are the late

night hours where you will ﬁnally wish you had used a panorama head. . .

7.2.3.2 Masking

If you have images with overlapping areas, you can usually not force Hugin to take pixels from the image

which you ﬁnd best. you can however mask off an area from an image which you don’t want to see in the

output under any circumstances, e.g. a person’s arm or foot in one image. Just open the image in the

Mask

tab and either press

Add new mask

and draw the mask polygon covering the unwanted area, or use the crop

settings to deﬁne rectangular areas to use.

7.2.3.3 Exposure disbalance

In the

Photos

tab, select

Photometric parameters

on the right side. The EV column lists the Exposure Value.

If you see disbalance here and in the preview window, you can run a photometric optimization with the

lowest button on the

Photos

tab. Simply select Low dynamic range and press

Calculate

. The preview

should now show a seamless image. If all else fails, you can edit the EV values directly.

Advanced photographers may want to correct exposures in their RAW images before creating JPG or

TIF images to combine with Hugin. This unfortunately may create exposure disbalance because the EXIF

tags may not be adjusted accordingly, so based on different exposure/f-stop combinations Hugin may think

it has to re-balance the values. In these cases, don’t run the photometric optimizer. Some image exposure

values have to be changed manually, and the effect supervised in the preview window. Usually the smooth

blending in the subprogam enblend called by Hugin will hide remaining differences.

7.2.3.4 Stitching

When you are happy with the panorama in the preview window and the match-points promise a good ﬁt, it is

time to ﬁnally create the panorama image. Hugin can create a large number of different projections which

all have their application. For Stellarium, we can only use the equirectangular projection. You still have 2

options:

spherical

landscapes (see 7.1.3) require single equirectangular images, the maximum size depends on your

graphics hardware and Qt limitations and is likely not larger than 8192× 4096 pixels.

old_style

landscapes (see 7.1.4) can use several textures for the ring along the horizon, and one image for

the nadir zone. If you need high resolution, you should aim for creating this one.

Sometimes, creating the nadir zone is difﬁcult: this is where usually the view is blocked by the tripod,

and we are not interested in views of tripod or our own feet. For our purpose it is usually enough to ﬁll in

the feet area using the clone stamp, or a monochrome color, or, for

old_style

landscapes, you can instead

insert an oriented site map or wind rose.

There is a button

create optimal size

in Hugin. It may recommend a panorama width around 13.000

pixels for an average camera and photos taken with a wide-angle lens. Increasing this size will most likely

not lead to higher optical resolution! The panorama width which you can most usefully create depends on

the resolution of the source images (which leads to the result given by Hugin) and on your needs. If you need

arc-minute resolution, you would aim for

360× 60 = 21600

pixels, which cannot be loaded into graphics

memory in a single piece, i.e., is too large for Stellarium, and must be conﬁgured as

old_style

landscape.

In this case, 10 or 11 tiles of 2048 × 2048 pixels (totalling 20480 or 22528 pixels) is the closest meaningful

7.3 Panorama Postprocessing 85

setting, i.e., you could create an image of 20480 pixels width and cut this into usable pieces. Usually, a

size of

4096× 2048

8192× 4096

pixels (for better computers) is enough, and can be used in a

spherical

landscape.

We have to edit the ﬁle after stitching, therefore select creation of an image in the TIFF format. LZW

compression is non-lossy, so use this to keep ﬁle size reasonably small.

For regular images, it is enough to create “Exposure corrected, low dynamic range”. If you have a

problem with persons that have moved between your images, you may want to post-process the ﬁnal result

with import of the distorted sub-images and manually deﬁning the best blending line. For this, ﬁnd the

“Remapped Images” group and again activate “Exposure corrected, low dynamic range”.

Now, press the

Stitch!

button in the lower right corner. This opens a helper program which supervises

the stitching process. Depending on your computer and size of the image, it will require a few minutes of

processing.

In case stitching fails with a cryptic error message, try to add the option --ﬁne-mask to the enblend

options.

Store a copy of the Hugin project ﬁle to always be able to go back to the settings you used to create the

last panorama. We will get back to it when we want to make a truly calibrated panorama (see 7.3.3).

7.3 Panorama Postprocessing

The image created has to be further processed to be used in Stellarium. The most obvious change is the

need for a transparent sky, which we can easily create in programs like Adobe Photoshop or the free and

open-source GIMP. I will describe only the free and open-source solution.

After that, we have to bring the image into shape for Stellarium, which may include some trimming.

While we could also slice an image with interactive tools, higher accuracy and repeatable results can be

achieved with command-line programs, which makes the ImageMagick suite the tool of our choice.

7.3.1 The GIMP

The GIMP (GNU Image Manipulation Program) has been developed as free alternative to the leading

commercial product, Adobe Photoshop. While it may look a bit different, basic concepts are similar. Not

everybody can (or wants to) afford Photoshop, therefore let’s use the GIMP.

Like Photoshop, the GIMP is a layer-aware image editor. To understand the concept, it is easiest to

imagine you operate on a growing stack of overhead slides. You can put a new transparent slide (“layer”) on

top of the stack and paint on this without modifying the lower layers.

A few important commands:

Zooming

Ctrl

Mouse Wheel

Layer visibility and transparency

Make sure to have layer dialog shown (

Windows Dockable Dialogs

A gray bar indicates opacity for the currently active layer. Note the mouse cursor in this opacity

bar (often also called transparency bar): near the top of the bar the upward pointer immediately sets

percentage. A bit lower the pointer looks different and can be used for ﬁne-tuning.

The most obvious post-processing need for our panorama is making the sky transparent. The optimal

tool usually is the “Fuzzy Select”, which is equivalent to the “Magic Wand” tool in Photoshop. Simply

mark the sky, and then delete it. The checkerboard background indicates transparent pixels.

It sometimes helps to put an intensive bright red or blue background layer under the panorama photo to

see the last remaining clouds and other specks. In the layer dialog, create a new layer, bucket-ﬁll with blue

or red, and drag it in the layer dialog below the pano layer. Write-protect this layer, work on the image layer,

and before exporting the image layer with transparent sky to PNG, don’t forget to switch off the background.

We need this layer functionality especially to align the panorama on a calibration grid, see section 7.3.3.

7.3.2 ImageMagick

ImageMagick (IM)

can be described as “Swiss Army Knife of image manipulation”. It can do most

operations usually applied to images in a GUI program, but is called from the command line. This allows

also to include IM in your own command scripts

. We will use it to do our ﬁnal cut and resize operations. I

cannot give an exhaustive tutorial about more than a few of IM’s functions, but the commands given here

should be enough for our purpose.

https://www.imagemagick.org/

These may typically be .BAT ﬁles on Windows, or various shell scripts on Linux or Mac.

86 Chapter 7. Landscapes

To open a command window (console, a.k.a. DOS window), press the Windows key and enter

cmd

, then

press . (On Linux and Mac, you surely know how to open a console window.)

There are some things you might need to know:

•

The command line is not your enemy, but a way to call expert tools.

•

The Windows command line processor cmd.exe is far from user friendly.

•

There are remedies and alternatives. See notes on clink (7.5.3) for a considerable improvement, and

WSL (7.5.4) for experts.

7.3.2.1 Command-line magick for spherical landscapes

Let’s start with the commands for ﬁnal dressing of an equirectangular panorama to be used as spherical

landscape which has been created in size

4096× 2048

, but where you have seen that nothing interesting is in

the image above 11.25°. This means we can cut away the sky area and compress the image to

4096× 1024

save graphics memory.

To understand the numbers in the example, consider that in a panorama image of

4096× 2048

pixels,

1024 pixels represent 90°,

512px = 45

°,

256px = 22.5

°,

128px = 11.25

°. To keep a top line of

11.25

°, we

keep an image height of 1024+ 128 = 1152px, but the crop starts at pixel Y = 1024− 128 = 896.

convert lands cape . png - crop 4096 x1152 +0+896

- resize 4096 x1024 ! l andsc ape_c roppe d . png

Note the exclamation mark in the -resize argument, which is required to stretch the image in a non-

proportional way.

Alternatively, you can operate with IM’s “gravity”, which indicates the corner or edge geometric offsets

are referred to. Given that we want the lower part of the image to exist completely, you only need to compute

the size of the cropped image:

convert lands cape . png - g ravity S ou thWest - crop 4096 x1152 +0+0

- resize 4096 x1024 ! l andsc ape_c roppe d . png

You still need the addition

+0+0

in the -crop option, else the image will be cut into several pieces. In the ﬁle

landscape.ini, you then have to set maptex_top=11.25.

7.3.2.2 Command-line magick for old_style landscapes

Let us assume we want to create a high-resolution landscape from a pano image of width 16384 which we

have carefully aligned and calibrated on an oversized grid template that also shows a measured horizon line

(see 7.3.3). Usually it is not necessary to create the full-size image, but only the horizon range, in this high

resolution. Assume this image has been aligned and justiﬁed on our grid image and is

HEIGHT

pixels high,

the left border is at pixel

X_LEFT

, and top border (i.e., the point where relevant content like the highest tree is

visible) is on pixel

Y_TOP

. Assume our graphics card is a bit oldish or you aim for maximum compatibility,

so we can load only textures of at most 2048 pixels in size. Given that the horizon area usually only covers a

few degrees, a vertical extent of

2048px

seem a pretty good range for that most interesting zone. The ground

can then be ﬁlled with some low-resolution image of grass, soil, or a properly oriented site map, or you can

use Hugin to create a ground image (and using the maximum of

2048× 2048

also here usually is far more

than enough).

In GIMP (or Photoshop, . . . ), we must ﬁnd the values for

X_LEFT

Y_TOP

and

HEIGHT

is being

resized to 2048, strictly, by the exclamation mark in the resize command. We can create our image tiles

now with this singular beast of a command line (write all in 1 line!), which puts our ﬁles directly into

STELLARIUM_LANDSCAPEPATH/LANDSCAPE_NAME:

convert PANO . png -crop 16384 xHEIGH T + X_LEFT + Y_TOP + repage

- resize 16384 x2048 !

- type Tr ue Color Ma tte - depth 8

- crop 2048 x2048 + repage

png : S TEL LAR IUM _L AND SCA PEP ATH / L ANDSCAP E_ NAME / Horiz -% d . png

This creates 8 images. See section 7.1.4 for the

landscape.ini

where these images can be referenced.

Don’t forget to read off top and bottom lines (altitudes in degrees) from your grid, the vertical extent will

form the decor_alt_angle, and the bottom line the decor_angle_shift entries in this ﬁle.

Most modern graphics cards no longer require the “powers of two” image sizes, but we keep this practice to increase

compatibility.

7.3 Panorama Postprocessing 87

Creating a ground image for old_style landscapes

When you want a good ground image for an

old_style

landscape from your panorama and not just ﬁll the

groundtex

with a monochrome texture or a map, you have to create a ground view in Hugin. But you may

have already created a huge pano! This can also be used as source image, and a ground shot can be extracted

with a reversed operation. In principle, all you need to know is the ﬁeld of view around the nadir. Figure 7.5

shows a simple conﬁguration ﬁle.

# hugin project file

# hu gin_p tover si on 2

p f0 w2048 h2048 v92 E0 R0 n" TIFF_m c : LZW r : CROP "

m g1 i0 f0 m2 p0 .00 784314

# image lines

# - hugin c ro pF actor =1

i w16384 h8192 f4 v360 Ra0 Rb0 Rc0 Rd0 Re0 Eev0 Er1 Eb1 r0

p90 y0 TrX0 TrY0 TrZ0 Tpy0 Tpp0 j0 a0 b0 c0 d0 e0 g0 t0

Va1 Vb0 Vc0 Vd0 Vx0 Vy0 Vm5 n" E qirec t_ Pano3 60 .png "

Figure 7.5: Project ﬁle

ground.pto

usable to create the ground image with Hugin or, on the

command line, its nona stitcher. The last line, starting with

, has been wrapped, but must be 1 line.

Say, the side panels extend down to

decor_angle_shift=-44

degrees, which means you must close

the ground with a Nadir

FoV = 2× (90− 44)= 92

. For maximum compatibility, we will again make an image

of width and height both 2048

. These values can be found in the

line in Figure 7.5. The

line describes

the input image, which is our full equirectangular pano of width

w= 16384

and height

h= 8192

. The last

argument of that line is the image ﬁle name.

For processing, we do not use the Hugin GUI, but simply the command line. The actual program to call

is nona. If your stitched panorama is a 16-bit TIFF, nona will also make a 16-bit image, but our textures are

limited to 8-bit PNGs. We apply our most useful tool, convert from the ImageMagick suite.

nona -v -m PNG ground . pto -o ground . png

convert ground . png - depth 8 gr ound_8bit . png

The ﬁle ground_8bit.png is then used in the groundtex ﬁeld on landscape.ini.

7.3.3 Final Calibration

The creation of a calibrated panorama (which can be regarded as dependable proxy for further measurements

taken inside Stellarium) requires reference measurements to match the photos against. We must take

azimuth/altitude measurements with a theodolite or total station, in the optimal case along the full horizon,

and in addition I recommend to take azimuth and altitudes of some distinct features along the horizon which

must also be visible in the photographs: mountain summits, electrical towers, church towers, . . .

I recommend you create grid templates of the sizes you are going to create, e.g. 4096, 8192, 16386 and

20480 pixels wide with some diagram tool. On these, you can then also draw the measured horizon line.

Now, load a panorama on top of this in the GIMP, i.e., copy it into a separate layer over the grid image,

and set it semi-transparent.

Try to align the center of the image (where the geometric anchor has been deﬁned; remember: this

should be the image pointing south!) with the measured horizon line or the distinct features.

The optimal solution consists of a photo panorama which aligns perfectly with the measured line and

features. We now have to iteratively bring deviations to a minimum. The process depends on processor

speed, image size, your training and – most of all – your requirements in accuracy!

In the GIMP, load your grid image with horizon line. Now select

File Open as Layers. . .

, load your

photo panorama, and then set layer transparency in the

Layers

dialog to about 50%.

Select the double-arrow tool to move the panorama via mouse drag and cursor keys over the grid, and

align the outline of the photo horizon’s southern point with the measured line. Now it’s time to estimate the

quality of the panorama.

In Hugin’s

Photos

tab, select the

Positions

view on the right side. Now you see “Yaw”, “Pitch” and

“Roll” values of camera-to-world orientation listed in the photos list. It should now be possible, by changing

88 Chapter 7. Landscapes

Figure 7.6: Hugin’s Fast Panorama Preview can be used to check which images are connected to its

neighbors. Most important are good matches along the horizon, the images in the lower rows are

clearly less important. If captured on a tripod, they should still match.

the values only for the anchor image and re-optimizing, to come to a panorama with only minimal error. In the

process, start with Optimizing

Positions incremental from anchor

, then go for view and barrel optimization,

and so on. Always try to remove foreground match points which have large error and are irrelevant for the

task to match the horizon. Those are especially cross-matches of horizon and sub-horizon rows of images.

Only vertically and horizontally adjacent images should be required to match. For handheld panoramas, also

links between adjacent images in the non-horizontal rows are usually too erroneous to be useful, just remove

these match points. Use the

Layout

tab in the Fast Panorama Preview to see the relations between images

(Fig. 7.6): Red lines have big errors, green lines are good, thin gray lines indicate possible overlap without

speciﬁed match points. After each optimization step, export a new pano image, load as layer in GIMP, and

check again.

Basic rules to observe (use obvious inverses).

•

If image aligns well in azimuth but overshoots the grid to the right: Increase yaw accordingly

(0.022°/pixel if image is 16384 pixels wide).

•

If the north end (left and right borders) is higher than the southern contact point: Increase pitch

angle.

•

If north and south points are OK, but the western (right) half is higher than the eastern (left) half:

Increase Roll angle.

The corrections required for pitch and roll may be surprisingly small!

Within a few rounds of adjustments, panorama creation, adding as layer in the image editor, and

comparing to the reference data, you should achieve a match to ﬁt your needs.

In case you have taken photographs in several rings but without a panorama tripod, you may have to ﬁrst

align only the horizontal images (deselect the lower images to exclude from optimization), and when the

horizon ring is aligned perfectly, deactivate further optimization in Hugin for those photos while “attaching”

(optimizing) the lower photos. In Hugin’s

Photos

tab, select

Optimize Geometric Custom Parameters

This opens an extra tab

Optimizer

, where you can ﬁne-tune your needs: Switch off all variables for the

photos in the horizon ring, and make sure the lower photos ﬁt in the preview after optimization.

It may even help to deﬁne that the lower rows have been taken with a different Lens, so the ﬁeld of view

and distortion settings of the horizon row will be used as it had been found during the horizon-only match.

By now you should have enough experience what level of error may be acceptable for you.

7.3 Panorama Postprocessing 89

7.3.4 Artiﬁcial Panoramas

I have created a website

where you can enter geographical coordinates and download a ﬁle

pano.kml

which helps with image creation from Google Earth imagery. Store this ﬁle for a site, let us call it MYPLACE,

into a new directory GE_MYPLACE inside your landscapes directory.

Store all scenes visible from the respective viewpoint MYPLACE as picture into one common folder

in your

landscapes/GE_MYPLACE

under the viewpoint name, e.g.,

75-30.jpg

, which means 75 degrees

from Nadir, azimuth 30 degrees. Also, double-click the pano entry or the marker in Google Earth to

open a window with the basic content of your

landscape.ini

. Copy and paste from there into a new

ﬁle

landscape.ini

and adjust the obvious entries. Complete as required with the entries described in

section 7.1.3.

On loading of the images, Hugin will not be able to detect any EXIF lens data and ask you for the

horizontal ﬁeld of view. Enter 60 degrees, which is the standard value for Google Earth screenshots

The viewpoint names translate almost directly to the yaw and pitch angles which you can enter in the

image list in Hugin’s

Photos

tab. For example, switch to the

Positions

display on the right window edge in

the

Photo

tab, mark all images that start with

25-

and assign a pitch angle of

−90+ 25 = −65

. The second

part of the names is directly the azimuth. In this case, don’t run the optimizer, but you can immediately

set an output resolution and stitch (see 7.2.3.4). To get rid of the image decorations (compass etc), apply

masks

. Post-processing steps are the same as for photo-panoramas: make sky invisible, crop, etc.

It is also interesting to switch on the 3D buildings layer before creating the images. If temples or other

buildings are accurate, this will give an even closer approximation to what would be visible on-site. Note

however that not every building will be modelled in usable quality, and that usually vegetation is not included

in the 3D buildings layer. Also, if you are too close to buildings, they may be cut away by the near clipping

plane of the rendering.

These images, based on Google Earth imagery and the SRTM topographic model, seem usable as ﬁrst

rough approximation to a photo-based or surveyed panorama. Note that it is deﬁnitely not accurate enough

for representing nearby horizon features or critically important mountain peaks, and please note that Google

has image copyright which at least requires you to acknowledge when displaying these pictures.

7.3.5 Nightscape Layer

Since version 0.13, Stellarium can simulate artiﬁcial illumination, like streetlamps, bright windows, or the

skyglow over cities (Zotti and Wuchterl, 2016). One way to create this layer is to make 2 panorama series

during the day and night and process these in the same Hugin project to align those photos, and then stitch

two separate images by selecting either the daylight or the nighttime shots. The night panorama has to be

processed to remove stars, airplanes, etc.

The other way is a simple layer overpainted in the image processing program. As rough recommendation,

use several layers to prepare this feature:

•

Put a semitransparent black layer over your daylight image, this helps you to place your painted

pixels.

•

Paint windows, street lamps, signs, . . . . You may apply a layer style to produce some glow.

•

To draw an impression of more light in the atmosphere (city skyglow), use a gradient with some

brownish color. Generally the color depends on the appropriate mix of city lights (sodium, mercury

vapour, etc.). Note that on the city outskirts a simple vertical gradient will not work, towards the city

the horizon is much brighter. Use a huge but weak brush to make a more spotty sky.

•

Use the existing landscape as template for the layer mask for this gradient sky layer. (You want to

hide skyglow by leaves in the foreground!)

•

If you want to add only a few lights to an

old_style

landscape, you need to provide only the panels

showing those lights. Just load a side panel for reference, place a new layer on top, and paint the

lights on windows, lamps etc. There is no light option for the ground texture. This makes

old_style

landscapes best suited for localized light pollution, not city skyglow.

The resulting image is then declared in the

maptex_illum

line of

landscape.ini

. Try also to balance

the global strength of light pollution with the

light_pollution

key, and a probable minimal brightness

with the minimal_brightness key.

https://homepage.univie.ac.at/Georg.Zotti/php/panoCam.php

Note that if you work with Google Earth Pro, you can create different FoV!

There is a wide overlap in the images to allow generous trimming.

90 Chapter 7. Landscapes

Try to match the visual appearance, not necessarily what photographs may have recorded. E.g., the

Grossmugl sky shows horizon glow mostly towards the city of Vienna, where long-time exposures may

already be saturated.

The possibilities seem limited only by your time and skills!

7.4 Troubleshooting

If something does not work as described and Stellarium does not show your landscape as expected but maybe

just a bright magenta-colored box, don’t panic. Double and triple-check the entries in

landscape.ini

Make sure the texture is in PNG format and the ﬁle name is correct. Check the logﬁle for error messages.

If the image is too large, it will be re-scaled on loading, but it is more efﬁcient to keep images as small as

required. Only few systems can use textures larger than

16384× 16384

Pixels. If you need high resolution,

use the old_style type (see section 7.1.4).

7.5 Other recommended software

Here is a short collection of other useful programs for (panorama) image manipulation and other tasks on

Windows.

7.5.1 IrfanView

IrfanView is a free image viewer for Windows with many options. It can show almost any image format,

including several camera RAW formats, in windowed and full-screen mode. It is deﬁnitely preferable over

any image viewer built into Windows. Unfortunately however, it has no panorama viewer function!

7.5.2 FSPViewer

FSPViewer

by Fulvio Senore is an excellent panorama viewer for equirectanglar images. Images centered

along the horizon can be viewed directly, while settings for images with different minimum and maximum

angles, as well as “hotspots” (similar to hyperlinks) which move to neighboring panoramas, can be conﬁgured

in an .FSV text ﬁle like ﬁgure 7.7.

ImageName = H orizo n_Ros enbur g . jpg

WindowTi tl e = Horiz on _Ro se nbu rg

hFov =70

# Formula : HP =100*( h /2 - upper )/( lower - upper ) in Hugin crop , or

# HP =100* zer oRow / imgHeight

Ho ri zonPo sition =33.8

Figure 7.7: FSP conﬁguration ﬁle (example)

7.5.3 Clink and GNUWin32

Clink

is a command line enhancement for Windows developed by Martin Ridgers. If you have ever worked

under a Linux bash-like command line, you will easily feel that Windows’ cmd.exe is extremely limited.

Clink provides several useful features, most notably a really usable command-line completion. It is not

essential for our tasks, but a general improvement of usability of the Windows command line which else has

not caused me any trouble.

Compared to Linux, the command line of Windows can still be a humbling experience. None of the

wonderful helpers taken for granted on Linux are available. Many of the nice tools known and taken for

granted by Linux users (make, sed, awk etc.) have also been made available as standalone commands for

Windows. If you don’t need the inline scripting capabilities in

Makefile

s which you would get from a more

complete Linux installation but just want to call awk or sed inside your .BAT scripts, maybe this is enough.

Further details are available on its home page http://www.fsoft.it/FSPViewer/.

http://mridgers.github.io/clink/

7.5 Other recommended software 91

7.5.4 WSL – Windows Subsystem for Linux

Finally, the 64-bit editions of Windows 10 come with an optional feature that allows you to install a complete

Linux distribution like Ubuntu inside your Windows system. Combined with an X11 server like XMing

you can even run graphic applications like Stellarium, and all the command-line tools are available.

https://sourceforge.net/projects/xming/

8. Deep-Sky Objects

Since version 0.10.0 Stellarium uses the “json” cataloguing system of conﬁguring textures. At the same time

the Simbad online catalogue was added to the search feature, making the catalog somewhat redundant and

used now only as a ﬁrst search point or if there is no Internet connection.

If the object has a name (not just a catalogue number), you should add one or more records to the ﬁle

.../nebulae/default/names.dat

(where

...

is either the installation directory or (preferably) the user

directory). See section 8.1.2 Modifying names.dat for details of the ﬁle format.

If you wish to associate a texture (image) with the object, you must add a record to the ﬁle

.../nebulae/default/textures.json

See section 8.1.3 for details.

If you wish to associate an outline with the object, you must add the series of lines to the ﬁle

.../nebulae/default/outlines.dat. See section 8.1.4 for details.

8.1 Stellarium DSO Catalog

Stellarium’s DSO Catalog contains over 94000 objects

(up to

15.5

for galaxies) and is available for end

users as collection of ﬁles:

catalog.txt Stellarium DSO Catalog in ASCII format for editing data

catalog.dat Stellarium DSO Catalog in zipped binary format for usage within Stellarium

names.dat List of proper names of the objects from ﬁle catalog.dat

An edited ASCII ﬁle can be converted into binary format through enabling an option in the ﬁle

config.ini (See 5.4):

[ devel ]

co nve rt _ds o_cat alo g = true

The ﬁle

catalog.txt

should be put into the directory

.../nebulae/default/

and you should create

an empty ﬁle

catalog.pack

to storing the binary catalog. After converting the data into binary format you

should gzip them by the command

gzip -nc catalog . pack > catalog . dat

Stellarium DSO Catalog contains data and supports the designations for follow catalogs

NGC New General Catalogue

IC Index Catalogue

M Messier Catalog

An extended edition of this catalog with over one million objects may be downloaded and installed manually (see

section 5.5.2).

The ﬁle name

catalog-VERSION.dat

is used for extended edition of DSO Catalog, where VERSION is version

of catalog.

Abell Catalog of Planetary Nebulae was added in v0.18.2 and removed in v0.20.1

94 Chapter 8. Deep-Sky Objects

C Caldwell Catalogue

B Barnard Catalogue (Barnard, 1927)

SH2 Sharpless Catalogue (Sharpless, 1959)

vdB van den Bergh Catalogue of reﬂection nebulae (van den Bergh, 1966)

RCW

A catalogue of H

-emission regions in the southern Milky Way (Rodgers, Campbell, and

Whiteoak, 1960)

LDN Lynds’ Catalogue of Dark Nebulae (Lynds, 1962)

LBN Lynds’ Catalogue of Bright Nebulae (Lynds, 1965)

Cr Collinder Catalogue (Collinder, 1931)

Mel Melotte Catalogue of Deep Sky Objects (Melotte, 1915)

PGC HYPERLEDA. I. Catalog of galaxies

UGC The Uppsala General Catalogue of Galaxies

Ced Cederblad Catalog of bright diffuse Galactic nebulae (Cederblad, 1946)

Arp Atlas of peculiar galaxies

(Arp, 1966)

The catalogue of interacting galaxies by Vorontsov-Velyaminov (Vorontsov-Velyaminov,

Noskova, and Arkhipova, 2001)

PK Version 2000 of the Catalogue of Galactic Planetary Nebulae (Kohoutek, 2001)

PN G The Strasbourg-ESO Catalogue of Galactic Planetary Nebulae

(Acker et al., 1992)

SNR G A catalogue of Galactic supernova remnants (Green, 2025)

Abell A Catalog of Rich Clusters of Galaxies (Abell, Corwin, and Olowin, 1989)

HCG Atlas of compact groups of galaxies (Hickson, 1993)

ESO ESO/Uppsala Survey of the ESO(B) Atlas (Lauberts, 1982)

vdBH Catalogue of southern stars embedded in nebulosity

(van den Bergh and Herbst, 1975)

DWB

Catalogue and distances of optically visible H II regions (Dickel, Wendker, and Bieritz,

1969)

Tr Trumpler Catalog

St Stock Catalog

Ru Ruprecht Catalog

vdB-Ha van den Bergh-Hagen Catalog (van den Bergh and Hagen, 1975)

Other

deep-sky objects without designations and sky regions — by formal rules objects from this

list are not included in any catalog known to Stellarium

Cross-index data for Stellarium’s DSO Catalog is partially obtained from “Merged catalogue of reﬂection

nebulae” (Magakian, 2003) and astronomical databases SIMBAD

(Wenger et al., 2000) and NED

Distances for some deep-sky objects obtained from “The Magellanic Cloud Calibration of the Galactic

Planetary Nebula Distance Scale” (Stanghellini, Shaw, and Villaver, 2008), “A 1.4 GHz Arecibo Survey

for Pulsars in Globular Clusters” (Hessels et al., 2007), “Distance measurements of LYNDS galactic dark

nebulae.” (J. Hilton and Lahulla, 1995) and “A Catalog of Parameters for Globular Clusters in the Milky

Way” (Harris, 1996).

Morphological class for many open clusters obtained from “Classiﬁcation of open star clusters” (Ruprecht,

1966).

Visual magnitudes for Messier objects obtained from “Revised New General Catalogue and Index Catalogue”

by Dr. Wolfgang Steinicke (Version: 2 February 2021 — NI2021)

The PGC and UGC catalogs are partially supported

Arp, VV and PK was added in version 0.16.0

PN G, SNR G and Abell was added in version 0.16.1

vdBH and DWB was added in version 0.19.2

Tr, St, Ru and vdB-Ha was added in version 0.20.2

SIMBAD Astronomical Database — https://simbad.u-strasbg.fr/simbad/

NASA/IPAC Extragalactic Database (NED) — https://ned.ipac.caltech.edu/

Discovery and Cataloguing of Nebulae and Star Clusters —

http://www.klima-luft.de/steinicke/index

_e.htm

8.1 Stellarium DSO Catalog 95

8.1.1 Modifying catalog.dat

This section describes the inner structure of the ﬁles

catalog.dat

(binary format) and

catalog.txt

(ASCII format). Stellarium can convert ASCII ﬁle into the binary format ﬁle for faster usage within the

program.

Each line contains one record, each record consisting of the following ﬁelds with tab char as delimiter:

Column Type Description

1 integer Deep-Sky Object Identiﬁcator

ﬂoat RA (decimal degrees)

ﬂoat Dec (decimal degrees)

ﬂoat B magnitude

ﬂoat V magnitude

string Object type (See section 8.1.1.1 for details).

string Morphological type of object

ﬂoat Major axis size or radius (arcmin)

ﬂoat Minor axis size (arcmin)

integer Orientation angle (degrees)

ﬂoat Redshift

ﬂoat Error of redshift

ﬂoat Parallax (mas)

ﬂoat Error of parallax (mas)

ﬂoat Non-redshift distance (Mpc for galaxies, kpc for other objects)

ﬂoat Error of non-redsift distance (Mpc for galaxies, kpc for other objects)

integer NGC number (New General Catalogue)

integer IC number (Index Catalogue)

integer M number (Messier Catalog)

integer C number (Caldwell Catalogue)

integer B number (Barnard Catalogue)

integer SH2 number (Sharpless Catalogue)

integer vdB number (van den Bergh Catalogue of reﬂection nebulae)

integer

RCW number (A catalogue of H

-emission regions in the southern Milky Way)

25 integer LDN number (Lynds’ Catalogue of Dark Nebulae)

integer LBN number (Lynds’ Catalogue of Bright Nebulae)

integer Cr number (Collinder Catalogue)

integer Mel number (Melotte Catalogue of Deep Sky Objects)

integer PGC number (HYPERLEDA. I. Catalog of galaxies); partial

integer UGC number (The Uppsala General Catalogue of Galaxies); partial

string Ced identiﬁcator (Cederblad Catalog of bright diffuse Galactic nebulae)

integer Arp number (Atlas of Peculiar Galaxies)

integer VV number (The catalogue of interacting galaxies)

string PK identiﬁcator (Catalogue of Galactic Planetary Nebulae)

string

PN G identiﬁcator (The Strasbourg-ESO Catalogue of Galactic Planetary Nebu-

lae)

string SNR G identiﬁcator (A catalogue of Galactic supernova remnants)

string Abell identiﬁcator (A Catalog of Rich Clusters of Galaxies)

string HCG identiﬁcator (Atlas of compact groups of galaxies)

string ESO identiﬁcator (ESO/Uppsala Survey of the ESO(B) Atlas)

string vdBH identiﬁcator (Catalogue of southern stars embedded in nebulosity)

integer DWB identiﬁcator (Catalogue and distances of optically visible H II regions)

integer Tr identiﬁcator (Trumpler Catalogue)

integer St identiﬁcator (Stock Catalogue)

44 integer Ru identiﬁcator (Ruprecht Catalogue)

integer

vdB-Ha identiﬁcator (Uniform survey of clusters in the Southern Milky Way —

van den Bergh-Hagen Catalogue)

96 Chapter 8. Deep-Sky Objects

8.1.1.1 Types of Objects

Possible values for type of objects in the ﬁle catalog.dat.

Type Description

G Galaxy

Galaxy

AGX

Active Galaxy

Radio Galaxy

Interacting Galaxy

Globular Cluster

Open Cluster

Nebula

Planetary Nebula

Dark Nebula

Reﬂection Nebula

C+N

Cluster associated with nebulosity

HII

HII Region

SNR

Supernova Remnant

SNC

Supernova Candidate

SNRC

Supernova Remnant Candidate

Bipolar Nebula

Emission Nebula

Stellar Association

Star Cloud

Cluster

Infra-Red Object

QSO

Quasar

Possible Quasar

ISM

Interstellar Matter

EMO

Emission Object

LIN

LINEAR-type Active Galaxies

BLL

BL Lac Object

BLA

Blazar

MOC

Molecular Cloud

YSO

Young Stellar Object

PN?

Possible Planetary Nebula

PPN

Protoplanetary Nebula

∗

Star

∗∗

Double Star

MUL

Multiple Star

SY∗

Symbiotic Star

EM∗

Emission-line Star

CLG

Cluster of galaxies

empty

Unknown type, catalog errors, Unidentiﬁed Southern Objects etc.

8.1.2 Modifying names.dat

Each line in the ﬁle

names.dat

contains one record. A record relates an extended object catalog number

(from catalog.dat) with a name. A single catalogue number may have more than one record in this ﬁle.

The record structure is as follows:

Offset Length Type Description

0 5 %5s Designator for catalog (preﬁx)

15 %d Identiﬁcator for object in the catalog

20 end %s Proper name of the object (translatable) [# references]

If an object has more than one record in the ﬁle

names.dat

, the last record in the ﬁle will be used for the

nebula label.

8.1 Stellarium DSO Catalog 97

8.1.2.1 Too many names?

Over the years, a large collection of names from many references has been added. DSO names are not

v 25.1

standardized and are generally not used by professional astronomers, but are often used for popularisation

of objects. Some of the collected names may be too fanciful for your taste. If you can identify that those

names that annoy you all come from a single or just a few entries of the reference list, you can exclude those

sources, and thus the names they bring. Note that if a fancy name comes from more than one book, you

would have to exclude all books to ban that name from your display.

To exclude entries, add the following key to config.ini:

[ astro ]

ne bul a_e xcl ude _refe ren ces = defa ult :ADI , DSC -HT

Here,

default

names the nebula set, and the comma-separated entries are references you want excluded

from nebulae/default/names.dat.

8.1.3 Modifying textures.json

This ﬁle is used to describe each nebula image. The ﬁle structure follows the JSON format, a detailed

description of which may be found at

www.json.org

. The

textures.json

ﬁle which ships with Stellarium

has the following structure:

serverCredits (optional) a structure containing the following key/value pairs:

short a short identiﬁer of a server where the json ﬁle is found, e.g. “ESO”

full a longer description of a server, e.g. “ESO Online Digitized Sky Survey Server”

infoURL a URL pointing at a page with information about the server

imageCredits

a structure containing the same parts as a serverCredits structure but referring to the image

data itself

shortName an identiﬁer for the set of images, to be used inside Stellarium

minResolution

minimum resolution, applies to all images in the set, unless otherwise speciﬁed at the image

level

maxBrightness

the maximum brightness of an image, applies to all images in the set, unless otherwise

speciﬁed at the image level

subTiles

a list of structures describing individual image tiles, or referring to another json ﬁle. Each subTile

may contain:

minResolution

maxBrightness

worldCoords

subTiles

imageCredits

imageUrl

textureCoords

shortName (name for the whole set of images, e.g. “Nebulae”)

miniResolution (applies to all images in set)

alphaBlend (applies to all images in set)

subTiles list of images. Each image record has the following properties:

imageCredits (itself a list of key/pairs)

imageUrl (e.g. ﬁle name)

worldCoords (a list of four pairs of coordinates representing the corners of the image)

textureCoords (a list of four pairs of corner descriptions. i.e. which is top left of image etc)

minResolution (over-rides ﬁle-level setting)

maxBrightness

Items enclosed in Quotation marks are strings for use in the program. Syntax is extremely important.

Look at the ﬁle with a text editor to see the format. Items in <> are user provided strings and values to suit

the texture and source.

{

" imageCredits " : { " sho rt " : " < author name >" ,

" inf o Url " : " http :// < m ysite . org >"

" imag e U rl " : " < myPhot o . png >" ,

" worldCoords " : [[[ X0 , Y0 ], [ X1 , Y1 ], [ X2 , Y2 ], [ X3 , Y3 ] ]] ,

98 Chapter 8. Deep-Sky Objects

" textureCoords " : [[[ 0 ,0] ,[1 ,0] ,[1 ,1] ,[0 ,1]]] ,

" minResolution " : 0.2148 810463 ,

" maxBrightness " : <mag >

where

worldCoords

Decimal numerical values of the J2000 coordinates (RA and dec both in degrees) of the

corners of the texture. These values are usually given to 4 decimal places.

textureCoords

Where 0,0 is South Left, 1,0 the South Right, 1,1 North Right, 0,1 North Left corners of the

texture.

minResolution UNDOCUMENTED VALUE! Sorry!

maxBrightness total object brightness, magnitude

Calculating of the coordinates of the corners of the images (plate solving) is a time consuming project

and needs to be ﬁne tuned from the screen display. As most images will be two dimensional, display on

a spherical display will limit the size to about 1 degree before distortion becomes evident. Larger images

should be sectioned into a mosaic of smaller textures for a more accurate display.

8.1.4 Modifying outlines.dat

Each line in the ﬁle

outlines.dat

contains three “columns” of data for outline elements. The structure for

each line is as follows:

Offset Length Type Description

0 8 %d Right ascension (decimal hours)

18 %d Declination (decimal degrees)

60 %s Command

Coordinates for each point of outline is represented in the equatorial coordinate system for epoch J2000.0.

The possible values of the third “column” (Command) are:

start

This command marks a start point of the outline. This command should also contain the designation

of the deep-sky object.

vertex This command marks an intermediate point of the outline.

end This command marks an end point of the outline.

Example for outline of M42:

05.56 401 -05.49880 start M 42

05.56 759 -05.39201 vertex

05.56 635 -05.31749 vertex

05.57 158 -05.21922 vertex

05.57 601 -05.21716 vertex

05.58 830 -05.30164 vertex

05.59 140 -05.34341 vertex

05.59 028 -05.37076 vertex

05.59 008 -05.38175 vertex

05.59 581 -05.37159 vertex

05.59 943 -05.47123 vertex

05.59 912 -05.65838 vertex

05.59 520 -05.73212 vertex

05.58 490 -05.68102 vertex

05.56 948 -05.57675 end

The format of the ﬁle

outlines.dat

is compatible with the similar ﬁle of the SkyChart (Cartes du

Ciel) planetarium.

8.2 Adding Extra Nebula Images 99

8.2 Adding Extra Nebula Images

GLENN NEWELL

Figure 8.1: Screen shot of nebula images displayed in Stellarium

In previous versions of this guide, the technique for preparing Deep Space Object (DSO) images for inclusion

in Stellarium involved plate solving the image to ﬁnd its center on the sky, and then calculating the corners

of the image in the World Coordinate System (WCS

) using the scale of the image, arc-seconds/pixel.

The problem with that approach is that it did not account for any spatial distortion in the image, due

to telescope optics or sensor tilt, etc. This resulted in a labor intensive manual process of trial and error to

adjust the WCS corners of the image until the stars in the image aligned with those displayed in Stellarium.

Fortunately, this problem has been solved for us by astronomers with similar needs, extending FITS

ﬁle headers to include information on how to map every pixel in an image correctly onto WCS coordinates.

This information can be added to your image when you plate solve it on nova.astrometry.net, or similar

services (local copies of astrometry.net, such as ansvr, or in Pixinsight, etc.). This system of correcting for

distortions in astronomical images was reﬁned for the Spitzer Space Telescope

It is now possible to utilize this pixel to WCS transformation data included in plate solved images

to prepare images for Stellarium that map perfectly to the Stellarium sky without manual WCS corner

adjustments.

There are Python libraries, namely astropy and a related “channel” astroquery, that can automate some

or all of the needed steps, and there are both manual and fully automated scripts for that purpose available

on Stellarium’s GitHub site. These scripts can be run on Windows, Mac, or Linux platforms, using the

Anaconda Python distribution.

Nowadays, you can quickly plate solve deep space images and add them to the custom texture module

using the Nebula Textures plugin (see section 13.9).

8.2.1 Image requirements for inclusion in Stellarium

The ﬁnal image must be aligned with the equatorial (J2000.0) coordinate system so that north is directly up

and not inverted side to side or up and down as can happen with photos taken with a diagonal mirror in the

path (In the WCS system, “Parity” must be 1.)

Next you will need to crop and/or re-scale the picture, setting the main feature at the center and making

the cropped size a power of 2, e.g. 64, 128, 256, 512, 1024 or 2048 pixels square (or elongated like

512× 1024

). If this requirement is not met, your textures may not be visible, or graphics performance may be

seriously impacted on some systems. Textures larger than 2048 may only be supported on high-end hardware.

Images must be in PNG format. When cropping, make sure you leave at least six prominent background

stars for plate solving). The next step is to process your photo to make the background black, really black.

https://fits.gsfc.nasa.gov/fits_wcs.html

The Flexible Image Transport System is the dominating image format used in astronomy.

https://www.cs.helsinki.fi/group/goa/viewing/viewtransf/viewTrans.html

100 Chapter 8. Deep-Sky Objects

This will ensure that your background will meld with the Stellarium background and not be noticed as ugly

gray square. Do not use “transparent” pixels available in the PNG format as they will show as white, not

black, in Stellarium.

Images covering more than 10 degrees of sky should be divided into separate images, and images with

pixel scales less than 1 arc-sec per pixel should be re-scaled so as to have a pixel scale of 1 arc-sec per pixel

or larger.

8.2.2 Processing requirements

•

Python 3.7 (Anaconda 64 bit installer

) During installation, follow directions, taking defaults to

install for just your user (vs. everyone on your computer)

•

Astropy (included in Anaconda)

•

Astroquery (latest version) To install on Windows, open an “Anaconda Prompt”. On Mac and Linux,

just open a terminal. At the prompt, enter:

pip install -- pre -- upgrad e ast ro query

•

For the fully automated process:

– An API Key from your account at https://nova.astrometry.net:

○ Create an account (or log in with google, etc.) at https://nova.astrometry.net

○ On the API tab, copy your API key (shown in green)

○

Using a text editor (e.g., Notepad++ on Windows, Text Wrangler on Mac OS), paste

that key over the

’s in

Stellarium_Nebulae_Images_Prep.py

’s

ast.api_key =

’XXXXXXXXXXXXXXXX’

•

For the more manual process:

–

Images plate solved at

https://nova. astrometry.net

(or Pixinsight – not yet tested) so

that WCS data is created

–

Graphics software to ﬂip, rotate, scale, etc. and save as

.png

, e.g., Photoshop, GIMP, Pixinsight,

etc.

8.2.2.1 Script and Shortcut placement

Download the Python scripts from Stellarium’s site at Github

•

WCS_corners.py script

•

Stellarium_Nebulae_Image_Prep.py script

Windows

•

Place the two .py and .bat scripts into %USERPROFILE%\Anaconda3\

•

Place the two Shortcuts on your desktop or an astro tools folder (optional)

•

You can now drag and drop one or more images or

wcs.fits

ﬁles onto the shortcuts (or

.bat

scripts) for processing

Mac

•

Place the two

.py

script ﬁles in the

anaconda3

directory, which should be inside your home

directory (the directory with your username).

•

Place the two .app ﬁles on your desktop or an astro tools folder (optional)

•

You can now drag and drop one or more images or

wcs.fits

ﬁles onto the Automator app

icons for processing

Linux

•

Place the two

.py

script ﬁles in the

anaconda3

directory, which should be inside your home

directory (the directory with your username).

•

Place the two .desktop ﬁles on your desktop or an astro tools folder (optional)

•

You can now drag and drop one or more images or

wcs.fits

ﬁles onto the desktop icons for

processing

8.2.3 Manual processing

We present the more manual of the two workﬂows and script ﬁrst, WCS_Corners.py, so you understand the

process, before introducing the completely automated image processing pipeline. It is also possible that if

plate solving fails in the fully automated script, you could continue, using this manual process:

Plate Solve

https://www.anaconda.com/distribution/

https://github.com/Stellarium/stellarium-data/tree/master/adding-nebula-images

8.2 Adding Extra Nebula Images 101

Figure 8.2: Online plate solving

Figure 8.3: Python processing. If you just leave a space after

python WCS_corners.py

, you can

drag and drop your wcs.fits ﬁle into Windows’ Anaconda Prompt window.

102 Chapter 8. Deep-Sky Objects

•

Plate solve your image @ nova.astrometry.net (Fig. 8.2)

•

Note pixel scale and orientation

Adjust Parity

•

Download the

wcs.fits

ﬁle from the “Results” page and run WCS_Corners.py on it (Fig. 8.3).

•

If Parity is -1, ﬂip your image horizontally (do this before rotate step below)

Rotate

Rotate your image so “up” is exactly “North”. i.e., if the orientation of your image was “261 degrees

East of North” then rotate your image 261 degrees CW.

“Blacken” Sky

Fill in the blank areas of your rotated image with black pixels, and set your “sky” back-

ground to be black.

Crop

Crop your image so that both

and

dimensions are powers of two pixels, e.g.

512× 512

1024× 1024

2048× 2048, 1024× 2048, etc.

Save PNG

•

Save your image as .png ﬁle

•

Place a copy into the %USERDIR%/nebulae/default directory

Plate Solve ﬁnal image

•

Plate Solve your ﬂipped, rotated, and cropped image again @ nova.astrometry.net

•

Download the new wcs.fits ﬁle.

Calculate WCS corners

•

Run WCS_Corners.py on the ﬁnal wcs.fits ﬁle

•

Edit Stellarium’s

textures.json

with the image ﬁle name and the generated world coordinates

Finalize image

Try to minimize the number of stars visible around your nebula in your image. Stellarium

draws its own stars, and a rectangle of excessive stars may look bad. Just blacken them out.

Restart Stellarium

View your image in Stellarium (and adjust

maxBrightness

textures.json

needed)

Some additional information you should be aware of:

•

Images in Stellarium are NOT tied to an object, just placed on the sky by worldCoords

– So multiple image can overlap. E.g., the bubble nebula has overlapping textures

– Black is rendered transparent

– “Transparent” areas of .png show as white

•

See section 5.1 on Directories for where to put your own copy of the default images + yours, so yours

won’t get overwritten by Stellarium Updates

•

If plate solve fails: adjust gamma/blackpoint so “only” stars are showing (Fig. 8.4)

→

Figure 8.4: Reduce gamma to temporarily help the plate solving algorithm ﬁnding stars.

Stellarium keyboard shortcuts you may ﬁnd useful when adding images:

8.2 Adding Extra Nebula Images 103

Figure 8.5: Automated Python processing with Stellarium_Nebulae_Image_Prep.py

brings up object search – Tab through search results

to remove ground (in case your object is currently behind the landscape)

to remove atmosphere (in case it is daytime)

to toggle nebulae images on and off – use to test star alignment

to toggle Milky Way on and off

to zoom into selected object

to zoom back out

8.2.4 Automated processing

With the recent addition of astrometry.net queries to the Python astroquery library it is now possible to au-

tomate the entire image processing pipeline as well as automatically create full

.json

entries for each image

for inclusion in the

textures.json

ﬁle. The python script for this is Stellar ium_Nebulae_Image_Prep.py.

Wrapper scripts Stellarium_Nebulae_Image_Prep.bat and Stellarium_Nebulae_Image_Prep.sh are also

included so you can process multiple images at once. With the desktop links you can even process one or

more .jpg or .tiff ﬁles by drag and drop, on Windows, Mac, and Linux systems.

Figure 8.5 is an example run of Stellarium_Nebulae_Image_Prep.py. This converts (rotates, scales,

etc.) the JPEG image as seen in Fig. 8.6, and a

.json

ﬁle for inclusion in

textures.json

(Fig. 8.7), along

with two “unstretched” _stars.jpg images used for plate solving, which can be deleted.

→

Figure 8.6: Automatic processing of a DSO image.

8.2.5 Troubleshooting

If no images show up in Stellarium, chances are you have introduced one or more errors in the

textures.json

ﬁle. You can use Json Lint

to check for problems.

Just paste the entire contents of the ﬁle in and press “Validate JSON”.

However, the original textures.json ﬁle as shipped in v0.19.1 also fails:

•

Missing leading zeros in front of decimal points

An online service available at https://jsonlint.com/

104 Chapter 8. Deep-Sky Objects

Figure 8.7: .json result from processing with Stellarium_Nebulae_Image_Prep.py

•

White space (a tab in this case) before http in infoUrl entries

These minor issues seem however not to irritate Stellarium.

9. Adding Sky Cultures

GEORG ZOTTI, WITH ADDITIONS BY ALEXANDER WOLF AND SUSANNE M. HOFF-

MANN

Stellarium comes with a nice set of sky cultures from all over the world (see section 4.4.6). For ethnographers

or historians of science it may be a worthwhile consideration to illustrate the sky culture of the people they

are studying. It is not very hard to do so, but depending on your data, may require some skills in image

processing.

Version 25.1 introduces a completely new format for skyculture data. If you are interested in the old

v 25.1

format, please refer to the 24.4 edition of the User Guide. In case you have created your own skycultures in

the old format, we have created a format converter described in section 9.3.

If you add a new sky culture, please adhere to this description for an optimal result! Some features

regarding translation and multilinguality have evolved over the years, and not all sky cultures currently

included in Stellarium adhere to the standards described in the following sections. Incomplete skycultures

may be improved, or removed when found too deﬁcient.

A sky culture in Stellarium is the entity that consists of

•

a description of the role these constellations and other celestial features (clouds, polar lights (aurorae),

meteors, comets, ... ) had or still have for the human culture that used or use these constellations,

including some relevant background on the culture.

•

a set of names for constellations

•

stick ﬁgure deﬁnitions connecting stars into those constellations

•

(optional) a list of names for individual stars

•

(optional) artwork supporting the stick ﬁgures

•

(optional) a description of boundaries or borders between the constellations

•

(optional) names and stick ﬁgure deﬁnitions of additional ﬁgures of lesser importance, termed

asterisms.

•

A CC-licence that the author of the SC chooses; this is valid for the entire set of ﬁles, i.e. all texts and

images provided.

9.1 Text descr iption

A sky culture must contain the ﬁle

description.md

, this is a text in Markdown format. Markdown is a

plaintext format which allows the simple declaration of text regions like sections, subsections, lists, images,

or references. The ﬁle is automatically broken into pieces, translated and converted to HTML for display or

else processed for speech output. Also some important skyculture components are extracted from here.

The ﬁrst line of the ﬁle starts with the only Level 1 header, i.e., a line starting with a single hash (

), a

space and then the name of the skyculture. This name is used in the selection list in the Sky Culture GUI

106 Chapter 9. Adding Sky Cultures

(see 4.4.6).

The other sections typically start with Level 2 or 3 headers (with two or three hash characters) which are

displayed as smaller section and subsection titles (HTML:

, respectively). All header lines (except

the ﬁrst) should be enclosed by empty lines.

The continuous text should be formatted like that, please do not add newlines where they do not signal

the end of a paragraph with an empty line. Use an editor which just auto-wraps long lines to the window

width. These long lines/paragraphs are automatically fed into the translation system. References (see 9.1.2)

should be given like [#42].

You should provide a good description in the interest of future users: some cultural/ethnographical

background of the users of this sky culture, the history or background of sky culture research that provided

this work, tables of names/translations, links to external resources, whatever seems suitable. The length of

the description texts is not limited, but of course if this is your PhD thesis work, there is no need to repeat all

500 pages, you can add a link to the references.

The skyculture description should include the following Level 2 sections. Any other section must be a

subsection (i.e. Level 3 or deeper) of one of these sections. Each of these sections except

Constellations

will have its own entry in the translations ﬁles. The

Constellations

section will be split, so that each

constellation’s description will be translated separately.

Introduction – a summary that could ideally be shown on a small screen entirely.

Description – the actual text of the description.

Constellations

– a sequence of Level 5 sections, where the header is the

"english"

name of a constel-

lation (as given in the

index.json

ﬁle), and the body gives some information on this constellation.

This text is used for display and speech output when the constellation is selected.v 25.4

References – a list of references, see 9.1.2 for details.

Authors – all authors and acknowledgments go here.

License

– either a license id (see 9.1.3), or a sequence of lines separated by empty lines (i.e. Markdown

paragraphs) describing which part of the culture has which license, in the format "Sky culture item:

License-ID".

Note that the

Constellations

section has the strict format described above. In particular, there’s no

place for an introduction for all the constellations, or closing remarks or a similar deviation from the format

of this section. If this kind of text is desired, it can be placed in a subsection of the Description section.

To allow the correct display of special characters like ÄÖÜßáé you must provide the ﬁle in UTF-8

encoding. If you write only English/ASCII, this may not be relevant.

9.1.1 Images

You can also have embedded images in the ﬁle (your book cover? Views of sacred landscapes/buildings/art-

work/.. . ?), just provide them in PNG or JPG format please. Use the following syntax, where the last line is

ﬁxed and is required for proper formatting.

![]( il l u s t r a t i o n s / my_ i mage . png )

My i mage captio n

{: . img_and_capti o n }

Alternatively, you can format an image in HTML if you need specialized extras like right-alignment or

size speciﬁcations:

My i mage captio n

{: . img_and_capti o n }

or (note the manual )

My i mage captio n

{: . img_and_capti o n }

9.1 Text descr iption 107

9.1.2 References

The optional Level 2 section “References” contains a list of information sources. Each line of the section

contains one record of 2 discernible ﬁelds: a hyphen followed by a numerical key in brackets, a colon and

then the actual description of the reference. The latter may include hyperlinks, e.g.:

- [# 1]: Kunitzsch , P .; S mart T . (2 0 06). "A D i c tionary of Moder n star Names : ...

This list is most important for “traditional” sky cultures collected from various sources to provide

traceable references.

Caution!

These reference numbers are not only used in the text, but also in the data description. If you re-arrange

references, you must also ﬁx all affected references in the JSON ﬁle (9.2).

9.1.3 License

The level 2 section “License” is mandatory if you want your sky culture to be distributed with Stellarium to

prevent “unexpected” distribution of your content to other software or applications out of our hands.

We recommend to use one of the following possible licenses in this section:

GNU GPL v2.0 (or later)

– this is the most famous “copyleft” license for code and it may be acceptable

also for text and data.

CC0

(No Rights Reserved) – this is a “don’t care” license. Content may be freely distributed without

attribution for all purposes.

CC BY

(Creative Commons Attribution License) – this license lets others distribute, remix, adapt, and build

upon your work, even commercially, as long as they credit you for the original creation. This is the

most accommodating of licenses offered. Recommended for maximum dissemination and use of

licensed materials.

CC BY-SA

(Creative Commons Attribution-ShareAlike License) – this license lets others remix, adapt, and

build upon your work even for commercial purposes, as long as they credit you and license their new

creations under the identical terms. This license is often compared to “copyleft” free and open source

software licenses. All new works based on yours will carry the same license, so any derivatives will

also allow commercial use. This is the license used by Wikipedia, and is recommended for materials

that would beneﬁt from incorporating content from Wikipedia and similarly licensed projects.

CC BY-ND

(Creative Commons Attribution-NoDerivatives License) – this license lets others reuse the

work for any purpose, including commercially; however, it cannot be shared with others in adapted

form, and credit must be provided to you.

CC BY-NC

(Creative Commons Attribution-NonCommercial License) – this license lets others remix, adapt,

and build upon your work non-commercially, and although their new works must also acknowledge

you and be non-commercial, they don’t have to license their derivative works on the same terms.

CC BY-NC-SA

(Creative Commons Attribution-NonCommercial-ShareAlike License) – this license lets

others remix, adapt, and build upon your work non-commercially, as long as they credit you and

license their new creations under the identical terms.

CC BY-NC-ND

(Creative Commons Attribution-NonCommercial-NoDerivatives License) – this license is

the most restrictive of the six main Creative Commons licenses, only allowing others to download

your works and share them with others as long as they credit you, but they can’t change them in any

way or use them commercially.

FAL

For illustrations we also expect usage of the Free Art License

(in addition to any other licenses) – it

is a “copyleft” license that grants the right to freely copy, distribute, and transform creative works.

You can specify, e.g., “GPL2, FAL” to indicate that the images are additionally released under Free

Art License.

Creative Commons provides a range of licenses

, each of which grants different rights to use the materials

Creative Commons are free and some are non-free. For example you can apply only the most permissive of

its licenses (CC0, CC BY and CC BY-SA) to material you create, to meets the Freedom Deﬁned deﬁnition

of a “Free Cultural Work”.

https://artlibre.org/licence/lal/en/

Creative Commons License Chooser – https://creativecommons.org/choose/

See Creative Commons website to details –

https://creativecommons.org/share-your-work/public-d

omain/freeworks

108 Chapter 9. Adding Sky Cultures

If you have used one of the keys above in your

license

entry, a short (unofﬁcial! Informative only)

description of license conditions will be displayed. You can use other licenses as well, but then please

describe the conditions sufﬁciently well in this section.

Caution for users!

While Stellarium is provided under the free GPL v2.0 licence which allows for commercial use, some of our

sky cultures have been contributed under CC NC/ND licenses, i.e., are for noncommercial use only. Please

respect their heritage holders and check the CC licence version in the description before you use sky cultures

in public events like TV documentaries, YouTube videos, lectures, planetarium shows or printed matter. If in

doubt, contact the respective authors.

9.1.4 Technical Test

Using correct syntax is required for making display and translation work. If you have checked out Stellarium’s

sources, you can run

util / skycul tu re s / generate - pot . py -s m y_ cu lt ur e

This may emit some warnings about issues that should be ﬁxed (if any remain). It will also generate a

.po

directory in the skycultures directory, but these ﬁles aren’t supposed to be committed, you can remove it.

9.2 Technical data: index.json

The ﬁle

index.json

contains all “technical data” of the skyculture. JSON is a text-based format in which

strings, numerical values and arrays can be stored in nested dictionaries, i.e. unordered collections of comma-

separated

"tag": value

pairs in braces:

{ "Tag1": "Value1", "number": 123.456 }

. Values

can be strings, numbers, arrays or other dictionaries. Arrays are ordered sequences in

[...]

delimiters. You

must take care to close any open brackets and separate entries by commas.

{

" id " : " mo dern " ,

" region ": " World " ,

" classificat i o n " : [" t r a ditional " ] ,

" f a l l ba ck_to_ i n t er nation a l _ n ames " : false ,

" asteri s m s " : [ ... ] ,

" constellati o n s " : [ ... ] ,

" edges_ty p e ": " iau " ,

" edges_source " : " h ttps :// pb a rbier . com / constellations / e d ges_18 . txt " ,

" edges_epoch ": " B187 5 " ,

" ed ges ": [ ... ] ,

" common_names " : { ... }

}

in which

"id" A unique identiﬁer for program-internal use. It is never displayed to users.

"region" See 9.2.1

"classification" See 9.2.2

"fallback_to_international_names"

true

, the IAU-approved star names are loaded after all names

given here, so names will be mixed without a clear separation, and newly-approved star names will

just appear automatically. Also all DSO names from

nebulae/default/names.dat

are loaded.

This is most useful for skycultures which have no names of their own, or where such mix is intended,

"personal"

contemporary skycultures (see 9.2.2) which are allowed to auto-adapt to newly

given names.

"common_names" includes names for star, planet and deep-sky objects, see 9.2.7

"constellations" describes constellations, see 9.2.4

"edges..." describes boundaries between constellations, see 9.2.3

"asterisms" describes asterisms, see 9.2.5

Tags not described here may be used in other programs but are ignored by Stellarium.

9.2 Technical data: index.json 109

9.2.1 Region

The “region” tag marks the origin region of the respective sky culture. It allows some form of additional

grouping. The names of regions are following the United Nations geoscheme UN M49

Northern Africa – Algeria, Egypt, Libya, Morocco, Sudan, Tunisia, Western Sahara.

Eastern Africa

– British Indian Ocean Territory, Burundi, Comoros, Djibouti, Eritrea, Ethiopia, French

Southern Territories, Kenya, Madagascar, Malawi, Mauritius, Mayotte, Mozambique, Réunion,

Rwanda, Seychelles, Somalia, South Sudan, Uganda, United Republic of Tanzania, Zambia, Zim-

babwe.

Central Africa

– Angola, Cameroon, Central African Republic, Chad, Congo, Democratic Republic of the

Congo, Equatorial Guinea, Gabon, Sao Tome and Principe.

Southern Africa – Botswana, Eswatini, Lesotho, Namibia, South Africa.

Western Africa

– Benin, Burkina Faso, Cabo Verde, Côte d’Ivoire, Gambia, Ghana, Guinea, Guinea-Bissau,

Liberia, Mali, Mauritania, Niger, Nigeria, Saint Helena, Senegal, Sierra Leone, Togo.

Caribbean

– Anguilla, Antigua and Barbuda, Aruba, Bahamas, Barbados, Bonaire, Sint Eustatius and Saba,

British Virgin Islands, Cayman Islands, Cuba, Curaçao, Dominica, Dominican Republic, Grenada,

Guadeloupe, Haiti, Jamaica, Martinique, Montserrat, Puerto Rico, Saint Barthélemy, Saint Kitts and

Nevis, Saint Lucia, Saint Martin (French Part), Saint Vincent and the Grenadines, Sint Maarten (Dutch

part), Trinidad and Tobago, Turks and Caicos Islands, United States Virgin Islands.

Central America – Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama.

Southern America

– Argentina, Bolivia (Plurinational State of), Bouvet Island, Brazil, Chile, Colombia,

Ecuador, Falkland Islands (Malvinas), French Guiana, Guyana, Paraguay, Peru, South Georgia and

the South Sandwich Islands, Suriname, Uruguay, Venezuela (Bolivarian Republic of).

Northern America – Bermuda, Canada, Greenland, Saint Pierre and Miquelon, United States of America.

Antarctica – Antarctica.

Northern Asia – Russian Federation (Asian part).

Central Asia – Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan.

Eastern Asia

– China, Hong Kong Special Administrative Region of China, Macao Special Administrative

Region of China, Democratic People’s Republic of Korea, Japan, Mongolia, Republic of Korea,

Taiwan.

South-eastern Asia

– Brunei Darussalam, Cambodia, Indonesia, Lao People’s Democratic Republic,

Malaysia, Myanmar, Philippines, Singapore, Thailand, Timor-Leste, Viet Nam.

Southern Asia

– Afghanistan, Bangladesh, Bhutan, India, Iran (Islamic Republic of), Maldives, Nepal,

Pakistan, Sri Lanka.

Western Asia

– Armenia, Azerbaijan, Bahrain, Cyprus, Georgia, Iraq, Israel, Jordan, Kuwait, Lebanon,

Oman, Qatar, Saudi Arabia, State of Palestine, Syrian Arab Republic, Türkiye, United Arab Emirates,

Yemen.

Eastern Europe

– Belarus, Bulgaria, Czechia, Hungary, Poland, Republic of Moldova, Romania, Russian

Federation (European part), Slovakia, Ukraine.

Northern Europe

– Åland Islands, Channel Islands, Denmark, Estonia, Faroe Islands, Finland, Iceland,

Ireland, Isle of Man, Latvia, Lithuania, Norway, Svalbard and Jan Mayen Islands, Sweden, United

Kingdom of Great Britain and Northern Ireland.

Southern Europe

– Albania, Andorra, Bosnia and Herzegovina, Croatia, Gibraltar, Greece, Holy See, Italy,

Malta, Montenegro, North Macedonia, Portugal, San Marino, Serbia, Slovenia, Spain.

Western Europe

– Austria, Belgium, France, Germany, Liechtenstein, Luxembourg, Monaco, Netherlands,

Switzerland.

Australasia

– Australia, Christmas Island, Cocos (Keeling) Islands, Heard Island and McDonald Islands,

New Zealand, Norfolk Island.

Melanesia – Fiji, New Caledonia, Papua New Guinea, Solomon Islands, Vanuatu.

Micronesia

– Guam, Kiribati, Marshall Islands, Micronesia (Federated States of), Nauru, Northern Mariana

Islands, Palau, United States Minor Outlying Islands.

Polynesia

– American Samoa, Cook Islands, French Polynesia, Niue, Pitcairn, Samoa, Tokelau, Tonga,

Tuvalu, Wallis and Futuna Islands.

For “modern” sky cultures we use the special region name World to deﬁne worldwide applicable data.

Standard country or area codes for statistical use (M49) – https://unstats.un.org/unsd/methodology/m4

110 Chapter 9. Adding Sky Cultures

Figure 9.1: Africa: subregions as delineated by United Nations geographic classiﬁcation scheme:

Eastern Africa, Central Africa, Northern Africa, Southern Africa, Western Africa.

Wikipedia / CC BY-SA 3.0

9.2 Technical data: index.json 111

Figure 9.2: Asia: subregions as delineated by United Nations geographic classiﬁcation scheme:

Central Asia, Eastern Asia, South-eastern Asia, Southern Asia, Western Asia,

Northern Asia. Wikipedia / CC BY-SA 3.0

Figure 9.3: Europe: subregions as delineated by United Nations geographic classiﬁcation scheme:

Eastern Europe, Northern Europe, Southern Europe, Western Europe. Wikipedia / CC

BY-SA 3.0

112 Chapter 9. Adding Sky Cultures

Figure 9.4: Americas: subregions as delineated by United Nations geographic classiﬁcation scheme:

Caribbean, Central America, Northern America, Southern America. Wikipedia / CC

BY-SA 3.0

Figure 9.5: Oceania: subregions as delineated by United Nations geographic classiﬁcation scheme:

Australasia, Melanesia, Micronesia, Polynesia. Wikipedia / CC BY-SA 3.0

9.2 Technical data: index.json 113

9.2.2 Classiﬁcation

The tag “classiﬁcation” allows describing the origin and intended use of this skyculture:

personal

– this is a personally developed sky culture which is not founded in published historical or

ethnological research. Stellarium may include it when it is “pretty enough” without really approving

its contents.

traditional

– (default value) content represents “common” knowledge by several members of an ethnic

community, and the sky culture has been developed by members of such community. Our “Modern”

sky culture is a key example: rooted in antiquity it has evolved for about 2500 years in what is now

commonly known as “western” world, and modern astronomers use it.

ethnographic – provided by ethnographic researchers based on interviews of indigenous people.

historical – based on historical written sources from a (usually short) period of the past.

single – represents a single source like a historical atlas, or related publications of a single author.

comparative

– special-purpose compositions of e.g. artwork from one and stick ﬁgures from another sky

culture, and optionally asterisms as representations of a third. Or comparison of two stick ﬁgure sets

in constellations and asterisms. These ﬁgures sometimes will appear not to ﬁt together well. This may

be intended, to explain and highlight just those differences! The description text must clearly explain

and identify all sources and how these differences should be interpreted.

9.2.3 Constellation boundaries

In the late 18th century, when variable stars started to be catalogued by a code that included the star’s

constellation, a necessity arose to deﬁne which sky region belonged to which constellation. Atlases of

this period showed curved boundaries between the constellations. Such boundaries are hard to describe

by coordinates, though. The Uranographia Argentina (Gould, 1879) proposed a different approach. The

boundaries were described by mostly straight segments along great circles of equal right ascension and small

circles of equal declination. The atlas used coordinates for epoch B1875.0. Based on this work, in 1930

the International Astronomical Union (IAU) ratiﬁed a partition of the sky into the 88 constellations (now

only using lines along constant right ascension/declination of B1875.0) used by scientists and amateurs ever

since. When looking at these boundaries in J2000.0 coordinates, we can see they are no longer parallel to the

J2000.0 coordinate grid, the deviation caused by precession.

Partitions of the full sky into contiguous regions deﬁned by edges between coordinate vertices deﬁned in

equatorial coordinates at a certain epoch can be described in the following elements of the index.json:

" edges_ty p e ": " iau " ,

" edges_source " : " h ttps :// pb a rbier . com / constellations / e d ges_18 . txt " ,

" edges_epoch ": " B187 5 " ,

" ed ges ": [

" 001 : 002 M + 2 2 :52:00 +34:3 0 : 0 0 2 2:52:00 +5 2:30:00 AND LAC " ,

" 002 : 003 P + 2 2 :52:00 +52:3 0 : 0 0 2 3:20:00 +5 2:30:00 AND CAS " ,

" 004 : 005 P + 2 3 :20:00 +50:0 0 : 0 0 2 3:35:00 +5 0:00:00 AND CAS " ,

...

]

where

"edges_type" is optional and may contain the following values:

"none"

— (default) designates that this culture doesn’t have constellation boundaries, and any

edges

entry is ignored.

"iau" — use this value for variants of “modern” sky cultures to declare use of IAU boundaries.

"own" — used for cultures which have their own set of constellation boundaries.

"edges_source" is optional and only given for reference. It is not evaluated.

"edges_epoch" describes the coordinate epoch. Allowed values:

"J2000" (default)

"B1875" used for the edge list deﬁning the IAU borders.

"Byyyy.y" (a number with B prepended) Arbitrary epoch as Besselian year.

"Jyyyy.y" (a number with J prepended) Arbitrary epoch as Julian year.

"JDddddddd.ddd" (a number with JD prepended) Arbitrary epoch as Julian Day number.

"ddddddd.ddd" (a pure number) Arbitrary epoch as Julian Day number.

The lines in the array “edges” were taken from the given reference. The ﬁrst component is ignored. The

next element provides information whether the segment runs along a meridian (

, right ascension) or parallel

(

, declination) circle in ascending

or descending

sense. Then it provides

in sexagesimal

114 Chapter 9. Adding Sky Cultures

numbers (

in HH:MM:SS,

in DD:MM:SS format) and the uppercased constellation abbreviations. As

described in the original source ﬁle, Serpens has been split into

SER1

and

SER2

, these tags are treated both

as SER.

These edges are used to deﬁne isolated boundaries for each constellation (for proper working of the

Select single constellation

option).

9.2.4 Constellations

Constellations are coded as array of dictionaries:

" constellati o n s " : [

{

" id " : " CON mode rn Aql " ,

" li nes ": [ [ 9 8036 , 9764 9 , 9727 8 ] , [9 7 6 49 , 9 5 5 01 , 9 7 804] , [9 947 3 , 9780 4 ] ,

[95 5 0 1 , 9 3 7 47 , 9 3 2 44] , [ 9550 1 , 938 0 5 ]] ,

" im age ": {

" file " : " illustrations / a quil a . png " ,

" size " : [51 2 , 512 ] ,

" anc h ors " : [

{" pos ": [1 6 3 , 232 ] , " hip " : 976 4 9 },

{" pos ": [3 8 5 , 131 ] , " hip " : 932 4 4 },

{" pos ": [3 9 7 , 397 ] , " hip " : 938 0 5 }

]

} ,

" common_name ": { " english ": " Aq uila " , " nativ e " : " Aq uila "}

} , ...

] , ...

where

"id"

A unique ﬁgure identiﬁer, consisting of

CON

(for constellations), skyculture id, and a short Latin-

character based label still unique within the skyculture. For IAU-based skycultures, these short

labels must be the IAU standard labels. For others, you can invent your own. It is not necessary

to have exactly 3-letter keys, but they should act as mnemonic support, so numerical keys are not

recommended: the short label is displayed when enabling abbreviated screen labels (s. 4.4.6). If you

want to prevent certain abbreviations from being displayed, let them start with a dot. See the effect in

the

Modern (H.A.Rey)

sky culture: with abbreviated labels enabled, only the ofﬁcial abbreviations

are displayed.

"lines"

an array of arrays, each describing a polyline with star numbers. The star numbers are usually the

Hipparcos (HIP) numbers. For very dim stars, the longer numbers from the Gaia DR3 catalog are

acceptable, but they must be written as string. Even Deep-Sky objects (like a naked-eye open cluster)

v 25.2

can be added to a constellation line when written as string starting with "DSO:", like "DSO:M7".

To describe dark constellations formed from dust clouds in the Milky Way or other non-stellar items,

v 25.2

another variant can use coordinate lists and is technically an array of arrays of 2-part arrays of ﬂoat

numbers, each pair being right ascension

(decimal hours) and declination

(decimal degrees) in

equinox J2000.0. See below how Stellarium can help you write these arrays.

Single-star constellations or particular highlights can be described with just one star repeated in a

v 25.1

two-element segment. The respective star will be encircled with a radius of

"single_star_radius" (ﬂoat, default 0.5).v 25.1

"hull_extension"

(optional) A vector of star IDs (HIP number as integer, Gaia DR3 long integer

v 25.2

number as string, or a Deep-Sky object (like a naked-eye cluster) as string starting with

"DSO:"

, like

"DSO:M44" that are seen as part of the constellation. See below about convex hull.

"hull_radius" (ﬂoat, defaults to "single_star_radius" or (if that is not deﬁned)0.5).v 25.2

"image" Optional, see 9.2.4.1

"common_name" Dictionary of names.

"native" name in the original language of the skyculture.

"english" translation of the name’s meaning. This is translated to users’ language.

"byname"

an optional explanatory addition to the name. May be helpful to explain mythological

v 25.3

ﬁgures. This is translated to users’ language, but is not included in search functions.

"pronounce"

(optional, but recommended) a Latin-character based transliteration/pronunciation

aid, e.g. Pinyin for Chinese. This may also be translated to user language.

"transliteration"

(optional) a scientiﬁc Latin-character based transliteration where applicable.

This is not translatable or adaptable to user language conventions, but may include extended

9.2 Technical data: index.json 115

diacritics. An example is Wylie for Tibetan, which is not meant to help in pronunciation.

"IPA" (optional) International Phonetic Alphabet, a standardardized phonetic spelling.

These names are used in the sky culture name style settings (s. 4.4.6). If your sky culture is a variant

of the

Modern

sky culture, please use the canonical Latin as

"native"

name and the

"english"

names from the default Modern skyculture, they have all been translated already. Also star names

should provide both

"native"

and

"english"

entries, even if both are identical, to allow transla-

tion/transliteration to languages with other script systems or spelling variants.

If your sky culture is not a variant of the generally known

Modern

(western) sky culture, please

make sure to provide an

"english"

translation (where possible) in addition to the name given in the

"native"

language, or a

"byname"

which may help better understanding a ﬁgure. Else translators

will not be able to translate the name, and users will be less interested to learn about the culture. Also

make very sure to use the same spelling consistently in

index.json

and

description.md

, and

explain the context of stars (how these stars are used, or what they mean to the respective members of

the culture), especially where only an untranslatable proper name is given.

"label_offset"

optional. An array of

[deltaRA, deltaDE]

(decimal degrees) used as offset that shifts

the auto-computed label positions.

"label_positions"

optional. An array of sub-arrays of

[RA, DE]

tuples (decimal hours, decimal

degrees) used as label positions. By default, the label position is computed from the star positions

used in the

"lines"

. With this entry you can set specialized positions, or also use more than one

label per constellation.

"visibility"

(optional) special cases for rule-based visibility, e.g. seasonally changing aspects of ﬁgures.

Currently only a

"months"

rule has been deﬁned. Its “payload” is an array of two integers, start and

end of visibility in months, e.g:

" visibility ": {" months ": [6 , 3 ]} ,

This speciﬁes that the afﬂicted constellation is visible only from June to March, wrapping over the

12-month cycle. A second entry of the same constellation (with possibly different lines, artwork, or

even name) that would be visible from April to May, would be speciﬁed as:

" visibility ": {" months ": [4 , 5 ]} ,

Drawing dark constellations

The outlines of ﬁgures like the “Emu in the Sky” cannot be described with connect-the-dot star patterns, as

v 25.2

they are formed from the absence of luminous patterns. We need to describe them using coordinate lists. To

make the process less tedious, we can extend setting Markers (see 3.6). For this to work, add the following

key to config.ini:

[ devel ]

ma rkers _to_l ogf il e = true

After program restart, setting a marker also writes a numbered line into the logﬁle, containing marker number

and the array of coordinates (

[RA, dec]

). In the text editor you are using to edit

index.json

, the arrays

can be collated into the format required to code coordinate lists for dark constellations.

Constellation area (convex hull)

The constellation area, or convex hull of a constellation, is an area of the sky described by a convex polygon

v 25.2

which surrounds all stars that are part of the lines that form the constellation “stick ﬁgure”, plus those

objects which are listed in

"hull_extension"

. While the IAU has deﬁned 88 constellation areas in 1930,

constellations of other cultures are not as clearly deﬁned. These areas can help analyzing historical records.

Note that a point may lie in zero, one or more than one constellation area(s) when it overlaps two or even

more adjacent ﬁgures.

Technically, the stars are projected perspectively onto a tangential plane to the celestial sphere at the

balance point of all involved stars. Then a simple package wrapping algorithm (Sedgewick, 1990, ch.25)

can be applied to ﬁnd the convex hull. Straight lines in the projection are great circle arcs. Note that this

limits constellation size to less than 180 degrees in the sky, outlying stars will currently be discarded. (Please

report an error if this affects you, so we might ﬁnd a better solution.)

This functionality is an advanced topic mostly used by sky culture researchers (e.g. S. M. Hoffmann,

2017, pages 94–98) who are also not afraid of calling scripting functions (see ch. 17), and is therefore hidden

116 Chapter 9. Adding Sky Cultures

from beginning users. To make use of it, edit your config.ini and add a key:

[ gui ]

sk ycu ltu re_en abl e_h ull s = true

The constellation areas of a skyculture can be queried by a scripting function:

ConstellationMgr.outputHullAreas(<filename_start>);

The argument

<filename_start>

is optional and defaults to

"hullAreas"

. The created CSV ﬁle

<filename_start>_skycultureName.csv

in your Stellarium user data directory lists hull areas for

all constellations of the current skyculture.

You can list stars which belong to a thusly deﬁned constellation with a scripting function:

ConstellationMgr.starsInHullOf("Taurus", false, 12.0, <start>);

This creates a ﬁle

hullStars_Modern_Taurus-12.00.csv

in your Stellarium user data directory which

contains all stars within the convex hull of Taurus in the current (here: “Modern”) sky culture. The arguments

to the function are:

constellation string; name or abbreviation.

hipOnly

Boolean, optional, defaults to

true

; if you are only interested in brighter stars contained in the

Hipparcos catalog, set it true.

maxMag

ﬂoat, optional, default: 25.0. Dimmest stellar magnitude to use. The default value just makes sure

all stars that are contained in the catalogs are listed, the result will only have few entries dimmer than

mag 18.

<start> string, optional, default hullStars; the start of the ﬁlename can be changed here.

9.2.4.1 Constellation Artwork

Constellation artwork is optional, but may give your sky culture the ﬁnal touch, if it requires artwork at all.

E.g., H. A. Rey’s variant of the

Modern

sky culture deliberately does not contain artwork other than his new

set of stick ﬁgures.

Each constellation artwork is linked to 3 stars in its constellation. This is programmed in the

"image"

dictionary. It contains entries

"file"

is the ﬁle name of your texture. All constellation artwork ﬁles should reside in a subdirectory

illustrations

. For best efﬁciency it should be sized in a power of two, like

512× 512

1024× 2048

etc. Avoid dimensions larger than 2048, they are not supported on all systems. Use as little border in

your textures as possible instead. You can distort images to better exploit the pixels, the texture will

be stretched back. The background of the artwork image must be absolutely black.

"size"

Image size (width, height) in pixels. This size speciﬁed here, and not the real image size, is relevant

for the

"anchors"

entry. This may be important on very memory limited systems where you decide

to downscale all textures.

"anchors" An array of three similar dicts with

"pos" pixel addresses [x, y] given from upper left corner (ﬁnd those in any image editor)

"hip"

The star index as Hipparcos (HIP) number, given as integer. This may technically also be a

Gaia DR3 number when given as string.

In case the artwork is only available in a certain projection (e.g., an all-sky map), or is otherwise heavily

distorted so that the match is not satisfactory, you may have to re-project the image somehow. For aligning,

you should switch Stellarium to Stereographic projection for optimal results.

You don’t have to shutdown and restart Stellarium during creation/matching, you can just press

Ctrl

Alt

to reload.

9.2.5 Asterisms and help rays

Sometimes auxiliary ﬁgures were created for easier orientation. Some part of a constellation may have

been redeﬁned into a ﬁgure in its own right, or parts from different constellations were merged into one big

ﬁgure — e.g. “Big Dipper” as part of Ursa Major, or the “Summer Triangle” consisting of 3 stars from the

constellations Cygnus, Lyra and Aquila. After the codiﬁcation of the ofﬁcial 88 constellations by the IAU,

those additional ﬁgures have generally been called asterisms.

In a more generalized context when describing the sky of other cultures, the distinction may be less strict, and the

term “asterism” may even be used for the “primary ﬁgures” observed by those cultures.

9.2 Technical data: index.json 117

Other simple ﬁgures might be used as navigation and orientation helpers: the help rays. As example

to help in orientation in the sky the additional lines between constellations Ursa Major, Ursa Minor and

Cassiopeia might be useful. The asterisms and help rays are listed in

"asterisms"

which is similar to the

"constellations" dict, but has no "figures" entry:

" asteri s m s " : [

{

" id " : " AST mode rn HeG " ,

" common_name ": { " english ": " Heav e nly G " , " referenc e s ": [3 0 ,3 2]} ,

" li nes ": [ [ 2 1421 , 2460 8 , 3685 0 , 378 2 6 , 372 7 9 , 32 3 4 9, 24 4 3 6 , 25 3 3 6 , 2 7 9 89]]

} , ...

]

"id"

A unique asterism identiﬁer, consisting of

AST

(for asterism), skyculture id, and a short Latin-character

based label still unique within the skyculture. It is not necessary to have exactly 3-letter keys, but they

should act as mnemonic support, so numerical keys are not recommended: the short label is displayed

when activating abbbreviated labels (s. 4.4.6). If you want to prevent certain abbreviations from being

displayed at all, let them start with a dot.

"common_name"

Another dict with entries

"native"

(as used in the source),

"english"

(the translatable

english name),

"pronounce"

"transliteration"

"IPA"

and

"byname"

as deﬁned for constella-

tions, and an optional array

"references"

which lists from which sources (from 9.1.2) this asterism

was taken.

Collecting sources and giving such references is always a good idea. If you feel ther are more in the

collection than you like, read 9.2.9.1 about suppressing excessive entries.

"label_offset"

optional. An array of

[deltaRA, deltaDE]

(decimal degrees) used as offset that shifts

the auto-computed label positions.

"label_positions"

optional. An array of sub-arrays of

[RA, DE]

tuples (decimal hours, decimal

degrees) used as label positions. By default, the label position is computed from the star positions

used in the

"lines"

. With this entry you can set specialized positions, or also use more than one

label per asterism.

"is_ray_helper"

(optional, default=

false

). Set to

true

to declare this asterism as “ray helper” which is

shown in a different color and without label.

"lines"

an array of arrays, each describing a polygon with integer star numbers. The star numbers are

usually the Hipparcos (HIP) numbers. For the very dim stars of telescopic asterisms, the longer

numbers from the Gaia DR3 catalog are acceptable, but they must be written as string. Another variant

can use coordinate lists and is technically an array of arrays of 2-part arrays of ﬂoat numbers, each

pair being right ascension

(decimal hours) and declination

(decimal degrees) in equinox J2000.0.

Single-star asterisms can be described with a two-element array that repeats the ﬁrst entry (star or

v 25.1

coordinate pair) – the respective star/coordinate will be encircled with a radius of

"single_star_radius"

(ﬂoat, default 0.5) radius of a circle (degrees) marking single-star segments in

v 25.1

"lines".

9.2.6 Culture Relevant Coordinate Systems: Zodiac and Lunar Systems

Ancient high cultures in and around Asia took special note of the zone where the planets move: along the

v 25.2

path of the Moon, a system of 27 or 28 lunar stations or lunar mansions were formed, and later the Sun’s

annual path was split into 12 equal-size parts of 30 degrees along the ecliptic.

The best-known system in modern times is that of the tropical zodiac of

12× 30

degrees along the ecliptic,

counted from the equinox point (First point of Aries

). The 12 sections, or zodiacal signs, were named

after the constellations which resided there at the time the system was codiﬁed. Precessional movement

since antiquity moved the stars eastwards along the ecliptic by about one full sign, so that meanwhile

there is usually a mismatch between the constellation the sun is in and the sign which you ﬁnd listed in

bad newspapers’ horoscope pages. Astronomically, the zodiacal sign is just an old-fashioned way to write

ecliptical coordinates of date.

In India, the partitions were deﬁned so that the star Spica rests at the 180° mark, so that the Indian or

sidereal zodiac moves along the ecliptic with precession.

" zodiac ": {

" name " : { " pronounc e ": "R¯aśi" , " engl i sh " : " In dian Z odiac "} ,

" con t ext " : " i ndian z odiac sign " ,

" partitio n s ": [ 1 2 , 3, 2 , 5 ],

" extent ": 9 ,

118 Chapter 9. Adding Sky Cultures

" link " : { " star ": 6 5 4 74 , " offs et " : 180 } ,

" na mes ": [ { " s ymbol " : "\ u26 48 " , " nativ e " : " ... " , " en g lish ": " Ram "} ,

{ " sym bol " : " \ u2649 " , " native ": " ... " , " englis h " : " Bull "} ,

...

{ " sym bol " : " \ u2653 " , " native ": " ... " , " englis h " : " Fis hes "} ] },

where

"name" cultural name as described in 9.2.7.

"context"

(optional, recommended) context data for all English names in zodiac (enhancement of local-

ization support).

"comment" (optional) commentary for zodiac, it will be used as extra commentary for translators also.

"partitions"

regular division of the centerline. The ﬁrst element commonly is 12 (30-degree sign). The

other elements (up to 3) are used to describe the tick marks in decreasing order. The example means,

the 30 degrees are further divided in 3 sections (large 10-degree ticks), these are split in 2 5-degree

sections with 5 sections (1-degrees) each.

"extent"

The zone of interest is closed off by parallel lines this many degrees north and south of the

centerline. A zodiac of 9 degrees encloses extreme positions of all major planets.

"link"

(optional) The Indian sidereal zodiac is described to be deﬁned with the longitude of a certain star.

Usually and in this sample, Spica (

Vir, HIP 65474) is declared to lie at 180°. If missing, the zodiac

starts from à.

"names"

Sequence of names. In addition to the elements listed in 9.2.7,

"symbol"

provides a Unicode

symbol (as shown here, these are the common zodiacal signs) or 1-2 letter string (for practical reasons,

a number seems generally useful). The number of entries must be equal to (or larger than) the ﬁrst

element of "partitions". Excessive entries are ignored.

More important for Indians however, and still relevant today, is the traditional system of lunar stations, the

nakshatras. the ecliptic is split into 27 equal-sized partitions, which are then further split into 4 equal parts.

" lunar_system " : {

" name " : { " nat ive " : " ... " , ... , " engl ish " : " Na k s h atras " } ,

" con t ext " : " i ndian luna r mansio n " ,

" partitio n s ": [ 2 7 , 4] ,

" extent ": 5 ,

" link " : { " star ": 6 5 4 74 , " offs et " : 180 } ,

" na mes ": [ { " s ymbol " : "1 " , " na tive ": " ... " , ... , " englis h " : " Physic i a n to the

↪ Gods " } ,

{ " sym bol " : " 2" , " native " : " ... " , ... , " engli s h " : " Be arer "} ,

{ " sym bol " : " 3" , " native " : " ... " , ... , " engli s h " : " Plei a des " } ,

...

where

"name" cultural name as described in 9.2.7.

"context"

(optional, recommended) context data for all English names in lunar mansions (enhancement

of localization support).

"comment"

(optional) commentary for lunar system, it will be used as extra commentary for translators

also.

"partitions" regular division of the centerline. 27 stations which are further divided in 4 equal parts.

"extent"

The zone of interest. With an obliquity of the Lunar orbit of about 5 degrees, a 5-degree zone

seems appropriate.

"link"

(optional) The Indian system is again described to be deﬁned with the longitude of Spica (

Vir,

HIP 65474) to lie at 180°. If missing, the count starts from à.

"names"

Sequence of names. In addition to the elements listed in 9.2.7,

"symbol"

provides a Unicode

symbol or 1-2 letter string (for practical reasons, a sequential number seems generally useful). The

number of entries must be equal to (or larger than) the ﬁrst element of

"partitions"

. Excessive

entries are ignored.

In the Arabian peninsula, a similar system of 28 lunar stations is in use until today, but the actual asterism

appears to be more important than the regularity of the ecliptic partition. The ﬁrst station is centered around

al-Thurayya (the Pleiades star cluster). In some skycultures the “band” of stations around the ecliptic is

shown irregular, with boxes trying to frame the associated asterisms:

" lunar_system " : {

" name " : {" engl i sh " : " Lunar S t ations " , " nativ e " : " ... " , " pr o n o unce " : " Ma n azil

↪ alQamar ", " IPA " : " manazilulqamar " } ,

9.2 Technical data: index.json 119

" partitio n s ": [ 2 8 , 3, 2] ,

" extent ": [ 1 0.0 , -1 0.0 , 1 0 .0 , -1 0 .0 , 1 0 . 0 , - 1 5 .0 , 1 0 . 0 , -1 5 .0 , 1 5 . 0 , ... ] ,

" con t ext " : " arabian luna r station s ",

" link " : { " star ": 1 7 7 02 , " offs et " : 6.4 2 8 5714 2 8 5714 2 9 , " comm e nt " : " center of

↪ f irst s tation is Lucida P l eiadum "} ,

" na mes ": [ { " s ymbol ": " 1 ", " engl i sh " : "Al - Thuray y a " , " nat ive ": " ... " , ... } ,

{ " sym bol " : "2 " , " en g lish ": " Al - Da b aran " , " nat ive ": " ... " , ... } ,

...

where

"partitions"

regular division of the centerline. 28 stations which are further divided into 3 equal parts

that are further halved.

"extent"

As array of latitude coordinates, they provide alternating north and south latitudes for all stations.

v 25.3

The number of entries must be twice the number of partitions.

In China, the 28 lunar mansions are deﬁned in a different way. 28 deﬁning stars mark the begin (western

edge) of each mansion, and great circles are drawn from the celestial poles through these stars. In Stellarium,

the deﬁning stars are marked with a little circle. The mansions are quite different in width.

" lunar_system " : {

" name " : { " nat ive " : " ... " , " pr onounce " : "Xiù" , " e n glish ": " Lunar Mans i on " } ,

" con t ext " : " chinese luna r mansi o n " ,

" defining_st a r s " : [6 5 4 74 , 6 9 4 27 , ... ] ,

" coor d s ys " : " equato r i a l " ,

" extent ": 9 0 ,

" na mes ": [ { " s ymbol " : "1 " , " na tive ": " ... " , " pron o u n ce " : "Jiˇao", " eng l ish " :

↪ " Horn " } ,

{ " sym bol " : " 2" , " native " : " ... " , " pro n o u nce " : "Kàng", " en glish ":

↪ " Neck " } ,

...

where

"name" cultural name as described in 9.2.7.

"context"

(optional, recommended) context data for all English names in lunar mansions (enhancement

of localization support).

"comment"

(optional) commentary for lunar system, it will be used as extra commentary for translators

also.

"defining_stars" List of HIP numbers of the 28 deﬁning stars.

"coordsys" may be "equatorial" or "ecliptical" (default).

"extent" The zone of interest. The Chinese mansions extend from pole to pole.

"names"

Sequence of names. In addition to the elements listed in 9.2.7,

"symbol"

provides a Unicode

symbol or 1-2 letter string (for practical reasons, a number seems generally useful). The number of

entries must be equal to (or larger than) the number of elements of

"defining_stars"

. Excessive

entries are ignored.

9.2.7 Names of Stars, Planets and Nonstellar Objects

Many cultures have deﬁned their own names for stars, planets and even a few deep-sky objects bright enough

to be seen with the unaided eye. The

"common_names"

dict in a skyculture ﬁle

index.json

contains entries

of arrays tagged with HIP catalog numbers or other names.

Names for stars, constellations, asterisms, planets and DSOs can be speciﬁed with a plethora of options:

v 25.2

"native" name in the original language of the skyculture.

"english" translation of the name’s meaning. This is translated to users’ language.

"pronounce"

(optional, but recommended) a Latin-character based transliteration/pronunciation aid, re-

quired when

"native"

is written in non-Latin-based glyphs (e.g., Chinese, Arab, Hindu, Tibetan,

. . . ), e.g. Pinyin for Chinese. This is usually written with simple characters found on typewriters and

may also be translated to user language to adopt different customs.

"transliteration"

(optional) a scientiﬁc Latin-character based transliteration where applicable. Not

translatable to user language, but may use extended diacritics. The scheme may not be helpful as

pronunciation aid. For example, Wylie for Tibetan.

"IPA" (optional) International Phonetic Alphabet, a standardardized phonetic spelling.

"byname"

an optional explanatory addition to the name. May be helpful to explain mythological ﬁgures.

v 25.3

This is translated to users’ language, but is not included in search functions.

120 Chapter 9. Adding Sky Cultures

"translator_comments" (optional): comments to be shown to translators on Transifex.

"references" (optional): array of integers, referring to the references list in description.md.

As example, we show a part of the Samoan skyculture:

" common_names " : {

" HIP 32349 ": [ { " eng lish " : " G l iding Star " , " native ": "F¯et¯usolonu

‘

u"}] ,

" HIP 68702 ": [ { " eng lish " : " Mea " , " n ative " : " Mea " } ] ,

" HIP 71683 ": [ { " eng lish " : " Fil o " , " native " : " Filo " }] ,

" M45 " : [{" engli sh " : " Face of Li

‘

i", " nat ive " : "Mat¯ali

‘

i"}] ,

" NGC 2 055 " : [ {" eng l ish " : " Pale Clo ud " , " n ative ": " Aotea " }] ,

" NGC292 ": [ { " en g lish ": " F lyin g Cloud " , " native " : " Aol ele " } ] ,

" NGC 6 093 " : [ {" eng l ish " : " Pae " } ] ,

" NGC 6 121 " : [ {" eng l ish " : " Suga " } ] ,

" NAME Earth " : [ {" engl i sh " : " Earth " , " na tive ": " L alolagi "} ] ,

" NAME Jupite r " : [{ " e nglish ": " Und ying Mys t ery " , " native " : "Tupual¯egase"}] ,

" NAME Mars ": [ { " eng lish " : " R e ddish Face / S urface " , " nat ive " : " Ma tamemea "} ] ,

" NAME Mercur y " : [{ " e nglish ": " Brow n ish " , " native ": "Ta ' elo "}] ,

" NAME Moon ": [ { " eng lish " : " Moo n " , " native " : "M¯asina"}] ,

" NAME Satur n " : [{" englis h " : " Gar l and Star " , " nati ve " : "F¯et¯u

‘

¯asoa"}] ,

" NAME Sun ": [ { " english ": " Sun " , " na tive ": "L¯a"} ] ,

" NAME Venus " : [ {" engl i sh " : " Mo rning Star / F o r b idden Radian c e " , " nat ive ":

↪ " Tapu ' itea "}]

}

9.2.7.1 No translation in Modern Skyculture?

The star names that have been collected over the years in our default Modern skyculture come from an

extensive collection of sources. Some names from Latin and Arab sources have a well-known meaning. In

contrast to what we recommend for non-modern skycultures, we still keep the original name as translation in

the

"english"

string, as such names are used internationally, without thinking about the translated meaning.

Translated names may show slight, language dependent, spelling variations, or transliterations to other glyph

systems, though. At best, the "byname" can transport a translation of the meaning to user language.

9.2.7.2 Star names

The Keys for stars generally start with

"HIP "

. The associated array contains again dicts providing

"native"

(original) and

"english"

(translatable) spellings of the star names, and

"references"

(optional but highly

recommended) which indicates in which sources (see 9.1.2) these star names or particular spellings occur.

The

"english"

name will be translated. An additional

"native"

entry can be given, which is the culture-

native version of the spelling (also in language-speciﬁc glyphs when available in UTF8 and the current font)

and will never be translated but can be shown on screen if so conﬁgured.

" c o mmo n_n ame s ": {

" HIP 6 7 7 " : [{ " nat i ve " : " Alp h era t z " , " e ngli s h " : " Alph e rat z " , " re fer e nce s " : [ 1

↪ , 2 , 5 ,6 ,1 1 ,12 ,3 7] } ,

{" n ative " : " Si r rah " , "e n glis h ": " S i rrah " , " r ef e ren c es " : [2 3 ,37 ]} ] ,

" HIP 7 4 6 " : [{ " nat i ve " : " C aph " , " en g lish " : " Caph " , " r efe ren c es " : [1

↪ , 2 , 6 ,1 1 ,12 ,2 3 ,37 ]} ,

{" n ative " : " Al S a nam al Nakah " , " en g lish ": " Al S a n am al Nakah " , " r e fer e nce s " : [ 37 ]} ] ,

... }

When there is more than one name for a star, the ﬁrst in the list is used as screen label.

9.2.7.3 Planet Names

The "common_names" array can also contain dicts of native names of the planets. For these, the JSON key

is formed from

"NAME "

, a space and the English name of the planet. The value array provides the dict

entries ("native", "english", . . . ) listed above.

Currently, if more than one

"english"

strings are given, the ﬁrst is used as screen label. This may

change as the features further evolve.

In some cultures, Venus and even Mercury may have different names, depending on evening or morning

v 25.2

visibility. We can add a tag

"visible"

which may be either

"morning"

"evening"

to select the name.

If the base name should be the screen label, you must repeat it as ﬁrst entry of the object’s

"NAME "

name

array. If the elongation-dependent name should be screen label, place the names with

"visible"

ﬁrst, then

repeat the standard name to be shown in the Info text. See the examples for Venus as Morning Star and

Evening Star in the modern skyculture.

In earlier versions it was recommended to combine the native name with an English translation. In the

new format here we should keep them separate, and the actual screen label can be combined from available

components on the ﬂy (see 4.4.6).v 25.2

9.2 Technical data: index.json 121

9.2.8 Deep-Sky Objects Names

"common_names"

can also contain native names for deep-sky objects (DSO). The content of the dicts is

similar to the format for planet names above. Known tags are

"english" English meaning

"native" (optional) Native name. May be in native glyphs when supported in UTF8.

"pronounce" (optional) Native name in European glyphs, if needed. For Chinese, expect Pinyin here.

"translators_comments"

(optional) English explanations that help in translation. Not displayed in the

program.

"references" (optional) the sources for these names where applicable

9.2.9 User Settings for the Skycultures

The large number of label combinations requires storing them in a user accessible way. In essence, we are

v 25.2

using a 6-bit scheme with name elements that either show up or are omitted.

Native to show the native name in native glyphs.

Pronounce to show a Latin-character based transliteration usable as pronunciation aid.

Translit to show a scienticic transliteration that is not necessarily aimed at pronunciation.

Translated to show the meaning of the name translated to user language.

IPA to show the name in International Phonetic Alphabet.

Modern to show the contemporary scientiﬁc object name.

The names for the active parts are joined with commas (the sequence of entries is irrelevant and does not

inﬂuence displayed order), and the resulting strings stored in config.ini in two dedicated sections like:

[ SCIn f o L a b e l S t y le ]

arabic _ a r a bi an_penin s u l a = Native , Pron oun ce , Modern

bo o rong = Native , T r a n s lated

ch i nese = Native , Pronounce , Tran slat ed , Mo dern

mo dern = Native , Moder n

russian_siber i a n = Native , Pronounce , Tra nslit , Tran slat ed ,IPA , Mode rn

[ SC S c r e e n L ab e lS t yl e ]

arabic _ a r a bi an_penin s u l a = Pronou nce , Transla ted , Modern

aztec = Native , T r a n s l ated

ch i nese = Pronounce , Translate d , Mod ern

mo dern = Native , Moder n

russian_siber i a n = Pronounce , Translate d , Modern

9.2.9.1 Not enough, or too many names?

Over the years, we have collected a quite extensive list of star names from many references. Until recently,

the scientiﬁc community was not interested in standardizing names. With the introduction of Exoplanet

naming contests, the International Astronomical Union started to also be concerned with the names of the

brighter stars, and a proper Working Group on Star Names has formed.

Stellarium comes with a list of standardized names in

skycultures/common_star_names.fab

. These

are always used when a skyculture shows

"fallback_to_international_names"

(see 9.2). If you always

want to see these names, regardless of whether they are used or not in the respective skyculture, add the

following to your config.ini:

[ viewing ]

fl a g_s kyc u ltu re_ a lwa ys_ f all bac k _to _in t ern ati o nal _na mes = true

Activating this ﬂag for non-modern skycultures may feel weird, though, as it mixes these names into the

other-cultural namespace.

Excluding excessive names

In contrast, some of the collected names may be too fanciful for your taste. If you can identify that those

v 25.2

names that irritate you all come from a single or just a few entries of the reference list, you can exclude those

sources, and thus the names they bring into the program. Note that if a fancy name comes from more than

one book, you would have to exclude all books to ban that name from your display.

In a similar way, some of the collected asterisms (secondary ﬁgures), especially in the default Modern sky

culture, may be too much for you. There are overlapping entries like the “Winter Hexagon” vs. “Heavenly

G”, or parts of constellations like Orion’s shield and cudgel are marked as asterism. Some users may ﬁnd

that this clutters their screens too much. If you cannot identify a reference which introduces the unwanted

122 Chapter 9. Adding Sky Cultures

asterism (for some entries we cannot specify a source, unfortunately), you can also exclude them by their

unique abbreviation, which is the last part of their "id" entries.

To exclude entries from being displayed for a particular skyculture, add an entry like this to

config.ini

[ SC Exc ludeR efere nce s ]

modern = 11 ,36 , OrB ,OrS , OSh ,OrC , HeG ,Sal , TPT

Here,

modern

names the skyculture, and the comma-separated entries are references listed in the ﬁle

description.md or asterism abbreviations you want to be ignored.

9.3 The Skyculture Converter

Many sky cultures have been created and maintained outside of Stellarium. They follow the old format,

which is no longer supported since Stellarium version 25.1. To ease the transition we have developed a

converter tool. It is a console application that takes a path to the old-format sky culture directory, and a path

where to put the converted sky culture.

The converter is installed together with the program, but there is no menu entry for it. On Windows,

press the Windows key and type cmd to startup the command console.

Let us assume you have created a skyculture following the format used until version 24.4 and described

in previous editions of this Guide, and that this skyculture

mine

resides in the default user data directory on

Windows (see 5.1 for other platforms). First we rename the skyculture to indicate that it is old and outdated.

Then we must call the converter in its absolute path name, with names of old (source) and new (target)

directories as program arguments.

Example command to run it:

cd c :\ Users \< ME >\ AppD ata \ Roaming \ s kycu lture s

move mine mine . old

"c :\ Program Files \ ste llari um \ skyculture - conver ter " mine . old mine

While the converter tries hard to convert the description text from HTML to Markdown adding some

sections from other parts of the sky culture, the conversion result may not be perfect. Formerly the description

was completely free in structure, while now there are some structural requirements on it, so the text may

need some editing to conform.

If you have gettext translation ﬁles (the ones whose names are in the form

locale-name.po

) for the

names of stars, constellations etc., you can pass the path to the directory that contains them as an optional

third positional argument to the converter.

Additionally, there are some options that you can use to control the conversion:

--footnotes-to-references

Convert footnotes in a particular form to references. Such footnotes are

expected to be in the form of

This is a footnot e

while the references to them are expected to be in the form of

--untrans-names-are-native

Put the names that in

star_names.fab

or in

dso_names.fab

are de-

noted without an underscore into the

"native"

section of the name, rather than

"english"

. For

example, with this option

32349|("F¯et¯usolonu

‘

u")

would be used for the

"native"

name, while

32349|_("Gliding Star") would be used for the "english" tag.

--native-locale LOCALE

In addition to ﬁles

star_names.fab

dso_names.fab

, some sky cultures

have localized versions of them, like e.g.

star_names.zh_CN.fab

, that were never actually used

but do contain useful information. If you pass the locale (

zh_CN

in this example) as the

LOCALE

parameter, these names will be read and put into the

"native"

section of the corresponding JSON

entry. Note that the order of stars/DSOs in the normal and localized ﬁles must be the same, otherwise

there’s no way to match the names.

--translated-md

To check the look of the translated description texts you can use this option. The output

directory will contain ﬁles named like

description.es_419.DO_NOT_COMMIT.md

, in addition to

description.md

, with the

DO_NOT_COMMIT

part reminding you that they are not a part of the sky

culture.

9.4 Publish Your Work 123

After the run, read the notes and warnings, and adjust your text accordingly. Make especially sure to prepare

and adjust your old

description.en.utf8

for successful conversion. For example, it must start with an

HTML header of level

<h1>

(the only such header in this ﬁle!) which is expected to match the skyculture

name given in the old info.ini. If in doubt, the latter will be used in the new ﬁles.

Generally, clean HTML should be converted successfully. Given the wide variety of writing styles, not

every conversion may however work ﬂawlessly, and you may have to adjust the result, also in light of the

new features. To protect any changes you may have added after conversion, running the converter again

needs a new target directory.

9.4 Publish Your Work

If you are willing to let other users enjoy the result of your hard work (and we certainly hope you do!),

when you are done, please write a note in the Forum or at GitHub. We will decide about acceptability and

classiﬁcation, or may ask for better descriptions for the beneﬁt of our users.

Please put the imagery and text under some compatible open-source license (see 9.1.3). Else the sky

culture cannot be hosted by us. While we cannot be held responsible for legal problems, it seems that CC BY

4.0 International

or CC BY-SA 4.0 International

licenses are best suited. See notes in section 9.1.3 above.

https://creativecommons.org/licenses/by/4.0/

https://creativecommons.org/licenses/by-sa/4.0/

10. Surveys

GUILLAUME CHÉREAU

10.1 Introduction

A sky survey is a map of the sky stored as a hierarchical set of a potentially large number of smaller images

(called tiles). The advantage compared to a regular texture is that we need to render only the visible tiles of

a potentially gigantic image at the lowest resolution needed. This is particularly interesting for rendering

online images that can be stored on a server, while the client only has to download the parts he currently uses.

Since version 0.18.0, Stellarium added some preliminary support for loading and rendering online

surveys in the Hierarchical Progressive Surveys (HiPS) format, developed by the International Virtual

Observatory Alliance. A full description of the format can be found on the IVOA website

10.2 Hipslist ﬁle and default surveys

Hipslist ﬁles are text ﬁles used to describe catalogs of HiPS surveys. The full speciﬁcation is part of the

HiPS format, and looks like that:

# Exa m ple of a h i pslist file .

# Date : 2018 -03 -19

obs _ t i tle = call i s to

hips_service_ u r l = https :// data . stellari u m . org / surve y s / ca llisto

hips_relea s e _ d a t e = 2018 -03 -18 T14 :01 Z

hips_s t a t u s = pub lic mi rror clonableOnce

...

Stellarium by default tries to load HiPS from two sources:

•

http://alasky.u-strasbg.fr/MocServer/query?*/P/*&get=record (deep sky)

•

https://data.stellarium.org/surveys/hipslist (planets)

This can be changed with the

sources

entries in the

[hips]

section of the conﬁguration ﬁle (see also

section D.1.29). You can add your own private HiPS surveys by either running your own (even machine-local)

webserver, or just placing your ﬁles into any directory and adding a file:// URL:

[ hips ]

so u rces /1/ url = http :// alas ky .u - strasbg .fr / MocServ e r / query ?*/ P /*& get = recor d

so u rces /2/ url = http s :// data . s t e llarium . org / sur veys / h ipslist

so u rces /3/ url = http :// localhost / Ste l l a r i um / hips / h ipslist

so u rces /4/ url = file :/// D :/ Stel l a r i u m / hips / h ipslist

so u rces / size = 4

https://www.ivoa.net/documents/HiPS/20170519/REC-HIPS-1.0-20170519.pdf

126 Chapter 10. Surveys

10.3 Solar system HiPS survey

Though not speciﬁed in the HiPS standard, Stellarium recognises HiPS surveys representing planet textures,

as opposed to sky surveys. If the

obs_frame

property of a survey is set to the name of a planet or other solar

system body, Stellarium will render it in place of the default texture used for the body.

10.4 Digitized Sky Survey 2 (TOAST Survey)

GEORG ZOTTI, ALEXANDER WOLF

The older way to provide a tessellated all-sky survey uses the TOAST encoding

. Stellarium provides access

to the Digitized Sky Survey 2, a combination of high-resolution scans of red- and blue-sensitive photographic

plates taken in 1983–2006 at Palomar Observatory and the Anglo-Australian Observatory.

To enable access to the DSS layer, see section 4.3.3 and enable the DSS button. Then just press that

DSS button in the lower button bar, wait a moment, zoom in and enjoy!

10.4.1 Local Installation

This display normally requires access to the Internet. However, in some situations like frequent and extensive

use in ﬁxed observatories, or use in the ﬁeld when Internet connection is not possible, you can download all

image tiles to your local harddisk for local use. Please be considerate, don’t waste bandwidth, and do this

only if you really need it.

The images are stored in subdirectories that increase in size and number of ﬁles (see Table 10.1).

Zooming in loads the next level if available.

Level No of ﬁles Filespace (kB)

Level No of ﬁles Filespace (kB) Level No of ﬁles Filespace (kB)

0 1 32 4 256 7.172 8 65.536 1.661.808

1 4 124

5 1.024 27.920 9 262.144 6.119.092

2 16 472

6 4.096 109.628 10 1.048.576 20.250.216

3 64 1.820

7 16.384 429.800 11 4.194.305 83.583.724

Table 10.1: Number of ﬁles and storage requirements for local DSS TOAST installation

For partial downloads, you can limit the maximally used level (e.g. 9 or 10). The difference from level

10 to 11 is really hardly noticeable, yet level 11 contains almost 75% of all data. On a small system like

Raspberry Pi 3, you may run into troubles with too little texture memory when level is more than 7.

Another issue: the level 11 subdirectory holds over 4 million ﬁles. Windows Explorer is not optimized

to open and display this number of ﬁles and will take a long time to open. Just unpack this archive, but don’t

access the folder with Explorer.

If all that does not discourage you, you can download the archives at

https://dss.stellarium.org

/offline/.

Then add a few entries to the

[astro]

section in Stellarium’s

config.ini

. On Windows, if you have

a harddisk

with path

T:\StelDSS

that contains the unpacked image subdirectories 0, 1, 2, . . . , 10, the

section may look like

[ astro ]

to ast _surv ey_ dir ector y = StelDSS

to ast_s urvey _host = T :/

to ast _s urv ey_le vel s = 10

On Linux, with the ﬁles stored in

/usr/local/share/Stellarium/StelDSS

, the same section could look

[ astro ]

to ast _surv ey_ dir ector y = usr / local / share / Stellarium / StelDSS

to ast_s urvey _host = /

to ast _s urv ey_le vel s = 10

Please see http://montage.ipac.caltech.edu/docs/WWT/ for details

The original data are available at https://archive.stsci.edu/cgi-bin/dss_form.

11. Stellarium’s Skylight Models

GEORG ZOTTI

11.1 Introduction

Stellarium’s main aim is a realistic simulation of the night sky. This is more than just the creation of a star

map. Especially a realistic simulation of twilight and the visibility of stars, deep-sky objects or the Zodiacal

light is a challenge. Since early in its history Stellarium has used models from the computer graphics

literature to achieve its goals. For most users, the models seem to work well, but more advanced users may

want to tweak some of the values.

11.2 The Skylight Models

11.2.1 Legacy Mode: The Preetham Skylight Model

A well-known fast computer graphics model for daylight has been presented by Preetham, Shirley, and Smits

(1999). Its brightness distribution is based on an all-weather model for sky luminance distribution by Perez,

Seals, and Michalsky (1993) and models chromaticity distribution with similarly-shaped functions. It works

reasonably well for average conditions, and a “turbidity” parameter

allows a simple modelling of visibility

conditions. In terms of the atmospheric extinction coefﬁcient k (see 19.13.1), we can deﬁne

T = 25(k − 0.16)+ 1 (11.1)

In Stellarium, a value of

T = 5

has been used for many years, and the chromaticity parameters have been

slightly changed for a more pleasing color distribution at this value for

. Recently, we have made the many

parameters of the Preetham model accessible for users to ﬁne-tune. Not many users will even want to do this,

and therefore you must enable this manually by editing config.ini:

[ Sky light ]

enable_gui = true

Only with this setting, a button will be available in the View settings, Sky tab (section 4.4.1.2).

All settings described here will immediately be stored in config.ini.

One setting allows to compute T from k with the above relation 11.1.

Please note that the parameters are far from intuitive, therefore we added two sets of reset functions. One

sets the values to those in the original paper, the other re-establishes Stellarium’s sky colors from version

0.21.3 and earlier, which however seem only suitable for T = 5.

128 Chapter 11. Stellarium’s Skylight Models

A sky brightness model better suited for astronomical simulation, including twilight and brightness

contributions of the Moon and airglow, was presented by B. E. Schaefer (1989-93 and 1993). By default,

Stellarium uses this model in combination with chromaticity from the Preetham model. For experiments,

you can however revert from the Schaefer brightness model to the Preetham model. The parameters of the

Schaefer model are currently not accessible for further experiments.

Some more parameters ﬁne-tune some aspects of rendering of the Solar disk and the solar glare. It makes

a slight difference whether the Sun’s disk is plotted before or after the glare, and whether the solar sphere is

rendered after the atmosphere.

11.2.2 Advanced Mode: The ShowMySky Skylight Model

A much more advanced skylight model has been presented by Bruneton and Neyret (2008). An implementa-

tion of this has been developed by Ruslan Kabatsayev just in time for inclusion in version 1.0. Switching

between the models is described in section 4.4.1.2.

It requires graphics hardware which uses OpenGL 3.3 or better and consists of two components.

Atmospheric data (a description of gas composition) is processed by an auxiliary program, CalcMySky,

which creates a lot of textures and shaders. For ﬁnal display, a software component (the ShowMySky library)

is used that processes these data in real-time to compute the ﬁnal sky colors. This model and its default

atmosphere data especially can deliver stunning reality of twilight colors in a dry atmosphere, and also

provides special modes for the “circular twilight” during a Total Solar Eclipse.

To choose a dataset

press near the Path to data entry ﬁeld, and in the dialog that opens, choose the

directory with the dataset. Stellarium comes with a default dataset that’s automatically chosen after a

fresh installation. Power users can use CalcMySky

to generate other atmospheres. Creating a new

dataset requires some understanding of the physics of light scattering.

Eclipse simulation quality

option lets you conﬁgure the balance between realism of skylight simulation

during a solar eclipse. The values of this option can be:

This is the fastest and crudest mode. The atmosphere is simply dimmed to account for the lower

amount of direct sunlight.

This is the ﬁrst mode that actually tries to simulate an eclipse. It uses precomputed textures, and

may look blocky in some cases like e.g. very low Sun (and Moon).

This mode is much slower than the previous one (2.5 FPS on an NVIDIA GeForce GTX 750Ti).

In this mode part of the calculation is done on the ﬂy for the current eclipse phase to improve

correctness of the simulation, unlike the previous mode where a texture was used that contains

data only for totality, other phases being approximated from this.

This is the slowest mode (1.1 FPS on NVIDIA GeForce GTX 750Ti), but computation is done on

the ﬂy for the whole simulation, which yields best quality.

To achieve higher frame rates on slow systems, the conﬁguration parameter in config.ini:

[ landsca pe ]

at mos phe re_ reso lut ion _re duc tio n = 4

allows reducing the resolution of the skylight texture. Preferred values are:

1 full resolution (default)

2 half resolution

4 quarter resolution

The conﬁguration switch in config.ini:

[ landsca pe ]

fl ag_ a tmo sph ere _dy nam ic_ res o lut ion = true

allows to use the reduced resolution only while moving the view, when panning, zooming, dimming

or in time-lapse mode. With the real-time display, on the other hand, the full resolution is retained.

Possible values are:

false static resolution (default)

true dynamic resolution

https://github.com/10110111/CalcMySky

11.3 Light Pollution 129

Note:

In dynamic resolution mode, a motion analyzer selects either full or reduced resolution. The change

in resolution could be particularly visible in close proximity to the Sun. Especially at full resolution,

frames will be skipped depending on the speed of movement.

A more detailed description of how to create a custom atmosphere will be given in a future version of this

User Guide.

11.3 Light Pollution

In urban and suburban areas the night sky is lit by ground sources of light. This light is scattered by the

atmosphere, and the sky appears brighter. This reduces visibility of astronomical objects.

Stellarium simulates this effect. The main physical quantity that describes light pollution is zenith

luminance, measured in candelas per square meter (

cdm

). It can be measured using a device called sky

quality meter (SQM).

For astronomical observations often another unit of sky brightness is useful: magnitudes per square

arcsecond (magarcsec

). It is related to cdm

L = 10.8× 10

4−0.4M

, (11.2)

where

is the value in

cdm

, and

is the value in

magarcsec

. Some SQMs give readings in

magarcsec

Stellarium supports input in both units.

Another way to characterize light pollution is by deﬁning the naked-eye limiting magnitude (NELM).

Unlike luminance, which, although based on human vision, is well-standardized (in particular, the candela is

part of the SI), NELM is subjective and variable: it is based on human vision, depends on weather conditions,

and is not standardized. In Stellarium the calculations follow B. E. Schaefer (1990). In particular, equation

(18)

is used, assuming observer’s acuity

= 1

(as suggested in the text as “typical observer”), and absorption

term k

= 0.3 (as suggested for “typical weather”).

A related subjective characterization of light pollution is the Bortle Dark Sky Scale, which assigns an

integral number from 1 to 9 to the sky based on its brightness. This scale is described in detail in Appendix B.

Stellarium calculates both Bortle class and NELM for user convenience. They aren’t used in the actual

calculations for visualization.

11.4 Tone Mapping

Tone mapping is the process which attempts to compress the brightness values found in nature into the

range of brightness values which can be achieved on a display device so that an image of a natural scene

looks reasonably natural and realistic. The process has been described by Tumblin and Rushmeier (1993),

Larson, Rushmeier, and Piatko (1997) and Devlin et al. (2002). For low-light conditions like night and the

transitional phase, twilight, special considerations have to be taken, ﬁrst described by Jensen et al. (2000).

Stellarium’s transformation from skylight model to display colors is based on these papers.

Parameters to tweak the tone mapping can be reached in the view settings dialog after pressing

Display max luminance

maximal brightness of the used screen. This used to be

100cdm

applicable

for CRT monitors, but more modern screens can achieve much higher luminances of

250cdm

more, to be found in the spec sheets. Adjust this value to inﬂuence the displayed brightness along the

horizon.

Display adaptation luminance

describes the view environment where the screen is set up. For an average

ofﬁce environment,

50cdm

seems a usable default. In an outdoor setting, much higher values are

possible.

Display Gamma

describes the exponent of a nonlinear correlation between input values and output lumi-

nance of the screen. Higher values push the average image brightness.

Use extra Gamma term The original implementation of tone mapping included a gamma term which did

not exactly follow the description from Larson, Rushmeier, and Piatko (1997), but looks better (more

colorful) than the implementation without the gamma term. You can now play with it to ﬁnd your

preferred setting. This ﬂag is only used with the Preetham skylight model.

Use sRGB

The ﬁnal step of color creation is a transformation from CIE Yxy to some display RGB color

space. Nowadays most monitors can display the sRGB color space, therefore this ﬂag is usually

enabled. Disabling this ﬂag will lead to using the Adobe RGB (1998) color space. The colors may

look a bit better on monitors which are set to display Adobe RGB, but washed-out on sRGB monitors.

III

Extending Stellarium

12 Plugins: An Introduction . . . . . . . . . . . . . 133

12.1 Enabling plugins . . . . . . . . . . . . . . . . . . . . . . . . 133

12.2 Data for plugins . . . . . . . . . . . . . . . . . . . . . . . . 133

13 Interface Extensions . . . . . . . . . . . . . . . . 135

13.1 Angle Measure Plugin . . . . . . . . . . . . . . . . . . . 135

13.2 Equation of Time Plugin . . . . . . . . . . . . . . . . . . 137

13.3 Pointer Coordinates Plugin . . . . . . . . . . . . . . . 138

13.4 Text User Interface Plugin . . . . . . . . . . . . . . . . . 139

13.5 Remote Control Plugin . . . . . . . . . . . . . . . . . . . 142

13.6 Remote Sync Plugin . . . . . . . . . . . . . . . . . . . . . 145

13.7 OnlineQueries Plugin . . . . . . . . . . . . . . . . . . . . 148

13.8 Solar System Editor Plugin . . . . . . . . . . . . . . . . 149

13.9 Nebula Textures Plugin . . . . . . . . . . . . . . . . . . . 152

13.10 Calendars Plugin . . . . . . . . . . . . . . . . . . . . . . . 154

14 Object Catalog Plugins . . . . . . . . . . . . . 159

14.1 Bright Novae Plugin . . . . . . . . . . . . . . . . . . . . . 159

14.2 Historical Supernovae Plugin . . . . . . . . . . . . . . 161

14.3 Exoplanets Plugin . . . . . . . . . . . . . . . . . . . . . . . 164

14.4 Pulsars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . . 176

14.5 Quasars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . 178

14.6 Meteor Showers Plugin . . . . . . . . . . . . . . . . . . . 179

14.7 Navigational Stars Plugin . . . . . . . . . . . . . . . . . 182

14.8 Satellites Plugin . . . . . . . . . . . . . . . . . . . . . . . . 185

14.9 ArchaeoLines Plugin . . . . . . . . . . . . . . . . . . . . 190

15 Scenery3d – 3D Landscapes . . . . . . . . 195

15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

15.2 Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

15.3 Hardware Requirements & Performance . . . . . 196

15.4 Model Conﬁguration . . . . . . . . . . . . . . . . . . . . 196

15.5 Predeﬁned views . . . . . . . . . . . . . . . . . . . . . . . 203

15.6 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

15.7 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

16 Stellarium at the Telescope . . . . . . . . . 207

16.1 Oculars Plugin . . . . . . . . . . . . . . . . . . . . . . . . . 207

16.2 TelescopeControl Plugin . . . . . . . . . . . . . . . . . 220

16.3 Observability Plugin . . . . . . . . . . . . . . . . . . . . . 228

16.4 Mosaic Camera Plugin . . . . . . . . . . . . . . . . . . 229

17 Scripting . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

17.2 The Script Console . . . . . . . . . . . . . . . . . . . . . . 234

17.3 Includes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.4 Minimal Scripts . . . . . . . . . . . . . . . . . . . . . . . . . 234

17.5

Critical Scripting Differences introduced with ver-

sion 1.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

17.6 Example: Retrograde motion of Mars . . . . . . . 235

17.7 More Examples . . . . . . . . . . . . . . . . . . . . . . . . 239

12. Plugins: An Introduction

Starting with version 0.10.3, Stellarium’s packages have included a steadily growing number of optional

extensions called plug-ins which are presented in the following chapters. All these plug-ins are “built-in” in

the standard Stellarium distribution and don’t need to be downloaded separately.

12.1 Enabling plugins

To enable a plugin:

1. Open the Conﬁguration dialog (press

or use the left tool bar button

)

2. Select the Plugins tab

3. Select the plugin you want to enable from the list

4. Check the Load at startup option

5. Restart Stellarium

If the plugin has conﬁguration options, the conﬁguration button will be enabled when the plugin has been

loaded and clicking it will open the plugin’s conﬁguration dialog. When you only just activated loading of a

plugin, you must restart Stellarium to access the plugin’s conﬁguration dialog. The plugin’s conﬁguration

dialog is also available by right-clicking on the respective plugin’s main button in the bottom button bar.

12.2 Data for plugins

Some plugins contain ﬁles with different data, e.g., catalogs. JSON is a typical format for those ﬁles, and

you can edit its contents manually. Of course, each plugin has a speciﬁc format of data for its own catalogs,

and you should read the documentation for the plugin before editing its catalog.

You can read some common instructions for editing catalogs of plugins below. In this example we use

ﬁle name catalog.json for identiﬁcation of the catalog for a typical plugin.

You can modify the

catalog.json

ﬁles manually using a text editor. If you are using Windows, it

is strongly recommended to use an advanced text editor such as Notepad++

to avoid problems with

end-of-line characters. (It will also color the JSON code and make it easier to read.)

Warning: Before editing your

catalog.json

ﬁle, make a backup copy. Leaving out the smallest detail

(such as a comma or forgetting to close a curly bracket) may prevent Stellarium from starting.

As stated in section 5, the path to the directory

which contains catalog.json ﬁle is something like:

Windows C:\Users\UserName\AppData\Roaming\Stellarium\modules\PluginName

Mac OS X HomeDirectory/Library/Application Support/Stellarium/modules/PluginName

Linux and UNIX-like OS ~/.stellarium/modules/PluginName

https://notepad-plus-plus.org/

This is a hidden folder, so in order to ﬁnd it you may need to change your computer’s settings to display hidden

ﬁles and folders.

13. Interface Extensions

Most users will soon be familiar with the usual user interface. A few plugins are available which extend the

regular user interface with a few small additions which are presented ﬁrst. However, some applications and

installations of Stellarium require completely different user interfaces. Mostly, these serve to avoid showing

the user interface panels to an audience, be that in your astronomy club presentations, a domed planetarium

or in a museum installation.

13.1 Angle Measure Plugin

goes misty eyed

I recall measuring the size of the Cassini Division when I was a student. It was not the high

academic glamor one might expect. . . It was cloudy. . . It was rainy. . . The observatory lab had

some old scopes set up at one end, pointing at a photograph of Saturn at the other end of the lab.

We measured. We calculated. We wished we were in Hawaii. A picture is worth a thousand

words.

Figure 13.1: Interface of Angle Measure plugin

The Angle Measure plugin is a small tool which is used to measure the angular distance between two points

136 Chapter 13. Interface Extensions

on the sky.

Enable the tool by clicking the tool-bar button , or by pressing

Ctrl

. A message will appear

at the bottom of the screen to tell you that the tool is active.

2. Drag a line from the ﬁrst point to the second point using the left mouse button.

3. To measure to a different endpoint, click the right mouse button.

To deactivate the angle measure tool, press the tool-bar button again, or press

Ctrl

on the

keyboard.

In the conﬁguration dialog, you can conﬁgure if you want to have distances given on the rotating sphere, or

in horizontal (alt-azimuthal) coordinates. You can also link one point to the resting horizon, the other to the

sky and observe how angles change. You can choose where to display the measurement.

When option “Allow snap to selected object” is activated the process of measurement is changed:

•

The left mouse button is not used for angle measurement, so you can pan the screen and left-click to

select an object as usual.

•

To draw the angle dimension line, you can drag with the right mouse button.

•

A right click moves the end of the angle line that is closest to the mouse pointer.

•

If an object is selected, right-clicking will snap the end of the protractor line (closest to the mouse

pointer) to the selected object.

•

Double-click the right mouse button to capture the end of the line. Another double click with the right

mouse button removes the angle measuring line.

•

Which end of the protractor line is chosen depends on the position of the mouse pointer in relation to

the two ends of the line. The end of the line that is closer to the mouse pointer is moved and deﬁned

as the new end point. The end of the line farther from the mouse pointer is not moved and is deﬁned

as the new starting point.

13.2 Equation of Time Plugin 137

13.2 Equation of Time Plugin

-20 -15 -10 -5 0 5 10 15 20

-25

-20

-15

-10

-5

Ari

Tau

Gem

Cnc

Leo

Vir

Lib

Sco

Sgr

Cap

Aqr

Psc

-20 -15 -10 -5 0 5 10 15 20

-25

-20

-15

-10

-5

Ari

Tau

Gem

Cnc

Leo

Vir

Lib

Sco

Sgr

Cap

Aqr

Psc

Figure 13.2: Figure-8 plots for Equation of Time, for years 1000 (left) and 2000 (right). These

plots, often found on sundials, link solar declination (vertical axis) and its deviation at mean noon

from the meridian, in minutes. Labeled dots indicate when the sun entered the respective Zodiacal

sign (30°section of the ecliptic). Figures by Georg Zotti.

The Equation of Time plugin shows the solution of the equation of time. This describes the discrepancy

between two kinds of solar time:

Apparent solar time directly tracks the motion of the sun. Most sundials show this time.

Mean solar time tracks a ﬁctitious “mean” sun with noons 24 hours apart.

There is no universally accepted deﬁnition of the sign of the equation of time. Some publications show

it as positive when a sundial is ahead of a clock; others when the clock is ahead of the sundial. In the

English-speaking world, the former usage is the more common, but is not always followed. Anyone who

makes use of a published table or graph should ﬁrst check its sign usage.

If enabled (see section 12.1), click on the Equation of Time button on the bottom toolbar to display

the value for the equation of time on top of the screen.

13.2.1 Section

[

EquationOfTime

]

in conﬁg.ini ﬁle

You can edit

config.ini

ﬁle by yourself for changes of the settings for the Equation of Time plugin – just

make it carefully!

ID Type Description

enable_at_startup bool Display solution of the equation of time at startup of Stellarium

ﬂag_use_ms_format

bool

Set format for the displayed solution – minutes and seconds or

decimal minutes

ﬂag_use_inverted_value

bool Change sign of the equation of time

ﬂag_show_button

bool Show the tool’s button on the bottom toolbar

text_color

R,G,B Font color for the displayed solution of the equation of time

font_size

int Font size for the displayed solution of the equation of time

138 Chapter 13. Interface Extensions

13.3 Pointer Coordinates Plugin

Figure 13.3: Interface of Pointer Coordinates plugin

The Pointer Coordinates plugin shows the coordinates of the mouse pointer. If enabled, click on the plugin

button on the bottom toolbar to display the coordinates of the mouse pointer.

13.3.1 Section

[

PointerCoordinates

]

in conﬁg.ini ﬁle

You can edit

config.ini

ﬁle by yourself for changes of the settings for the Pointer Coordinates plugin –

just make it carefully!

ID Type Description

enable_at_startup bool

Enable displaying mouse pointer coordinates at program

startup

ﬂag_show_button

bool Show the plugin’s tool button on the bottom toolbar

text_color

R,G,B Color for coordinates text of the mouse pointer

font_size

int Font size for the displayed mouse pointer coordinates

current_displaying_place

string

Speciﬁes the place of displaying coordinates of the

mouse pointer. Possible values:

TopRight

TopCenter

RightBottomCorner, Custom. Default value: TopRight.

custom_coordinates

int,int

Speciﬁes the screen coordinates of the custom place for

displaying coordinates of the mouse pointer

current_coordinate_system

string

Speciﬁes the coordinate system. Possible values:

RaDecJ2000

RaDec

HourAngle

Ecliptic

AltAzi

Galactic. Default value: RaDecJ2000.

ﬂag_show_constellation

bool

Add the 3-letter IAU abbreviation for the constellation of

the mouse pointer location (Roman, 1987).

ﬂag_show_crossed_lines

bool Show crossed lines under mouse cursor.

13.4 Text User Interface Plugin 139

13.4 Text User Interface Plugin

This plugin re-implements the “TUI” of the pre-0.10 versions of Stellarium, an unobtrusive menu used

primarily by planetarium system operators to change settings, run scripts and so on.

A full list of the commands for the TUI plugin is given in section 13.4.2.

13.4.1 Using the Text User Interface

1. Activate the text menu using the

Alt

key.

2. Navigate the menu using the cursors keys.

To edit a value, press the right cursor until the value you wish to change it highlighted with > and <

marks, e.g. >3.142<. Then press the cursor keys and to change the value. You may also type

in a new value with the other keys on the keyboard.

13.4.2 TUI Commands

1 Location (menu group)

1.1

Latitude Set the latitude of the observer in degrees

1.2

Longitude Set the longitude of the observer in degrees

1.3

Altitude Set the altitude of the observer in meters

1.4

Solar System Body Select the solar system body on which the observer is

2 Set Time (menu group)

2.1

Current date/time

Set the time and date for which Stellarium will generate the

view

2.2

Set Time Zone (disabled in 0.15)

2.3

Days keys (disabled in 0.15)

2.4

Startup date/time preset

Select the time which Stellarium starts with (if the “Sky Time

At Start-up” setting is “Preset Time”

2.5

Startup date and time

The setting “system” sets Stellarium’s time to the computer

clock when Stellarium runs. The setting “preset” selects a

time set in menu item “2.4 - Startup date/time preset”

2.6

Date Display Format

Change how Stellarium formats date values. “system_default”

takes the format from the computer settings, or it is possible

to select “yyyymmdd”, “ddmmyyyy” or “mmddyyyy” modes

2.7 Time Display Format

Change how Stellarium formats time values. “system_default”

takes the format from the computer settings, or it is possible

to select “24h” or “12h” clock modes

3 General (menu group)

3.1

Sky Culture

Select the sky culture to use (changes constellation lines,

names, artwork)

3.2

Sky Language Change the language used to describe objects in the sky

3.3

App Language Change the application language (used in GUIs)

4 Stars (menu group)

4.1

Show stars Turn on/off star rendering

4.2

Relative Scale

Change the relative brightness of the stars. Larger values

make bright stars much larger.

4.3

Absolute Scale

Change the absolute brightness of the stars. Large values

show more stars. Leave at 1 for realistic views.

4.4

Twinkle

Sets how strong the star twinkling effect is - zero is off, the

higher the value the more the stars will twinkle.

4.5

Mag limit Sets a custom magnitude cutoff for stars

4.6

Use mag limit Activates this magnitude limit

4.7

Spiky stars Use pointed star ﬁgures

This used to be hard-coded to

before version 0.15, but

Alt

is better to remember as it runs parallel with

Ctrl

for switching the GUI panels, and frees up

for the Milky Way. The

Alt

keybinding is hard-coded,

i.e., cannot be reconﬁgured by the user, and should not be used for another function.

140 Chapter 13. Interface Extensions

4.8 Labels and Markers conﬁgures the amount of labels

4.9

Show additional star names

4.10

Use designations for screen la-

bels

5 Colors (menu group) change color/brightness of the. . .

5.1

Constellation lines constellation lines

5.2

Constellation labels labels used to name stars

5.3

Art brightness constellation art

5.4

Constellation boundaries constellation boundary lines

5.5

Cardinal points cardinal points markers

5.6

Planet labels labels for planets

5.7

Planet orbits orbital guide lines for planets

5.8

Planet trails planet trails lines

5.9

Meridian Line meridian line

5.10

Azimuthal Grid lines and labels for the azimuthal grid

5.11

Equatorial Grid lines and labels for the equatorial grid

5.12

Equatorial J2000 Grid lines and labels for the equatorial J2000.0 grid

5.13

Equator Line equator line

5.14

Ecliptic Line ecliptic line

5.15

Ecliptic Line (J2000) J2000 ecliptic line

5.16

Nebula names labels for nebulae

5.17

Nebula hints circles used to mark positions of unspeciﬁed nebulae

5.18

Galaxy hints ellipses used to mark positions of galaxies

5.19

Bright nebula hints squares used to mark positions of bright nebulae

5.20

Dark nebula hints squares used to mark positions of dark nebulae

5.21

Clusters hints symbols used to mark positions of clusters

5.22

Horizon line horizon line

5.23

Galactic grid galactic grid

5.24

Galactic equator line galactic equator line

5.25

Opposition/conjunction longi-

tude line

opposition/conjunction line

5.26

Sky background

sky background. Note that anything but black is only useful

for artistic works.

6 Effects (menu group)

6.1

Light Pollution

Changes the intensity of the light pollution (see Appendix B

Bortle Scale index)

6.2

Landscape

Select the landscape which Stellarium draws when ground

drawing is enabled. Press to activate.

6.3

Setting Landscape Sets Location

If “Yes” then changing the landscape will move the observer

location to the location for that landscape (if one is known).

Setting this to “No” means the observer location is not modi-

ﬁed when the landscape is changed.

6.4

Auto zoom out returns to initial

. . . view

Changes the behavior when zooming out from a selected

object. When set to “Off”, selected object will stay in center.

When set to “On”, view will return to startup view.

6.5

Zoom Duration Sets the time for zoom operations to take (in seconds)

6.6

Milky Way intensity Changes the brightness of the Milky Way

6.6

Milky Way saturation Changes the saturation of the Milky Way

6.7

Zodiacal light intensity Changes the brightness of the Zodiacal light

7 Scripts (menu group)

7.1

Run local script

Run a script from the scripts sub-directory of the User Di-

rectory or Installation Directory (see section 5 (Files and

Directories))

7.1

Stop running script Stop execution of a currently running script

8 Administration (menu group)

13.4 Text User Interface Plugin 141

8.1 Load default conﬁguration Reset all settings according to the main conﬁguration ﬁle

8.2

Save current conﬁguration Save the current settings to the main conﬁguration ﬁle

8.3

Shutdown Emits a command conﬁgured in

13.4.3 Section

[

tui

]

in conﬁg.ini ﬁle

The section in

config.ini

for this plugin is named only

[tui]

for historical reasons. As always, be careful

when editing!

ID Type Description

tui_font_color R,G,B Font color for TUI text

tui_font_size

int Font size for the TUI

ﬂag_show_gravity_ui

bool

Bend menu text around the screen center. May be useful in

planetarium setups, and should then be used together with

“Disc viewport” in the conﬁguration menu (see 4.3.5).

ﬂag_show_tui_datetime

bool Show date and time in lower center.

ﬂag_show_tui_short_obj_info

bool

Show some object info in lower right, or (in planetarium setups

with “Disc viewport” active,) wrapped along the outer circle

border.

admin_shutdown_cmd

string

executable command to shutdown your system. Best used on

Linux or Mac systems. E.g. shutdown -h now

142 Chapter 13. Interface Extensions

13.5 Remote Control Plugin

The Remote Control plugin enables the user to control Stellarium through an external web interface using

a standard web browser like Firefox or Chrome, instead of using the main GUI. This works on the same

computer Stellarium runs as well as over the network. Even more, multiple “remote controls” can access

the same Stellarium instance at the same time, without getting in the way of each other. Apart from system

conﬁguration options, most of the functionality the main interface provides is available through it (Zotti,

Schaukowitsch, and Wimmer, 2017).

The plugin may be most useful for presentation scenarios, hiding the GUI from the audience and allowing

the presenter to change settings on a separate monitor without showing distracting dialog windows. It also

allows to start and stop scripts remotely.

Because the web interface can be customized (or completely replaced) with some knowledge of HTML,

CSS and JavaScript, another possibility is a kiosk mode, where untrusted users can execute a variety of

predeﬁned actions (like starting recorded tours) without having access to all Stellarium settings. The web

API can also be accessed directly (without using a browser and the HTML interface), allowing control of

Stellarium with external programs and scripts using HTTP calls like with the tools wget and curl.

This plugin allows also interfacing other programs with Stellarium.

13.5.1 Using the plugin

Figure 13.4: The default remote control web interface

After enabling the plugin, you can set it up through the conﬁguration dialog. You can conﬁgure it to start

the web server automatically whenever Stellarium starts or manually start/stop the server using the “Server

enabled” checkbox or the button

in the toolbar.

The plugin starts an HTTP server on the speciﬁed port. The default port is 8090, so you should

reach the remote control after enabling it by starting a web browser on the same computer and entering

http://localhost:8090

in the address bar. When trying to access the remote control from another

computer, you need the IP address or the hostname of the server on which Stellarium runs. On a small tablet,

you may want to use http://myserver:8090/tablet7in.html instead.

The plugin shows the locally detected address, but depending on your network or if you need external

access you might need to use a different one — contact your network administrator if you need help with

that.

13.5.1.1 Password

The access to the remote control may optionally be restricted with a simple password.

13.5 Remote Control Plugin 143

Warning: currently no network encryption is used, meaning that an attacker having access to your

network can easily ﬁnd out the password by waiting for a user entering it. Access from the Internet to the

plugin should generally be restricted, except if countermeasures such as VPN usage are taken! If you are in

a home network using NAT (network access translation), this should be enough for basic security except if

port forwarding or a DMZ is conﬁgured.

13.5.1.2 CORS

The Web API also supports Cross-Origin Resource Sharing (CORS). By enabling CORS, compatible websites

and web apps can be used to control your Stellarium server.

Enable CORS by checking the “Enable CORS for the following origin” option in the conﬁguration

dialog. Then, enter the URL of the website you’d like to use to control Stellarium – e.g.

https://telesc

opius.com. Specify “*” to let any website take control. Do this at your own risk.

13.5.2 Remote Control Web Interface

If you are familiar with the main Stellarium interface, you should easily ﬁnd your way around the web

interface. The remote control automatically uses the same language as set in the main program. Tabs at the

top allow access to different settings and controls.

Main

Contains the time controls and most of the buttons of the main bottom toolbar. An additional control

allows moving the view like when dragging the mouse or using the arrow keys in Stellarium, and a

slider enables the changing of the ﬁeld of view. There are also buttons to quickly execute time jumps

using the commonly used astronomical time intervals.

Selection

Allows searching and selecting objects like in section 4.5. SIMBAD search is also supported.

Quick select buttons are available for the primary solar system objects. It also displays the information

text for current selection.

Sky Settings related to the sky display as shown in the “View” dialog as shown in subsection 4.4.1.

DSO The deep-sky object catalog, ﬁlter and display settings like in subsection 4.4.4.

Landscape Changing and conﬁguring the background landscape, see subsection 4.4.5

Actions and scripts

Lists all registered actions, and allows starting and stopping of scripts (chapter 17).

If there is no button for the action you want in another tab, you can ﬁnd all actions which can be

conﬁgured as a keyboard shortcut (section 4.3) here.

Location

Allows changing the location, like in section 4.2. Custom location saving is currently not

supported.

Projection Switch the projection method used, like subsection 4.4.4.

13.5.3 Remote Control API

Apart from retrieving quick object info in your browser with e.g.

http://localh ost:8090/api/obj

ects/info?format=json&name=Sun

, you can access a running instance of Stellarium with various

programming languages. A few examples:

13.5.3.1 Commandline

It is possible to send commands via command line, e.g.:

curl -d "x =1& y =0.3 " htt p :// localhost : 8090/ api / main / move

wget -- post - data " id = show . ssc " http :// stella :8 090/ api / scrip t s / run -O / dev / null

curl -d " id = myScript . ssc " http :// localhost : 8090/ api / scri p ts / run

curl -d " id = La n d s c a p e M g r . fo g D i s p l a y e d & v alue = f alse " \

http :// local h o s t :809 0/ api / stelpropert y / set

This allows triggering automatic show setups for museums etc. via some centralized schedulers like cron.

To get a complete pretty-printed list of properties and actions, use:

curl -G -d " p ropId = -2& ac t ionId = -2 " http :// localhost : 8090/ api / main / stat us | \

py thon -m js on . tool

13.5.3.2 Node.js

If you want to use node.js to build your own interface app, you may ﬁnd the following example helpful.

sets the view direction in one of 3 coordinate systems, depending on the argument:

" j2 000 " : " [x ,y ,z] " ,

" jNow " : " [x ,y ,z ] ",

" al tAz " : " [x ,y ,z] "

Thanks to user FogoVoar

144 Chapter 13. Interface Extensions

The vector

[x, y, z]

should be a normalized vector (unit length), derived from either J2000.0 or current

equatorial coordinates

(α, δ )

, or from alt-azimuthal coordinates

(Az, alt)

which are however always counted

from south (

[1, 0, 0]

) towards east (

[0, 1, 0]

), with the azimuth

′

counted from South towards East,

′

180− Az.

x = cos(

δ)∗ cos(α)

y = cos(

δ)∗ sin(α)

z = sin(

δ)

x = cos(alt)∗ cos(Az

′

)

y = cos(alt)∗ sin(Az

′

)

z = sin(alt)

const url = ’ http ://192.168. xxx . xxx :8090/ api / main / vie w ? j2000 =[ 0.5 , 0.3 ,0.2] ’ ;

fetch (url , {

me thod : ’ POST ’ ,

he a ders : {

’ Content - Type ’: ’ ap p l i c a t ion / jso n ’

}

})

. then ( response => {

res p onse . text (). then ( text = > co n sole . log ( ’ Raw respons e :’ , text ));

re turn res p onse . json ();

})

13.5.3.3 Python

An example for time control:

im port req u ests

STELLARIUM_URL = ’ http : / / 1 9 2. 16 8. 1. 10 0: 80 90 / api / main ’

def set_time ( ju lian_day , timera t e ):

url = f"{ S T E L L A R I U M _ U R L }/ time "

data = " time = "+ str ( j u l i an_day )+ " & ti merate =" + str ( timer a t e )

print (f" Reque s t URL : { url } ")

print (f" Reque s t Data : { data }" )

try :

res p onse = r equests . post ( url , data = data )

print (f" Respons e S tatus Code : { r esponse . status _ c o d e }")

print (f" Respons e C o ntent : { respon s e . text } " )

res p onse . r a i s e_ f o r_ s t a tu s ()

if re sponse . text . strip () == " ok " :

re turn {" stat us " : " success ", " mes s age " : " Time set su c c e s s f u l l y "}

else :

re turn {" stat us " : " e rror " , " mes s age " : r e sponse . text }

ex cept req u ests . e x ceptions . R e q u e st E x ce p t i on as e:

print (f" Err or set t ing time : {e} " )

re turn {" stat us " : " e rror " , " mes s age " : str (e )}

13.5.4 Developer information

If you are a developer and would like to add functionality to the Remote Control API, customize the web

interface or access the API through another program, further information can be found in the plugin’s

developer documentation

13.5.5 Acknowledgements

This plugin was created by Florian Schaukowitsch in the 2015 campaign of the ESA Summer of Code in

Space

programme.

If you are using this plugin in your scientiﬁc publications, please cite Zotti, Schaukowitsch, and Wimmer

(2017).

https://stellarium.org/doc/head/remoteControlDoc.html

https://socis.esa.int/

13.6 Remote Sync Plugin 145

13.6 Remote Sync Plugin

The Remote Sync plugin enables setups which connect several instances of Stellarium running on a network.

This may be useful in installations where one presenter wants to allow a larger audience to follow the actions

on several dim screens (e.g., when you need to avoid a projector’s bright light in a public observatory).

The actions performed on a “master” instance, which acts as a server, are automatically replicated on all

connected clients. These clients may run on the same device the server runs, or may access the server over a

network.

The plugin is still quite experimental, but is provided for testing and developing purposes. You can

conﬁgure it through the standard plugin settings dialog (Figure 13.5). One Stellarium instance can either

run in the server mode or connect to an existing server as a client. A custom TCP protocol is used for the

connection. The port used by the server is conﬁgurable, and the clients must know the IP address or host

name and the port of the server.

Figure 13.5: RemoteSync settings window

Alternatively, you may start the plugin through command line arguments. This is useful for automated

setups or when multiple instances are running on the same computer. To start the instance as a server, use

the

--syncMode=server

argument with the optional

--syncPort

parameter to specify the port to listen

on. To start a client instance, use

--syncMode=client

and use

--syncHost

and

--syncPort

to specify

the server to connect to.

In the settings window, you can also specify what should happen when the client loses the connection to

its server, and what to do when the server quits normally. You can choose between

Do nothing:

connection is lost and will not be re-established. Stellarium client keeps running in whatever

state it was, waiting for keyboard/mouse interaction.

Try reconnecting:

Assume Stellarium is switched off on the server but may come back online again, or

assume some temporary network problem. Stellarium client just keeps running in whatever state it

146 Chapter 13. Interface Extensions

was, but tries to reconnect.

Quit:

Assume the server always runs until switched off at the end of operating hours. This is intended for

pure client screens without keyboards. When the server is shut down, assume this is the end of the

day, and exit Stellarium. An enclosing run script can then shutdown the client computer before power

is switched off with some main switch.

By default, the following things are synchronized:

•

simulation time

•

viewer location

•

the selected object

•

view direction

•

current ﬁeld of view

•

all StelProperty-based settings except for GUI-related properties. This includes almost all settings

visible in the conﬁguration dialogs such as projection type, sky and view options, landscape settings,

line colors, etc.

Because there is currently no full time synchronization implemented, for the best results all client computers

should make sure their system clocks are set as close as possible to the server computer’s clock (preferably a

few milliseconds difference at most). This can be done for example by using an NTP server.

If all your

Stellarium instances run on the same device, this is of course not necessary.

Figure 13.6: RemoteSync client settings window

It is also possible to exclude some state from being synchronized. On each client, the client conﬁguration

GUI (Figure 13.6) allows to disable speciﬁc settings from being synchronized on this client.

The lower part of this dialog allows you to ﬁne-tune which named StelProperties (which hold parts

of the internal program state) should be excluded from synchronization. The conﬁguration dialog lists all

available properties which usually have easy to understand names on the left side. Highlight one or more

properties which you don’t want synchronized and press the arrow button to move them to the list of excluded

properties.

For historic reasons there are two kinds of Properties: Actions (Boolean switches, for which also hotkeys

can be assigned) and (genuine) StelProperties. The latter have names indicating which module they belong

to and may have other data types (numbers, colors, . . .). Note that the actions frequently are just alias names

of Boolean StelProperties, so in order to inhibit a certain property from being synchronized, you must ﬁnd

Instructions on how to use the public NTP server pool for the most common operating systems can be found at

https://www.pool.ntp.org/en/use.html.

13.6 Remote Sync Plugin 147

both entries.

Properties of plugins will only be visible when the respective plugin has been enabled. When a plugin

has been disabled, its properties may vanish from the stored list of non-synchronized properties.

Each client can have different settings. This could allow installations with several screens where on one

screen you show the constellation ﬁgures, another screen shows the distribution of deep-sky objects in the

same frame, and a third screen may show a close-up view of the currently centered object. Or just show

several sky cultures, or show the sky at different locations, . . . .

The names of all available StelProperties from which you might want to select a few to exclude from

synchronisation can also be found with a little scripting (see chapter 17). Open the script console

F12

and

enter the following call:

core.output(core.getPropertyList());

Run the script and inspect the output tab. It may take a little guesswork to select the right names, but the

general structure of property names like

should help you to ﬁnd your way around.

13.6.1 Developer notes

Usually the synchronisation fails if you attempt to use different versions of Stellarium. You can override this

behaviour with an entry in the respective section of config.ini:

[ RemoteSy n c ]

allowVe r s i o n M is ma tc h = true

13.6.2 Finetuning

This plugin makes use of the QLoggingCategory infrastructure. By default it is very verbose and prints each

transmitted property to the logﬁle. To reduce verbosity when it works, conﬁgure an environment variable

with these entries (Note the closing semicolon!):

QT_LOGGING_RU L E S =" stel . plugi n . re m oteSync . debug = true ;

stel . pl ugin . remoteS y n c . client . d ebug = f alse ;

stel . pl ugin . remoteS y n c . pr o tocol . debug = false ;"

The ﬁnal parts may be debug|info|warning|critical = true|false. Default: true.

Author and Acknowledgements

This plugin was created mostly by Florian Schaukowitsch in the 2015-16 campaigns of the ESA Summer of

Code in Space

programme.

https://socis.esa.int/

148 Chapter 13. Interface Extensions

13.7 OnlineQueries Plugin

Stellarium includes and provides lots of information about many kinds of objects. However, there are

scientiﬁc websites which provide even more specialized information about particular objects. This plugin

(Zotti, S. M. Hoffmann, et al., 2023) allows online access to several websites on a variety of special topics.

To retrieve information, select the ﬁrst tab and press the respective button labeled with the information source.

The result is displayed in a browser view

Wikipedia

The free online encyclopedia provides information about many bright stars, the planets, moons

and many asteroids, as well as many deep-sky objects. The lookup is based on the English proper

name.

AAVSO

The International Variable Star Index

of the American Association of Variable Star Observers

(AAVSO) provides data about variable stars.

GCVS

The General Catalogue of Variable Stars

of the Sternberg Astronomical Institute and the Institute

of Astronomy of the Russian Academy of Sciences in Moscow.

In addition, you can conﬁgure up to three further websites. These must provide some public website

which takes a query for a Hipparcos star number or object name.

Regardless of the current program language, the result is always presented in English or the language of

the respective website.

13.7.1 Section

[

OnlineQueries

]

in conﬁg.ini ﬁle

You can edit the

config.ini

ﬁle to change settings of the OnlineQueries plugin. The only strings you

should need to touch are the

customN_...

entries (

N ∈ {1, 2, 3}

). The placeholder

will be ﬁlled by either

the Hipparcos number (if the respective

customN_use_hip

true

) or by the ﬁrst English name used in

Stellarium. The

customN_use_hip

should be

true

to use a star’s Hipparcos number, or

false

to use the

English name as key.

ID Type Default

aavso_hip_url string (don’t override)

aavso_oid_url

string (don’t override)

gcvs_url

string (don’t override)

wikipedia_url

string (don’t override)

custom1_url string

custom2_url string

custom3_url string

custom1_use_hip boolean true

custom2_use_hip

boolean true

custom3_use_hip

boolean true

disable_webview boolean false

For technical reasons, on some platforms the result is displayed in the system’s default web browser. On some

other platforms, e.g. Windows/WSL with Ubuntu or some ARM computers, the web view fails to work properly. On

these platforms you should manually edit config.ini and set the disable_webview entry in the conﬁg ﬁle.

https://www.aavso.org/vsx/

http://www.sai.msu.su/gcvs/

13.8 Solar System Editor Plugin 149

13.8 Solar System Editor Plugin

Stellarium stores its data (orbital elements and other details) about solar system objects (planets, their moons,

minor bodies) in two ﬁles. File

data/ssystem_major.ini

in the installation directory contains data for the

planets and their moons, and should never be touched by users. File

data/ssystem_minor.ini

contains

data for minor bodies, i.e., planetoids and comets. The ﬁle will be taken from the user data directory if it also

exists there, which means that users can add minor planets or comets as they become observable by editing

this ﬁle.

The orbits of minor bodies (minor planets and comets) are speciﬁed with orbital elements for Kepler

orbits (after JOHANNES KEPLER (1572–1630) who found the true shape of the orbit of a small body around

a large one being a conic section, i.e., circle, ellipse, parabola or hyperbola). These elements describe the

instantaneous shape and orientation of the object’s orbit around the Sun at a particular time called the epoch.

We compute positions from these osculating elements of minor body orbits, but the result is only valid for a

moderately short timespan around the epoch, because the major planets can exert noticeable gravitational

perturbations on the objects when they come close, and so these orbital elements, which are mere snapshots

in time, need to be updated on a regular basis. Stellarium does not perform numerical integration that could

work out the orbital changes automatically, and so the element ﬁle needs to be modiﬁed to compute positions

further away from the orbit’s epoch. See Appendix D.2 for more details, and see e.g. Meeus (2007) for a

discussion of a few interesting examples of orbital development. When you go out hunting for asteroids and

comets, this plugin is for you.

This plugin provides access to the Minor Planet Center (MPC

) server where the latest Solar System

information can be found. When this plugin is loaded (see section 12.1) and you open the conﬁguration

dialog, the ﬁrst tab allows to import, export or reset your

ssystem_minor.ini

, and also to load extra

data for minor bodies in Stellarium’s

.ini

format. For example, the installation directory contains a ﬁle

ssystem_1000comets.ini

which contains data for over 1000 historical comets. Currently it is not possible

to select only a few from that, so try loading this only on a reasonably fast computer, and think about deleting

comets again (or resetting the ﬁle) when you don’t require them.

Figure 13.7: Interface of Solar System Editor plugin: Conﬁguration ﬁle tab

The second tab lists all currently loaded minor bodies (see ﬁgure 13.8). It is recommended to remove

old entries of yesteryear’s comets if you don’t need them any longer. Just select one or more objects and

press

Remove

. If you have a very weak computer, you may want to reduce the number of minor bodies to

https://www.minorplanetcenter.net

150 Chapter 13. Interface Extensions

just a handful to improve performance.

Figure 13.8: Interface of Solar System Editor plugin: Solar System tab

On this tab, you also ﬁnd the option to connect to the MPC and download current orbital elements, or

load a text ﬁle in the format provided by MPC (see ﬁgures 13.9 and 13.10).

Once MPC data has been downloaded, the user can select objects for updating the user’s

ssystem_minor.ini

13.8 Solar System Editor Plugin 151

Figure 13.9: Interface of Solar System Editor plugin: Import data dialog

Figure 13.10: Interface of Solar System Editor plugin: Import data dialog — view after downloading

and parsing the MPC data.

152 Chapter 13. Interface Extensions

13.9 Nebula Textures Plugin

The Nebula Textures plugin allows users to customize deep-sky object (DSO) textures, precisely rendering

them in Stellarium like default textures. Astronomy amateurs can use it to create a collection of their own

astrophotography, visual-like sketches, paintings, and even more in Stellarium. It also serves as a simple

client for Astrometry.net, enabling blind-solving and precise positioning of astronomical images. The

plugin’s full functionality includes online plate-solving and positioning of astronomical images, as well as

the management and rendering of custom textures.

13.9.1 Online Solving and Texture Management

Instructions for integrating astrophotography images via online plate solving.

Prepare an Image: Prepare a processed rectangular bitmap ﬁle of a deep-sky object, in a format

that supports both Astrometry analysis and rendering, such as PNG, JPG, TIF, or GIF. You should

adjust the image background brightness to suit Stellarium by referencing the nebulae images in the

Stellarium

nebulae/default

directory. Typical astrophotography images with TAN projections are

ﬁne, but avoid images with high ﬁeld distortion. If the image’s FOV is too large, it is recommended

to manually split it into multiple sub-images beforehand. Ensure that the image is not ﬂipped

horizontally or vertically!!! It’s recommended to use a descriptive ID or nickname as the ﬁlename.

While Nova Astrometry does not strictly limit image size, keeping it below 20 MP ensures efﬁcient

plate solving.

Open Image: By default, the plugin opens the “Solve and Add” page. Click the

Open File

button to

select an image ﬁle or paste the ﬁle path into the “Image Filepath” text box.

Enter API Key: Paste your Astrometry API key into the corresponding text box (password mode by

default). If you don’t have one, click

Astrometry API key

to obtain it after registering or logging in.

Check

2 Remember me

to store the key for future use.

Upload and Solve: Click

Online Solve

to begin uploading and solving the image. Ensure system

proxies are disabled to avoid errors. The solving process may take seconds to minutes, depending on

the Astrometry.net server. If you need to stop the solving process, click the

Cancel

button.

View Solving Results: After successful solving, the image’s center and corners’ J2000 equatorial

coordinates (in decimal degrees) will be displayed.

6. Optional Testing:

•

Click

Goto Center

to locate the texture’s center.

•

Use

Test this texture

to preview the texture. If it overlaps with default textures, you should

check

Disable default textures

to avoid visual conﬂicts. The

Test this texture

button will toggle

between “Test this texture” and “Stop test” to start and stop the rendering process. Remember

to click

Stop Test

afterward to restore the rendering of the default nebula textures!

•

When testing is active, modifying the coordinate spinboxes (including using the mouse wheel)

will immediately update and redraw the texture in real-time, enabling an interactive experience

for ﬁne-tuning alignment.

•

For images solved via Astrometry.net, if manual coordinate adjustments deviate too much,

Reset

will appear. Click it to reset the coordinates back to the original astrometric solution.

•

The dropdown menu is used to adjust texture brightness, with three options: Bright, Normal,

and Dark. The default Normal setting is suitable for most cases.

•

You can repeatedly press the

key in the main view to toggle star visibility and verify whether

the image is aligned accurately.

Add Texture to Storage: Click

Add the Texture to Custom Storage

to permanently save the texture.

The original image will be copied to Stellarium’s plugin folder in the user directory. After adding a

texture, you should restart Stellarium to fully integrate the texture into the module.

Display Settings: After restarting Stellarium, switch to the

Custom Textures

page of the plugin to

manage your custom textures. Options include

Show Custom Textures

(showing/hiding textures),

Avoid Area Conﬂict

(avoiding overlaps with default textures), and

Reload

(reloading custom tex-

tures).

9. Locate a Texture: Double-clicking a texture item in the list will center the view on that texture.

10.

Remove a Texture: To remove a texture, switch to the

Custom Textures

page, select it in the list

view and click

Remove selected item in Custom Textures

. The conﬁguration ﬁle will update, and the

corresponding image ﬁle in the plugin folder will be deleted. However, Stellarium may continue

rendering the texture until it is restarted.

13.9 Nebula Textures Plugin 153

13.9.2 Manual Texture Addition)

Instructions for adding manual textures (e.g., sketches, paintings). The process is similar to the one above,

but performing online solving is not required:

•

Open the image ﬁle. Stars in non-astrophotographic images may not align precisely with the software’s

stars, so it is recommended to use the texture without stars (de-star it).

•

Input the J2000 equatorial coordinates (in decimal degrees) for the image corners, aligning with the

bitmap display.

•

If needed, use an astrophotography image with a similar ﬁeld of view (FOV) to obtain approximate

corner coordinates via online solving ﬁrst. Alternatively, enable Digitized Sky Survey layers in

Stellarium (Disable constellation lines, illustrations, grids, and other unrelated elements to approximate

a realistic effect), adjust the ﬁeld of view and rotation to match the texture, and capture a screenshot

for solving. After obtaining the solved coordinates, replace the image path with the texture path.

•

Then, debug and render the texture, adjusting coordinates until the texture stars align accurately with

Stellarium stars. Finally, add the texture to the custom storage.

13.9.3 Notes

All uploaded images are automatically assigned a CC BY-NC-ND 3.0 license by Astrometry.net and

are not publicly visible by default. Avoid excessive uploads to prevent server congestion or issues

with your API key.

After adding a texture, you must restart Stellarium to fully integrate the texture into the module. The

same applies when deleting a texture.

To back up your texture library or share it with others, copy the plugin folder from your user conﬁg

directory. You can ﬁnd the exact plugin storage path in the “About” section of the plugin GUI. For

Windows systems, this path is usually something like:

%APPDATA%\Stellarium\modules\NebulaTextures

You can then share this folder with others, and they can place it in the same directory on their system

to use the custom textures.

154 Chapter 13. Interface Extensions

13.10 Calendars Plugin

GEORG ZOTTI

13.10.1 Introduction

The calendar dates in the main program behave like most other astronomical software titles:

•

Dates are given in the Gregorian calendar for all dates beginning with October 15, 1582.

•

All earlier dates are given in the Julian Calendar in its ﬁnalized form by AUGUSTUS. Historically,

only dates beginning with March 1st, 4 A.D. coincide with historically recorded dates: the Roman

priesthood messed up the 4-year count introduced by JULIUS CAESAR and counted leap years every

third year. AUGUSTUS decreed to omit leap days from 12 B.C. to 4 A.D. to move the seasons to

where JULIUS CAESAR had placed them.

•

Given the errors in the Julian calendar, simulation in early prehistory will provide non-intuitive

calendar dates for the seasons’ beginnings.

•

Astronomical counting of years includes a year zero and negative years. Historical calendars don’t

have a year zero. 1 A.D. is preceded by 1 B.C. Therefore a negative year in Stellarium may look

uncommon to historians who may think Stellarium is one year off.

Since earliest times people all over the world have observed the sky and used its phenomena to structure

their lives, agree on future events (“we shall meet here again and exchange goods at the third Full Moon

from now”), record and measure time. Over millennia, various systematic calendars evolved. A classic

and often-cited presentation of calendars from the pre-computer era is still the monumental work by Ginzel

(1906; 1908; 1911). The next challenge was then to describe the systematic of these algorithmically and

make them available for computer programs. Reingold and Dershowitz (2018) have presented a modern

masterpiece of this kind and are our preferred source of algorithms. This plugin will evolve over the next

time to bring a good sample of calendars into Stellarium.

In the conﬁguration panel you can select which calendars you want to display in the lower right corner

of the screen, and you can also directly interact with some of them.

The calendars displayed in this plugin come with their own logic. Historically, when a calendar was

introduced, dates which precede its starting point (era) were of little interest to its users, therefore if a date

bears negative years (or negative units of its largest component) those dates may not be useful.

Note that in some calendars the day did not begin at midnight, but for example at sunrise, sunset, or

dawn. This cannot be reﬂected in this plugin. Dates should be correct at noon, and may be one day off

dependent on these aspects.

13.10.2 The Calendars

13.10.2.1 Lunisolar European calendars

Julian

JULIUS CAESAR introduced this calendar, advised by the Egyptian astronomer SOSIGENES. Every

4th year is a leap year of 366 instead of 365 days, yielding a mean length of the year of 365.25 days.

In contrast to the default calendar display of Stellarium, this implementation utilizes historical year

counting, i.e., has no year zero. Years are marked A.D. or B.C., respectively. The omission of year

zero makes negative leap years break the simple 4-year count. Now they are 1 B.C., 5 B.C., 9 B.C.

etc. However, note that before 8 A.D. leap years are just counted proleptic, but the Romans did not

keep the leap years commanded by JULIUS CAESAR until AUGUSTUS put things back in order. This

means, displayed dates before 8 A.D. may be off by up to 3 days from historical accounts written by

contemporaries.

Gregorian

This implementation acts like Stellarium with respect to year counting and counts signed

negative and positive years, with a year zero between them. It shows dates in a Proleptic Gregorian

calendar for dates before October 15, 1582. Given its improved rules for leap years which provide a

mean length of the year of 365.2425 days, it keeps the seasons’ beginnings closer to the commonly

known dates, at least for many more centuries in the past than the Julian calendar commonly used by

historians.

Revised Julian Calendar

(also named Milankovi

c Calendar) In 1923, the Serbian scientist MILUTIN

MILANKOVI

C (1879–1958) proposed a calendar which should overcome the then 13-day calendar

At the current point of implementation I cannot exclude further errors! The plugin reproduces the given sample

dates, but we cannot give any guarantee about the accuracy of historical dates. If you are more familiar with any of the

non-European calendars, you are invited to identify errors or at least additions to this documentation, e.g. variants to the

schemes used.

13.10 Calendars Plugin 155

gap between the Eastern European Orthodox churches who still adhered to the Julian calendar and the

rest of the world which followed the Gregorian calendar. It amends the 4-year Julian leap year cycle

by omitting century years except for those where division by 900 leaves a remainder of 200 or 600.

Therefore the mean length of the year is 365.242

2 days, 24 seconds less than the Gregorian and within

2 seconds of the correct length of the mean tropical year. For a synchronisation with the Gregorian,

October 1-13 1923 were omitted. Between March 1600 and February 2800 the calendar dates are

identical to those in the Gregorian calendar. The calendar was adopted by several but not all Eastern

Orthodox churches, although date of Easter is still computed according to the Julian calendar

In historical context giving dates in the Revised Julian calendar for years before the dates of religious

festivals were deﬁned in the calendar makes no sense. Its idea was to have a continuous calendar as it

was in use at the concile of Nicaea in A.D.325. Therefore dates before A.D.325 are displayed like in

the traditional Julian calendar.

ISO Week

The International Standards Organization describes weeks in the Gregorian calendar from

Monday (Day 1) to Sunday (Day 7). Week 1 of each year contains the ﬁrst Thursday of the year.

Years may have a week 53, where the last days already belong to the next Gregorian year.

Icelandic calendar

Since 1700, this counts weeks in summer and winter seasons, 12 months of 30 days

with a few extra days and the occasional leap week after the third month of summer. Year numbers

concur with the Gregorian, but start with summer in late April.

Roman calendar

This presents the Roman way of writing calendar dates in the Julian calendar and provides

dates ab urbe condita (A.U.C.).

Olympic calendar

Another way to write the years in the Julian calendar uses the Greek Olympiads, a

4-year cycle starting in 776 B.C.E. The Olympic games of antiquity were held in year 1 of each cycle.

13.10.2.2 Near Eastern Solar calendars

Several calendars with 12 months of 30 days plus 5 (6 for leap years in some calendars) epagomenae days,

with different calendar eras.

Egyptian

A 365 day year without leap days. Following the tradition of PTOLEMY, we use the era of

Nabonassar.

Armenian also has no leap days.

Zoroastrian

also has no leap days. This uses different names for each day of the month and for each

epagomenae day. Month names are from Ginzel (1906, §69) with transliteration adapted to Reingold

and Dershowitz (2018).

Coptic

uses Month names derived from the Egyptian calendar, but observes leap years every 4th year. Its

era martyrum is also called Diocletian era.

Ethiopic

like the Coptic calendar, just with different year numbers, counted from the ethiopic era of mercy.

Persian

a Solar calendar adopted in 1925, but based on the earlier Jal

ı calendar of the 11th century A.D.

Years begin at the Vernal equinox (nowruz) and follow a complicated leap year cycle of 2820 years.

Days begin at midnight (zone time). An identical calendar with different month names was adopted

in Afghanistan in 1957.

Stellarium provides both versions: the algorithmic version and the astronomically speciﬁed one. They

occasionally deviate from each other by 1 day.

Bahá’í

is a Solar calendar with years beginning on the day of Vernal equinox. In the algorithmic version

v 1.2

used in the West, March 21 in the Gregorian calendar was used, but the astronomical version used

since 2015 uses Tehran as reference location. Days begin at sunset. The calendar uses a 7-day

week but is else based on cycles of the number 19: 19 named months of 19 named days plus 4-5

additional days after month 18. In addition, years are structured in named 19-years (V

id, “unity”)

and numbered 19

= 361-years (Kull-i-shay) cycles.

13.10.2.3 Near Eastern calendar s

Several more calendars have been worked out in algorithmic forms:

Islamic

is a strict Lunar calendar without observance of seasons. Days begin at sunset, but we cannot

currently show this. The date should be correct at Noon. The week begins on Sunday. Note that this

algorithmic solution may deviate from the dates given by religious authorities on basis of observation.

Hebrew

is a Lunisolar calendar with strict Lunar months, but adherence to the seasons. It has 12 or 13

months, and 353-355 or 383-385 days per year. The algorithmic form was introduced in the mid-4th

century A.D.

More details can be found on https://en.wikipedia.org/wiki/Revised_Julian_calendar

156 Chapter 13. Interface Extensions

13.10.2.4 Asian calendars

Old Hindu Solar

used before about 1100 A.D. The implementation follows the (First)

Arya Siddh

anta of

Aryabha

a (499 C.E.), as amended by Lalla (circa 720–790 C.E.). The year is split into 12 months

(saura) of equal length. Days begin with sunrise, simpliﬁed as 6 am. Years are counted as elapsed

years (starting at 0) from the Kali Yuga (Iron Age) epoch (Feb. 18., 3102 B.C. jul.).

Old Hindu Lunisolar

used before about 1100 A.D. This implementation shows the south-Indian method

with months starting at New Moon (am

anta scheme). (In the north, the p

anta scheme describes

months starting with Full Moon. There are also some local differences.) It also shows the K.Y. day

count (ahargan

a), i.e., days elapsed since the K.Y. epoch.

New Hindu Solar and Lunisolar

This is the Hindu calendar from the S

urya-Siddh

anta (ca. 1000 A.D.). It

is based on epicyclical motions of the Sun and Moon around the Earth. While still an approximation,

this provides more accurate models of the motions at cost of much more complicated computation.

The Solar month begins when the Sun enters a sign on the Sidereal Zodiac. Months are therefore 29

to 32 days long. Solar days begin at sunrise, and the zodiacal position of the sun at sunrise in Ujjain,

India, decides on the date. Years given for the Solar calendar are counted from the Saka era (A.D. 78).

The lunar month name is determined by the (ﬁrst) zodiacal sign entered by the sun during the month.

When no sign is entered, the month is “leap” (adhika) and named after the following month. When a

Solar month passes without a New Moon, a lunar month can also be skipped (kshaya). The Lunisolar

year has 12 or 13 months, of which up to 2 can be leap and one skipped!

A lunar day varies in length from 21.5 to 26.2 hours, and therefore may occasionally have to be

repeated (here the second day is the leap day or adhika), or skipped.

Years are given in the Vikrama era which began in 58 B.C. Both months schemes share the same 12

names.

Also this calendar is shown in the am

anta scheme, i.e., months start at New Moon. There are again

several local variants, and of course a longitude difference to the reference location may also lead to

deviations.

In addition to the New Hindu Lunisolar date, the Hindu panchang is shown, a 5-part description of

the day consisting of

Tithi (lunar day)

Weekday

Naks

atra the part of the ecliptic the Moon is in at time of sunrise (in Ujjain).

Yoga a cycle of 27 names resulting from the “addition” of Solar and Lunar longitudes.

Karan

a count of 60 lunar half-days resulting in 11 names. The kara

a at time of sunrise (in Ujjain)

governs the karan

a for the day

Hindu Astronomical Solar and Lunisolar

These are similar to the New Hindu calendars, but with even

more accurate positional computations from the S

urya-Siddh

anta for Solar and Lunar positions.

Tibetan calendar

is actually only one of several calendars used in Tibet. We show the date in the ofﬁcial

Phuglugs (or Phug-pa, Phukluk) version of the K

alacakra calendar, derived from the K

alacakra

Tantra which was translated from Sanskrit to Tibetan in the 11th century, and has been sanctioned by

the Dalai Lama. It is similar to the Hindu Lunisolar calendar, but has also regional variants where

astronomical events are computed in local time. In Tibet, the actual calendar is issued only annually

(after empirical corrections) by the Tibetan School for Astro and Medicine and may diverge from the

calendar shown here.

Months are 29 or 30 days long and numbered 1 to 12. Leap months precede their “regular” counterparts

but else have the same name.

Years are counted from the date of ascension of the ﬁrst Yarlung king, NYATRI TSENPO, in 128 B.C.

(We write “A.T.” for Anno Tibetorum.) However, it is more common to designate years in a cycle of

60 years, with 5 elements which label two consecutive years which are further named “male” and

“female”, and a parallel cycle of 12 animal totems. This cycle has been synchronized with the similar

Chinese 60-years cycle.

Balinese Pawukon

is a 10-part sequence of day names with cycle lengths of 2 to 10, which can also be

written as numbers or symbols. Some numbers repeat in simple cycles, while others follow more

complicated rules. A full cycle takes 210 days. Due to space reasons this needs two lines on the

For technical reasons this is currently shown for midnight UTC. It is currently unclear if yoga should be given for

the time of sunrise or for the current moment.

Again, this is unconﬁrmed. If you know better, please tell us!

13.10 Calendars Plugin 157

display. Formatting may improve in later versions.

13.10.2.5 Chinese calendars

v 1.2

The Chinese calendar (and related Japanese, Korean and Vietnamese) is a Lunisolar calendar based on

astronomical events. Days begin at midnight. Lunar months begin on the day of New Moon. The position of

the Sun along the Zodiac is given by Major (zh

ongqì) and Minor (jiéqì) Solar Terms.

Chinese

The version here is the 1645 version. Earlier dates may be wrong. The calendar’s location for

astronomical computations is Beijing.

Japanese

The same principles of the Chinese calendar have been followed since 1844, but with Tokyo as

reference location. The years given are in the kigen count (years from 660 BCE).

Korean

Korea adopted the Gregorian calendar in 1896, but the older Chinese-based calendar is still used

for traditional purposes. The reference location for computing Solar longitudes and lunar phases is

Seoul City Hall. Years are counted in the Danki system starting in 2333 BCE.

Vietnamese

From 1813-1967 the Chinese calendar was used directly. The currently used traditional calendar

parallels the Chinese, but with Saigon as reference location. Years are not counted, only named. It

also seems that Solar terms are not used.

13.10.2.6 Mesoamerican calendars

Maya Long Count

is a 5-part sequence of numbers, conventionally written with dot separators. Just like

most modern people write numbers in the decimal system (base 10), and the Mesopotamians developed

a scheme with base 60 still used today for angular and temporal minutes and seconds, the Maya used

base 20 as their unit. However, this count uses a mixed-base system. The lowest (rightmost) number

(kin) runs from 0 to 19, the second-lowest (uinal) from 0 to 17, the others from 0 to 19 again. It is

assumed these lowest places of

18× 20 = 360

days have been used to approximate the solar year, so

that the third number from the right (tun) increases about once per year. The higher places are called

katun and baktun. Most scientists agree that the zero point of the long count corresponds to Monday,

September 6, 3114 B.C. (Julian), but in many sources dates in the proleptic Gregorian calendar are

listed, where this date is given as August 11, -3113. This plugin ﬁnally allows the use of both systems,

and of Long Count dates directly.

In December of 2012 some people were afraid that the switchover from baktun 12 to 13 (something

which occurs about every 400 years) would cause Armageddon, just as other people prefer to be afraid

of turns of centuries or millennia of the Christian year count.

Maya Haab

is a calendar of 18 “months” of 20 days each (counted 1 to 20), plus 5 days (Uayeb) at the

end, providing “years” of 365 days. Years are not counted, but you can use buttons in the calendar

interface to move forth and back to the previous or next, respectively, day with the same Haab name.

Maya Tzolkin

is described as ritual calendar consisting of two cycles with 13 day numbers (1 to 13) and

20 names. Each day both counters are advanced. Date names repeat after 260 days. Usually Haab and

Tzolkin calendars were both used to deﬁne a unique date which repeats only after a calendar round of

52 Haab years, corresponding to 73 Tzolkin cycles.

Aztec Xihuitl

is similar to the Maya Haab, consisting of 18 “months” of 20 days, plus 5 nemontemi

(worthless days). Days are counted from 1 to 20. The Aztecs may have used intercalation, but details

have been lost. The correlation in use here is based on the recorded Aztec date of the fall of their

empire to HERNÁN CORTÉS in 1521 and should provide correct dates in the early 16th century.

Aztec Tonalpohualli

is similar in structure to the Mayan Tzolkin. Also an Aztec date is usually given by

both systems.

13.10.2.7 French Revolution calendar

The French Revolution of 1789 brought also a calendar reform. After a few years with different year count

only, a new calendar was introduced effective on November 24, 1793 (4. Frimaire, II). This was based on an

astronomical determination of the autumnal equinox at Paris, which marked the start of the years.

The calendar has 12 months of

3× 10

days (décades), plus 5 (in leap years: 6) extra days at the end of

the year. These 10-day “weeks” made it pretty unpopular. The months were given names that alluded to the

climate or vegetation.

In 1795, an arithmetic version was proposed which got rid of the difﬁcult astronomical computation

with a leap year scheme similar to the Gregorian. However, this version of the calendar never came into use.

Stellarium also shows this calendar, which may be off from the original by 1 day.

With the end of Gregorian year 1805, the calendar was abolished, but re-introduced for a few days in

May 1871.

158 Chapter 13. Interface Extensions

13.10.3 Scripting

Advanced users who have the book at hand may ﬁnd it useful that almost all functions from Reingold

and Dershowitz (2018) are available as scripting functions (as far as the implementation of the described

calendars has come). Whenever a location is needed, the current location is used, or you can use a location

from the location database by giving its name like “Vienna, Austria” or “Madrid, Western Europe”. This

should also work for user-speciﬁed locations. Take care to use a “real” name for the timezone, or specify an

UTC based zone exactly like “UTC+03:15”, else timezone will be read as zero. Full documentation for this

can be found at https://stellarium.org/doc/head/group__calendars.html.

13.10.4 Conﬁguration Options

The conﬁguration dialog allows the selection of the calendars which are of interest to you, and also provides

direct interaction with the calendars. The Mayan and Aztec calendars allow moving to the previous or next

date of that respective name.

Section

[

Calendars

]

in conﬁg.ini ﬁle

Apart from changing settings using the plugin conﬁguration dialog, you can also edit the

config.ini

ﬁle to

change settings for the Calendars plugin – just make it carefully!

ID Type Default ID Type Default

show bool true

ﬂag_text_color_override bool false text_color R,G,B 0.5,0.5,0.7

show_julian bool true show_gregorian bool true

show_revised_julian bool false show_iso bool true

show_icelandic bool false

show_roman bool false show_olympic bool false

show_egyptian bool false

show_armenian bool false show_zoroastrian bool false

show_coptic bool false show_ethiopic bool false

show_persian_astronomical bool false show_persian_arithmetic bool false

show_bahai_astronomical bool false show_bahai_arithmetic bool false

show_islamic bool true show_hebrew bool true

show_old_hindu_solar bool false show_old_hindu_lunar bool false

show_new_hindu_solar

bool true show_new_hindu_lunar bool true

show_astro_hindu_solar bool false show_astro_hindu_lunar bool false

show_tibetan bool false show_balinese_pawukon bool false

show_chinese bool false show_japanese bool false

show_korean bool false show_vietnamese bool false

show_maya_long_count bool true

show_maya_haab bool false show_maya_tzolkin bool false

show_aztec_tonalpohualli bool false show_aztec_xihuitl bool false

show_french_astronomical bool false show_french_arithmetic bool false

13.10.5 Further development

The plugin is still in development. More calendars will be added in later versions, and formatting and setting

options may be improved. Members of non-European cultures who are actually using the output and can

judge its correctness are invited to report errors or suggest better formatting for their respective calendars.

For example, our source book (Reingold and Dershowitz, 2018) describes one solution for the “New

Hindu” calendars, but notes several variants, which are in fact also location dependent. We cannot show

every variant here, but hope to have the version described in the book correct. If you know what you are

doing: we are accepting improvements and extensions in form of working code plus documentation where

this variant is used. Not just a few example dates, but an algorithmic solution.

13.10.6 Acknowledgments

If you are using this plugin in scientiﬁc publications, please cite Zotti, S. Hoffmann, et al. (2021).

14. Object Catalog Plugins

Several plugins provide users with some more object classes.

14.1 Bright Novae Plugin

Figure 14.1: Nova Cygni 1975 (also known as V1500 Cyg)

The Bright Novae plugin provides visualization of some bright novae in the Milky Way galaxy. If enabled

(see section 12.1), bright novae from the past will be presented in the sky at the correct times. For example,

set date and time to 30 August 1975, look at the constellation Cygnus to see Nova Cygni 1975

(Fig. 14.1).

14.1.1 Section

[

Novae

]

in conﬁg.ini ﬁle

You can edit

config.ini

ﬁle by yourself for changes of the settings for the Bright Novae plugin – just make

it carefully!

ID Type Description

last_update string Date and time of last update

update_frequency_days

int Frequency of updates, in days

updates_enable

bool Enable updates of bright novae catalog from Internet

url

string URL of bright novae catalog

14.1.2 Format of bright novae catalog

To add a new nova, open a new line after line 5 and paste the following, note commas and brackets, they are

important:

https://en.wikipedia.org/wiki/V1500_Cygni

160 Chapter 14. Object Catalog Plugins

" Nova d es ig nation ":

{

" name ": " name of nova ",

" type ": " type of nova ",

" maxM ag ni tude ": value of maximal visual magnitude ,

" minM ag ni tude ": value of minimal visual magnitude ,

" peakJD ": JD for maximal visual magnitude ,

" m2 " : Time to d ecline by 2 mag from ma ximum ( in days ),

" m3 " : Time to d ecline by 3 mag from ma ximum ( in days ),

" m6 " : Time to d ecline by 6 mag from ma ximum ( in days ),

" m9 " : Time to d ecline by 9 mag from ma ximum ( in days ),

" dis tance ": value of distance between nova and

Earth ( in th ousands of Light Years ) ,

" RA " : " Right ascensio n ( J2000 )" ,

" Dec ": " Declination ( J2000 )"

For example, the record for Nova Cygni 1975 (V1500 Cyg) looks like:

" V1500 Cyg ":

{

" name ": " Nova Cygni 1975 " ,

" type ": " NA " ,

" maxM ag ni tude ": 1.69 ,

" minM ag ni tude ": 21 ,

" peakJD ": 2442655 ,

" m2 " : 2,

" m3 " : 4,

" m6 " : 32 ,

" m9 " : 263

" dis tance ": 6.36 ,

" RA " : " 21 h11m36 .6 s " ,

" Dec ": " 48 d09m02s "

14.1.3 Light curves

This plugin uses a very simple model for calculation of light curves for novae stars. This model is based on

time for decay by

magnitudes from the maximum value, where

is 2, 3, 6 and 9. If a nova has no values

for decay of magnitude then this plugin will use generalized values for it.

14.2 Historical Supernovae Plugin 161

14.2 Historical Supernovae Plugin

Figure 14.2: Supernova 1604 (also known as Kepler’s Supernova, Kepler’s Nova or Kepler’s

Star)

Similar to the Historical Novae plugin (section 14.1), the Historical Supernovae plugin provides visualization

of bright historical supernovae (Fig. 14.2) from the table below. If enabled (see section 12.1), bright

supernovae from the past will be presented in the sky at the correct times. For example, set date and time to

29 April 1006, and look at the constellation Lupus to see SN 1006A.

14.2.1 List of supernovae in default ca talog

Supernova Date of max. brightness Max. apparent mag. Type Name

SN 185A

7 December -6.0 Ia

SN 386A 24 April 1.5 II

SN 1006A

29 April -7.5 I

SN 1054A

3 July -6.0 II

SN 1181A

4 August -2.0 II

SN 1572A

5 November -4.0 I Tycho’s Supernova

SN 1604A

8 October -2.0 I Kepler’s Supernova

SN 1680A

15 August 6.0 IIb Cassiopeia A

https://en.wikipedia.org/wiki/SN_185

https://en.wikipedia.org/wiki/SN_1006

https://en.wikipedia.org/wiki/SN_1054

https://en.wikipedia.org/wiki/SN_1181

https://en.wikipedia.org/wiki/SN_1572

https://en.wikipedia.org/wiki/SN_1604

https://en.wikipedia.org/wiki/Cassiopeia_A

162 Chapter 14. Object Catalog Plugins

SN 1885A

17 August 5.8 IPec S Andromedae

SN 1895B 5 July 8.0 I

SN 1919A 14 March 11.0 I

SN 1920A 17 December 11.7 II

SN 1921C 11 December 11.0 I

SN 1937C 21 August 8.5 Ia

SN 1937D 15 September 11.87 Ia

SN 1960F 21 April 11.6 Ia

SN 1960R 19 December 12.0 I

SN 1961H 8 May 11.8 Ia

SN 1962M 26 November 11.5 II

SN 1965I 19 Juni 11.8 Ia

SN 1966J 2 December 11.3 I

SN 1968L 12 July 11.9 IIP

SN 1970G 30 July 11.4 IIL

SN 1971I 29 May 11.9 Ia

SN 1972E

8 May 8.4 Ia

SN 1974G 27 April 11.8 Ia

SN 1979C 15 April 11.6 IIL

SN 1980K 31 October 11.6 IIL

SN 1981B 9 March 12.0 Ia

SN 1983N 17 July 11.4 Ib

SN 1986G 12 May 11.44 Ia Pec

SN 1987A

24 February 2.9 IIPec

SN 1989B 6 February 11.9 Ia

SN 1991T 26 April 11.6 IaPec

SN 1993J

30 March 10.8 IIb

SN 1994ae 12 January 12.0 Ia

SN 1994D 31 March 11.8 Ia

SN 1998bu 21 May 11.9 Ia

SN 2004dj 31 July 11.3 IIP

SN 2004et 2 October 11.57 II

SN 2011fe

13 September 10.06 Ia

SN 2012cg 6 Juni 11.954 Ia

SN 2012fr 16 November 11.95 Ia

SN 2013aa 13 February 11.9 Ia

SN 2014j 30 January 10.5 Ia

SN 2017cbv 22 March 11.5 Ia

14.2.2 Light curves

In this plugin a simple model of light curves for different supernovae has been implemented (Figure 14.3).

While Type I supernovae show a peak and slow but steady decay, Type II supernovae show a longer “plateau”

in the decay curve.

In both images for light curves the maximum brightness is marked as day 0.

https://en.wikipedia.org/wiki/S_Andromedae

https://en.wikipedia.org/wiki/SN1972e

https://en.wikipedia.org/wiki/SN_1987A

https://en.wikipedia.org/wiki/SN_1993J

https://en.wikipedia.org/wiki/SN_2011fe

14.2 Historical Supernovae Plugin 163

Figure 14.3: Light Curves of Supernovae Types I (left) and II (right)

14.2.3 Section

[

Super novae

]

in conﬁg.ini ﬁle

You can edit

config.ini

ﬁle by yourself for changes of the settings for the Historical Supernovae plugin –

just make it carefully!

ID Type Description

last_update

string Date and time of last update

update_frequency_days

int Frequency of updates, in days

updates_enable

bool Enable updates of bright novae catalog from Internet

url

string URL of bright novae catalog

14.2.4 Format of historical supernovae catalog

To add a new nova, open a new line after line 5 and paste the following, note commas and brackets, they are

important:

" Superno va designation " :

{

" type ": " type of su pernova " ,

" maxM ag ni tude ": value of maximal visual magnitude ,

" peakJD ": JD for maximal visual magnitude ,

" alpha " : " Right ascension ( J2000 )",

" delta " : " Declination ( J2000 ) " ,

" dis tance ": value of distance between s upernova and

Earth ( in th ousands of Light Years ) ,

" note ": " notes for supernova "

For example, the record for SN 1604A (Kepler’s Supernova) looks like:

" 1604 A" :

{

" type ": " I " ,

" maxM ag ni tude ": -2 ,

" peakJD ": 2307190 ,

" alpha " : " 17 h30m36 .00 s" ,

" delta " : " -21 d29m00 .0 s " ,

" dis tance ": 14 ,

" note ": " Kepler ’ s Supernova "

164 Chapter 14. Object Catalog Plugins

14.3 Exoplanets Plugin

Figure 14.4: Planetary system τ Ceti

This plugin plots the position of stars with exoplanets. Exoplanets data is derived from “The Extrasolar

Planets Encyclopaedia”

. List of potential habitable exoplanets and data about them were taken from “The

Habitable Exoplanets Catalog”

by the Planetary Habitability Laboratory

. If enabled (see section 12.1),

just click on the Exoplanet button on the bottom toolbar to display markers for the stars with known

exoplanets. You can then either click on such a marked star or ﬁnd the stars with exoplanets by their

designation (e.g., 24 Sex) in the

dialog (see 4.5).

A large number of exoplanets was discovered by the Kepler space observatory mission (2009–18) which

in its primary mission observed a small ﬁeld in the Cyg/Lib/Dra area. Accordingly you will ﬁnd a huge

concentration of exoplanets there. This should give us a hint about how many more must be out there. Its

extended mission added many more exoplanet systems along the ecliptic.

The second tab in the plugin’s dialog shows a scatter plot relating two selectable properties. In some

cases a logarithmic axis is more useful, but if the original values can be negative only the positive data are

shown in log plots. Additional entry ﬁelds allow ﬁltering the data range.

14.3.1 Potential habitable exoplanets

This plugin can display potential habitable exoplanets (orange marker) and some information about those

planets.

Planetary Class

Planet classiﬁcation from host star spectral type (F, G, K, M; see section 19.2.4), habitable

zone (hot, warm, cold) and size (miniterran, subterran, terran, superterran, jovian, neptunian) (Earth =

G-Warm Terran).

Equilibrium Temperature

The planetary equilibrium temperature

is a theoretical temperature (in °C)

that the planet would be at when considered simply as if it were a black body being heated only by its

parent star (assuming a 0.3 bond albedo). As example the planetary equilibrium temperature of Earth

is -18.15°C (255 K).

Earth Similarity Index (ESI)

Similarity to Earth

on a scale from 0 to 1, with 1 being the most Earth-like.

ESI depends on the planet’s radius, density, escape velocity, and surface temperature.

http://exoplanet.eu/

https://phl.upr.edu/projects/habitable-exoplanets-catalog

https://phl.upr.edu/home

https://en.wikipedia.org/wiki/Planetary_equilibrium_temperature

https://phl.upr.edu/projects/earth-similarity-index-esi

14.3 Exoplanets Plugin 165

14.3.2 Proper names

In December 2015

and in December 2019

, the International Astronomical Union (IAU) has ofﬁcially

approved names for several exoplanets after a public vote.

Veritate * (14 And) – From the latin Veritas, truth. The ablative form means where there is truth

Spe * (14 And b) – From the latin Spes, hope. The ablative form means where there is hope.

Musica (18 Del) – Musica is Latin for music.

Arion

(18 Del b) – Arion was a genius of poetry and music in ancient Greece. According to legend, his life

was saved at sea by dolphins after attracting their attention by the playing of his kithara.

Fafnir (42 Dra) – Fafnir was a Norse mythological dwarf who turned into a dragon.

Orbitar

(42 Dra b) – Orbitar is a contrived word paying homage to the space launch and orbital operations

of NASA.

Chalawan (47 UMa) – Chalawan is a mythological crocodile king from a Thai folktale.

Taphao Thong

(47 UMa b) – Taphao Thong is one of two sisters associated with the Thai folk tale of

Chalawan.

Taphao Kaew

(47 UMa c) – Taphao Kae is one of two sisters associated with the Thai folk tale of Chalawan.

Helvetios

(51 Peg) – Helvetios is Celtic for the Helvetian and refers to the Celtic tribe that lived in

Switzerland during antiquity.

Dimidium

(51 Peg b) – Dimidium is Latin for half, referring to the planet’s mass of at least half the mass of

Jupiter.

Copernicus

(55 Cnc) – Nicolaus Copernicus or Mikolaj Kopernik (1473-1543) was a Polish astronomer

who proposed the heliocentric model of the solar system in his book “De revolutionibus orbium

coelestium”.

Galileo

(55 Cnc b) – Galileo Galilei (1564-1642) was an Italian astronomer and physicist often called the

father of observational astronomy and the father of modern physics. Using a telescope, he discovered

the four largest satellites of Jupiter, and the reported the ﬁrst telescopic observations of the phases of

Venus, among other discoveries.

Brahe

(55 Cnc c) – Tycho Brahe (1546-1601) was a Danish astronomer and nobleman who recorded

accurate astronomical observations of the stars and planets. These observations were critical to

Kepler’s formulation of his three laws of planetary motion.

Lipperhey

* (55 Cnc d) – Hans Lipperhey (1570-1619) was a German-Dutch lens grinder and spectacle

maker who is often attributed with the invention of the refracting telescope in 1608

Janssen

(55 Cnc e) – Zacharias Janssen (1580s-1630s) was a Dutch spectacle maker who is often attributed

with invention of the microscope, and more controversially with the invention of the telescope.

Harriot

(55 Cnc f) – Thomas Harriot (ca. 1560-1621) was an English astronomer, mathematician, ethno-

grapher, and translator, who is attributed with the ﬁrst drawing of the Moon through telescopic

observations.

Amateru

* (

Tau b) – Amateru is a common Japanese appellation for shrines when they enshrine Amaterasu,

the Shinto goddess of the Sun, born from the left eye of the god Izanagi

Hypatia

(

Dra b) – Hypatia was a famous Greek astronomer, mathematician, and philosopher. She was

head of the Neo-Platonic school at Alexandria in the early

century, until murdered by a Christian

mob in 415.

Ran

* (

Eri) – Ran is the Norse goddess of the sea, who stirs up the waves and captures sailors with her net.

AEgir * (ε Eri b) – Ægir is Ran’s husband, the personiﬁed god of the ocean. Ægir and Ran both represent

the Jotuns who reign in the outer Universe; together they had nine daughters

Tadmor

* (

Cep b) – Ancient Semitic name and modern Arabic name for the city of Palmyra, a UNESCO

World Heritage Site.

Dagon (

α PsA b) – Dagon was a Semitic deity, often represented as half-man, half-ﬁsh.

Tonatiuh (HD 104985) – Tonatiuh was the Aztec god of the Sun.

https://www.iau.org/news/pressreleases/detail/iau1514/

https://www.iau.org/news/pressreleases/detail/iau1912/

The original name proposed, Veritas, is that of an asteroid important for the study of the solar system.

The original spelling of Lippershey was corrected to Lipperhey on 15.01.2016. The commonly seen spelling

Lippershey (with an s) results in fact from a typographical error dating back from 1831, thus should be avoided.

The name originally proposed, Amaterasu, is already used for an asteroid.

Note the typographical difference between Ægir and Aegir, the Norwegian transliteration. The same name, with the

spelling Aegir, has been attributed to one of Saturn’s satellites, discovered in 2004.

166 Chapter 14. Object Catalog Plugins

Meztli (HD 104985 b) – Meztli was the Aztec goddess of the Moon.

Ogma

* (HD 149026) – Ogma was a deity of eloquence, writing, and great physical strength in the Celtic

mythologies of Ireland and Scotland, and may be related to the Gallo-Roman deity Ogmios

Smertrios (HD 149026 b) – Smertrios was a Gallic deity of war.

Intercrus

(HD 81688) – Intercrus means between the legs in Latin style, referring to the star’s position in

the constellation Ursa Major.

Arkas (HD 81688 b) – Arkas was the son of Callisto (Ursa Major) in Greek mythology.

Cervantes

(

Ara) – Miguel de Cervantes Saavedra (1547-1616) was a famous Spanish writer and author

of “El Ingenioso Hidalgo Don Quixote de la Mancha”.

Quijote

(

Ara b) – Lead ﬁctional character from Cervantes’s “El Ingenioso Hidalgo Don Quixote de la

Mancha”.

Dulcinea

(

Ara c) — Fictional character and love interest of Don Quijote (or Quixote) in Cervantes’s “El

Ingenioso Hidalgo Don Quixote de la Mancha”.

Rocinante

(

Ara d) – Fictional horse of Don Quijote in Cervantes’s “El Ingenioso Hidalgo Don Quixote

de la Mancha”.

Sancho

(

Ara e) – Fictional squire of Don Quijote in Cervantes’s “El Ingenioso Hidalgo Don Quixote de

la Mancha”.

Thestias

* (

Gem b) – Thestias is the patronym of Leda and her sister Althaea, the daughters of Thestius.

Leda was a Greek queen, mother of Pollux and of his twin Castor, and of Helen and Clytemnestra

Lich

(PSR B1257+12) – Lich is a ﬁctional undead creature known for controlling other undead creatures

with magic.

Draugr (PSR B1257+12 b) – Draugr refers to undead creatures in Norse mythology.

Poltergeist

(PSR B1257+12 c) – Poltergeist is a name for supernatural beings that create physical distur-

bances, from German for noisy ghost.

Phobetor

(PSR B1257+12 d) – Phobetor is a Greek mythological deity of nightmares, the son of Nyx, the

primordial deity of night.

Titawin

(

And) – Titawin (also known as Medina of Tetouan) is a settlement in northern Morocco

and UNESCO World Heritage Site. Historically it was an important point of contact between two

civilizations (Spanish and Arab) and two continents (Europe and Africa) after the 8

century.

Saffar

(

And b) – Saffar is named for Abu al-Qasim Ahmed Ibn-Abd Allah Ibn-Omar al Ghaﬁqi Ibn-

al-Saffar, who taught arithmetic, geometry, and astronomy in

century Cordova in Andalusia

(modern Spain), and wrote an inﬂuential treatise on the uses of the astrolabe.

Samh

(

And c) – Samh is named for Abu al-Qasim ’Asbagh ibn Muhammad ibn al-Samh al-Mahri (or Ibn

al-Samh), a noted 11

century astronomer and mathematician in the school of al Majriti in Cordova

(Andalusia, now modern Spain).

Majriti

(

And d) – Majriti is named for Abu al-Qasim al-Qurtubi al-Majriti, a notable mathematician,

astronomer, scholar, and teacher in 10

century and early 11

century Andalusia (modern Spain).

Libertas

* (

Aql) – Libertas is Latin for liberty. Liberty refers to social and political freedoms, and a

reminder that there are people deprived of liberty in the world even today. The constellation Aquila

represents an eagle – a popular symbol of liberty.

Fortitudo

* (

Aql b) – Fortitudo is Latin for fortitude. Fortitude means emotional and mental strength in

the face of adversity, as embodied by the eagle (represented by the constellation Aquila).

Illyrian

(HD 82886) – Historians largely believe that the Albanians are descendants of the Illyrians, a term

Albanians proudly call themselves.

Arber (HD 82886 b) – Arber is the term for the inhabitants of Albania during the middle ages.

Hoggar

(HD 28678) – Hoggar is the name of the main mountain range in the Sahara Desert in southern

Algeria.

Tassili

(HD 28678 b) – Tassili is a UNESCO World Heritage Site situated in the Sahara Desert and is

renowned for its prehistoric cave art and scenic geological formations.

Arcalís

(HD 131496) – Arcalis is a famous peak in the north of Andorra, where the Sun passes through a

hole in the mountain twice a year at ﬁxed dates. It was used as a primitive solar calendar and reference

point for shepherds and early inhabitants of Andorra.

Madriu

(HD 131496 b) – Madriu (Mare del riu in Catalan, Mother of the River in English) is the name of a

Ogmios is a name already attributed to an asteroid.

The original proposed name Leda is already attributed to an asteroid and to one of Jupiter’s satellites. The name

Althaea is also attributed to an asteroid.

14.3 Exoplanets Plugin 167

glacial valley and of the river that runs through it in the southeast of Andorra. It is the main part of

the Madriu-Peraﬁta-Claror UNESCO World Heritage Site.

Nosaxa

(HD 48265) – Nosaxa means spring in the Moqoit language. The word comes from a combination

of nosahuec, which means renew, and ñaaxa, which means year.

Naqaya

(HD 48265 b) – Naqaya means brother-family-relative in the Moqoit language and leads us to call

all humans, indigenous or non-indigenous, brother.

Malmok

(WASP-39) – Malmok is an indigenous name given to a beach in Aruba with a narrow sandy

stretch that interrupts the limestone and rocky terrace along the coast. Its shallow clear Caribbean

waters make it a popular snorkelling spot.

Bocaprins

(WASP-39 b) – Boca Prins is a secluded beach with white dunes and iconic scenery situated in

Arikok National Park along the northeast coast of Aruba. It is named after Plantation Prins where

coconuts are cultivated.

Bubup (HD 38283) – Bubup is the Boonwurrung word for child.

Yanyan (HD 38283 b) – YanYan is the Boonwurrung word for boy.

Franz

(HAT-P-14) – Franz is a character in the movie “Sissi” embodying an emperor of Austria in the

century. The role is played by the actor Karlheinz Böhm.

Sissi

(HAT-P-14 b) – Sissi is a character in the movie “Sissi”, who is married with Franz. The role is played

by the actress Romy Schneider.

Mahsati

(HD 152581) – Mahsati Ganjavi (1089–1159) is one of the brightest shining stars of Azerbaijani

poetry. She was said to have associated with both Omar Khayyam and Nizami and was well educated

and talented and played numerous musical instruments.

Ganja

(HD 152581 b) – Ganja is an ancient city of Azerbaijan, and is the birth place of many prominent

people such as the poets Mahsati and Nizami. It is the ancient capital of Azerbaijan, the ﬁrst capital

of the Azerbaijan Democratic Republic and the city with the spirit of wisdom and freedom.

Timir

(HD 148427) – Timir means darkness in Bengali language, alluding to the star being far away in the

darkness of space.

Tondra

(HD 148427 b) – Tondra means nap in Bengali language, alluding to the symbolic notion that the

planet was asleep until discovered.

Nervia (HD 49674) – Nervia, adapted from Nervii, was a prominent Belgian Celtic tribe.

Eburonia (HD 49674 b) – Eburonia, adapted from Eburones, was a prominent Belgian Celtic tribe.

Gakyid

(HD 73534) – Gakyid means happiness. Gross National Happiness is the development philosophy

conceived and followed in Bhutan and is one of Bhutan’s contributions to the world.

Drukyul

(HD 73534 b) – Drukyul (land of the thunder dragon) is the native name for Bhutan, the country

that came up with the philosophy of Gross National Happiness.

Tapecue

(HD 63765) – Tapecue means eternal path in Guarani and represents the Milky Way through

which the ﬁrst inhabitants of the Earth arrived and could return.

Yvaga

(HD 63765 b) – Yvaga means paradise for the Guarani and the Milky Way was known as the road to

Yvaga or paradise.

Bosona

(HD 206610) – Bosona is the name given to the territory of Bosnia in the

century. Later, the

name was transformed to Bosnia originating from the name of the Bosna river.

Naron

(HD 206610 b) – Naron is one of the names given to the Neretva river in Herzegovina (and partly in

Croatia) in antiquity originating with the Celts who called it Nera Etwa which means the Flowing

Divinity.

Tupi

(HD 23079) – Tupi is the name of the most populous Indigenous People living on the eastern coast of

South America, before the Portuguese arrived in the 16

century.

Guarani

(HD 23079 b) – Guarani is the name of the most populous Indigenous people living in South

Brazil and parts of Argentina, Paraguay and Uruguay.

Gumala

(HD 179949) – Gumala is a Malay word, which means a magic bezoar stone found in snakes,

dragons, etc.

Mastika

(HD 179949 b) – Mastika is a Malay word, which means a gem, precious stone, jewel or the

prettiest, the most beautiful.

Tangra (WASP-21) – Tangra is the supreme celestial god that early Bulgars worshiped.

Bendida

(WASP-21 b) – Bendida is the Great Mother Goddess of the Thracians. She was especially revered

as a goddess of marriage and living nature.

Mouhoun

(HD 30856) – Mouhoun, also called Volta Noire, is the largest river in Burkina Faso and plays

an important role in the lives of the people in the areas it passes through.

Nakanbé

(HD 30856 b) – The Nakanbé, also called Volta Blanche, is the second largest river in Burkina

168 Chapter 14. Object Catalog Plugins

Faso. Its source is in the heart of the Sahara Burkinabe and ends in Ghana.

Nikawiy (HD 136418) – Nikawiy is the word for mother in the Indigenous Cree language of Canada.

Awasis (HD 136418 b) – Awasis is the word for child in the Indigenous Cree language of Canada.

Pincoya

(HD 164604) – Pincoya is a female water spirit from southern Chilean mythology who is said to

bring drowned sailors to the Caleuche so that they can live in the afterlife.

Caleuche

(HD 164604 b) – Caleuche is a large ghost ship from southern Chilean mythology which sails the

seas around the island of Chiloé at night.

Lionrock

(HD 212771) – Lion Rock is a lion-shaped peak overlooking Hong Kong and is a cultural symbol

with deep respect from the local community.

Victoriapeak

(HD 212771 b) – Victoria Peak overlooks the bustling Victoria Harbour and is regarded as an

ambassadorial gateway for foreign visitors wishing to experience Hong Kong ﬁrst hand.

Xihe

(HD 173416) – Xiheis the goddess of the sun in the Chinese mythology and also represents the earliest

astronomers and developers of calendars in ancient China.

Wangshu

(HD 173416 b) – Wangshu is the goddess who drives for the Moon and also represents the Moon

in Chinese mythology.

Formosa

(HD 100655) – Formosa is the historical name of Taiwan used in the

century, meaning

beautiful in Latin.

Sazum

(HD 100655 b) – Sazum is the traditional name of Yuchi, a Township in Nantou county, in which

the famous Sun-Moon Lake lies. Sazum means water in the language of the Thao people who are a

tribe of Taiwanese aborigines who lived in the region for hundreds of years.

Macondo

(HD 93083) – Macondo is the mythical village of the novel “One Hundred Years of Solitude”

(“Cien años de soledad”) the classic novel by Gabriel García Marquez. Macondo is a ﬁctional place

where magic and reality are mixed.

Melquíades

(HD 93083 b) – Melquíades is a ﬁctional character that walks around Macondo, like a planet

orbiting a star, connecting it with the external world by introducing new knowledge using his inventions

as well as his stories.

Poerava

(HD 221287) – Poerava is the word in the Cook Islands Maori language for a large mystical black

pearl of utter beauty and perfection.

Pipitea

(HD 221287 b) – Pipitea is a small, white and gold pearl found in Penrhyn lagoon in the northern

group of the Cook Islands.

Dìwö

(WASP-17) – Dìwö in Bribri language means the sun (bigger than the sun we know) and that never

turns off.

Ditsö (WASP-17 b) – Ditsö is the name that the god Sibö gave to the ﬁrst Bribri people.

Stribor

(HD 75898) – Stribor is God of winds in Slavic mythology, as well as a literature character in the

book Pri

ce iz davnine (Croatian Tales of Long Ago) by the Croatian author Ivana Brli

c-Mažurani

Veles (HD 75898 b) – Veles is a major Slavic god of earth, waters and the underworld.

Felixvarela

(BD-17 63) – Felix Varela (1788–1853) was the ﬁrst to teach science in Cuba at the San Carlos

and San Ambrosio Seminary. He opened the way to education for all, and began the experimental

teaching of physics in Cuba.

Finlay

(BD-17 63 b) – Carlos Juan Finlay (1833–1915) was an epidemiologist recognized as a pioneer in

the research of yellow fever, determining that it was transmitted through mosquitoes.

Alasia

(HD 168746) – Alasia is the ﬁrst historically recorded name of Cyprus, dating back to mid-ﬁfteenth

century BC.

Onasilos

(HD 168746 b) – Onasilos is the oldest historically recorded doctor in Cyprus, inscribed on the

ﬁfth century BC Idalion Tablet. Also known as the Onasilou Plate, it is considered as the oldest legal

contract found in the world.

Absolutno

(XO-5) – Absolutno is a ﬁctional miraculous substance in the sci-ﬁ novel “Továrna na absolutno”

(“The Factory for the Absolute”) by inﬂuential Czech writer Karel

Capek.

Makropulos

(XO-5 b) – Makropulos is the name from Karel

Capek’s play V

ec Makropulos (The Makropu-

los Affair), dealing with problems of immortality and consequences of an artiﬁcial prolongation of

life.

Muspelheim

(HAT-P-29) – Muspelheim is the Norse mythological realm of ﬁre. The ﬁrst gods used the

sparks of Muspelheim to form the sun, moon, planets, and stars.

Surt

(HAT-P-29 b) – Surt is the ruler of Muspelheim and the ﬁre giants there in Norse mythology. At

Ragnarok, the end of the world, he will lead the attack on our world and destroy it in ﬂames.

Márohu

(WASP-6) – Márohu the god of drought is the protector of the Sun and is engraved at a higher

position on the stalagmite than Boinayel in the El Puente cave, where the Sun makes its way down

14.3 Exoplanets Plugin 169

every 21 December.

Boinayel

(WASP-6 b) – Boinayel the god of rain that fertilizes the soil is engraved on the stalagmite at a

lower position than Márohu in the El Puente cave.

Nenque

(HD 6434) – Nenque means the Sun in the language spoken by the Indigenous Waorani tribes of

the Amazon regions of Ecuador

Eyeke

(HD 6434 b) – Eyeke means near in the language spoken by the Indigenous Waorani tribes of the

Amazon regions of Ecuador. This word is suggested for the exoplanet owing to the proximity of the

planet to the host star.

Citalá (HD 52265) – Citalá means River of stars in the native Nahuat language.

Cayahuanca

(HD 52265 b) – Cayahuanca means The rock looking at the stars in the native Nahuat language.

Koit (XO-4) – Koit is Estonian for the time when the Sun rises in the morning (dawn).

Hämarik (XO-4 b) – Hämarik is Estonian for the time when the Sun goes down in the evening (twilight).

Buna (HD 16175) – Buna is the commonly used word for coffee in Ethiopia.

Abol

(HD 16175 b) – Abol is the ﬁrst of three rounds of coffee in the Ethiopian traditional coffee ceremony.

Horna (HAT-P-38) – Horna is hell or the underworld from Finnic mythology.

Hiisi (HAT-P-38 b) – Hiisi represents sacred localities and later evil spirits from Finnic mythology.

Bélénos (HD 8574) – Bélénos was the god of light, of the Sun, and of health in Gaulish mythology.

Bélisama

(HD 8574 b) – Bélisama was the goddess of ﬁre, notably of the hearth and of metallurgy and

glasswork, in Gaulish mythology.

Itonda (HD 208487) – Itonda, in the Myene tongue, corresponds to all that is beautiful.

Mintome

(HD 208487 b) – Mintome, in the Fang tongue, is a mythical land where a brotherhood of brave

men live.

Mago

(HD 32518) – Mago is a National Park in Ethiopia noted for its giraffes. The star also happens to be

in the constellation of Camelopardis (the giraffe).

Neri (HD 32518 b) – The Neri river in Ethiopia runs through parts of the Mago National park.

Sika (HD 181720) – Sika means gold in the Ewe language and gold is one of Ghana’s principal exports.

Toge (HD 181720 b) – Toge means earring in the Ewe language.

Lerna (HAT-P-42) – Lerna was the name of a lake in the eastern Peloponnese, where the Lernaean Hydra,

an immortal mythical nine-headed beast lived. The star lies in the constellation of Hydra.

Iolaus

(HAT-P-42 b) – Iolaus was the nephew of Heracles from Greek mythology, moving around lake Lerna

in helping Heracles to exterminate the Lernaean Hydra. Similarly this exoplanet in the constellation

of Hydra moves around its parent star.

Tojil (WASP-22) – Tojil is the name of one of the Mayan deities related to rain, storms, and ﬁre.

Koyopa’

(WASP-22 b) – Koyopa’ is the word associated with lightning in K’iche’ (Quiché) Mayan language.

Citadelle

(HD 1502) – The Citadelle is a large mountaintop fortress in Nord, Haiti built after Haiti’s

independence, and was designated a UNESCO World Heritage site along with the nearby Sans-Souci

Palace.

Indépendance

(HD 1502 b) – Indépendance is named after the Haitian Declaration of Independence on 1

January 1804, when Haiti became the ﬁrst independent black republic.

Hunahpú

(HD 98219) – Hunahpú was one of the twin gods who became the Sun in K’iche’ (Quiché)

Mayan mythology as recounted in the Popol Vuh.

Ixbalanqué

(HD 98219 b) – Ixbalanqué was one of the twin gods who became the Moon in K’iche’ (Quiché)

Mayan mythology as recounted in the Popol Vuh.

Hunor

(HAT-P-2) – Hunor was a legendary ancestor of the Huns and the Hungarian nation, and brother of

Magor.

Magor

(HAT-P-2 b) – Magor was a legendary ancestor of the Magyar people and the Hungarian nation, and

brother of Hunor.

Funi (HD 109246) – Funi is an old Icelandic word meaning ﬁre or blaze.

Fold (HD 109246 b) – Fold is an old Icelandic word meaning earth or soil.

Bibh

(HD 86081) – Bibh

a is the Bengali pronunciation of the Sanskrit word Vibha, which means a bright

beam of light.

Santamasa

(HD 86081 b) – Santamasa in Sanskrit means clouded, which alludes to the exoplanet’s

atmosphere.

Doﬁda (HD 117618) – Doﬁda means our star in Nias language.

Noifasui

(HD 117618 b) – Noifasui means revolve around in Nias language, derived from the word ifasui,

meaning to revolve around, and no, indicating that the action occurred in the past and continued to the

present time.

170 Chapter 14. Object Catalog Plugins

Kaveh

(HD 175541) – Kaveh is one of the heroes of Shahnameh, the epic poem composed by Persian poet

Ferdowsi between 977 and 1010 CE. Kaveh is a blacksmith who symbolises justice.

Kavian

(HD 175541 b) – Kaveh carries a banner called Derafsh Kaviani (Derafsh: banner, Kaviani: relating

to Kaveh).

Uruk

(HD 231701) – Uruk was an ancient city of the Sumer and Babylonian civilizations in Mesopotamia

situated along an ancient channel of the Euphrates river in modern-day Iraq.

Babylonia

(HD 231701 b) – Babylonia was a key kingdom in ancient Mesopotamia from the

centuries BC whose name-giving capital city was built on the Euphrates river.

Tuiren

(HAT-P-36) – Tuiren was the aunt of the hunterwarrior Fionn mac Cumhaill of Irish legend, who

was turned into a hound by the jealous fairy Uchtdealbh.

Bran

(HAT-P-36 b) – Tuiren’s son Bran was a hound and cousin of the hunterwarrior Fionn mac Cumhaill

of Irish legend.

Tevel

(HAT-P-9) – Tevel means Universe or everything and begins with the letter Taf, the last letter in the

Hebrew alphabet.

Alef (HAT-P-9 b) – Alef is the ﬁrst letter in the Hebrew alphabet and also means bull.

Flegetonte

(HD 102195) – Flegetonte is the underworld river of ﬁre from Greek Mythology in the Italian

narrative poem on the afterlife “Divina Commedia” (“Divine Commedy”) by Dante Alighieri, chosen

as an allusion to the star’s ﬁery nature.

Lete

(HD 102195 b) – Lete is the oblivion river made of fog from Greek Mythology in the Italian narrative

poem on the afterlife “Divina Commedia” (“Divine Commedy”) by Dante Alighieri, chosen as an

allusion to the planet’s gaseous nature.

Nyamien (WASP-15) – Nyamien refers to the supreme creator deity of Akan mythology.

Asye (WASP-15 b) – Asye refers to the Earth goddess of Akan mythology.

Kamui

(HD 145457) – Kamui is a word in the Ainu language denoting a supernatural entity possessing

spiritual energy.

Chura (HD 145457 b) – Chura is a word in the Ryukyuan/Okinawan language meaning natural beauty.

Petra

(WASP-80) – Petra is a historical and archaeological city in southern Jordan and a UNESCO World

Heritage site.

Wadirum

(WASP-80 b) – Wadi Rum (Valley of the Moon) is located at the far south of Jordan, it is the

largest valley in Jordan, set on the high plateau at the western edge of the Arabian Desert.

Kalausi

(HD 83443) – The word Kalausi means a very strong whirling column of wind in the Dholuo

language of Kenya.

Buru

(HD 83443 b) – Buru means dust in the Dholuo language of Kenya and is typically associated with

wind storms.

Liesma

(HD 118203) – Liesma means ﬂame, and it is the name of a character from the Latvian poem

Staburags un Liesma.

Staburags

(HD 118203 b) – Staburags is the name of a character from the Latvian poem Staburags un

Liesma, and denotes a rock with symbolic meaning in literature and history.

Phoenicia

(HD 192263) – Phoenicia was an ancient thalassocratic civilisation of the Mediterranean that

originated from the area of modern-day Lebanon.

Beirut

(HD 192263 b) – Beirut is one of the oldest continuously inhabited cities in the world and was a

Phoenician port. Beirut is now the capital and largest city of Lebanon.

Pipoltr

(TrES-3) – In the local dialect of Triesenberg, Pipoltr is a bright and visible butterﬂy, alluding to the

properties of a star.

Umbäässa

(TrES-3 b) – In the local dialect of southern Liechtenstein, Umbäässa is a small and barely

visible ant, alluding to the properties of a planet with respect to its star.

Taika (HAT-P-40) – Taika means peace in the Lithuanian language.

Vytis (HAT-P-40 b) – Vytis is the symbol of the Lithuanian coat of arms.

Lucilinburhuc

(HD 45350) – The Lucilinburhuc fortress was built in 963 by the founder of Luxembourg,

Count Siegfried.

Peitruss

(HD 45350 b) – Peitruss is derived from the name of the Luxembourg river Pétrusse, with the

river’s bend around Lucilinburhuc fortress alluding to the orbit of the planet around its star.

Rapeto (HD 153950) – Rapeto is a giant creature from Malagasy tales.

Trimobe (HD 153950 b) – Trimobe is a rich ogre from Malagasy tales.

Intan

(HD 20868) – Intan means diamond in the Malay language (Bahasa Melayu), alluding to the shining

of a star.

Baiduri

(HD 20868 b) – Baiduri means opal in Malay language (Bahasa Melayu), alluding to the mysterious

14.3 Exoplanets Plugin 171

beauty of the planet.

Sansuna

(HAT-P-34) – Sansuna is the name of the mythological giant from traditional Maltese folk tales

that carried the stones of the Gozo megalithic temples on her head.

Ggantija

(HAT-P-34 b) –

Ggantija means giantess: the megalithic temple complex on the island of Gozo,

which alludes to the grandeur of this gas giant exoplanet.

Diya

(WASP-72) – Diya is an oil lamp that is brought by Indian ancestors to Mauritius in the 1820’s, and is

used for lighting during special occasions, including the light festival of Diwali.

Cuptor

(WASP-72 b) – Cuptor is a thermally insulated chamber used for baking or drying substances, that

has long disappeared in Mauritius and has been replaced by more sophisticated ovens.

Axólotl

(HD 224693) – Axólotl means water animal in the native Nahuatl language, which is a unique and

culturally signiﬁcant endemic amphibious species from the basin of Mexico.

Xólotl

(HD 224693 b) – Xólotl means animal in the native Nahuatl language and was an Aztec deity

associated with the evening star (Venus).

Tislit

(WASP-161) – Tislit is the name of a lake in the Atlas mountains of Morocco. It means the bride in

the Amazigh language and it is associated with a heartbroken beautiful girl in an ancient local legend.

Isli

(WASP-161 b) – Isli is the name of a lake in the Atlas mountains of Morocco. It means the groom in the

Amazigh language and it is associated with a heartbroken handsome boy in an ancient local legend.

Emiw

(HD 7199) – Emiw represents love in the local Makhuwa language of the northern region of

Mozambique.

Hairu

(HD 7199 b) – Hairu represents unity in the local Makhuwa language of the northern region of

Mozambique.

Ayeyarwady (HD 18742) – Ayeyarwady is the largest and most important river in Myanmar.

Bagan (HD 18742 b) – Bagan is one of Myanmar’s ancient cities that lies beside the Ayeyarwardy river.

Sagarmatha

(HD 100777) – Sagarmatha is the Nepali name for the highest peak in the world (also known

as Mount Everest) and symbol of national pride of Nepal.

Laligurans

(HD 100777 b) – Laligurans are the Nepali variation of the rhododendron ﬂower and is the

national ﬂower of Nepal.

Sterrennacht

(HAT-P-6) – The Sterrennacht (Starry Night) is a world-famous painting by Dutch grand

master Van Gogh that was painted in France in 1889 and now belongs to the permanent collection of

New York’s Museum of Modern Art.

Nachtwacht

(HAT-P-6 b) – The Nachtwacht (Night Watch) is a world-famous painting by Dutch grand

master Rembrandt that was completed in 1642 and now belongs to the collection of the Rijksmuseum

in Amsterdam.

Karaka

(HD 137388) – Karaka is the word in the M

aori language for a plant endemic to New Zealand that

produces a bright orange, ﬂeshy fruit.

Kerer

(HD 137388 b) – Kerer

u is the word in the M

aori language for a large bush pigeon native to New

Zealand.

Cocibolca

(HD 4208) – Cocibolca is the Nahualt name for the largest lake in Central America in Nicaragua.

Xolotlan

(HD 4208 b) – Xolotlan is the name of the second largest lake of Nicaragua and its name is from

the Nahualt language of the indigenous tribe that settled in Nicaragua, which symbolises a native god

and a refuge for animals.

Amadioha

(HD 43197) – Amadioha is the god of thunder in Igbo mythology. As well as representing

justice, Amadioha is also a god of love, peace and unity.

Equiano

(HD 43197 b) – Equiano was a writer and abolitionist from Ihiala, Nigeria who fought injustice

and the elimination of the slave trade.

Násti (HD 68988) – Násti means star in the Northern Sami language of Norway.

Albmi (HD 68988 b) – Albmi means sky in the Northern Sami language of Norway.

Shama

(HAT-P-23) – Shama is an Urdu literary term meaning a small lamp or ﬂame, symbolic of the light

of the star.

Perwana

(HAT-P-23 b) – Perwana means moth in Urdu, alluding to the eternal love of an object circling the

source of light (the lamp).

Moriah (HD 99109) – Moriah is an ancient name for the mountain within the Old City of Jerusalem.

Jebus

(HD 99109 b) – Jebus was the ancient name of Jerusalem in

millennium BC when populated by

the Canaanite tribe of Jebusites.

Montuno

(WASP-79) – Montuno is the traditional costume the man wears in the “El Punto”, a Panamanian

dance in which a man and woman dance to the sound of drums.

Pollera

(WASP-79 b) – Pollera is the traditional costume the woman wears in the El Punto, a Panamanian

172 Chapter 14. Object Catalog Plugins

dance in which a man and woman dance to the sound of drums.

Tupã

(HD 108147) – Tupã is one of four principle gods of the Guarani Cosmogony in popular Paraguayan

folklore that helped the supreme god Ñamandu to create the Universe.

Tumearandu

(HD 108147 b) – Tume Arandu is a son of Rupavê and Sypavê, the original man and woman

of the Universe, who is known as the Father of Wisdom in popular Paraguayan folklore.

Inquill

(HD 156411) – Inquil was one half of the couple involved in the tragic love story Way to the Sun by

famous Peruvian writer Abraham Valdelomar.

Sumajmajta

(HD 156411 b) – Sumaj Majta was one half of the couple involved in a tragic love story Way

to the Sun by famous Peruvian writer Abraham Valdelomar.

Amansinaya

(WASP-34) – Aman Sinaya is one of the two trinity deities of the Philippine’s Tagalog

mythology, and is the primordial deity of the ocean and protector of ﬁsherman.

Haik

(WASP-34 b) – Haik is the successor of the primordial Aman Sinaya as the God of the Sea of the

Philippine’s Tagalog mythology.

Uklun (HD 102117) – Uklun means us or we in the Pitkern language of the people of Pitcairn Islands.

Leklsullun

(HD 102117 b) – Lekl Sullun means child or children in the Pitkern language of the people of

Pitcairn Islands.

Solaris

(BD+14 4559) – Solaris is the title of a 1961 science ﬁction novel about an ocean-covered exoplanet

by Polish writer Stanislaw Lem.

Pirx

(BD+14 4559 b) – Pirx is a ﬁctional character from books by Polish science-ﬁction writer Stanislaw

Lem.

Lusitânia

(HD 45652) – Lusitânia is the ancient name of the western region of the Iberic Peninsula where

the Lusitanian people lived and where most of modern-day Portugal is situated.

Viriato

(HD 45652 b) – Viriato was a legendary leader of the Lusitanian people, a herdsman and hunter

who led the resistance against Roman invaders during 2

century B.C.

Koeia

(HIP 12961) – Koeia was the word for star in the language of the Taíno Indigenous People of the

Caribbean.

Aumatex

(HIP 12961 b) – Aumatex was the God of Wind in the mythology of the Taíno Indigenous People

of the Caribbean.

Moldoveanu

(XO-1) – Moldoveanu is the highest peak in Romania of the F

ara

mountain range with an

altitude of 2544 metres.

Negoiu

(XO-1 b) – Negoiu is the second highest peak in Romania of the F

ara

mountain range with an

altitude of 2535 metres.

Dombay

(HAT-P-3) – Dombay is a resort region in the North Caucasus mountains that is enclosed by

mountain forests and rich wildlife, including bears (as this star lies in the constellation Ursa Major,

the great bear).

Teberda

(HAT-P-3 b) – Teberda is a mountain river in Dombay region with a rapid water ﬂow, symbolising

the planet’s rapid motion around its host star.

Belel (HD 181342) – Belel is a rare source of water in the north of Senegal.

Dopere

(HD 181342 b) – Dopere is an expansive historical area in the north of Senegal where Belel was

located.

Morava (WASP-60) – Morava is the longest river system in Serbia.

Vlasina (WASP-60 b) – Vlasina is one of the most signiﬁcant tributaries of the South Morava river.

Parumleo

(WASP-32) – Parumleo is a Latin term for little lion, symbolising Singapore’s struggle for

independence.

Viculus

(WASP-32 b) – Viculus is a Latin term for little village, embodying the spirit of the Singaporean

people.

Chaso

n (HAT-P-5) – Chaso

n is an ancient Slovak term for Sun.

Král’omoc (HAT-P-5 b) – Král’omoc is an ancient Slovak term for the planet Jupiter.

Irena

(WASP-38) – Irena is a leading character in the novel “Under the Free Sun: a Story of the Ancient

Grandfathers” by Slovene writer Fran Saleški Finžgar. Irena is a woman of the court.

Iztok

(WASP-38 b) – Iztok is a leading character in the novel “Under the Free Sun: a Story of the Ancient

Grandfathers” by Slovene writer Fran Saleški Finžgar. Iztok is a freedom ﬁghter for the Slavic people.

Naledi

(WASP-62) – Naledi means star in the Sesotho, SeTswana and SePedi languages and is typically

given as a name to girls in the hope that they will bring light, joy and peace to their communities.

Krotoa

(WASP-62 b) – Krotoa is considered the Mother of Africa and member of the indigenous Khoi

people, who was a community builder and educator during colonial times.

Baekdu

(8 Umi) – Baekdu is the highest mountain on the Korean peninsula, situated in North Korea, and

14.3 Exoplanets Plugin 173

symbolises the national spirit of Korea.

Halla

(8 Umi b) – Halla is the highest mountain in South Korea and is regarded as a sacred place in the

region.

Rosalíadecastro

(HD 149143) – Rosalía de Castro was a signiﬁcant ﬁgure of Galician culture and prominent

Spanish writer, whose pioneeting work often referenced the night and celestial objects.

Riosar

(HD 149143 b) – Rio Sar is the name of a river that was present in much of the literary work of the

pioneering Spanish author Rosalía de Castro.

amaya (HD 205739) – S

amaya means peace in the Sinhalese language.

Samagiya (HD 205739 b) – Samagiya means togetherness and unity in the Sinhalese language.

Aniara

(HD 102956) – Aniara is the name of a spaceship in the epic poem Aniara by Swedish author Harry

Martinson.

Isagel

(HD 102956 b) – Isagel is the name of the spaceship pilot in the epic science ﬁction poem Aniara

written by Swedish author Harry Martinson.

Mönch (HD 130322) – Mönch is one of the prominent peaks of the Bernese Alps in Switzerland.

Eiger

(HD 130322 b) – Eiger is one of the prominent peaks of the Bernese Alps, in the Jungfrau-Aletsch

protected area.

Ebla

(HD 218566) – Ebla was one of the earliest kingdoms in Syria, and served as a prominent region in

the 2

and 3

millennia B.C.

Ugarit

(HD 218566 b) – Ugarit was a city where its scribes devised the Ugaritic alphabet around 1400 B.C.

The alphabet was made up of thirty letters and was inscribed on clay tablets.

Mpingo

(WASP-71) – Mpingo is a famous tree that grows in southern Tanzania and produces ebony wood

used for musical instruments and curios.

Tanzanite

(WASP-71 b) – Tanzanite is the name of a precious stone mined in Tanzania and is treasured

worldwide.

Chaophraya (WASP-50) – Chao Phraya is the great river of Thailand.

Maeping (WASP-50 b) – Mae Ping is one of the tributaries of Thailand’s great river Chao Phraya.

Atakoraka (WASP-64) – Atakoraka means the chain of the Atacora: the largest mountain range in Togo.

Agouto

(WASP-64 b) – Agouto (Mount Agou) is the highest mountain in Togo and a treasured region of

the Atakoraka.

Dingolay

(HD 96063) – Dingolay means to dance, twist and turn in elaborate movements, symbolising the

culture and language of the ancestors of the people of Trinidad and Tobago.

Ramajay

(HD 96063 b) – Ramajay means to sing and make music in a steelpan style, representing the love

of culture and languages of the ancestors of the people of Trinidad and Tobago.

Chechia

(HD 192699) – Chechia is a ﬂat-surfaced, traditional red wool hat worn by men and women,

symbolising the country’s rich traditions and is considered as the national headdress for in Tunisia.

Khomsa

(HD 192699 b) – Khomsa is a palm-shaped amulet that is popular in Tunisia, used in jewelry and

decorations. It depicts an open right hand and is often found in modern designs.

Anadolu

(WASP-52) – Anadolu is the primary homeland of Turkey and refers to the motherland in Turkish

culture.

Göktürk

(WASP-52 b) – Göktürk refers to the historical origin of the Turkish people, as it was the ﬁrst

established state in Turkey in

century AD. It is also the name of a Turkish satellite and is the

combination of two words, of which “Gök” means sky.

Berehinya

(HAT-P-15) – Berehinya was a Slavic deity of waters and riverbanks but in more recent times

her status has been promoted to that of a national goddess — “hearth mother, protectress of the earth”.

Tryzub

(HAT-P-15 b) – Tryzub is the most recognised ancient symbol of Ukraine, that was minted on the

coins of Prince Volodymyr the Great and today remains one of the country’s state symbols (a small

coat).

Sharjah

(HIP 79431) – Sharjah is the cultural capital of United Arab Emirates, and considered the city of

knowledge due to its many educational centers, institutes, museums, libraries and heritage centers.

Barajeel

(HIP 79431 b) – A barajeel is a wind tower used to direct the ﬂow of the wind so that air can be

recirculated as a form of air conditioning.

Gloas (WASP-13) – In Manx Gaelic, Gloas means to shine (like a star).

Cruinlagh (WASP-13 b) – In Manx Gaelic, Cruinlagh means to orbit (like a planet around its star).

Nushagak

(HD 17156) – Nushagak is a regional river near Dilingham, Alaska, which is famous for its wild

salmon that sustain local Indigenous communities.

Mulchatna

(HD 17156 b) – The Mulchatna River is a tributary of the Nushagak River in southwestern

Alaska, USA.

174 Chapter 14. Object Catalog Plugins

Ceibo (HD 63454) – Ceibo is the name of the native tree of Uruguay that gives rise to the national ﬂower.

Ibirapitá

(HD 63454 b) – Ibirapitá is the name of a native tree that is characteristic of the country of

Uruguay, and is also known as Artigas’ tree, after the national hero.

Natasha (HD 85390) – Natasha means thank you in many languages of Zambia.

Madalitso (HD 85390 b) – Madalitso means blessings in the native language of Nyanja in Zambia.

All names with asterix mark (*) are modiﬁed based on the original proposals, to be consistent with the

IAU rules.

14.3.3 Section

[

Exoplanets

]

in conﬁg.ini ﬁle

You can edit config.ini ﬁle to change the settings for the Exoplanets plugin – just make it carefully!

ID Type Description

last_update string Date and time of last update

update_frequency_hours

int Frequency of updates, in hours

updates_enable

bool Enable updates of exoplanets catalog from Internet

url

string URL of exoplanets catalog

ﬂag_show_exoplanets_button

bool Enable showing button of exoplanets on bottom bar

distribution_enabled

bool Enable distribution mode of display

timeline_enabled

bool Enable timeline mode of display

habitable_enabled

bool Enable habitable mode of display

enable_at_startup

bool Enable displaying exoplanets at startup of the plugin

exoplanet_marker_color

R,G,B Color for marker of star with planetary system

habitable_exoplanet_marker_color

R,G,B

Color for marker of star with planetary system with

potential habitable exoplanets

temperature_scale

string

Temperature scale for equilibrium temperature of exo-

planets. Possible values: Kelvin, Celsius, Fahrenheit.

Default value: Celsius.

14.3.4 Format of exoplanets catalog

To add a new exoplanet system, open a new line after line 5 and paste the following, note commas and

brackets, they are important:

" Star desi gnat ion ":

{

" e xopla nets ":

[

{

" mass " : mass of exopla net (M jup ),

" radiu s ": ra di u s of exop lanet ( R jup ) ,

" perio d ": pe ri o d of exop lanet ( days ) ,

" se miAxis ": semi - major axis ( AU ) ,

" e ccen tric ity ": orbit ’s eccentricity ,

" i ncli natio n ": orbit ’s in clin ation ( degree ),

" a ngle Dis tanc e " : angle di stance from star ( arcsec onds ),

" d iscov ered ": ex oplan et dis cover ed year ,

" d ete ctio nMe thod ": " exo planet detect ion method " ,

" pclas s ": " pla netary class " ,

" EqTem p ": equil ibri um te mpera ture ( K) ,

" c onse rvat ive ": co nser vati ve or o ptimi stic

hab itabi lity of the exoplanet ,

" ESI " : Earth Simi larit y Index (*100) ,

" p lan etP rope rNa me ": " prop er name of planet " ,

" p lanet Name ": " des ignat ion of p la ne t "

{

" mass " : mass of exopla net (M jup ),

" radiu s ": ra di u s of exop lanet ( R jup ) ,

" perio d ": pe ri o d of exop lanet ( days ) ,

" se miAxis ": semi - major axis ( AU ) ,

14.3 Exoplanets Plugin 175

" e ccen tric ity ": orbit ’s eccentricity ,

" i ncli natio n ": orbit ’s in clin ation ( degree ),

" a ngle Dis tanc e " : angle di stance from star ( arcsec onds ),

" d iscov ered ": ex oplan et dis cover ed year ,

" d ete ctio nMe thod ": " exo planet detect ion method " ,

" pclas s ": " pla netary class " ,

" EqTem p ": equil ibri um te mpera ture ( K) ,

" c onse rvat ive ": co nser vati ve or o ptimi stic habi tabi l ity of the

exoplanet ,

" ESI " : Earth Simi larit y Index (*100) ,

" p lan etP rope rNa me ": " prop er name of planet " ,

" p lanet Name ": " des ignat ion of p la ne t "

}

" di stance ": value of distanc e to star ( pc ) ,

" stype ": " sp ectral type of star " ,

" smass ": value of mass of star (M sun ) ,

" smeta l ": value of metal lici ty of star ,

" Vmag " : value of vi sua l magni tude of star ,

" sra dius " : value of radius of star (R sun ) ,

" e ffec tiv eTem p " : value of effec tive t emper atur e of star ( K) ,

" s tar Prop erNa me ": " pro pe r name of the star ",

" hasHP ": boolea n ( has pote ntial h abita ble plane ts ) ,

" RA ": " Right ascen sion ( J2000 )" ,

" DE ": " De clina tion ( J2000 ) "

For example, the record for 24 Sex looks like:

" 24 Sex ":

{

" e xopla nets ":

[

{

" mass " : 1.99 ,

" perio d ": 452.8 ,

" se miAxis ": 1.333 ,

" e ccen tric ity ": 0.09 ,

" a ngle Dis tanc e " : 0.017821 ,

" d iscov ered ": 2010 ,

" p lanet Name ": " b"

{

" mass " : 0.86 ,

" perio d ": 883.0 ,

" se miAxis ": 2.08 ,

" e ccen tric ity ": 0.29 ,

" a ngle Dis tanc e " : 0.027807 ,

" d iscov ered ": 2010 ,

" p lanet Name ": " c"

}

" di stance ": 74.8 ,

" stype ": " G5 " ,

" smass ": 1.54 ,

" smeta l ": -0.03 ,

" Vmag " : 7.38 ,

" sra dius " : 4.9 ,

" e ffec tiv eTem p " : 5098 ,

" RA ": "10 h23m28s " ,

" DE ": " -00 d54m08 s "

176 Chapter 14. Object Catalog Plugins

14.4 Pulsars Plugin

Figure 14.5: PSR J0332+5434

This plugin plots the position of various pulsars, with object information about each one. Pulsar data is

derived from “The Australia Telescope National Facility Pulsar Catalogue” (Manchester et al., 2005).

If enabled (see section 12.1), use the button to activate display of pulsars. The GUI allows a few

conﬁguration options. You can also ﬁnd a pulsar (

) by its designation (e.g., PSR J0437-4715).

14.4.1 Section

[

Pulsars

]

in conﬁg.ini ﬁle

ID Type Description

last_update string Date and time of last update

update_frequency_days

int Frequency of updates [days]

updates_enable

bool Enable updates of pulsars catalog from Internet

url

string URL of pulsars catalog

enable_at_startup

bool Enable displaying of pulsars at startup of Stellarium

distribution_enabled

bool Enable distribution mode for the pulsars

ﬂag_show_pulsars_button

bool Enable displaying pulsars button on toolbar

marker_color

R,G,B Color for marker of the pulsars

glitch_color

R,G,B Color for marker of the pulsars with glitches

use_separate_colors

bool Use separate colors for different types of the pulsars

14.4 Pulsars Plugin 177

14.4.2 Format of pulsars catalog

To add a new pulsar, open a new line after line 5 and paste the following, note commas and brackets, they are

important:

" Pulsar designation ":

{

" RA " : " Right ascensio n ( J2000 )" ,

" DE " : " De cl in ation ( J2000 )" ,

" notes " : " type of pulsar " ,

" dis tance ": value of distance based on electro n density

model ( kpc ),

" period ": value of baryc en tr ic period of the pulsar ( s),

" par allax ": value of annual parallax ( mas ) ,

" bperiod ": value of binary period of pulsar ( days ) ,

" pderivativ e ": value of time derivativ e of ba rcycentric

period ,

" dme asure ": value of disper si on measure ( pc /( cm * cm * cm )) ,

" frequen cy " : value of ba ry ce nt ri c rot ation frequency ( Hz ) ,

" pfrequency ": value of time deriva ti ve of barycentric

rotat ion f re quency (1/( s * s ))

" ecce nt ri city ": value of eccentricity ,

" w50 ": value of profi le width at 50% of peak ( ms ),

" s400 ": value of time averaged flux d ensity at

400 MHz ( mJy ),

" s600 ": value of time averaged flux d ensity at

600 MHz ( mJy ),

" s1400 " : value of time av eraged flux density at

1400 MHz ( mJy )

For example, the record for PSR J0014+4746 looks like:

" PSR J0014 +4746 ":

{

" dis tance ": 1.82 ,

" dme asure ": 30.85 ,

" frequen cy " : 0.80 5997239145 ,

" pfrequency ": -3.6669E -16 ,

" w50 ": 88.7 ,

" s400 ": 14 ,

" s600 ": 9 ,

" s1400 " : 3,

" RA " : " 00 h14m17 .75 s" ,

" DE " : " 47 d46m33 .4 s "

178 Chapter 14. Object Catalog Plugins

14.5 Quasars Plugin

The Quasars plugin provides visualization of some quasars brighter than 16 visual magnitude. The catalogue

of quasars has been compiled from “A catalogue of quasars and active nuclei: 13th edition” (Véron-Cetty

and Véron, 2010).

Figure 14.6: 3C 249.1, also known as LEDA 2821945 or 4C 77.09

If enabled (see section 12.1), use the button to activate display of quasars. The GUI allows a few

conﬁguration options. You can also ﬁnd a quasar (

) by its designation (e.g., 3C 273).

14.5.1 Section

[

Quasars

]

in conﬁg.ini ﬁle

ID Type Description

last_update string Date and time of last update

update_frequency_days

int Frequency of updates, in days

updates_enable

bool Enable updates of quasars catalog from Internet

url

string URL of quasars catalog

enable_at_startup

bool Enable displaying of quasars at startup of Stellarium

distribution_enabled

bool Enable distribution mode for the quasars

ﬂag_show_quasars_button

bool Enable displaying quasars button on toolbar

marker_color

R,G,B Color for marker of the quasars

14.5.2 Format of quasars catalog

To add a new quasar, open a new line after line 5 and create a new section. For example, the record for 3C

249.1 looks like (note commas and brackets – they are important!):

"3C 249.1 " : // Quasar des ignation

{

" RA " : " 11 h04m13 .8 s " , // Right ascensi on ( J2000 )

" DE " : " +76 d58m58 s " , // De cl in at ion ( J2000 )

" Amag ": -25.1 , // value of ab solute magni tu de

" Vmag ": 15.72 , // value of visual magnitude

"z" : 0.313 , // value of Z ( r edshift )

" bV " : -0.02 // value of B - V colour

14.6 Meteor Showers Plugin 179

14.6 Meteor Showers Plugin

Figure 14.7: The 1833 Leonids replayed with the Meteor Showers plugin.

In contrast and extension of the random shooting stars feature of Stellarium (see section 19.6), this plugin

provides data for real meteor showers and a marker for each active and inactive radiant, showing real

information about its activity. If enabled (see section 12.1), just click on the Meteor Showers button on

the bottom toolbar to display markers for the radiants.

14.6.1 Terms

Meteor shower

A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from

one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering

Earth’s atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of

sand, so almost all of them disintegrate and never hit the Earth’s surface. Intense or unusual meteor showers

are known as meteor outbursts and meteor storms, which may produce greater than 1,000 meteors an hour.

Radiant

The radiant or apparent radiant of a meteor shower is the point in the sky from which (to a planetary

observer) meteors appear to originate. The Perseids, for example, are meteors which appear to come from a

point within the constellation of Perseus.

An observer might see such a meteor anywhere in the sky but the direction of motion, when traced back,

will point to the radiant. A meteor that does not point back to the known radiant for a given shower is known

as a sporadic and is not considered part of that shower.

Many showers have a radiant point that changes position during the interval when it appears. For

example, the radiant point for the Delta Aurigids drifts by more than a degree per night.

Zenithal Hourly Rate (ZHR)

The Zenithal Hourly Rate (ZHR) of a meteor shower is the number of meteors a single observer would see in

one hour under a clear, dark sky (limiting apparent magnitude of 6.5) if the radiant of the shower were at the

zenith. The rate that can effectively be seen is nearly always lower and decreases the closer the radiant is to

the horizon.

Population index

The population index indicates the magnitude distribution of the meteor showers. Values below 2.5 correspond

to distributions where bright meteors are more frequent than average, while values above 3.0 mean that the

share of faint meteors is larger than usual.

180 Chapter 14. Object Catalog Plugins

Solar longitude

The solar longitude (equinox J2000) gives the position of the Earth on its orbit. It is a more appropriate

information on a meteor shower than the date.

14.6.2 Section

[

MeteorShowers

]

in conﬁg.ini ﬁle

You can edit

config.ini

ﬁle by yourself for changes of the settings for the Meteor Showers plugin – just

make it carefully!

ID Type Description

last_update string Date and time of last update

update_frequency_hours

int Frequency of updates, in hours

updates_enable

bool Enable updates of the meteor showers catalog from Internet

url

string URL of the meteor showers catalog

ﬂag_show_ms_button

bool Enable showing button of the meteor showers on bottom bar

ﬂag_show_radiants

bool Enable displaying markers for the radiants of the meteor showers

ﬂag_active_radiants

bool

Flag for displaying markers for the radiants of the active meteor

showers only

enable_at_startup

bool Enable displaying meteor showers at startup plugin

show_radiants_labels

bool

Flag for displaying labels near markers of the radiants of the meteor

showers

font_size

int

Font size for label of markers of the radiants of the meteor showers

colorARG R,G,B Color for marker of active meteor showers with generic data

colorARR

R,G,B Color for marker of active meteor showers with real data

colorIR

R,G,B Color for marker of inactive meteor showers

14.6.3 Format of Meteor Showers catalog

To add a new meteor shower, you just need to:

1. Copy the code of some valid meteor shower;

2. Paste it in the line 6 (right after the “showers”: {) of the MeteorShowers.json document;

3. Replace the information according with your needs.

Note commas and brackets, they are very important!

" Three - lett er code " :

{

" d esig natio n " : " Name " ,

" IAUNo ": " IAU show er nu mb er " ,

" ac tivity ":

[{

" year " : " gene ric " ,

" zhr " : Maximu m ZHR ( -1 if variabl e ) ,

" va riable ": " Minimum - maximum ( if va riable )" ,

" start ": Solar longi tude at start ,

" finis h ": Solar lo ngitu de at finish ,

" peak " : Solar lo ngitud e at peak ,

" di sttype ": Type of dis trib utio n funct ion

(0= Gauss , 1= Lorentz ),

" b1 ": Slope of dist ribu tion fu nction

before peak ,

" b2 ": Slope of dist ribu tion fu nction

after peak

}] ,

" speed ": Geo centr ic speed ( km /s ),

" r adia ntAl pha ": Right Asce nsion ( J2000 ) ( degree ) ,

" r adia ntDe lta ": De clin ation ( J2000 ) ( degree ),

" d riftA lpha ": Rad ia nt drift in Right Ascension ,

" d riftD elta ": Rad ia nt drift in Dec linat ion ,

" color s ":

[{

" color ": " white " ,

" i ntensi ty " : 70

14.6 Meteor Showers Plugin 181

{

" color ": " blueGr een " ,

" i ntensi ty " : 30

}] ,

" p arentO bj " : " Pa re nt obj ec t " ,

" pidx " : popul ation index

For example, below is a record for the Northern Taurids:

" NTA " :

{

" designation ": " N o rthern Tau rids " ,

" IA UNo ": " 17 " ,

" acti v i ty " :

[{

" year " : " gen e ric " ,

" zhr " : 5,

" st art ": 206 ,

" finish ": 258 ,

" peak " : 230

}] ,

" sp eed ": 29 ,

" radiantAlpha " : 58 ,

" radiantDelta " : 22 ,

" driftAlp h a ": 1.03 ,

" driftDel t a ": 0.26 ,

" colors ":

[{

" co lor ": " yell ow " ,

" intens i t y " : 80

{

" co lor ": " whi te " ,

" intens i t y " : 20

}] ,

" parent O b j " : " Co met 2P/ Enc ke " ,

" pidx " : 2.3

14.6.4 Notes

•

This plugin uses two models (P. Jenniskens, 1994) and (Peter Jenniskens et al., 1998) to calculate

ZHR, assuming that the activity proﬁle of meteor shower follows a double exponential shape.

•

To predict the local hourly rate, altitude of radiant and limiting magnitude of the sky are taken into

account. Moonlight can also reduce the hourly rate, but is not taken into account.

•

Most of the numerical data for past meteor outbursts (Leonids, etc.) come from (P. Jenniskens, 2006).

There is a wide range of reported values for the maximum ZHR for the 1833 and 1966 Leonids

(P. Brown, 1999). We decided to use a maximum number of 150,000 to demonstrate meteor outbursts

with very high rate.

14.6.5 Further Information

You can get more info about meteor showers here:

•

Wikipedia about Meteor showers: https://en.wikipedia.org/wiki/Meteor_Showers

•

International Meteor Organization: https://www.imo.net/

•

IAU Meteor Data Center: https://www.ta3.sk/IAUC22DB/MDC2007/

Acknowledgements

This plugin was initially created as project of ESA Summer of Code in Space 2013

http://sophia.estec.esa.int/socis2013/?q=about

182 Chapter 14. Object Catalog Plugins

14.7 Navigational Stars Plugin

Figure 14.8: Navigational stars on the screen

This plugin marks navigational stars from a selected set (Figure 14.9):

Anglo-American

— the 57 “selected stars” that are listed in The Nautical Almanac

jointly published by

Her Majesty’s Nautical Almanac Ofﬁce and the US Naval Observatory since 1958; consequently,

these stars are also used in navigational aids such as the 2102-D Star Finder

and Identiﬁer.

French

— the 81 stars that are listed in the Ephémérides Nautiques published by the French Bureau des

Longitudes.

Russian — the 160 stars that are listed in the Russian Nautical Almanac.

German

— the 80 stars that are listed in the German Nautical Almanac (The original German title is

Nautisches Jahrbuch) published by the Federal Maritime and Hydrographic Agency of Germany.

If enabled (see section 12.1), just click on the Sextant button on the bottom toolbar to display markers

for the navigational stars. This can help you in training your skills in astronomical navigation before you

cruise the ocean in the traditional way, with your sextant and chronometer.

In the second tab (“Today”, see Figure 14.10) in the plugin’s dialog (right-click the button) you can see

times of sunrise and sunset, twilights, moonrise and moonset.

Civil Twilight

occurs when the zenith angle of the center of the Sun is less than

° (

° below the horizon)

and the available skylight is still typically sufﬁcient for most civilian outdoor activities. The apparent

horizon is still clearly visible against the glowing sky and only the brightest stars are beginning to

show.

Nautical Twilight

occurs when the zenith angle of the center of the Sun is less than

102

° (

° below the

horizon) and the available skylight is no longer sufﬁcient for detailed outdoor activities. However, the

outline of the apparent horizon, as well as most large topographical features, are still distinguishable

and the key stars used for navigational purposes have all typically become visible.

Astronomical Twilight

occurs when the zenith angle of the center of the Sun is less than

108

° (

° below

the horizon) and the available skylight is effectively imperceptible compared to moonlight and starlight.

Beyond this angle there is no longer any discernible atmospheric scattering of sunlight, so the time

after astronomical twilight is basically night.

The Nautical Almanac website – https://aa.usno.navy.mil/publications/docs/na.php

Rude Starﬁnder 2102-D description and usage instruction –

https://oceannavigation.blogspot.com/200

8/12/rude-starfinder-2102-d.html

14.7 Navigational Stars Plugin 183

Figure 14.9: Settings of the Navigational stars plugin

Figure 14.10: Today tab in the Navigational stars plugin

184 Chapter 14. Object Catalog Plugins

14.7.1 Section

[

NavigationalStars

]

in conﬁg.ini ﬁle

You can edit

config.ini

ﬁle by yourself for changes of the settings for the Navigational Stars plugin – just

make it carefully!

ID Type Description

navstars_color R,G,B Color of markers of navigational stars

enable_at_startup

bool Set to true to display navigational stars at startup of planetarium

use_utc_time

bool Set to true to use UTC time when navigational stars are displayed

extra_decimals

bool Set to true to show extra decimals in info

upper_limb

bool Set to true to use upper limb for Sun and Moon

tabulated_display

bool Set to true to show information as a tabulated list

limit_info_to_nav_stars

bool

Set to true to show extra information only for marked Navigation

Stars

highlight_when_visible

bool Set to true to highlight only visible stars

current_ns_set

string

Current set of navigational stars. Possible values: AngloAmerican,

French, Russian and German.

14.8 Satellites Plugin 185

14.8 Satellites Plugin

The Satellites plugin displays the positions of artiﬁcial satellites in Earth’s orbit based on a catalog of orbital

data. It allows automatic updates from online sources and manages a list of update ﬁle URLs.

To calculate satellite positions, the plugin uses an implementation of the SGP4/SDP4 algorithms (J.L.

Canales’ gsat library), using as its input data in NORAD’s two-line element set (TLE

) format. Lists with

TLEs for hundreds of satellites are available online and are regularly updated. The plugin downloads the lists

prepared by

https://celestrak.org

to keep itself up-to-date, but the users can specify other sources

online or load updates from local ﬁles.

Figure 14.11: Conﬁguration of the Satellites plugin

If the plugin has been enabled (see section 12.1), just click on the Satellite button on the bottom toolbar

to display markers for the satellites, or use right click to call the GUI.

You can search for artiﬁcial satellites using the regular search dialog (

). Note that at any given time,

most Satellites will be below the horizon.

Satellites can be either shown as white dots of appropriate brightness similar to moving stars (just like

they appear to the naked eye), or as satellite-shaped markers (icons). Especially this latter view shows

the huge number of satellites in orbit, most of which are invisible to the unaided eye. Satellites which are

v 25.4

reported to transit the penumbra (twilight) zone are rendered with a subdued color.

You can display circles representing the Earth’s shadow (penumbra and umbra, deﬁned just like for Lunar

eclipses, see section 19.11.2), at the altitude of the currently selected satellite, or at a ﬁxed (conﬁgurable)

altitude from Earth’s surface.

14.8.1 Satellite Properties

Name

Each satellite has a name. It’s displayed as a label of the satellite hint and in the list of satellites.

Names are not unique though, so they are used only for presentation purposes.

Catalog number

In the Satellite Catalog satellites are uniquely identiﬁed by their NORAD number, which

is encoded in TLEs.

I.D. (The International Designator)

In the Satellite Catalog satellites are also uniquely identiﬁed by their

International Designator also known as COSPAR ID, which is encoded in TLEs.

Standard magnitude

The standard magnitude may be an estimate based on the mean cross-sectional area

derived from its dimensions, or it may be a mean value derived from visual observations (see section

14.8.4).

RCS

The Radar Cross Section is a median value derived from the last several years of values in the Satellite

Situation Report. The units of the RCS are square meters (see section 14.8.4).

Perigee

The perigee is the nearest point respectively of a satellite’s direct orbit around the Earth. The unit

of perigee is kilometers.

TLE: https://en.wikipedia.org/wiki/Two-line_element_set

The height of the selected satellite is computed above the WGS84 ellipsoid, while the ﬁxed (conﬁgurable) altitude

from Earth’s surface is computed over the sphere. You may note these circles will deviate slightly from each other when

displayed altitudes are equal.

186 Chapter 14. Object Catalog Plugins

Figure 14.12: Conﬁguration of the Satellites plugin: satellite properties

Apogee

The apogee is the farthest point respectively of a satellite’s direct orbit around the Earth. The unit

of apogee is kilometers.

Period

The orbital period is simply how long an orbiting satellite takes to complete one orbit. The unit of

period is minutes.

Displayed

In the Satellite Catalog tab this property controls whether the selected satellite should be

displayed on the sky.

Orbit

In the Satellite Catalog tab this property controls whether the orbit of the selected satellite should be

displayed in the sky.

Do not update

In the Satellite Catalog tab this property marks satellites for which TLE should not be

updated.

Description The user-deﬁned notes for the selected satellite.

Groups

A satellite can belong to one or more groups such as “amateur”, “geostationary” or “navigation”.

They have no other function but to help the user organize the satellite collection. Group names are

arbitrary strings deﬁned in the Satellite Catalog for each satellite and are more similar to the concept

of tags than a hierarchical grouping. A satellite may also not belong to any group at all.

By convention, group names are in lowercase. The GUI translates some of the groups used in the

default catalog.

The group names also can be used as an additional ﬁlters for the satellites (see UI elements on the left

side).

TLE set

The raw TLE data of selected satellite. A two-line element set (TLE) is a data format encoding

a list of orbital elements of an Earth-orbiting object for a given point in time, the epoch. Using a

suitable prediction model, the state (position and velocity) at any point in the past or future can be

estimated to some accuracy.

Epoch of the TLE Human-readable epoch of current TLE set.

On the left side of this tab you may see tools for ﬁltering the satellites. The upper part shows a drop-down

list with many predeﬁned ﬁlters. Some ﬁlters are connected to user deﬁned groups to quickly get a list of

satellites in some group, such as all satellites from group “navigation”. Some ﬁlters are connected to orbital

properties of satellites, e.g., selecting the ﬁlter “[LEO]” will show all low-orbital satellites.

You can display a list of satellites by speciﬁc selection of their properties, when the ﬁlter “[custom ﬁlter]”

has been selected (Fig. 14.13). The settings of this ﬁlter are available through the button

, which is located

at the right of the drop-down list.

You can edit communication data for individual satellites by pressing (Fig. 14.14), where “Descrip-

tion” and “Frequency” are required ﬁelds and ﬁeld “Modulation” is optional. Some individual satellites and

their groups already have the communication data ﬁlled in the default catalog.

Abbreviations of some types of modulation:

14.8 Satellites Plugin 187

Figure 14.13: Conﬁguration of the Satellites plugin: satellites custom ﬁlter

Figure 14.14: Conﬁguration of the Satellites plugin: satellite communication data

APT Automatic Picture Transmission

LRPT Low Resolution Picture Transmission

HRPT High Resolution Picture Transmission

AHRPT Advanced High Resolution Picture Transmission

AX.25 Amateur Radio adaptation of X.25 packet protocol

CW Continuous Wave, Morse Code

AM Amplitude Modulation

FM Frequency Modulation

DUV Data Under Voice

FSK Frequency Shift Keying

GFSK Gaussian Frequency Shift Keying

GMSK Gaussian Minimum Shift Keying

AFSK Audio Frequency Shift Keying

ASK Amplitude-shift Keying

PSK Phase-shift Keying

BPSK Binary Phase-shift Keying

QPSK Quadrature Phase-shift Keying

OQPSK Offset Quadrature Phase-shift Keying

DPSK Differential Phase-shift Keying

BOC Binary Offset Carrier

MBOC Multiplexed Binary Offset Carrier

188 Chapter 14. Object Catalog Plugins

14.8.2 Satellite Catalog

The satellite catalog is stored on disk in JSON

format, in a ﬁle named

satellites.json

. A default copy

is embedded in the plug-in at compile time. A working copy is kept in the user data directory.

To add a new satellite, open a new line after line 5 and paste the following. Note the structure of commas

and brackets, they are important:

" NO RAD number " :

{

" name " : " name of the satell i t e "

" description ": " d e s c r i p t i o n goes here " ,

" co mms ": [

{

" description ": " d o wnlink 1" ,

" freque n c y " : 437.49 ,

" modulati o n ": " AFSK 1200 bps "

{

" description ": " d o wnlink 2" ,

" freque n c y " : 14 5 .825

}

" groups ": [ " g roup1 ", " gro up2 "] ,

" stdMag ": 2.0 ,

" tle1 " : "1 12345 U 90005 D 09 0 8 0 . 8 5 2 3 6 2 6 5 .0000001 4 00000 -0 20602 -4 0 5632 " ,

" tle2 " : "2 12345 98 . 2700 53.270 2 0 011918 71.1 7 76 289.07 0 5 1 4. 3 1 8 1 8 9 20 653 " ,

" vis i ble " : true

Explanation of the ﬁelds:

NORAD number

required parameter, surrounded by double quotes (

), followed by a colon (

). It is used

internally to identify the satellite. You should replace the text

"NORAD number"

with the ﬁrst number

on both lines of the TLE set (in this case, "12345"). It must match the number of the satellite in the

source you are adding from if you want the TLE to be automatically updated.

The remaining parameters should be listed between two curly brackets, and the closing curly bracket must be

followed by a comma to separate it from the next satellite in the list:

name

required parameter. It will be displayed on the screen and used when searching for the satellite with

the Find window. Use the description ﬁeld for a more readable name if you like.

description

optional parameter, double quoted. Appears when you click on the satellite. The description

ﬁeld can accept HTML tags such as (new line), bold, etc.

comms optional parameter, square bracketed list of curly bracketed communications information.

groups

optional parameter, comma separated list of double quoted group names contained in square brackets.

Used for grouping satellites in the drop down box on the conﬁg (see above)

tle1 required, line 1 of the TLE, must be contained in double quotes and begin with "1 "

tle2 required, line 2 of the TLE, must be contained in double quotes and begin with "2 "

visible

required parameter, set to true if you want to see it, this can be toggled from the conﬁguration

window once the satellite is loaded.

stdMag optional parameter, containing standard magnitude of satellite.

rcs

optional parameter, containing the satellite’s Radar Cross Section. The units of the RCS are square

meters.

You can edit the tags for a satellite, modify the description and comms data, and even add new satellites.

14.8.3 Conﬁguration

The plug-in’s conﬁguration data is stored in Stellarium’s main conﬁguration ﬁle.

14.8.4 The approximated visual magnitude

To calculate an approximated visual magnitude of satellites we use the radar cross section (RCS) data and

standard magnitudes from Mike McCants’ database (with permissions)

; the radar cross section (RCS) data

from CelesTrack database

; the standard magnitudes from database of the MMT-9 observatory (belongs to

https://www.json.org/

Mike McCants’ Satellite Tracking Web Pages — https://mmccants.org

Satellite Catalog (SATCAT) — https://celestrak.org/satcat/search.php

14.8 Satellites Plugin 189

Figure 14.15: Conﬁguration of the Satellites plugin: sources for TLE data

Kazan Federal University) (Beskin et al., 2017; Karpov et al., 2016).

We use a spherical shape of satellite to calculate an approximated visual magnitude from RCS values.

For modelling Starlink visual magnitudes we use Anthony Mallama’s formula

(Mallama, 2020) and Mike

McCants’ formula

for other satellites.

14.8.5 Sources for TLE data

TLE sets have to be accessed online. Occasionally the source path changes, and conﬁgurations set up with

previous versions may no longer be available. Use the bottom right button in the Sources tab (Figure 14.15)

to restore the installation defaults.

Celestrak

used as default update source, it also has TLE lists beyond those included by default in Satellite

plug-in

TLE.info

Space Track

the deﬁnitive source, requires sign-up, operated by United States Department of Defense

http://www.satobs.org/seesat/Aug-2020/0079.html

https://mmccants.org/tles/mccdesc.html

https://celestrak.org/NORAD/elements/

https://www.tle.info/joomla/index.php

https://www.space-track.org/

190 Chapter 14. Object Catalog Plugins

14.9 ArchaeoLines Plugin

GEORG ZOTTI

Figure 14.16: Declination Lines provided by the ArchaeoLines plugin

14.9.1 Introduction

In the archaeoastronomical literature, several astronomically derived orientation schemes are prevalent.

Often prehistorical and historical buildings are described as having been built with a main axis pointing to a

sunrise on summer or winter solstice. There can hardly be a better tool than Scenery3D (see chapter 15) to

investigate a 3D model of such a building, and this plugin has been introduced in version 0.13.3 as a further

tool in the archaeoastronomer’s toolbox (Zotti, 2016b).

When activated (see section 12.1), you can ﬁnd a a tool bar button (in the shape of a trilithon with

the sun shining through it). Press this, or

Ctrl

, to display the currently selected set of characteristical

diurnal arcs.

14.9.2 Characteristic Declinations

The ArchaeoLines plugin displays any combination of declination arcs

most relevant to archaeo- or

ethnoastronomical studies. Of course, principles used in this context are derived from natural observations,

and many of these declinations are still important in everyday astronomy.

•

Declinations of equinoxes (i.e., the equator,

δ = 0) and the solstices (δ = ±ε)

•

Declinations of the crossquarter days (days between solstices and equinoxes,

δ(λ = ±45

○

))

•

Declinations of the Major Lunar Standstills (

δ = ±(ε + i))

•

Declinations of the Minor Lunar Standstills (

δ = ±(ε − i))

•

Declination of the Zenith passage (

δ = ϕ)

•

Declination of the Nadir passage (

δ = −ϕ)

•

Declination

δ of the currently selected object

•

Current declination

of the sun

•

Current declination

of the moon

•

Current declination

of a naked-eye planet

The principal relation between declinations

, geographic latitude

, and the rising azimuth

computed from

cosA = −

sin

cosϕ

. (14.1)

This formula does not take into account local horizon elevation nor atmospheric refraction nor lunar

parallax correction. The effect applied to characteristic declinations is shown graphically for the present time

14.9 ArchaeoLines Plugin 191

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

Solstices, Equinoxes

Solar Crossquarters

Major Standstills

Minor Standstills

Zenith Passage

Nadir Passage

Rising Azimuths, Year 2000

Figure 14.17: Rising azimuths of a few important events for sun and moon, and zenith and nadir

passages depending on geographic latitudes (vertical axis).

(J2000.0) in ﬁgure 14.17. For example, in a latitude of 30°, an object which goes through the zenith rises

at azimuth 55°. Lunar major standstill risings occur at azimuths 56.7° and 123.5°, lunar minor standstill

risings at azimuths 69° and 111°. The summer solstice sun rises at 62.6°, the winter solstice sun at 117.3°.

An object which goes through the nadir rises at 125°.

The blue lines seem to vanish at

ϕ = 45

°: while there are still objects going through the zenith in higher

latitudes, they are circumpolar and do not cross the horizon.

For the lunar events, there are two lines each drawn by the plugin, for maximum and minimum distance

of the moon. The lunar extreme declinations are computed taking horizon parallax effects into account.

For technical reasons however, the derived declinations are then used to draw small circles of constant

declinations on the sphere, without taking the change of lunar horizontal parallax into account. Note that

therefore the observed declination of the moon at the major standstill can exceed the indicated limits if it is

high in the sky. The main purpose of this plugin is however to show an indication of the intersection of the

standstill lines with the horizon.

It may be very instructive to let the time run quite fast and observe the declination line of “current moon”

swinging between its north and south limits each month. These limits grow and shrink between the Major

and Minor Standstills in the course of 18.6 years.

The sun likewise swings between the solstices. Over centuries, the solstice declinations very slightly

move as well due to the slightly changing obliquity of the ecliptic.

14.9.3 Geographical Targets

Some religions, e.g., Islam or Bahai, adhere to a practice of observing a prayer direction towards a particular

location. Azimuth lines for two locations can be shown, these lines indicate the great circle direction towards

the locations which can be edited in the conﬁguration window. Default locations are Mecca (Kaaba) and

Jerusalem. The azimuth

towards a location

T = (λ

)

can be computed for an observer at

O = (λ

)

based on spherical trigonometry on a spherical Earth (Abdali, 1997) as

q = arctan

sin(

−

)

cosϕ

tan

− sin

cos(

−

)

(14.2)

192 Chapter 14. Object Catalog Plugins

You can set geographical coordinates and a name label directly, or select locations from Stellarium’s location

list by pressing the

Pick...

button. You can search for locations in the list. When you click on a location, its

data are taken as target.

14.9.4 Custom Lines

In addition, lines can be shown which indicate arbitrary azimuths (great circles through the zenith), altitudes,

and declinations. Note that these azimuths are always counted from north, regardless of the azimuth setting

described in section 4.3.5. These lines can be marked with a custom label.

When some celestial object is selected, you can take over its current respective data and name by pressing

the button, however the lines are not linked to the selected objects, and changing angle values or time

will make labels invalid.

14.9.5 Conﬁguration Options

The conﬁguration dialog allows the selection of the lines which are of interest to you. In addition, you can

select the color of the lines by clicking on the color swatches.

Section

[

ArchaeoLines

]

in conﬁg.ini ﬁle

ID Type Default

enable_at_startup bool false

line_thickness

int 1

color_equinox ﬂoat R,G,B 1.00,1.00,0.50

color_solstices ﬂoat R,G,B 1.00,1.00,0.25

color_crossquarters ﬂoat R,G,B 1.00,0.75,0.25

color_major_standstill ﬂoat R,G,B 0.25,1.00,0.25

color_minor_standstill ﬂoat R,G,B 0.20,0.75,0.20

color_zenith_passage ﬂoat R,G,B 1.00,0.75,0.75

color_nadir_passage ﬂoat R,G,B 1.00,0.75,0.75

color_selected_object ﬂoat R,G,B 1.00,1.00,1.00

color_current_sun ﬂoat R,G,B 1.00,1.00,0.75

color_current_moon ﬂoat R,G,B 0.50,1.00,0.50

color_current_planet ﬂoat R,G,B 0.25,0.80,1.00

color_geographic_location_1 ﬂoat R,G,B 0.25,1.00,0.25

color_geographic_location_2 ﬂoat R,G,B 0.25,0.25,1.00

color_custom_azimuth_1 ﬂoat R,G,B 0.25,1.00,0.25

color_custom_azimuth_2 ﬂoat R,G,B 0.25,0.50,0.75

color_custom_altitude_1 ﬂoat R,G,B 0.25,1.00,0.25

color_custom_altitude_2 ﬂoat R,G,B 0.25,0.50,0.75

color_custom_declination_1 ﬂoat R,G,B 0.45,1.00,0.15

color_custom_declination_2 ﬂoat R,G,B 0.45,0.50,0.65

show_equinox bool true

show_solstices

bool true

show_crossquarters

bool true

show_major_standstills

bool true

show_minor_standstills

bool true

show_zenith_passage

bool true

show_nadir_passage

bool true

show_selected_object

bool true

show_current_sun

bool true

show_current_moon

bool true

show_current_planet

string none

show_geographic_location_1 bool false

14.9 ArchaeoLines Plugin 193

show_geographic_location_2 bool false

geographic_location_1_longitude

double 39.826175

geographic_location_1_latitude

double 21.4276

geographic_location_1_label

string Mecca (Qibla)

geographic_location_2_longitude

double 35.235774

geographic_location_2_latitude

double 31.778087

geographic_location_2_label

string Jerusalem

show_custom_azimuth_1 bool false

show_custom_azimuth_2

bool false

custom_azimuth_1_angle

double 0.0

custom_azimuth_2_angle

double 0.0

custom_azimuth_1_label

string custAzi1

custom_azimuth_2_label

string custAzi2

show_custom_altitude_1

bool false

show_custom_altitude_2

bool false

custom_altitude_1_angle

double 0.0

custom_altitude_2_angle

double 0.0

custom_altitude_1_label

string custAlt1

custom_altitude_2_label

string custAlt2

show_custom_declination_1 bool false

show_custom_declination_2

bool false

custom_declination_1_angle

double 0.0

custom_declination_1_label

string custDec1

custom_declination_2_angle

double 0.0

custom_declination_2_label

string custDec2

14.9.6 Acknowledgements

If you are using this plugin in scientiﬁc publications, please cite Zotti (2016b).

15. Scenery3d – 3D Landscapes

GEORG ZOTTI AND FLORIAN SCHAUKOWITSCH

15.1 Introduction

Have you ever wished to be able to walk through Stonehenge or other ancient building structures described

as being constructed with astronomical orientation in mind, and experience such orientation in a 3D virtual

environment that also provides a good sky simulation?

The Stellarium Scenery3d plugin allows you to see architectural 3D models embedded in a landscape

combined with the excellent representation of the sky provided by Stellarium. You can walk around, check

for (or demonstrate) possible astronomical alignments of ancient architecture, see sundials and other shadow

casters in action, etc.

15.2 Usage

You activate the plugin with the circular enclosure button at screen bottom or by pressing

Ctrl

. A

right-click on that button (or

Ctrl

) opens the settings dialog. Once loaded and displaying, you

can walk around pressing

Ctrl

plus cursor keys. Change eye height with

Ctrl

Page

Ctrl

Page

keys.

Adding key increases speed by 10, adding

Alt

multiplies by 5 (pressing both keys multiplies by 50!). If

you release

Ctrl

before the cursor key, animation will continue. (Press

Ctrl

+any cursor key to stop moving.)

Further key bindings exist which can be conﬁgured using the Stellarium default key-binding interface.

Some options are also available in the Scenery3d dialog. For example, coordinate display can be enabled

with

Ctrl

. If your models are georeferenced in a true geographical coordinate grid, e.g. UTM or

Gauss-Krueger, you will especially like this, and this makes the plugin usable for scientiﬁc purposes. Display

shows grid name, Easting, Northing, Altitude of ground, and eye height above ground.

Other features include a virtual “torchlight”, which can be enabled with

Ctrl

to give additional

local illumination around the viewer to help to see in the dark. Interesting points of view can be saved and

restored later by the user, including a description of the view. Scene authors can also distribute predeﬁned

viewpoints in their scene.

The plugin also simulates the shadows of the scene’s objects cast by the Sun, Moon and even Venus (only

1 shadow caster used at a time, you will never see shadows cast by Venus in moonlight), so you could use it

for examining sundials, or analyze and simulate light-and-shadow interactions in archaeological structures.

Sometimes, light patches cast through small holes are important, e.g., in churches with meridiana

v 23.2

“sundial/calendar” lines. If these patches appear too dim, you can increase the power of the directional light

using the

Directional light enhancement

switch. (Use value 1.0 to revert to normal.)

196 Chapter 15. Scenery3d – 3D Landscapes

15.3 Hardware Requirements & Performance

In order to work with the non-linear projection models in Stellarium, this plugin uses a trick to create the

foreground renderings: it renders the scene into the six planes of a so-called cubemap, which is then correctly

reprojected onto the sides of a cube, depending on the current projection settings. Your graphics card must

be able to do this, i.e. it must support the OpenGL extension called

EXT_framebuffer_object

. Typical

modern 3D cards (by Nvidia or ATI/AMD) support this extension. In case your graphics hardware does not

support it, the plugin will still work, but you are limited to perspective projection.

You can inﬂuence rendering quality, but also speed, using the plugin’s GUI, which provides some options

such as enabling the use of shadows, bumpmapping (provides more realistic surface lighting) or conﬁguring

the sizes of the textures used for the cubemap or shadowmaps. Larger values there improve the quality, but

require faster hardware and more video memory for smooth results.

Because the “cubemap trick” requires quite a large amount of performance (in essence, the scene has to

be rendered 6 times), there are some options available that try to reduce this burden. The ﬁrst option is to

change the type of the “cubemap”. The most compatible setting is 6 textures, which seems to work best on

older integrated Intel GPUs. The recommended default is the second setting, Cubemap, which uses a more

modern OpenGL feature and generally works a bit faster than 6 textures on more modern graphics cards.

Finally, the Geometry shader option tries to render all 6 cube faces at once. This requires a more recent GPU

+ drivers (at least OpenGL 3.2 must be supported), the setting is disabled otherwise. Depending on your

hardware and the scene’s complexity, this method may give a speedup or may be slower, you must ﬁnd this

out yourself.

Another option prevents re-rendering of the cubemap if nothing relevant has changed. You can deﬁne

the interval (in Stellarium’s simulation time) in which nothing is updated in the GUI. You can still rotate the

camera without causing a re-draw, giving a subjective performance that is close to Stellarium’s performance

without Scenery3d. When moving, the cubemap will be updated. You can enable another option that only

causes 1 or 2 sides of the cubemap to be updated while you move, giving a speedup but causing some parts of

the image to be outdated and discontinuous. The cubemap will be completed again when you stop moving.

Shadow rendering may also cause quite a performance impact. The Simple shadows option can speed

this up a lot, at the cost of shadow quality especially in larger scenes. Another performance/quality factor is

shadow ﬁltering. The sharpest (and fastest) possible shadows are achieved with ﬁltering Off, but depending

on shadowmap resolution and scene size the shadows may look quite “blocky”. Hardware shadow ﬁltering

is usually very fast, but may not improve appearance a lot. Therefore, there are additional ﬁlter options

available, the High ﬁlter option is relatively expensive. Finally, the PCSS option allows to approximate the

increase of solar and lunar shadow penumbras relative to the distance from their shadow casters, i.e. shadows

are sharp near contact points, and more blurred further away. This again requires quite a bit of performance,

and only works if the shadow ﬁlter option is set to Low or High (without Hardware).

The conﬁguration GUI shows tooltips for most of its settings, which can explain what a setting does. All

settings are saved automatically, and restored when you reopen Stellarium.

15.3.1 Performance notes

This plugin clearly runs better with proper 3D graphics cards. On reasonably good hardware (tested on a

notebook PC with Nvidia M960), models with over 10.000.000 triangles are working nicely with shadows

and bumpmaps, although your mileage may vary. On very small hardware like single-board computers

with native OpenGL ES2, models may be limited to 64k vertices (points). If display is too slow, switch to

perspective projection: all other projections require almost sixfold effort! Or try the “lazy” cubemap mode

and lazy updates of tiles, where the scene is only rendered in speciﬁc timesteps or when movement happens.

15.4 Model Conﬁguration

The model format supported in Scenery3d is Wavefront .OBJ, which is pretty common for 3D models. You

can use several modeling programs to build your models. Software such as Blender, Maya, 3D Studio Max

etc. can export OBJ.

15.4.1 Exporting OBJ from Sketchup

A simple to use and cost-free modeling program is Sketchup, commonly used to create the 3D buildings

seen in Google Earth. It can be used to create georeferenced models. OBJ is not a native export format for

the standard version of Sketchup. If you are not willing to afford Sketchup Pro, you have to ﬁnd another

way to export a textured OBJ model.

15.4 Model Conﬁguration 197

Geometry Yes

Lights Yes

Clay No

Photomatched Yes

DefaultUVs No

Instanced No

Table 15.1: Kerkythea Export Settings

One good exporter is available in the Kerkythea renderer project

. You need SU2KT 3.17 or better, and

KT2OBJ 1.1.0 or better. Deselect any selection, then export your model to the Kerkythea XML format with

settings shown in 15.1. (Or, with selection enabled, make sure settings are No-Yes-Yes-No-Yes-No-No.)

You do not have to launch Kerkythea unless you want to create nice renderings of your model. Then, use the

KT2OBJ converter to create an OBJ. You can delete the XML after the conversion. Note that some texture

coordinates may not be exported correctly. The setting

Photomatched:Yes

seems now to have corrected

this issue, esp. with distorted/manually shifted textures.

Another free OBJ exporter has been made available by TIG:

OBJexporter.rb

. This is the only OBJ

exporter tested so far capable of handling large TIN landscapes (

> 450.000

triangles). As of version 2.6 it

seems to be the best OBJ exporter available for Sketchup.

This exporter swaps Y/Z coordinates, but you can add a key to the conﬁg ﬁle to correct swapped axes,

see below. Other exporters may also provide coordinates in any order of X, Y, Z – all those can be properly

conﬁgured.

Another quirk has to be ﬁxed manually though: in the material description ﬁle (MTL), TIG’s exporter

writes both

and

lines with the same value. Actually,

Tr = 1.0− d

according to OBJ/MTL documentation,

so you should edit away one line, or else the later line overwrites the value given earlier. Moreover, given that

Tr=1 should actually specify fully transparent objects, such a line will make your object entirely invisible!

Another (almost) working alternative: ObjExporter.rb by author Honing. Here, export with settings

0xxx00

. This will not create a

TX...

folder but dump all textures in the same directory as the OBJ and

MTL ﬁles. Unfortunately, currently some material assignments seem to be bad.

15.4.2 Notes on OBJ ﬁle format limitations

The OBJ format supported is only a subset of the full OBJ format: Only (optionally textured) triangle meshes

are supported, i.e., only lines containing statements:

mtllib

usemtl

(with three elements

only!), g. Negative vertex numbers (i.e., a speciﬁcation of relative positions) are not supported.

A further recommendation for correct illumination is that all vertices should have vertex normals.

Sketchup models exported with the Kerkythea or TIG plugins should have correct normals. If your model

does not provide them, default normals can be reconstructed from the triangle edges, resulting in a faceted

look.

If possible, the model should also be triangulated, but the current loader may also work with non-triangle

geometry. The correct use of objects (

) and groups (

) will improve performance: it is best if you pre-

combine all objects that use the same material into a single one. The loader will try to optimize it anyways if

this is not the case, but can do this only partly (to combine 2 objects with the same material into 1, it requires

them to follow directly after each other in the OBJ). A simple guide to use Blender

for this task follows:

File Import Wavefront .obj

- you may need to change the forward/up axes for correct orientation,

try “-Y forward” and “Z up”

2. Select an object which has a shared material

3. Press

and select ’By Material’

4. Select ’Join’ in the left (main) tool window

5. Repeat for other objects that have shared materials

Export the .obj, making sure to select the same forward/up axes as in the import, also make sure

“Write Normals”, “Write Materials” and “Include UVs” are checked

Available at http://www.kerkythea.net/cms/

Available from http://forums.sketchucation.com/viewtopic.php?f=323&t=33448

https://www.blender.org

198 Chapter 15. Scenery3d – 3D Landscapes

Parameter Default Range Meaning

Ka set to Kd values 0. . . 1 each R/G/B Ambient color

Kd 0.8 0.8 0.8 0. . . 1 each R/G/B Diffuse color

Ke 0.0 0.0 0.0 0. . . 1 each R/G/B Emissive color

Ks 0.0 0.0 0.0 0. . . 1 each R/G/B Specular color

Ns 8.0 0. . . ∞ shinyness

d or Tr 1.0 0. . . 1 opacity

bAlphatest 0 0 or 1 perform alpha test

bBackface 0 0 or 1 render backface

map_Kd (none) ﬁlename texture map to be mixed with Ka, Kd

map_Ke (none) ﬁlename texture map to be mixed with Ke

map_bump (none) ﬁlename normal map for surface roughness

illum 2 integer illumination mode in the standard MTL format.

vis_fadeIn (none) double see 15.4.5

vis_fadeOut (none) double see 15.4.5

Table 15.2: MTL parameters evaluated

For transparent objects (with a

value, alpha testing does NOT need this), this recommendation does

NOT hold: for optimal results, each separate transparent object should be exported as a separate “OBJ

object”. This is because they need to be sorted during rendering to achieve correct transparency. If the

objects are combined already, you can separate them using Blender:

1. Import .obj (see above)

2. Select the combined transparent object

3. Enter “Edit” mode with

and make sure everything is selected (press

if not)

4. Press

and select “By loose parts”, this should separate the object into its unconnected regions

5. Export .obj (see above), also check “Objects as OBJ Objects”

The MTL ﬁle speciﬁed by

mtllib

contains the material parameters. The minimum that should be speciﬁed

is either

map_Kd

or a

line specifying color values used for the respective faces. But there are other options

in MTL ﬁles, and the supported parameters and defaults are listed in Table 15.2.

If no ambient color is speciﬁed, the diffuse color values are taken for the ambient color. An optional

emissive term

can be added, which is modulated to only be visible during nighttime. This also requires

the landscape’s self-illumination layer to be enabled. It allows to model self-illuminating objects such as

street lights, windows etc. It can optionally also be modulated by the emissive texture map_Ke.

If a value for

is speciﬁed, specularity is evaluated using the Phong reﬂection model

with

the exponential shininess constant. Larger shininess means smaller specular highlights (more metal-like

appearance). Specularity is not modulated by the texture maps. Unfortunately, some 3D editors export

unusable default value combinations for

and

. Blender may create lines with

=1/1/1 and

=0. This

creates a look of “partial overexposed snow ﬁelds”. While the values are allowed in the speciﬁcation, in

most cases the result looks ugly. Make sure to set Ns to 1 or higher, or disable those two lines.

If a value for

exists, alpha blending is enabled for this material. This simulates transparency

effects. Transparency can be further controlled using the alpha channel of the map_Kd texture.

A simpler and usually more performant way to achieve simple “cutout” transparency effects is alpha-

testing, by setting

bAlphatest

to 1. This simply discards all pixels of the model where the alpha value of

the

map_Kd

is below the

transparency_threshold

value from

scenery3d.ini

, making “holes” in the

model. This also produces better shadows for such objects. If required, alpha testing can be combined with

“real” blending-based transparency.

Sometimes, exported objects only have a single side (“paper wall”), and are only visible from one side

when looked at in Scenery3d. This is caused by an optimization called back-face culling

, which skips

drawing the back sides of objects because they are usually not visible anyway. If possible, avoid such “thin”

geometry, this will also produce better shadows on the object. As a workaround, you can also set

bBackface

to 1 to disable back-face culling for this material.

The optional

map_bump

enables the use of a tangent-space normal maps

, which provides a dramatic

https://en.wikipedia.org/wiki/Phong_reflection_model

https://en.wikipedia.org/wiki/Back-face_culling

https://en.wikipedia.org/wiki/Normal_mapping

15.4 Model Conﬁguration 199

improvement in surface detail under illumination.

15.4.3 Conﬁguring OBJ for Scenery3d

The walkaround in your scene can use a ground level (piece of terrain) on which the observer can walk.

The observer eye will always stay “eye height” above ground. Currently, there is no collision detection

with walls implemented, so you can easily walk through walls, or jump on high towers, if their platform

or roof is exported in the ground layer. If your model has no explicit ground layer, walk will be on the

highest surface of the scenery layer. If you use the special name

NULL

as ground layer, walk will be above

zero_ground_height level.

Technically, if your model has cavities or doors, you should export your model twice. Once, just the

ground plane, i.e. where you will walk. Of course, for a temple or other building, this includes its socket

above soil, and any steps, but pillars should not be included. This plane is required to compute eye position

above ground. Note that it is not possible to walk in several ﬂoors of a building, or in a multi-plane staircase.

You may have to export several “ground” planes and conﬁgure several scenery directories for those rare

cases. For optimal performance, the ground model should consist of as few triangles as you can tolerate.

The second export includes all visible model parts, and will be used for rendering. Of course, this

requires the ground plane again, but also all building elements, walls, roofs, etc.

If you have not done so by yourself, it is recommended to separate ground and buildings into Sketchup

layers (or similar concepts in whichever editor you are using) in order to easily switch the model to the right

state prior to exporting.

Filename recommendations:

<Temple>.skp

Name of a Sketchup Model ﬁle. (The

brackets signal “use your own name

here!”) The SKP ﬁle is not used by Scenery3d, but you may want to leave it

in the folder for later improvements.

<Temple>.obj Model in OBJ format.

<Temple>_ground.obj Ground layer, if different from Model ﬁle.

OBJ export may also create folders

TX_<Temple>

and

TX_<Temple>_ground

. You can delete the folder

TX_<Temple>_ground, <Temple>_ground.obj is just used to compute vertical height.

Put the OBJ, MTL and TX directories into a subdirectory of your user directory (see section 5.1), e.g.

<USERDATA>/Stellarium/scenery3d/<Temple>

, and add a text ﬁle into it called

scenery3d.ini

(This

name is mandatory!) with content described as follows.

[model]

name=<Temple>

Unique ID within all models in scenery3d directory. Recommenda-

tion: use directory name.

landscape=<landscapename> Name of an available Stellarium landscape.

This is required if the landscape ﬁle includes geographical coordinates and your model does not: First,

the location coordinates of the

landscape.ini

ﬁle are used, then location coordinates given here. The

landscape also provides the background image of your scenery. If you want a zero-height (mathematical)

horizon, use the provided landscape called Zero Horizon.

scenery=<Temple>.obj The complete model, including visible ground.

ground=<Temple>_ground.obj Optional: separate ground plane. (NULL for zero altitude.)

description=<Description> A basic scene description (including HTML tags)

The

scenery3d.ini

may contain a simple scene description, but it is recommended to use the localizable

description format: in the scene’s directory (which contains

scenery3d.ini

) create ﬁles in the format

description.<lang>.utf8

which can contain arbitrary UTF-8–encoded HTML content.

<lang>

stands

for the ISO 639 language code.

author=<Your Name yourname@yourplace.com>

obj_order=XYZ

Use this if you have used an exporter which swaps Y/Z coordinates.

Defaults to XYZ, other options: XZY, YZX, YXZ, ZXY, ZYX

camNearZ=0.3

This deﬁnes the distance of the camera near plane, default 0.3.

Everything closer than this value to the camera can not be displayed.

Must be larger than zero. It may seem tempting to set this very

small, but this will lead to accuracy issues. Recommendation is

not to go under 0.1

camFarZ=10000 Deﬁnes the maximal viewing distance, default 10000.

200 Chapter 15. Scenery3d – 3D Landscapes

shadowDistance=<val>

The maximal distance shadows are displayed. If left out, the value

from

camFarZ

is used here. If this is set to a smaller value, this

may increase the quality of the shadows that are still visible.

shadowSplitWeight=0..1

Decimal value for further shadow tweaking. If you require better

shadows up close, try setting this to higher values. The default is

calculated using a heuristic that incorporates scene size.

[general]

The general section deﬁnes some further import/rendering options.

transparency_threshold=0.5

Deﬁnes the alpha threshold for alpha-testing, as described in sec-

tion 15.4.2. Default 0.5

scenery_generate_normals=0

Boolean, if true normals are recalculated by the plugin, instead of

imported. Default false

ground_generate_normals=0 Boolean, same as above, for ground model. Default false.

[location]

Optional section to specify geographic longitude

, latitude

, and altitude. The section is required if

coord/convergence_angle={from_grid|from_utm}, else location is inherited from landscape.

planet = Earth

latitude = +48d31’30.4" Required if coord/convergence_angle=from_{grid|utm}

longitude = +16d12’25.5" "–"

altitude =from_model|<int>

altitude (for astronomical computations) can be computed from the

model: if

from_model

, it is computed as

min

+ z

max

)2+ orig_H

i.e. from the model bounding box centre height.

display_fog = 0

atmospheric_extinction_coefficient = 0.2

atmospheric_temperature = 10.0

atmospheric_pressure = -1

light_pollution = 1

[coord]

Entries in the

[coord]

section are again optional, default to zero when not speciﬁed, but are required if

you want to display meaningful eye coordinates in your survey (world) coordinate system, like UTM or

Gauss-Krüger.

grid_name=<string>

Name of grid coordinates, e.g.

"UTM 33 U (WGS 84)"

"Gauss-Krüger M34"

"Relative to <Center>"

This name is only displayed, there is no evaluation of its

contents.

orig_E=<double> | (Easting) East-West-distance to zone central meridian

orig_N=<double> | (Northing) North distance from Equator

orig_H=<double> | (Height) Altitude above Mean Sea Level of model origin

These entries describe the offset, in metres, of the model coordinates relative to coordinates in a geographic

grid, like Gauss-Krüger or UTM. If you have your model vertices speciﬁed in grid coordinates, do not specify

orig_... data, but please deﬁnitely add start_... data, below.

Note that using grid coordinates without offset for the vertices is usually a bad idea for real-world

applications like surveyed sites in UTM coordinates. Coordinate values are often very large numbers

(ranging into millions of meters from equator and many thousands from the zone meridian). If you want to

assign millimetre values to model vertices, you will hit numerical problems with the usual single-precision

ﬂoating point arithmetic. Therefore we can specify this offset which is only necessary for coordinate display.

Typically, digital elevation models and building structures built on those are survey-grid aligned, so true

geographical north for a place with geographical longitude

and latitude

will in general not coincide with

grid north, the difference is known as meridian convergence

and, on a spherical globe, amounts to:

γ(λ , ϕ)= arctan(tan(λ − λ

)sin

ϕ) (15.1)

https://en.wikipedia.org/wiki/Transverse_Mercator_projection

15.4 Model Conﬁguration 201

This amount can be given in convergence_angle (degrees), so that your model will be rotated clockwise

by this amount around the vertical axis to be aligned with True North

co nverg ence_ angle = from_grid | from_ utm |< double >

gr id _m eridian = < double >|+ < int >d < int > ’<float >"

grid_meridian

is the central meridian

of the grid zone, e.g. for Gauss-Krüger, and is only required to

compute convergence angle if

convergence_angle=from_grid

. If your model coordinates is based on

UTM, you can use coord/convergence_angle=from_utm for a more accurate computation.

ze ro_gr ound_ hei gh t = < double >

height of terrain outside

<Temple>_ground.OBJ

, or if

ground=NULL

. Allows smooth approach from

outside. This value is relative to the model origin, or typically close to zero, i.e., use a Z value in model

coordinates, not world coordinates! (If you want the terrain height surrounding your model to be

orig_H

use 0, not the correct mean height above sea level!) Defaults to minimum of height of ground level (or model,

resp.) bounding box.

start_E=<double>

start_N=<double>

start_H=<double> only meaningful if ground==NULL, else H is derived from ground

start_Eye=<double> default: 1.65m

start_az_alt_fov=<az_deg>,<alt_deg>,<fov_deg>

initial view direction and ﬁeld of view.

start_...

deﬁnes the view position to be set after loading the scenery. Defaults to center of model

boundingbox.

It is advisable to use the grid coordinates of the location of the panoramic photo (landscape) as

start_...

coordinates, or the correct coordinates and some carefully selected

start_az_alt_fov

in case you want to

highlight a certain view corridor (temple axis, . . . ).

In some setups like digital full-dome planetaria it is advisable to disable the use of the

start_az_alt_fov

v 23.2

You can do that in the Scenery3D conﬁguration dialog or by the entry

ignore_start_az_alt_fov

config.ini.

15.4.4 Concatenating OBJ ﬁles

Some automated workﬂows may involve tiled landscape areas, e.g. to overcome texture limitations or

triangle count limits in simpler tools like Sketchup. In this case you can create separate meshes in the same

coordinate system, but you need to concatenate them. One powerful program to assemble your parts is again

Blender.

In Blender, import the OBJ ﬁles

File Import Wavefront .obj

. If your OBJ coordinates have Z as

vertical axis (common for terrestrial models), use “Z up”, “-Y Forward” as import settings for the coordinate

axes. The model will appear south-up.

Blender may not show anything except the default cube because of aggressive camera far plane clipping.

Press

and in the

View

set at least the far clipping plane as required to see the full extent of your terrain

model. Then press

View View All

(or

Home

The landscape may look white now. Switch on textured view if required (

Alt

). If the scene looks

almost black now, reconﬁgure the light to be sunlight: Select the lamp in the outliner graph, press the lamp

icon and in the

Lamp

select “Sun”. Now the scene should be in full color, and the Y axis should point

towards grid-south.

After importing the ﬁrst model, you may consider locking it in place to avoid errors. Select the model in

the outliner, select the cube button below, then open

Transform Locks

and lock all. The other model parts may

have to be transformed, and numerical transformation can be added in the

Transform

settings in this menu.

If you have created a VRML (WRL) of some structures in ArcScene, export that without shifting to

center, and import the WRL ﬁle in Blender with default orientation “Y up”, “Z forward”. Models from other

sources may still be different.

In the end, all parts should ﬁt neatly together. Blender is a very powerful program, you can enhance

your model as you wish.

Note that Sketchup’s georeferencing dictionary provides a NorthAngle entry, which is

360− convergence_angle

202 Chapter 15. Scenery3d – 3D Landscapes

When the model conﬁguration is complete, select all relevant parts which you want to have visible in

Stellarium (click on the lines in the outline view containing the object names to light them up gray, then

Rightclick-Select, so that the triangle (mesh) icon has a colored background circle) and press

Ctrl

optionally join them, then export to a single OBJ

File Export Wavefront .obj

. In the export options, apply

“Selection Only”, and “-Y Forward” and “Z Up”

Verify the new model loads correctly, e.g. in Meshlab

15.4.5 Beyond 3D: Temporally evolving Models

Stellarium working as “time machine” can display the sky for any calendar date in its range of valid dates.

Also landscapes and human-built structures evolve. Temples are being rebuilt, changed, re-dedicated or

repurposed, new windows are cut, old windows closed. To show landscape and buildings in the right shape

for the time in question, we can make material transparent, so that parts of the model are not displayed. To

allow for archaeological uncertainties in dating construction and destruction, we can gradually fade in and

fade out the model parts in question (Zotti, Schaukowitsch, and Wimmer, 2018).

To enable this magic, you must combine all your models into one (see section 15.4.4), export as one

OBJ/MTL as usual, and manually edit the MTL ﬁle. It is wise to give the material for the parts in question a

reasonable name that you can later identify in the MTL ﬁle. Then you simply add one or both of the new

keywords

vis_fadeIn

vis_fadeOut

to the material description, with 2 arguments which are the Julian

days of begin and end of a phase transition. For sharp transitions, just use the same JD dates.

# Some str ucture has been put up around -3100/ -3000

vis_fadeIn 588783.5 625308. 5

# Fade away between 500 AD /700 AD

vis_fade Ou t 190 36 82.5 1976732.5

15.4.6 Working with non-georeferenced OBJ ﬁles

There exists modeling software which produces nice models, but without concept of georeference. One

spectacular example is AutoDesk PhotoFly, a cloud application which delivers 3D models from a bunch of

photos uploaded via its program interface. This “technological preview” is in version 2 and free of cost as of

mid-2011.

The problem with these models is that you cannot assign surveyed coordinates to points in the model, so

either you can georeference the models in other applications, or you must ﬁnd the correct transformation

matrix. Importing the OBJ in Sketchup may take a long time for detailed photo-generated models, and the

texturing may suffer, so you can cut the model down to the minimum necessary e.g. in Meshlab, and import

just a stub required to georeference the model in Sketchup.

Now, how would you ﬁnd the proper orientation? The easiest chance would be with a structure visible in

the photo layer of Google Ear th. So, start a new model and immediately

add location

from the Google

Earth interface. Then you can import the OBJ with TIG’s importer plugin. If the imported model looks

perfect, you may just place the model into the Sketchup landscape and export a complete landscape just

like above. If not, or if you had to cut/simplify the OBJ to be able to import it, you can rotate/scale the OBJ

(it must be grouped!). If you see a shadow in the photos, you may want to set the date/time of the original

photos in the scene and verify that the shadows created by Sketchup illuminating the model match those in

the model’s photo texture. When you are satisﬁed with placement/orientation, you create a

scenery3d.ini

like above with the command

Plugins ASTROSIM/Stellarium scenery3d helpers Create scenery3d.ini

Then, you select the OBJ group, open the

Windows Ruby Console

and readout data by calling

Plugins

ASTROSIM/Stellarium scenery3d helpers Export transformation of selected group

On the Ruby console, you will ﬁnd a line of numbers (the

4 × 4

transformation matrix) which you

copy/paste (all in one line!) into the [model] section in scenery3d.ini.

ob j2 grid_ tr afo = < a11 >, < a12 >, < a13 >, < a14 >, < a21 >,< a22 >,< a23 >,< a24 >,

You edit the

scenery3d.ini

to use your full (unmodiﬁed) PhotoFly model and, if you don’t have a

panorama, take

Zero Horizon

landscape as (no-)background. It depends on the model if you want to be

https://blender.stackexchange.com/questions/3352/merging-multiple-obj-ﬁles

https://www.meshlab.net/

15.5 Predeﬁned views 203

able to step on it, or to declare

ground=NULL

for a constant-height ground. Run Stellarum once and adjust

the start_N, start_E and zero_ground_height.

15.4.7 Rotating OBJs with recognized survey points

If you have survey points measured in a survey grid plus an image-based model with those points visible,

you can use Meshlab to ﬁnd the model vertex coordinates in the photo model, and some other program

like CoordTrans in the JavaGraticule3D suite to ﬁnd either the matrix values to enter in

scenery3d.ini

or even rotate the OBJ points. However, this involves more math than can be described here; if you came

that far, you likely know the required steps. Here it really helps if you know how to operate automatic text

processors like AWK.

15.5 Predeﬁned views

You can also conﬁgure and distribute some predeﬁned views with optional date of interest with your model

in a

viewpoints.ini

ﬁle. The viewpoints can be loaded and stored with the viewpoint dialog which you

can call with the button. See the provided “Sterngarten” scene for an example. These entries are not

editable by the user through the interface. The user can always save his own views, they will be saved into

the ﬁle userviews.ini in the user’s Stellarium user directory, and are editable.

[ StoredViews ]

size =< int > De f ines how many en tries are in this file .

Pr efix each ent ry with its index !

1/ l abel = < string > The name of this en try

1/ de s c r i p tion = < string > A d e s c ription of this en try ( can includ e HTML )

1/ position =<x ,y ,z ,h > The x ,y ,z grid coor d i n a t e s

( like orig_ * or s tart_ * in scene r y 3 d . ini )

+ the curre n t eye height h

1/ view_fov =< az_deg , alt_deg ,fov_deg > The view d i rection + FOV

( like s t ar t _ az _ a lt _ f o v in scenery 3 d . ini )

; an exampl e for a sec ond entry ( note the 2 at the b e g i nning of each line !)

2/ l abel = Signs

2/ de s c r i p tion = Two signs that descr i b e the Ster n g a r t e n

2/ position = 5931 5 5 . 2 4 2 1 ,5333348.6304 ,325.7295809038 ,0.8805

2/ view_fov = 84 .31539 9 , - 8.1870 78 ,83.00 0000

2/ JD = 245154 5 . 5 [ op tional ]

15.6 Example

Let us add a quick example here. A recent paper (Pollard, 2017) claims that the Ufﬁngton White Horse, a

geoglyph carved into a hillsite in England during the Bronze Age, may depict the mythical “Sun Horse”, a

common conception of that period.

Unfortunately, as of 2017, the ofﬁcial UK Lidar repository does not include the Ufﬁngton area, so a

detailed GIS-based model is not available. We could use EUdem25 data with aerial imagery, or for a quick

look, we just use Sketchup. Yet another unfortunate development: Trimble declared that after the 5-year

transition period from Google to Trimble is over in May 2017, terrain modelling will be limited to Sketchup

Pro. But note that a fresh installation comes with a 30-day Pro trial time, this should be enough for this

example.

First, locate the site in Google Earth at

λ = −1.56718, ϕ = 51.582843

. (Or just search for “Ufﬁngton”.)

Try to identify which parts of the landscape may be visible from your site, so you can estimate which parts

of terrain should be included in the model. Open Sketchup, select the meter-based “Landscape Architecture”

template, add

View Toolbars. . .

: Locations. Click on the “Add Location” button of that toolbar. Enter

“Ufﬁngton” into the location search dialog. This brings you close to our site of interest. Clip a part of terrain

to import it to Sketchup. Optionally, add more terrain.

If installed, TIG’s OBJ exporter is available from the

File

menu, or you can use Sketchup Pro’s

built-in OBJ export. Export

UffingtonHorse.obj

to a subdirectory

scenery3d/Uffington

in your

Stellarium user data directory. The geolocation is stored in an “AttributeDictionary”. To read this, press

Window Ruby Console

to open the Ruby Console. Then write a few lines of Ruby to get access to the

Georeference dictionary and other data:

model = S ketchup . a ct iv e_ model

attrdicts = model . attri but e_d ic tio nar ies

204 Chapter 15. Scenery3d – 3D Landscapes

attrdicts . each {| d |

puts " A ttrib uteDi cti onary : %s " % d . name

d. each_pair { |k , v | puts " %s =% s" % [k , v ] }

}

model . sha do w_info . each {| k , v | puts " #{ k} #{ v } "}

utm = model . point_ to _u tm Geom :: Poin t3d . new (0 ,0 ,0)

puts (" gri d_name = UTM % i % s (% s ) " %

[ utm . zone_number , utm . zone_letter , model . get_datu m ])

Note the

ModelTranslation

values. Those are inches (of all units!) in the UTM reference frame and

deﬁne the model coordinate origin in world coordinates. (Actually, it uses the negative values.) Multiplication

by 2.54 gives cm, and by 0.0254, meters in the UTM coordinate system. We will use the negatives of these

values as

orig_E

orig_N

orig_H

. Additionally, we have found information about meridian convergence

correction (Sketchup’s

NorthAngle

), UTM zone number etc. All this goes into our conﬁguration ﬁle.

Create this ﬁle scenery3d.ini with the content seen in ﬁg. 15.1

15.7 Limitations

Models with up to 14 million triangles have been used successfully on a mid-range notebook PC from 2016.

However, take some restrictions into account:

•

The model is rendered in Cartesian coordinates. Earth’s surface is curved. If your model extends by

tens of kilometres, the visible horizon formed by faraway mountains may appear too high. You can

display a landscape polygon deﬁned in the currently displayed Landscape on top of your 3D scene by

activating

Draw horizon polyline in foreground

in the plugin’s settings dialog.

•

The OBJ format is static. Simulation of interaction with 3D objects is not possible with this plugin.

Authors and Acknowledgements

Scenery3d was conceived by Georg Zotti for the ASTROSIM

project. A ﬁrst prototype was implemented in

2010/2011 by Simon Parzer and Peter Neubauer as student work supervised by Michael Wimmer (TU Wien).

Models for accuracy tests (Sterngarten, Testscene), and later improvements in integration, user interaction,

.ini option handling, OBJ/MTL loader bugﬁxes and georeference testing by Georg Zotti.

Andrei Borza in 2011/12 further improved rendering quality (shadow mapping, normal mapping) and

speed (Zotti, 2015; Zotti and Neubauer, 2012a; Zotti and Neubauer, 2012b).

In 2014–17, Florian Schaukowitsch adapted the code to work with Qt 5 and the Stellarium 0.13 codebase,

replaced the renderer with a more efﬁcient, fully shader-based system, implemented various performance,

quality and usability enhancements, and did some code cleanup. Both Andrei and Florian were again

supervised by Michael Wimmer (Zotti, 2016a; Zotti, 2016b; Zotti, Schaukowitsch, and Wimmer, 2018).

This work has been originally created during the ASTROSIM project supported 2008-2012 by the

Austrian Science Fund (FWF) under grant number P 21208-G19. Further development has partially been

supported by the Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology in

Vienna, Austria

If you are using this plugin in scientiﬁc work, please cite: (Zotti, 2016a; Zotti, 2016b; Zotti, 2019; Zotti,

Frischer, et al., 2019; Zotti, S. Hoffmann, et al., 2021; Zotti, Schaukowitsch, and Wimmer, 2018).

https://astrosim.univie.ac.at

https://archpro.lbg.ac.at

15.7 Limitations 205

[ model ]

name = Uf fington Ho rse

; Either a fitting lands ca pe or just ’ Zero Horizon ’:

landscape = Zero Horizon

scenery = Uf fington Horse . obj

; act ivate the next line if you have a s eparate ground layer

; ground = Uff ingto nHo rse _g rou nd . obj

; If model Y - axis points up , act ivate the next line

; obj_ord er = XZY

author = Georg Zotti

descript io n = Uffington Horse may represen t the Sun Horse . \

See Joshua Pollard in Antiqu it y 91 3 56 (2 01 7) : 406 -20.

[ loc ation ]

name = Uf fington Ho rse

country = UK

planetName = Earth

; Set the f ollowing to a fit ting lan ds cape

land sc ap eKey = Zero Horizon

longitude = -1.567 18254089355

latit ude =5 1. 582 84 327 49 823

altit ude =137

[ coord ]

grid_name = UTM 30 U ( WGS 84)

gridT ype = UTM

orig_E =59 9273. 02119 57 8

orig_N = 57 156 15 .1507 9106

orig_H = 13 6.2 95 29762 6736

co nverg ence_ angle = 1.1 22 84363 77198 8

; Height used outside the terrain , to not " fall off " the rim .

ze ro_gr ound_ hei gh t =137

; You may want to reset these coord in at es .

; Obs erver is set to those on loading the s cenery .

start_E =5992 73 .0211 9578

start_N =5715 615.1 50791 06

st art_a z_ alt_f ov =50 ,10 ,83

Figure 15.1: scenery3d.ini for the Ufﬁngton example.

16. Stellarium at the Telescope

Stellarium is great for indoor use on the desktop, but it is also very useful outdoors under the real sky, and

several plugins enhance its usability particularly for observers.

Right at the telescope, Oculars (section 16.1) provides ﬁeld of view hints for telescopes, oculars and

sensors, and TelescopeControl (section 16.2), which allows you to send GOTO commands to most motorized

telescope mounts. Other GOTO telescopes are supported by external programs which you must install

separately: RTS2 (16.2.6), INDI (16.2.7) or ASCOM (16.2.8). This can also help DIY hardware tinkerers who

like to build their own control systems (section 16.2.10).

In addition, the Observability plugin (16.3) can be used for planning the best times to observe your

favorite objects, and the Mosaic Camera plugin (16.4) can be used to show the orientations of more

complicated camera mosaics.

16.1 Oculars Plugin

TIMOTHY REAVES, WITH ADDITIONS BY ALEXANDER WOLF

This plugin serves several purposes:

•

to see what the sky looks like through a particular combination of eyepiece, lens (Barlow or Shapley

types) and telescope. This plugin helps to get an idea of what you should see when looking through

a physical telescope, and understand why one eyepiece may be better suited to observe a particular

target than another. This can also be very useful for deciding what telescope is best suited to a style of

viewing. And with the support for binoculars, you also have the ability to understand just about any

type of optics-enhanced visual observing.

•

to show what a particular combination of camera and telescope (or photographic lens) would be able

to photograph of the sky.

•

lastly, with the help of the Telrad sight, understand where object in the sky are in relation to each

other. This can be helpful for star-hopping with a non-GOTO telescope.

None of these activities can take the place of hands-on experience, but they are a good way to supplement

your visual astronomy interests.

16.1.1 Using the Ocular plugin

The plugin is controlled through a popup menu or through an on-screen control panel (see top right corner

on screens in ﬁg. 16.17). By default, the hot key to display the popup is

Alt

(

Option

for Mac

users). This can be changed in the

Editing Keyboard Shortcuts

window (see section 4.8). The menu will

popup where your cursor is located.

The options available in the popup menu depend on what you are currently doing. In the default menu,

you can choose to conﬁgure the plugin, activate a CCD, or activate the Telrad ﬁnder (see ﬁg. 16.1). The

menu is navigated by either the arrow keys on your keyboard or by your mouse. The

and arrow

208 Chapter 16. Stellarium at the Telescope

Figure 16.1: The on-screen menu (top right) and popup menu (lower right) of the Oculars plugin.

keys move the selection up or down the menu, and the and arrow keys display or hide sub-menus.

activates an option.

Telrad Finder

The Telrad view can be used without deﬁning any of the items below. As a reﬂex sight is non-magnifying,

this feature can only be enabled when no eyepiece is selected. You still may want to zoom in a bit to better

see which stars are in the circles (ﬁg. 16.2). The three circles that appear in the center of the screen are

0.5

°,

2.0

°, and

4.0

° in diameter. They stay centered in the screen, so move the “telescope” (click-drag the

background) to center the circles on the object of interest.

While the Telrad ﬁnder is active, you can not activate a CCD with the popup menu, but only with the

on-screen menu.

CCD Sensors

This is a great way to get an idea of what a particular camera will be able to capture when attached to a

particular telescope or lens. For using camera lenses, describe them as telescope with the appropriate values

for the lens. When active, this feature will display a red bounding box of the area that will be captured, as

well as zoom in to give a better view of the surroundings. You can manually zoom in or out from there.

The default CCD view will appear similar to ﬁg. 16.3 or, when you are working without the on-screen

control panel, the information area in the upper right hand corner also shows angular size captured by the

CCD (see ﬁg. 16.4).

When a CCD view is displayed, the popup menu changes as seen in ﬁg. 16.5. You can select what

telescope to use, as well as progress to the previous or next CCD, or go to a speciﬁc CCD. You can also

rotate the CCD to better frame your subject, or to see if the CCD can be rotated in such a way as to catch

your area of interest (see ﬁg. 16.6). Once rotated, the CCD frame on screen displays the new orientation (see

ﬁg. 16.7).

Figure 16.2: The left image is the default 60°, and the right one is 40°.

16.1 Oculars Plugin 209

Figure 16.3: View of M37 through a CCD sensor of the Oculars plugin.

Figure 16.4: View of M37 through a CCD sensor of the Oculars plugin (without on-screen control

panel).

Oculars

•

Deﬁne some eyepieces and telescope (see section 16.1.2).

•

Select an object to view (i.e. a star, planet, etc.)

•

Click the toolbar button for toggling the Ocular view, or press

Ctrl

(

for Mac

users).

•

Swap between eye pieces and telescopes to see how the view changes.

This is really the area of interest to most telescopic observers. It is a great way to compare different

eyepiece/telescope combinations, to see how they change the view of the sky. And it is easy to do so with

binoculars too. To show this, let us use the M37 cluster as target. Through a pair of Celestron 15x70

binoculars, it would look like in ﬁg. 16.8.

A very pretty sight. Now, what would it look like through a Celestron 80 mm EDF ﬁnder ’scope, with an

Explore Scientiﬁc 14 mm 100° eyepiece? See ﬁg. 16.9!

Not bad at all. But we like to see more! So we move the eyepiece to a C1400. See ﬁg. 16.10 for the

resulting view.

Very nice indeed! So for this target, the C1400 is going to be the best bet. However, if my target was the

Pleiades, the C1400 with that eyepiece would not be good — the 80EDF would do much better!

When an eyepiece is active, the popup menu again changes. With a non-binocular eyepiece selected,

you also have the ability to select a particular eyepiece or telescope. When a binocular is active, you can

not select a telescope, as it is not relevant. Changing the eyepiece to a non-binocular will again allow the

210 Chapter 16. Stellarium at the Telescope

Figure 16.5: The CCD sensor popup menu of the Oculars plugin.

Figure 16.6: Setting rotation of CCD sensor in the popup menu.

Figure 16.7: A rotated CCD sensor frame of the Oculars plugin.

16.1 Oculars Plugin 211

Figure 16.8: The M37 cluster through a Celestron 15x70 binocular.

Figure 16.9: The M37 cluster through a Celestron 80 mm EDF with Explore Scientiﬁc 14 mm

eyepiece.

Figure 16.10: The M37 cluster through a Celestron C1400 with Tele Vue Nagler 31 mm eyepiece.

212 Chapter 16. Stellarium at the Telescope

telescope to be selected. Also notice that when your mouse cursor is very near the right hand border of the

screen, the popup menu’s sub-menus display to the left, not the right.

16.1.1.1 Star Scales

As you know from section 4.4.1, the number and relative size of stars of various magnitudes can be adjusted

to your personal preferences in the view settings window to approximate the appearance of the stars as seen

by the naked eye. Some observers prefer to have a simulated ocular view with very small, or more, stars,

quite different from what Stellarium usually shows. The Oculars plugin therefore keeps two additional sets

of scaling values for ocular views and CCD views, which are activated automatically when you switch to

ocular or CCD view, and which are stored immediately and permanently in the plugin’s ocular.ini ﬁle.

16.1.2 Conﬁguration

All conﬁguration is done through the user interface in the application. To open the conﬁguration dialog hit

the

Alt

key, or click the

conﬁgure

button on the plugin setup dialog (available in the

Plugins

tab of

Stellarium’s Conﬁguration window (opened by pressing

or the button in the left toolbar)), or the

rightmost button of the on-screen panel (if displayed in the top right corner of screen). There are six tabs in

the conﬁguration dialog: General, Eyepieces, Lenses, Sensors, Telescopes, and About. The ﬁrst ﬁve are the

ones we are interested in here.

General

The ﬁrst option allows you to deﬁne the general behavior of the plugin. The options are grouped by areas of

usage: Interface, Ocular view, Sensor view and Telrad view (see ﬁgure 16.11).

Figure 16.11: General tab of the Oculars plugin conﬁguration dialog.

Interface: this group of options allows to change behavior of the plugin in general.

On-screen control panel:

show an additional GUI panel in the top-right corner of the screen to

allow switching features of the plugin (in addition to the popup window).

Restore FOV to initial values and

Restore direction to initial values

options allow restoration ﬁeld of view and direction of view,

resp., to the initial values at program start at the end of the plugin usage (e.g., when disabling

the view through CCD frame).

Show resolution criteria

compute and show Rayleigh criterion, Dawes’, Abbe’s and Sparrow’s

limits for combination of telescope, lens and eyepiece. In addition, this option will show visual

resolution for selected “setup”. This option may be very helpful for double star observers.

Show oculars button on toolbar

option allows to toggle visibility the plugin button on main toolbar.

Arrow button scale allows to change the size of the arrow buttons in the ocular GUI panel.

The appearance of stars may depend on various other factors: telescope type, ocular type, quality of optics, seeing,

. . . Such details with all combinations cannot meaningfully be stored, though. These values should allow a rapid toggle

on any single night.

16.1 Oculars Plugin 213

Line Color Select color for ocular and sensor outlines and their labels.

Text Color

Select color for screen messages which are shown only when the on-screen control panel

is not shown.

Ocular view is a group of options that allows to change the plugin’s behavior in visual observation mode.

Enable only if an object is selected

– uncheck this option if you want to use the visual observation

mode when no object is selected.

Auto-limit stellar magnitude

sets the magnitude limitation for stars based on telescope diameter.

When disabled, the main program’s setting applies (see section 4.4.1). Note that two manual

limits for ocular view and main program are handled, and switching between ocular and main

view also switches those values.

Hide grids and lines when enabled

allows to hide grids and lines when you observe the sky through

the eyepiece and re-enables their visibility when leaving visual observation mode.

Scale image circle

option allows you to deﬁne whether or not to scale the images based on apparent

FOV. When deactivated, the image circle will ﬁll your screen. In general, we recommend you

not select this, unless you have a need to, because it can really reduce the image size on the

screen. It can however be very useful in comparing two eyepieces. If you set this option, the

on-screen image will be scaled based on the eyepieces and telescopes you deﬁne. See section

16.1.3 for information on what scaling means, and why you might want to use it.

Use semi-transparent mask

uncheck this option if you want to see visible ﬁeld of view as in real

telescope. You may deﬁne level of transparency for mask.

Hide grids and lines when enabled

allows to hide grids and lines when you observe the sky through

the eyepiece and re-enables their visibility when leaving visual observation mode.

Show FOV outline option enables drawing the border of the eyepiece’s FOV and it may be helpful

in combination with a semi-transparent mask.

Show compass rose

option enables drawing cardinal directions in the equatorial coordinate system.

Align crosshair

option enables alignment of the cross-hair according to the equatorial coordinate

system.

Sensor view

is group of options allows to change behavior of the plugin for photographic observations

mode.

Enable autozoom when switching CCD

Use degrees and minutes for FOV of CCD

– for many cases the use of decimal degrees for the

value of the ﬁeld of view is not comfortable, and this option allows to use the more human

readable format for FOV.

Use horizontal coordinates instead of equatorial (J2000.0) coordinates in the top left frame cor-

ner.

Show max exposure time for moving objects

For solar system objects, the top right edge can in-

dicate the maximum exposure time so that the object moves less than a pixel against the

stars.

Enable automatic switch of mount type

allows to store the CCD frame orientation when the type

of telescope mount is changed.

Show sensor crop overlay

toggles drawing a crop box within the CCD frame. In addition, a pixel

grid can be drawn within the crop overlay especially for astrophotographers.

Show focuser overlay

allows drawing a circle which represents the telescope’s focuser. We added

sizes of 3 common modern focusers to allow users to check the visible aberrations in the FOV

of the telescope.

Telrad view is a group of options which allows to change behavior of the plugin for Telrad mode.

Enable autozoom when switching Telrad

option allows you to deﬁne whether or not to zoom the

ﬁeld of view to twice the size of the Telrad circles.

FOV:

If you don’t use the original Telrad but a similar device, you may deﬁne up to 4 circles to show

its speciﬁc FOV in the sky.

Eyepieces

This is the tab used to enter your own eyepieces (see ﬁgures 16.12 and 16.13). By default, a few sample ones

have been added; feel free to delete those once you’ve entered your own.

The ﬁelds on this tab are:

Name

– a free-text description of the eye piece. You could modify this to match your personal descriptions

of eyepieces.

aFOV – apparent ﬁeld of view in degrees.

214 Chapter 16. Stellarium at the Telescope

Figure 16.12: Eyepieces tab of Oculars plugin conﬁguration dialog.

Figure 16.13: Eyepieces tab of Oculars plugin conﬁguration dialog (settings for binocular).

16.1 Oculars Plugin 215

Focal Length – eyepiece focal length in mm.

Field Stop

– the ﬁeld stop of the eyepiece in

. This is used to calculate the true ﬁeld of view of an

eyepiece. If you do not know what it is just leave it the default zero. Not all manufacturers provide

this value; Tele Vue is one that does.

Binoculars

– selecting this checkbox tells the system that this eyepiece is binoculars or ﬁnders; this means

that this eyepiece can be used without deﬁning a telescope.

Has permanent cross-hairs

– selecting this checkbox tells the system that this eyepiece or binocular (ﬁnder)

has also simple cross-hairs

When Binoculars are described, the relevant ﬁelds change to

tFOV

– true ﬁeld of view in degrees. The true ﬁeld of view can be given as meters at 1000 m. The

approximate conversion of this to degrees is to divide by 17.5. Thus, 87 m at 1000 m

= (8717.5)

≈ 5

°.

Magniﬁcation factor – the magniﬁcation of the binocular.

Diameter – the diameter of the binocular objective in mm.

For binoculars, we’re computed a few important factors in additional to the exit pupil

(these factors are

visible in an on-screen control panel):

Relative Brightness.

This is the square of the diameter of the exit pupil. For example, for a 10x50 binocular,

the exit pupil is 5

and relative brightness is

(5010)

= 5

= 25

. However, the calculation for

a 20x100 binocular, through which a great deal more can be seen, gives exactly the same relative

brightness:

(10020)

= 5

= 25

, so this is an inadequate rating to use for astronomical binoculars.

Relative brightness is a number used to compare the brightness of binoculars of similar magniﬁcation.

The larger the relative brightness number, the brighter the image.

Twilight Factor

(Twilight Index or Twilight Performance Factor). This was used by Carl Zeiss Interna-

tional as an indication of the distance at which comparable detail would be seen in different binoculars.

It’s calculated by ﬁnding the square root of the product of the magniﬁcation and aperture. For the two

binoculars above, the calculations are:



(10∗ 50)=



(500)= 22.36



(20∗ 100)=



(2000)= 44.72

In this instance, the larger binocular has an index that is double that of the smaller binocular. Twilight

factor is a number used to compare the effectiveness of binoculars used in low light. The larger the

twilight factor, the more detail you can see in low light.

Bishop Index

(or Visibility Factor). This is due to Roy Bishop (Bishop, 2002) and is evaluated simply by

multiplying the magniﬁcation by the aperture in mm. For our two binocular above, we obtain:

10∗ 50 = 500

20∗ 100 = 2000

The larger binocular has a visibility factor four times greater than the smaller one.

Adler Index

(or Astro Index). This is due to Alan Adler (Adler, 2002) and is evaluated as the product of

the magniﬁcation and the square root of the aperture in

. For our two binocular above, we obtain:

10∗

√

50 = 10∗ 7.1 = 71

20∗

√

100 = 20∗ 10 = 200

This gives the larger binocular an Astro Index of 2.8x the smaller one. At the moment this is the

best index to comparison of astronomical binoculars (of course for the simplest indexes, because

others have tried to expand on these by including the effect of coatings, bafﬂes, and other aspects of

individual quality).

Lenses

This is the tab used to enter your own focal extender or reducer lenses (see ﬁgure 16.14). By default, a few

sample ones have been added; feel free to delete them once you’ve entered your own.

The ﬁelds on this tab are:

Name

– a free-text description of the lens. You could modify this to match your personal descriptions of

lenses.

The Oculars plugin supports eyepieces with reticle patterns – both special eyepieces are available in the default list

of eyepieces, and the option Has permanent cross-hairs is not related to those eyepieces.

The exit pupil diameter is calculated by dividing the aperture by the magniﬁcation.

216 Chapter 16. Stellarium at the Telescope

Figure 16.14: Lenses tab of Oculars plugin conﬁguration dialog.

Multiplier

– a factor larger than 1 expands the focal length, and lenses with this type are named Barlow

lens; a factor less than 1 reduces the focal length, and lenses with this type are named Shapley lens or

focus reducer.

Sensors

This tab allows you to deﬁne sensors for any camera you may have (see ﬁgure 16.15). When deﬁned and

selected, this will draw a red bounding rectangle in the center of the eye piece view, showing what the CCD

will capture. Because of the way ﬂoating point numbers are stored, sometimes you may see one of your

deﬁned values change (for example from 2.2 to 2.19999) but this should not affect what you see.

Figure 16.15: Sensors tab of Oculars plugin conﬁguration dialog.

The ﬁelds on this tab are:

Name – A free-text description of the sensor.

Resolution x – the width of the sensor in pixels.

Resolution y – the height of the sensor in pixels.

Chip width – the width of the sensor in mm.

Chip height – the height of the sensor in mm.

Rotation Angle – the rotation angle of the sensor, in degrees.

Binning x – the binning factor for the width of the sensor.

Binning y – the binning factor for the height of the sensor.

Off-Axis guider

– selecting this checkbox tells the system that this sensor has support an off-axis guider

also.

Prism/CCD distance

– distance between center of prism/CCD of Off-Axis Guider and optical axis of

telescope in mm.

Prism/CCD width – the width of the prism/CCD of Off-Axis Guider in mm.

Prism/CCD height – the height of the prism/CCD of Off-Axis Guider in mm.

Position Angle – the position angle of the prism/CCD of Off-Axis Guider, in degrees.

The resolution is easy to ﬁnd: these are simply the image dimensions of a (non-binned) frame. The chip size

and pixel size may be more difﬁcult, but the manual, or searching the Internet, should turn up these values.

For a “full-frame” DSLR, this should be close to 36x24

, while APS-C should be around 22.5x15

Some cameras may have unsquare pixels.

16.1 Oculars Plugin 217

Telescopes

This is the tab used to enter your own telescopes and photographic objectives (see ﬁg. 16.16). The ﬁelds on

this tab are:

Figure 16.16: Telescopes tab of Oculars plugin conﬁguration dialog.

Name – A free-text description of the telescope.

Focal Length – telescope focal length f in mm.

Diameter

– telescope diameter (aperture

∅

) in

. If you add a photographic objective that does not

provide this information but provides a largest f stop like “100

f/2.8”, you can estimate from

∅ = f s, where s = 2.8 and thus ∅ = 1002.8 = 35.7mm in this example.

Horizontal ﬂip – if the view through this telescope should ﬂip horizontally.

Vertical ﬂip – if the view through this telescope should ﬂip vertically.

Equatorial Mount – select it if this telescope has an equatorial mount.

16.1.3 Scaling the eyepiece view

I (TR) would like to thank Al Nagler over at Tele Vue

for helping to set me straight on the topic of eyepieces.

They are a lot more complicated than you might think!

By default, the view drawn on your computer screen when the plugin is active ﬁlls the screen. That is,

there is a circle drawn to represent the view through the eyepiece, and this circle will ﬁll the screen. For

general use, this is what most people would want. There will be times that it’s not.

If you are going to be observing any deep space object, it can be very important to choose the best

eyepiece for that object. You will typically want an eyepiece that will magnify the object as much as possible,

while showing all of the object in the eyepiece view. Getting this can be tricky, especially if you do not like

changing eyepieces at the telescope. Or maybe you want to understand why one type of telescope may be

better than another type for observing what you are interested in. This is where you will want to scale the

image on screen based on your eyepiece.

Different eyepieces generally have a different apparent ﬁeld of view (aFOV). An easy way to think about

this is: the larger the aFOV, the bigger the picture you see in the eyepiece. Older types of eyepiece (some

types still built and in wide use today have been constructed in the 19th century) generally have their aFOV

in the

° range. Today, there are massive eyepieces available with

°, and recently even

100

° aFOV! These

eyepieces are huge, as they require a lot of very special glass to achieve their incredible ﬁelds of view. An

eyepiece of the same focal length with a

100

° aFOV will produce an image through the eyepiece that is twice

as wide as one produced by a 50° eyepiece.

Different telescopes, with an eyepiece of a given aFOV, will also produce a different true ﬁeld of view.

This is the actual size of the piece of sky that you see through the eyepiece. Getting these two “just right”

can be very important. It’s easy to assume that you want the biggest telescope you can get, with the eyepiece

that gives you the highest magniﬁcation. This is never true in reality. Depending on where you live, and

especially what you like to look at, a 100-120

quality refractor with a wide aFOV eyepiece may very

well be better than a large SCT with the same eyepiece. This is something I learned the hard way.

So how does scaling the eyepiece view help? The plugin will ﬁnd the eyepiece you have with the largest

aFOV. This aFOV becomes

100%

of the computer screen diameter. Then, any other eyepiece will have its

aFOV compared, and the view on screen will be scaled down accordingly. These

100

° aFOV eyepieces

makes the math here easy. If you have one, then when that eyepiece is used, the circle that represents the

view through the eyepiece will take up

100%

of the screen diameter. Next, if you select an eyepiece with an

https://www.televue.com/

218 Chapter 16. Stellarium at the Telescope

° aFOV, its view will be scaled to

82%

of the screen, and a

° aFOV eyepiece will be scaled to

62%

the screen.

Example in action

This is easier to understand in action, so let us look at an example that uses three eyepieces all with the same

focal length, so they all produce the same level of magniﬁcation (well, one has an 17.3

focal

length, but its magniﬁcation is nearly identical) and see how the view changes. These example all use a

Celestron C8 8" SCT telescope, and the target is the Great Orion Nebula.

We can see from the images in ﬁg. 16.17 that the target is all three images is the same size. The

100

image ﬁlls the screen, the

° is smaller, and the

° is smallest yet, ﬁlling

62%

of the computer screen.

Note that in each image, the ﬁeld of view that you see changes. The larger the aFOV, the more you can see

of the sky. So in this example, if you had an 8" telescope, you would want to use the 17

mm 100

° Ethos

eyepiece to see as much of the nebula as possible.

16.1 Oculars Plugin 219

Figure 16.17: Comparing apparent ﬁelds of view of (top) a 17

Tele Vue Ethos eyepiece with an

aFOV of

100

°. Magniﬁcation is

119.5×

. (center) a 17

Tele Vue Nagler eyepiece with an aFOV

°. Magniﬁcation is

119.5×

. (bottom) a 17.3

Tele Vue Delos eyepiece with an aFOV of

62°. Magniﬁcation is 117.5×.

220 Chapter 16. Stellarium at the Telescope

16.2 TelescopeControl Plugin

This plugin provides a simple control mechanism for motorized telescope mounts. The user selects an object

(i.e. by clicking on something – a planet, a star etc.) and presses the telescope go-to key, and the telescope

will be guided to the object.

Multiple telescopes may be controlled simultaneously.

WARNING

Stellarium cannot prevent your telescope from being pointed at the Sun. It is up to you to ensure proper

ﬁltering and safety measures are applied!

Never point your telescope at the Sun without a proper solar ﬁlter installed. The powerful light ampliﬁed

by the telescope WILL cause irreversible damage to your eyes and/or your equipment.

Even if you don’t do it deliberately, a slew during daylight hours may cause your telescope to point

at the sun on its way to the given destination, so it is strongly recommended to avoid using the telescope

control feature before sunset without appropriate protection.

16.2.1 Abilities and limita tions

This plug-in allows Stellarium to send ’slew’ (’go to’) commands to the device and to receive its current

position. There are some scopes which additionally support ’sync’ commands to be received in order to

update the internal pointing model of the mount. Some scopes also have the ability to abort a previous

slew command. However, users should always be aware of the possibility for mount collisions and similar

situations. You should always make sure that a slew does not cause parts of the telescope to collide with the

environment or mount itself.

Currently this plug-in does not allow satellite tracking unless the controlled telescope is an RTS2 system

(see section 16.2.6), and is not very suitable for lunar or planetary observations. Many mounts can be set to a

’lunar’ tracking speed, you may prefer this.

Some users are running Stellarium on little, low-power “Telescope computers” connected to their

powerful indoor PCs via RemoteDesktop or similar setups. Keep in mind that Stellarium is a graphics-heavy

program that may challenge the outdoor computer’s graphics subsystem or network. See framerate intent

settings on page 26 for optimizing your screen refresh rates. Better, run Stellarium on your indoor system

and use INDI or ASCOM network protocols.

16.2.2 Using this plug-in

Here are two general ways to control a device with this plug-in, depending on the situation:

DIRECT CONNECTION

A device supported by the plug-in is connected with a cable to the computer

running Stellarium

INDIRECT CONNECTION

local

A device is connected to the same computer but it is driven by a stand-alone telescope server

program or a third-party application that can ’talk’ to Stellarium;

remote

A device is connected to a remote computer and the software that drives it can ’talk’ to

Stellarium over the network; this software can be either one of Stellarium’s stand-alone telescope

servers, or a third party application.

Most older telescopes use cables that connect to a serial port (RS-232), the newer ones use USB (Universal

Serial Bus). On Linux and Max OS X, both cases are handled identically by the plug-in. On Windows,

a USB connection may require a ’virtual serial port’ software, if it is not supplied with the cable or the

telescope. Such a software creates a virtual (’fake’) COM port that corresponds to the real USB port so it can

be used by the plug-in. On all three platforms, if the computer has no ’classic’ serial ports and the telescope

can connect only to a serial port, a serial-to-USB (RS-232-to-USB) adapter may be necessary.

Telescope set-up (setting geographical coordinates, performing alignment, etc.) should be done before

connecting the telescope to Stellarium.

16.2.3 Main window (’Telescopes’)

The plug-in’s main window can be opened:

•

By pressing the

conﬁgure

button for the plug-in in the

Plugins

tab of Stellarium’s Conﬁguration

window (opened by pressing

or the

button in the left toolbar).

•

By pressing the

Conﬁgure telescopes...

button in the

Slew to

window (opened by pressing

Ctrl

or the respective button on the bottom toolbar).

The

Telescopes

tab displays a list of the telescope connections that have been set up:

16.2 TelescopeControl Plugin 221

•

The number (#) column shows the number used to control this telescope. For example, for slewing

telescope #2, the shortcut is

Ctrl

•

The Status column indicates if this connection is currently active or not. Unfortunately, there are some

cases in which ’Connected’ is displayed when no working connection exists.

•

The Type ﬁeld indicates what kind of connection this is:

virtual means a virtual telescope (test mode).

local, Stellarium means a DIRECT connection to the telescope (see above).

local, external means an INDIRECT connection to a program running on the same computer.

local, ASCOM

means an INDIRECT connection to a ASCOM driver running on the same computer.

remote, unknown means an INDIRECT connection over a network to a remote machine.

remote, RTS2 means an INDIRECT connection over a network to an RTS2 server.

remote, INDI means an INDIRECT connection over a network to an INDI server.

To set up a new telescope connection, press the

Add

button. To modify the conﬁguration of an existing

connection, select it in the list and press the

Conﬁgure

button. In both cases, a telescope connection

conﬁguration window will open.

16.2.4 Telescope conﬁguration window

Connection type

The topmost ﬁeld represents the choice between the types of connections (see section 16.2.2): Telescope

controlled by:

Stellarium, directly through a serial port is the DIRECT case

External software or a remote computer is an INDIRECT case

RTS2 Telescope is another INDIRECT case

INDI is another INDIRECT case

ASCOM is another INDIRECT case

Nothing, just simulate one (a moving reticle) is a virtual telescope (no connection)

Telescope properties

Name is the label that will be displayed on the screen next to the telescope reticle.

Connection delay

If the movement of the telescope reticle on the screen is uneven, you can try increasing

or decreasing this value.

Coordinate system

Some Celestron telescopes have had their ﬁrmware updated and now interpret the

coordinates they receive as coordinates that use the equinox of the date (EOD, also known as JNow),

making necessary this setting. With ASCOM telescopes it’s also possible to use this setting to override

the default device preference.

Start/connect at startup

Check this option if you want Stellarium to attempt to connect to the telescope

immediately after it starts. Otherwise, to start the telescope, you need to open the main window, select

that telescope and press the

Start/Connect

button.

Device settings

This section is active only for DIRECT connections (see above).

Serial port sets the serial port used by the telescope. A pop-up box suggests some default values:

•

On Windows, serial ports COM1 to COM10

•

On Linux, serial ports are labelled

/dev/ttyS0

/dev/ttyS3

and USB ports

/dev/ttyUSB0

/dev/ttyUSB3

. Make sure you have read/write access to the

tty

device. Depending on

your ﬂavour of Linux, this may e.g. require some group membership.

•

On Mac OS X, the list is empty as it names its ports in a peculiar way. If you are using a USB

cable, the default serial port of your telescope most probably is not in the list of suggestions. To

list all valid serial port names in Mac OS X, open a terminal and type:

ls / dev /*

This will list all devices, the full name of your serial port should be somewhere in the list (for

example, /dev/cu.usbserial-FTDFZVMK).

Device model : see 16.2.5 Supported devices.

Connection settings

Both ﬁelds here refer to INDIRECT connections, which implies communication over a network (TCP/IP).

Host

can be either a host name or an IPv4 address such as ’127.0.0.1’. The default value of ’localhost’

means ’this computer’.

222 Chapter 16. Stellarium at the Telescope

Modifying the default host name value makes sense only if you are attempting a remote connection

over a network. In this case, it should be the name or IP address of the computer that runs a program

that runs the telescope.

Port

refers to the TCP port used for communication. The default value depends on the telescope number

and ranges between 10001 and 10009.

RTS2 settings

(see also 16.2.6) You will need access to an RTS2 HTTPD server through HTTP/JSON calls. Please see

RTS2 documentation (man rts2-httpd) for details. You will as well need username and password for HTTPD.

Please be aware that in order to move the telescope, your user must have the telescope in the list of allowed

devices in the database. Please see man rts2-user for details on how to manipulate RTS2 users.

URL

points to RTS2 HTTPD. Can include anything a URL can have - port (:8889) and preﬁx path for RTS2

access.

Username username used for login to RTS2 HTTPD.

Password password for login to RTS2 HTTPD.

INDI settings

(see also 16.2.7) You will need access to an INDI server through a TCP/IP connection. Please see INDI

documentation for details. You will need to select the correct INDI device to manage it.

ASCOM settings

You can choose an ASCOM telescope driver installed in your system using the ASCOM chooser. Additionally

you can choose how Stellarium is determining the coordinate system used to communicate with the ASCOM

mount. For more information, please see 16.2.8.

User Interface Settings: Field of view indicators

A series of circles representing different ﬁelds of view can be added around the telescope marker. This is a

relic from the times before the Oculars plug-in (see 16.1) existed.

Activate the ’Use ﬁeld of view indicators’ option, then enter a list of values separated with commas in

the ﬁeld below. The values are interpreted as degrees of arc.

These marks can be used in combination with a virtual telescope to display a moving reticle with the

Telrad circles.

16.2.4.1 ’Slew telescope to’ window

The

Slew telescope to

window can be opened by pressing

Ctrl

or the respective button in the bottom

toolbar.

It contains two ﬁelds for entering celestial coordinates, selectors for the preferred format (Hours-Minutes-

Seconds, Degrees-Minutes-Seconds, or Decimal degrees), a drop-down list and two buttons.

The drop-down list contains the names of the currently connected devices. If no devices are connected,

it will remain empty, and the

Slew

button will be disabled.

Pressing the

Slew

button slews the selected device to the selected set of coordinates. See the section

about keyboard commands below for other ways of controlling the device.

Pressing the

Conﬁgure telescopes. . .

button opens the main window of the plug-in.

TIP: Inside the ’Slew’ window, underlined letters indicate that pressing

Alt

underlined letter

can be

used instead of clicking. For example, pressing

Alt

is equivalent to clicking the

Slew

button, pressing

Alt

switches to decimal degree format, etc.

16.2.4.2 Sending commands

Once a telescope is successfully started/connected, Stellarium displays a telescope reticle labelled with the

telescope’s name on its current position in the sky. The reticle is an object like every other in Stellarium - it

can be selected with the mouse, it can be tracked and it appears as an object in the ’Search’ window.

To point a device to an object: Select an object (e.g. a star) and press the number of the device while

holding down the

Ctrl

key. (For example,

Ctrl

for telescope #1.) This will move the telescope to

the selected object. Note that most telescopes can only execute a single command to move to that object’s

position, but if the telescope is an RTS2 telescope, you can even track a satellite (if the mount then is fast

enough to support it).

To point a device to the center of the view: Press the number of the device while holding down the Alt

key. (For example,

Alt

for telescope #1.) This will slew the device to the point in the center of the

Actually, the TLE orbital elements of the selected satellite are transmitted to RTS2, which does then compute the

satellite position itself.

16.2 TelescopeControl Plugin 223

current view. (If you move the view after issuing the command, the target won’t change unless you issue

another command.)

To point a device to a given set of coordinates: Use the

Slew to

window (press

Ctrl

16.2.5 Supported devices

16.2.5.1 Directly connected telescopes

All devices listed in the ’Device model’ list are convenience deﬁnitions using one of the two built-in

interfaces: the Meade LX200 (the Meade Autostar controller) interface and the Celestron NexStar interface.

The device list contains the following:

Celestron NexStar (compatible) Any device using the NexStar interface.

Losmandy G-11

A computerized telescope mount made by Losmandy (Meade LX-200/Autostar interface).

Meade Autostar compatible Any device using the LX-200/Autostar interface.

Meade ETX-70 (#494 Autostar, #506 CCS)

The Meade ETX-70 telescope with the #494 Autostar con-

troller and the #506 Connector Cable Set. According to the tester, it is a bit slow, so its default setting

of ’Connection delay’ is 1.5 seconds instead of 0.5 seconds.

Meade LX200 (compatible) Any device using the LX-200/Autostar interface.

Sky-Watcher SynScan AZ mount

The Sky-Watcher SynScan AZ GoTo mount is used in a number of

telescopes.

Sky-Watcher SynScan (version 3 or later)

SynScan is also the name of the hand controller used in other

Sky-Watcher GoTo mounts, and it seems that any mount that uses a SynScan controller version 3.0 or

greater is supported by the plug-in, as it uses the NexStar protocol.

Wildcard Innovations Argo Navis (Meade mode)

Argo Navis is a ’Digital Telescope Computer’ by Wild-

card Innovations. It is an advanced digital setting circle that turns an ordinary telescope (for example,

a dobsonian) into a ’Push To” telescope (a telescope that uses a computer to ﬁnd targets and human

power to move the telescope itself). Just don’t forget to set it to Meade compatibility mode and set the

baud rate to 9600B1.

16.2.5.2 RTS2 telescopes

Setting up a robotic telescope and dome control system with RTS2 is beyond the scope of this handbook, but

see section 16.2.6 for a few notes to be able to connect and command the telescope with Stellarium. Please

refer to the RTS2 Web pages

for further details.

Please be aware that some RTS2 usernames might have only read-only access. If this is case for your

username, the telescope marker will be painted red (or

color_telescope_readonly

from Stellarium’s

settings ﬁle).

16.2.5.3 INDI telescopes

Setting up a robotic telescope and dome control system with INDI is beyond the scope of this handbook, but

see section 16.2.7 for a few notes to be able to connect and command the telescope with Stellarium. Please

refer to the INDI web pages

for further details.

16.2.5.4 ASCOM telescopes

ASCOM speciﬁc settings can be conﬁgured when a ASCOM telescope was selected. Please see section 16.2.8

for further information about conﬁguration possibilities.

16.2.5.5 Virtual telescope

If you want to test this plug-in without an actual device connected to the computer, choose “Nothing, just

simulate one (a moving reticle)” in the

Telescope controlled by:

ﬁeld. It will show a telescope reticle that

will react in the same way as the reticle of a real telescope controlled by the plug-in. See the section above

about ﬁeld of view indicators for a possible practical application (emulating ’Telrad’ circles).

16.2.6 RTS2

RTS2, the Remote Telescope System 2, is a complete robotic observatory control system for Linux by Petr

Kubánek, who kindly provided the plugin code to make RTS2 interoperate with Stellarium. We cannot give a

full manual or any further support for RTS2 here, please refer to its website

for complete instructions about

dome control, cameras, ﬁlter wheels, weather sensors, etc. A few notes may be useful for beginners, though.

RTS2’s central piece is a daemon. Start the system:

https://rts2.org/

https://indilib.org

https://rts2.org

224 Chapter 16. Stellarium at the Telescope

sudo service rts2 start

RTS2’s main control screen is text-based, rts2-mon. For a quick check, switch on the system using

Telescope

is a dummy telescope which you can select and operate with commands like

move 120 35

(this moves to RA=120°=8h, DEC=35°, but only when this position is above your horizon).

Stellarium’s Telescope plugin can communicate with RTS2 using the RTS2 web interface. You must

run rts2-httpd for this, which may require the right permissions to write the lock ﬁles in

/var/run

. This

program requires that a database has been created as described in the ﬁle

RUN

in RTS2’s source directory and

on the RTS2 website

. Also, you must create a ’user’ for RTS2. This is not a regular Linux account, but an

entry in the RTS2 database. Create a user with rts2-user -a <user>. You should use a password different

from your regular Linux password, as this will be transmitted in plain text between the computer running

Stellarium and the RTS2 control computer, and may also be written into Stellarium’s logﬁle. Then you can

enable device control for the respective user. If you want to send slew commands from Stellarium, make

sure to allow access to telescope

. If not, Stellarium will be able to show the telescope marker, but you

will not be able to control the telescope. To enable control for existing users in the default stars database,

psql stars

update users set all owed_de vices = ’* ’;

In case you cannot properly connect to the RTS2 telescope or cannot send slew commands, check

Stellarium’s logﬁle log.txt for some diagnostic messages.

RTS2 is the only type of telescope supported by Stellarium which can autonomously track satellites.

Tracking accuracy fully depends on Stellarium’s TLE satellite elements being up-to-date (see section 14.8)

and the accuracy of your RTS2 installation.

16.2.7 INDI

INDI, the Instrument Neutral Distributed Interface, is a distributed control system (DCS) protocol to enable

control, data acquisition and exchange among hardware devices and software front ends, emphasizing

astronomical instrumentation

INDI client (v1.6.0) has been incorporated into Stellarium’s Telescope Control plugin by Alessandro

Siniscalchi to allow Stellarium to communicate with INDI hardware drivers via INDI server. INDI server is

a hub that sits between drivers and clients. It reroutes trafﬁc for control and data across distributed networks.

Each device or client in the network is a node and may communicate with other nodes whenever desired.

The server supports broadcasting, chaining, and marshalling of data.

Stellarium only supports INDI mounts (no other INDI devices), and you will need to select the correct

INDI device to manage it at the stage of conﬁguration of telescope. For this purpose the plug-in has a tool

to getting the list of connected devices from the INDI server (when the server is working!). Please deﬁne

hostname and port

in the “INDI Settings” block, press

Refresh devices

and select the required device in

the list “Devices”.

List of telescope types supported by INDI

•

Meade Autostar

•

Meade LX200 (Classic/GPS/16)

•

Celestron NexStar

•

Celestron NexStar Evolution

•

Orion Synscan Telescope

•

EQ-6 MCU Update

•

HEQ-5 MCU Update

•

LittleFoot Vpower

•

LittleFoot Elegance Photo

•

Astro-Electronic FS-2

•

EQMod

•

Pulsar2

•

SkySensor2000PC

https://rts2.org/faq.html

https://en.wikipedia.org/wiki/Instrument_Neutral_Distributed_Interface

The Internet Assigned Numbers Authority (IANA) has assigned to INDI the Transmission Control Protocol and

User Datagram Protocol (TCP/UDP) port 7624.

https://indilib.org/devices/telescopes/all.html

16.2 TelescopeControl Plugin 225

•

Takahashi Temma

•

10 Micron

•

Losmandy Gemini

•

Astrophysics

•

Skywatcher Virtuoso (Alt/Az)

•

IOptron IEQPro/CEM60

•

IOptron ZEQ25/SmartEQ

•

IOptron GotoNova Upgrade Kit 8400

16.2.8 ASCOM 7 (Windows only)

ASCOM is probably the most widely used way how to communicate with telescopes, mounts and other

astronomy equipment on Microsoft Windows operating systems. The ASCOM platform aims to decouple

device dependent speciﬁcs by introducing a common standard for communication between device drivers

and applications. Almost every telescope mount comes with an ASCOM driver and most of the astronomy

software and tools can communicate with ASCOM compatible devices.

The ASCOM telescope support has been added to Stellarium’s Telescope Control plugin by Gion Kunz

in version 0.19.3.

Note that in order for Stellarium to communicate with your ASCOM compatible mount, you will need to

have the ASCOM platform installed on your Windows machine (version 7 or higher

). Also, the ASCOM

driver of your telescope mount needs to be installed before you can start using the telescope in Stellarium.

Important: Most modern ASCOM drivers are written to run in 32bit and 64bit mode (any) and therefore

are compatible with the 64bit and 32bit version of Stellarium. However, if you happen to have a 32bit or

64bit only driver for your telescope mount, you will also need to install the respective Stellarium version.

In order to use your ASCOM telescope you need to select the correct device in the ASCOM chooser by

clicking the button

Choose ASCOM telescope

. The selected device is shown below that button.

By default, Stellarium is trying to ask the ASCOM driver in order to determine if JNow or J2000

coordinates should be used for communicating with the mount. If you’d like to override this behavior and

tell the ASCOM telescope to communicate in the coordinate system conﬁgured in the section Telescope

properties, you can switch the radio button

Let ASCOM device decide

Use Stellarium settings

in the

ASCOM settings of the Conﬁgure Telescope dialog.

16.2.9 StellariumScope

StellariumScope is a free add-on that enables you to control your ASCOM enabled telescope with Stellarium.

Note that Stellarium supports ASCOM telescopes natively since version 0.19.3. There’s no need to use

StellariumScope in order to use your ASCOM telescopes with Stellarium anymore. We are encouraging our

users to use the native ASCOM option unless they need particular features of StellariumScope.

The original StellariumScope program was designed and implemented by Scott of ByteArts but is no

longer available. It is now maintained by and available for download from Welsh Dragon Computing

Features

•

Provides an interface between Stellarium and ASCOM telescope drivers.

•

Provides the ability to both “Sync” and “Slew” the telescope. It’s also possible to issue a stop/cancel

command from Stellarium.

•

You can easily host Stellarium on one computer linked to another control computer that hosts the

telescope driver.

•

The installation program will automatically install the documentation, but the link to the documentation

is provided by the developer

so you can read it before installation.

Use this application (like all software that controls your mount) with supervision of your mount’s

movements.

Unfortunately ASCOM version 6 seems to be incompatible with Qt6. After numerous error reports we had to

disable ASCOM support on Qt6-based builds of version 24.3-24.4. However, preliminary tests showed that ASCOM 7

may work again, so this way of connection is back. Without proper instruments, the maintainers depend on your feedback,

though. If you depend on ASCOM support, please update to ASCOM version 7, or use a Qt5-based build of the same

version.

https://ascom-standards.org/Downloads/Index.htm

https://welshdragoncomputing.ca/x/index.php/home/stellariumscope/about-stellariumscope

StellariumScope User’s Guide —

https://welshdragoncomputing.ca/x/st/misc/stellariumscope_

user_guide.2016.03.05.pdf

226 Chapter 16. Stellarium at the Telescope

16.2.10 Other telescope servers and Stellarium

Other developers have also been busy creating hard- and software often involving Arduino or Raspberry

Pi boards which can control GOTO or PUSHTO (manually driven but position-aware, usually Dobsonian)

telescopes and are ultimately controlled from Stellarium. Those are not related nor authored by the Stel-

larium team, so while we welcome such development (esp. open-sourced) in general, we cannot provide

documentation nor any support.

A few examples:

iTelescope http://simonbox.info/index.php/astronomy/93-raspberry-pi-itelescope

node-telescope-server https://www.npmjs.com/package/node-telescope-server

OnStep https://groups.io/g/onstep

One anonymous user sent a troubleshooting solution when connecting Stellarium to the Celestron

NexRemote software:

One tricky Window XP issue I ﬁxed was that my older laptop would transiently lose connection

with Stellarium although the status would still be “Connected” and all looked normal. [. . . ]

I boosted the NexRemote.exe process in Windows XP to High under Set Priority under the

Windows Task Manager via

Ctrl

Alt

Del

All slews now proceed normally. Problem went away.

16.2.10.1 Stellarium Telescope Protocol

In the early days of Stellarium, telescope control required standalone server programs. These were later

integrated in the plugin. However, there are situations where external control servers are still useful, e.g.

when they are running on some tiny telescope computer while the user sits in the warm control room in front

of the powerful PC running Stellarium. For you DIYers out there, ﬁgure 16.18 shows the original protocol.

https://sourceforge.net/p/stellarium/discussion/278769/thread/16e4c054/?limit=25#8ffa

16.2 TelescopeControl Plugin 227

Author and Copyright of this file and of the stellarium telescope library:

Johannes Gajdosik, 2006

Stellarium Telescope Protocol version 1.0

The Stellarium Telescope Protocol works on top of TCP/IP.

The client is the stellarium program (or any similar program),

the server is called "telescope server" and controls the telescope.

Depending on the implementation the server may handle one or many

simultaneous clients. The reference server implementation accepts

an unlimited number of simultaneous clients.

The protocol is message based: both server and client may

spontaneousely send messages as often as they want.

When the server looses control of the telescope he should

actively close the connection to all clients.

The first two bytes of any message describes the total

length of that message in bytes (including the first 2 bytes).

The next 2 bytes of any message describe the type of this message.

The byte order for all kind of integers is always

"least significiant byte first".

-----------------------

server->client:

MessageCurrentPosition (type = 0):

LENGTH (2 bytes,integer): length of the message

TYPE (2 bytes,integer): 0

TIME (8 bytes,integer): current time on the server computer in microseconds

since 1970.01.01 UT. Currently unused.

RA (4 bytes,unsigned integer): right ascension of the telescope (J2000)

a value of 0x100000000 = 0x0 means 24h=0h,

a value of 0x80000000 means 12h

DEC (4 bytes,signed integer): declination of the telescope (J2000)

a value of -0x40000000 means -90degrees,

a value of 0x0 means 0degrees,

a value of 0x40000000 means 90degrees

STATUS (4 bytes,signed integer): status of the telescope, currently unused.

status=0 means ok, status<0 means some error

---------------------

client->server:

MessageGoto (type =0)

LENGTH (2 bytes,integer): length of the message

TYPE (2 bytes,integer): 0

TIME (8 bytes,integer): current time on the client computer in microseconds

since 1970.01.01 UT. Currently unused.

RA (4 bytes,unsigned integer): right ascension of the telescope (J2000)

a value of 0x100000000 = 0x0 means 24h=0h,

a value of 0x80000000 means 12h

DEC (4 bytes,signed integer): declination of the telescope (J2000)

a value of -0x40000000 means -90degrees,

a value of 0x0 means 0degrees,

a value of 0x40000000 means 90degrees

Figure 16.18: The Stellarium Telescope Protocol, version 1.0

228 Chapter 16. Stellarium at the Telescope

16.3 Observability Plugin

This Plugin is activated with the button . It analyzes the observability of the selected object (or the

screen center, if no object is selected). The plugin can show the best epoch of the year (i.e., largest angular

separation from the Sun), the date range when the source is above the horizon at dark night, and the dates of

Acronychal and Cosmical rise/set. Ephemerides of the Solar-System objects and parallax effects are taken

into account.

Explanation of some parameters

Sun altitude at twilight

Any celestial object will be considered visible when the Sun is below this altitude.

The altitude at astronomical twilight ranges usually between -12 and -18 degrees. This parameter is

only used for the estimate of the range of observable epochs (see below).

Horizon altitude Minimum observable altitude (due to obstructions or just a limited telescope mount).

Acronychal/Cosmical/Heliacal rise/set

The days of Cosmical rise/set of an object are estimated as the

days when the object rises (or sets) together with the rise/set of the Sun. The exact dates of these

events depend on the Observer’s location. In contrast, the Acronychal rise (or set) happens when the

star rises/sets with the setting/rising of the Sun (i.e., opposite to the Sun). It is obvious that the source

is hardly observable (or not observable at all) in the dates between Cosmical set and Cosmical rise.

On the other hand, the dates around the Acronychal set and rise are those when the altitude of the

celestial object uses to be high when the Sun is well below the horizon (hence the object can be well

observed). The date of Heliacal rise is the ﬁrst day of the year when a star becomes visible. It happens

when the star is close to the eastern horizon roughly before the end of the astronomical night (i.e., at

the astronomical twilight). In the following nights, the star will be visible during longer periods of

time, until it reaches its Heliacal set (i.e., the last night of the year when the star is still visible). At the

Heliacal set, the star sets roughly after the beginning of the astronomical night.

Largest Sun separation

Happens when the angular separation between the Sun and the celestial object

are maximum. In most cases, this is equivalent to say that the Equatorial longitudes of the Sun and

the object differ by 180 degrees, so the Sun is in opposition to the object. When an object is at its

maximum possible angular separation from the Sun (no matter if it is a planet or a star), it culminates

roughly at midnight, and on the darkest possible area of the Sky at that declination. Hence, that is the

’best’ night to observe a particular object.

Nights with source above horizon

The program computes the range of dates when the celestial object is

above the horizon at least during one moment of the night. By ’night’, the program considers the time

span when the Sun altitude is below that of the twilight (which can be set by the user; see above).

When the objects are ﬁxed on the sky (or are exterior planets), the range of observable epochs for the

current year can have two possible forms: either a range from one date to another (e.g., 20 Jan to 15

Sep) or in two steps (from 1 Jan to a given date and from another date to 31 Dec). In the ﬁrst case, the

ﬁrst date (20 Jan in our example) shall be close to the so-called ’Heliacal rise of a star’ and the second

date (15 Sep in our example) shall be close to the ’Heliacal set’. In the second case (e.g., a range in

the form 1 Jan to 20 May and 21 Sep to 31 Dec), the ﬁrst date (20 May in our example) would be

close to the Heliacal set and the second one (21 Sep in our example) to the Heliacal rise. More exact

equations to estimate the Heliacal rise/set of stars and planets (which will not depend on the mere

input of a twilight Sun elevation by the user) will be implemented in future versions of this plugin.

Full Moon

When the Moon is selected, the program can compute the exact closest dates of the Moon’s

opposition to the Sun.

Note on Terminology

The (sparse) literature on terminology about computing these Heliacal, Acronychal or Cosmic events seems

to disagree on which end of the night is to be computed. While all agree about Heliacal rises taking place in

the morning, Acronychal and Cosmic are sometimes applied in reverse order from those described here. In

case you use these data, make sure you keep this deﬁnition as well.

Author

This plugin has been contributed by Ivan Marti-Vidal (Onsala Space Observatory)

with some advice by

Alexander Wolf and Georg Zotti.

mailto:i.martividal@gmail.com

16.4 Mosaic Camera Plugin 229

Figure 16.19: The Mosaic Camera plugin in action. Overlays of LSSTCam(left), DECam (center),

and HyperSuprimeCam (right) are shown, as well as the conﬁguration dialog for the plugin (top

right).

16.4 Mosaic Camera Plugin

JOSH MEYERS

16.4.1 Introduction

This plugin overlays an outline of one or more mosaic cameras, i.e., cameras with multiple sensors, onto the

Stellarium celestial sphere. With this functionality, one may compare the ﬁelds of view of different cameras,

including potentially one’s own astrophotography setup. Combined with the scripting and remote control

features of Stellarium, various visualizations are possible, including real-time tracking of the observations of

telescopes, playback of past observations, or public outreach demonstrations of the capabilities of various

instruments.

16.4.2 Usage

From the “Cameras” tab of the Mosaic Camera conﬁguration window, you can select from the available

cameras, setting their RA, Dec, rotation, and visibility as desired.

16.4.3 Cameras

Multiple cameras can be individually conﬁgured and displayed.

16.4.3.1 Default Cameras

A few cameras come pre-packaged with Stellarium. These are:

mailto:jmeyers314@gmail.com

230 Chapter 16. Stellarium at the Telescope

LSSTCam

The largest (as of 2025) digital camera ever assembled at 3.2 gigapixels. Now mounted on the Simonyi

Survey Telescope at the Vera C. Rubin Observatory, this camera will be used to execute the Legacy Survey

of Space and Time, creating a 10-year multicolor ‘movie’ of the southern sky.

Note that the individual CCDs within this camera’s overlay are color-coded by their functionality: Two

shades of blue indicate the main science sensors. (LSSTCam features a hybrid focal plane. Light blue

corresponds to sensors made by Imaging Technology Laboratory, while dark blue corresponds to sensors

made by Imaging Teledyne e2v.) The white sensors in the middle show the ﬁeld-of-view of the Rubin

Commissioning Camera, a smaller camera used to commission the telescope mount and mirrors before the

main LSSTCam camera was ready. The red sensors in the corners are wavefront sensors, used to monitor

and correct the telescope’s optical alignment in real time. The green sensors are the guider sensors, used to

inform the telescope’s tracking system. See more at

https://rubinobservatory.org/explore/how-r

ubin-works/technology/camera.

HyperSuprimeCam (HSC)

A 900 megapixel camera mounted on the Subaru telescope at the Mauna Kea Observatory. See more at

https://www.naoj.org/Projects/HSC/.

Dark Energy Camera (DECam)

A 570 megapixel camera mounted on the Blanco telescope at the Cerro Tololo Inter-American Observatory.

See more at https://www.darkenergysurvey.org/the-des-project/instrument/.

MegaPrime

A 378 megapixel camera mounted on the Canada-France-Hawaii Telescope at Mauna Kea Observatory. See

more at https://www.cfht.hawaii.edu/Instruments/Imaging/MegaPrime/.

LATISS

The LSST Atmospheric Transmission Imager and Slitless Spectrograph. A 16 megapixel camera mounted

on the Rubin Observatory Auxiliary telescope. See more at

https://rubinobservatory.org/explore

/how-rubin-works/technology/auxtel.

JWST

The James Webb Space Telescope’s focal plane. See more at

https://jwst-docs.stsci.edu/jwst-o

bservatory-hardware/jwst-telescope/jwst-focal-plane#gsc.tab=0.

HST

The Hubble Space Telescope’s focal plane. See more at

https://hst-docs.stsci.edu/acsihb/chapt

er-3-acs-capabilities-design-and-operations/3-1-acs-location-in-the-hst-focal-p

lane.

Roman

The Nancy Grace Roman Space Telescope’s focal plane. See more at

https://roman.gsfc.nasa.gov/

science/WFI_technical.html.

Euclid

The Euclid Space Telescope’s focal plane. See more at

https://www.euclid-ec.org/public/missi

on/vis/.

16.4.3.2 Adding a Camera

When the Mosaic Camera plugin is ﬁrst enabled, it checks the user data directory for the existence of a

directory

<USERDATA>/modules/MosaicCamera/

. If this directory does not exist, it will be created and

populated with JSON ﬁles for each of the default cameras, and one JSON ﬁle

camera_order.json

which

speciﬁes the order in which the cameras are displayed.

To add a new camera, create a new JSON ﬁle inside this directory, and add a reference to it in the

camera_order.json ﬁle.

Camera sensors are speciﬁed via their corners, which are assumed to form spherical polygons. The

corners should be speciﬁed as gnomonic projections from the sphere to a tangent plane in radians. Multiple

groups of sensors can compose the same camera. For example, LSSTCam has separate sensor groups for

wavefront sensors, guider sensors, and each of two types of science sensors.

Each camera is deﬁned via a JSON ﬁle with the structure:

[

{

" camera_name ": " t e l e scope / camera full name " ,

" ca m e r a _ d e sc r ip t io n ": " t elescope / cam era description in HTML "

} ,

16.4 Mosaic Camera Plugin 231

{

" name " : " name - of - group -1 " ,

" cor n ers " : [

[

[ cor ner 1_x , c orner 1 _y ] ,

[ cor ner 2_x , c orner 2 _y ] ,

...

] , # senso r 1

[

...

] , # senso r 2

...

]

" co lor ": {

" va lue ": [R , G , B, alpha ]

}

} ,

{

" name " : " name - of - group -2 " ,

...

} ,

...

]

See the default camera JSON ﬁles for examples.

To reset the plugin to its default state, simply delete the

<USERDATA>/modules/MosaicCamera/

directory.

16.4.4 Control

There are several ways to control the Mosaic Camera plugin.

16.4.4.1 Mosaic Camera Settings Dialog

The Mosaic Camera settings dialog can be opened by right-clicking the MosaicCamera icon, or by selecting

“conﬁgure” from the Plugins tab of the main Stellarium Conﬁguration window. This dialog allows you to

conﬁgure the cameras, as well as the visibility of the overlays.

16.4.4.2 Keyboard Shortcuts

Keyboard shortcuts (see section 4.8) can be conﬁgured to perform the following actions:

•

Cycle the active camera forward or backward

•

Increase or decrease the rotation angle of the current camera by 5 degrees.

•

Set the pointing of the current camera to the current Stellarium view.

•

Toggle the visibility of Mosaic Camera overlays.

•

Toggle the Mosaic Camera settings dialog.

16.4.4.3 Stellarium Scripting

The Mosaic Camera plugin can be controlled via Stellarium’s scripting interface. In the following example,

we set the LSSTCam overlay to be centered at RA=3.0, Dec=4.0 (in J2000 degrees), with a rotation of 1.0

degrees.

MosaicCamera.setCurrentCamera("LSSTCam ")

MosaicCamera.setCurrentRA(3.0)

MosaicCamera.setCurrentDec(4.0)

MosaicCamera.setCurrentRotation(1.0)

an equivalent script is:

MosaicCamera.setRA("LSSTCam ", 3.0)

MosaicCamera.setDec("LSSTCam ", 4.0)

MosaicCamera.setRotation("LSSTCam ", 1.0)

or even:

MosaicCamera.setPosition("LSSTCam ", 3.0, 4.0, 1.0)

16.4.4.4 Stellarium Remote Control

The Mosaic Camera plugin is also accessible via Stellarium’s remote control interface (see 13.5). Here’s a

short python script equivalent to the above example:

232 Chapter 16. Stellarium at the Telescope

import requests

port = 8090 # Default Stellarium port

url = f"http :// localhost :{ port }/api/stelproperty/set"

for name, val in [

["MosaicCamera.currentCamera", " LSSTCam "],

["MosaicCamera.ra", 3.0],

["MosaicCamera.dec", 4.0],

["MosaicCamera.rotation ", 1.0]

requests.post(url, data={"id": name, "value ": val})

17. Scripting

A. WOLF, G. ZOTTI, WITH ADDITIONS BY WOLFGANG LAUN

17.1 Introduction

The scripting facility is Stellarium’s version of a Presentation, a feature that may be used to run an

astronomical or other show for instruction or entertainment from within the Stellarium program. The use of

scripts was recognized as a perfect way of arranging a presentation of a sequence of astronomical events

from the earliest versions of Stellarium.

The original Stratoscript was quite limited in what it could do, and so a new Stellarium Scripting System

has been developed.

Since version 0.10.1, Stellarium has included a scripting feature based on the Qt5 Scripting Engine

This made it possible to write small programs within Stellarium to produce automatic presentations, set up

custom conﬁgurations, and to automate repetitive tasks. By version 0.14.0 the new scripting engine had

reached a level where it had all required features for usage, and support of scripts for the old Stratoscript

engine has been discontinued.

The programming language ECMAScript

(also known as JavaScript) gives users access to all basic

ECMAScript language features such as ﬂow control, variables, string manipulation and so on. Its integration

with Qt’s QtScript module and the way Stellarium’s main components (“StelModule”s) have been designed

to work means that all module functions which are labeled as “slots” can be called from JavaScript.

Interaction with Stellarium-speciﬁc features is done via a collection of objects which represent compo-

nents of Stellarium itself. The various modules of Stellarium, and also activated plugins, can be called in

scripts to calculate, move the scene, switch on and off display of objects, etc. You can write text output into

text ﬁles with the output() command. You can call all public slots which are documented in the scripting

API documentation

With the adaptation to Qt6 in versions 1.0 and later we had to switch to yet another scripting engine in

2022. Qt6 comes with QJSEngine

, another JavaScript engine which behaves mostly similar to the older

QtScript. However, small differences exist, so that care must be taken if scripts should be developed for

both series of Stellarium. Some older scripts will not work on versions 1.0 and later or at least require some

adaptations described in section 17.5.

https://doc.qt.io/qt-5/qtscript-index.html

https://en.wikipedia.org/wiki/ECMAScript

https://www.stellarium.org/doc/25.0/scripting.html

https://doc.qt.io/qt-6/qtjavascript.html

234 Chapter 17. Scripting

17.2 The Script Console

It is possible to load, edit, run and save scripts using the script console window. To toggle the script console,

press

F12

17.2.1 The Tabs in the Console

The three tabs “Script”, “Log” and “Output” each provide a text ﬁeld. In the “Script” text ﬁeld you can edit a

script, which can be loaded from and saved to a ﬁle, and executed. The “Log” text ﬁeld receives all errors

and other messages resulting from the script’s execution; the “Output” text ﬁeld will show the results of

core.output() function calls.

The fourth tab, “Settings”, provides some conﬁguration options.

17.2.2 The Menu Bar

The menu bar contains buttons for loading and saving a script. A ﬁle dialog is shown for selecting the ﬁle.

The “clear” button lets you clear the contents of the text ﬁeld in the currently selected tab. The drop-down

menu “Execute:” offers a selection of menu entries, mainly intended to let you restore the sky to a clean

state. The entry “selected text as script” executes selected text in the “Script” text ﬁeld, allowing to test

scripts during development. Entries “remove screen text”, “remove screen images” and “remove screen

markers” remove labels, images and markers, respectively, that may have been left over on the screen from

previous script actions. Each of the “clear map” entries results in a call to

core.clear()

, using one of the

arguments “natural”, “starchart”, “deepspace”, “galactic” or “supergalactic”. These calls reset Stellarium’s

state, resulting in a basic state of the display and providing a clean starting point for another run of your

script.

The button SSC runs the Stellarium Script Preprocessor with the script in the text ﬁeld as input and

produces an output by recursively inserting all included scripts into the text. This output replaces the contents

of the Script text ﬁeld. Store the original script if you need it!

17.2.3 German Keyboards

There is a glitch in the keyboard module of the underlying system that is responsible for keyboard handling.

It affects users of Windows and Linux systems with a German, and probably also other international

keyboards: The key combinations

AltGr

and

AltGr

cannot be used for typing

[

and

]

. You need

to work around by copy-pasting these two characters. You can also try to use a command line argument like

-platform windows:altgr.

17.3 Includes

Stellarium provides a mechanism for splitting scripts into different ﬁles. Typical functions or lists of variables

or celestial objects can be stored in separate

.inc

ﬁles and used within other scripts through the include()

command:

include("common_objects .inc");

17.4 Minimal Scripts

This script prints “Hello Universe” in the Script Console log window and into log.txt:

core.debug("Hello Universe");

This script prints “Hello Universe” in the Script Console output window and into the ﬁle

output.txt

which

you will also ﬁnd in the user data directory. The absolute path to the ﬁle will also be given in log.txt.

core.output("Hello Universe");

The ﬁle

output.txt

will be rewritten on each run of Stellarium. In case you need to save a copy of the

current output ﬁle to another ﬁle, call

core.saveOutputAs("myImportantData .txt");

core.resetOutput();

This script uses the LabelMgr module to display “Hello Universe” in red, fontsize 20, on the screen for 3

seconds.

17.5 Critical Scripting Differences introduced with version 1.0 235

var label=LabelMgr.labelScreen("Hello Universe", 200, 200,

true, 20, "#ff0000 ");

core.wait(3);

LabelMgr.deleteLabel(label);

17.5 Critical Scripting Differences introduced with version 1.0

Qt5’s QtScript module which has been used in versions 0.10 to 0.22 was more ﬂexible and easier to ﬁne-tune

than Qt6’s QJSEngine, which is used in the Qt6-based 1.* series of the program, i.e., versions 1.0 (22.3) and

later. Still, most scripts that have been developed for Stellarium versions 0.10 to 0.22 still run without or

with just minor modiﬁcations as described in this section.

17.5.1 Pause/Resume

The Qt6-based builds (version 1.0 and later) do not offer a way to pause and resume a script as was available

in the Qt5-based builds (0.10 to 0.22).

17.5.2 The Vec3f problem

One of the most important little helper classes in the main program are three-dimensional vectors.

Vec3f

describe those with single-precision ﬂoating point data, and

Vec3d

are those with double-precision ﬂoating

point data.

As late as in version 0.19 we added

Vec3f

and later

Vec3d

data types to the Javascript environment.

These allowed addressing variables of C++ classes

Vec3f

Vec3d

with named sub-ﬁelds

(if used to

describe colors), or

(same data but contextually understood as 3D data). These functions may have

pleased the JavaScript connoisseur when running scripts with Qt5-based builds of Stellarium (series 0.*, and

now usually found on 32-bit and older systems), but we recommend to abstain from their use in new scripts.

Qt6’s scripting module cannot be extended that easily. The

Vec3d

and

Vec3f

data types are not directly

scriptable, but we can deal with method arguments of these types when they are mentioned in the API

documentation (see 17.1). To access internals of these classes, we must use wrapper classes which bear

different names:

V3d can be used where Vec3d must be accessed.

V3f can be used where Vec3f must be accessed.

Color can be used where a Vec3f must be accessed which represents a color value.

They behave slightly different when run using Qt5 or Qt6, as shown in Table 17.1. If you aim for

maximum compatibility between versions, only use the calls which provide equal results in both series. This

current state is far from optimal or even pretty, but a pragmatic solution that works. We invite advanced

developers to ﬁnd a better solution that works with both Qt5 and Qt6.

17.6 Example: Retrograde motion of Mars

A good way begin writing of scripts: set yourself a speciﬁc goal and try to achieve it with the help of few

simple steps. Any complex script can be split into simple parts or tasks, which may solve any newbie

problems in scripting.

Let me explain it with examples.

Imagine that you have set a goal to make a demonstration of a very beautiful, but longish phenomenon —

the retrograde motion of the planet Mars (Fig. 17.1).

17.6.1 Script header

Any “complex” script should contain a few lines in the ﬁrst part of the ﬁle, which contains important data for

humans — the name of the script and its description — and some rules for Stellarium. You can even assign

default shortcuts in the script header, but make sure you assign a key not used elsewhere! The shortcuts are

read during startup from all scripts in the

scripts

sub-directories of both program and user data directories

(see section 5.2). The description may cover several lines (until the end of the commented header) and should

therefore be the last entry of the header.

// Name: Retrograde motion of Mars

// Author: John Doe

// License: Public Domain

236 Chapter 17. Scripting

Input Result with Qt5 Result with Qt6

x var f1=new V3d(.1,.2,.3);

core.output(f1); [0.1, 0.2, 0.3] V3d(0x249a1cf37c0) [some address]

core.output(+f1.toString()); [0.1, 0.2, 0.3] V3d(0x249a1cf37c0) [some address]

x core.output(f1.toHex()); #19334c #19334c

x core.output(f1.toVec3d()); [0.1, 0.2, 0.3] [0.1, 0.2, 0.3]

x var f2=new V3d(f1.x(), 2*f1.y(), 3*f1.z());

core.output(f2); [0.1, 0.4, 0.9] V3d(0x249a1cf3a60) [some address]

x core.output(f2.toVec3d()); [0.1, 0.4, 0.8999999999999999] [0.1, 0.4, 0.9]

x var crimson=new Color("Crimson");

x core.output(crimson.toHex()); #dc143c #dc143c

core.output(crimson.toVec3f()); [r:0.8627451062202454, g:0.0784313753247261, b:0.23529411852359772] [0.862745, 0.0784314, 0.235294]

core.output(crimson.r); 0.8627451062202454 error

core.output(crimson.r()); error 0.8627451062202454

x core.output(crimson.getR()); 0.8627451062202454 0.8627451062202454

x core.output(crimson.getG()); 0.0784313753247261 0.0784313753247261

x core.output(crimson.getB()); 0.23529411852359772 0.23529411852359772

crimson.g=0.444; (works) (error)

crimson.setG(0.444); (error) (works)

x crimson=new Color(crimson.getR(), 0.444, crimson.getB()); (reassign crimson; recommended for Qt5 and Qt6)

x core.output(crimson.toRGBString()); [r:0.862745, g:0.444, b:0.235294] [r:0.862745, g:0.444, b:0.235294]

x var eq=new Color(GridLinesMgr.getColorEquatorJ2000Grid());

x core.output(eq.toHex()); #00aaff #00aaff

core.output(eq.toVec3f()); [r:0, g:0.6666669845581055, b:1] [0, 0.666667, 1]

core.output(eq.toVec3d()); (n.a.) [0, 0.666667, 1]

core.output(eq.toString()); [0, 0.666667, 1] Color(0x24a11712910) [some address]

x core.output(eq.toRGBString()); [r:0, g:0.666667, b:1] [r:0, g:0.666667, b:1]

x var c=new Color(core.vec3f(.3, .4, .5));

core.output(c.toString()); [0.3, 0.4, 0.5] Color(0x249a1e078b0) [some address]

core.output(c.toVec3f()); [r:0.30000001192092896, g:0.4000000059604645, b:0.5] [0.3, 0.4, 0.5]

x var d=c; // assign to other

core.output(d.toVec3f()); [r:0.30000001192092896, g:0.4000000059604645, b:0.5] [0.3, 0.4, 0.5]

x var c2=new Color(.3, .4, .5);

core.output(c2.toString()); [0.3, 0.4, 0.5] Color(0x24a11712a60) [some address]

core.output(c2.toVec3f()); [r:0.30000001192092896, g:0.4000000059604645, b:0.5] [0.3, 0.4, 0.5]

x var d2=c2; // assign to other

core.output(d2.toVec3f()); [r:0.30000001192092896, g:0.4000000059604645, b:0.5] [0.3, 0.4, 0.5]

Table 17.1: Use of V3d, V3f and Color wrapper classes. Only use the calls marked with x in scripts targeted at all versions of Stellarium.

17.6 Example: Retrograde motion of Mars 237

Figure 17.1: Retrograde motion of Mars in 2005. (Credit & Copyright: Tunc Tezel — APOD: 2006

April 22 – Z is for Mars.)

// Version: 1.0

// Shortcut : Ctrl+M

// Description : A demo of retrograde motion of Mars.

17.6.2 A body of script

At the ﬁrst stage of writing of the script for a demo of retrograde motion of Mars we should set some limits

for our demo. For example we want to see motion of Mars every day during 250 days since October

2009. Choosing a value of ﬁeld of view and of the coordinates of the center of the screen should be done at

the this stage also.

Let’s add few lines of code into the script after the header and run it:

core.setDate("2009-10 -01 T10 :00:00");

core.moveToRaDec("08h44m41s", " +18 d09m13s",1);

StelMovementMgr.zoomTo(40, 1);

for (i=0; i<250; i++)

{

core.setDate("+ 1 days ");

core.wait(0.2);

}

Note: The

wait(delay_seconds)

instruction inside the loop is important: when you are just setting the

time in rapid succession, there is no guarantee that the view is updated, or a textual result has been updated

when writing ephemerides, before executing the next time update! The

wait()

ensures the program can

update the main simulation loop and put the planets where they should be at that set time. The minimum

delay required may depend on your computer’s speed.

OK, Stellarium is doing something, but what exactly is it doing? The ground and atmosphere is enabled

and any motion of Mars is invisible. Let’s add an another few lines into the script (hiding the landscape and

atmosphere) after setting date and time:

LandscapeMgr.setFlagLandscape(false);

238 Chapter 17. Scripting

LandscapeMgr.setFlagAtmosphere(false);

The whole sky is moving now — let’s lock it! Add this line after previous lines:

StelMovementMgr.setFlagLockEquPos(true);

It looks better now, but what about cardinal points, elements of GUI and some “glitch of movement”?

Let’s change the script:

core.setDate("2009-10 -01 T10 :00:00");

LandscapeMgr.setFlagCardinalsPoints(false);

LandscapeMgr.setFlagLandscape(false);

LandscapeMgr.setFlagAtmosphere(false);

core.setGuiVisible(false);

core.moveToRaDec("08h44m41s", " +18 d09m13s",1);

StelMovementMgr.setFlagLockEquPos(true);

StelMovementMgr.zoomTo(40, 1);

core.wait(2);

for (i=0; i<250; i++)

{

core.setDate("+ 1 days ");

core.wait(0.2);

}

core.setGuiVisible(true);

It’s better, but let’s draw the “path” of Mars! Add those line before the loop:

core.selectObjectByName("Mars", false);

SolarSystem.setFlagIsolatedTrails(true);

SolarSystem.setFlagTrails(true);

Hmm. . . let’s add a few strings with info for users (insert those lines after the header):

var color = "#ff9900 ";

var info = LabelMgr.labelScreen("A motion of Mars", 20, 20,

false, 24, color);

var apx = LabelMgr.labelScreen("Setup best viewing angle , FOV

and date/ time.", 20, 50, false, 18, color);

LabelMgr.setLabelShow(info, true);

LabelMgr.setLabelShow(apx, true);

core.wait(2);

LabelMgr.setLabelShow(apx, false);

Let’s add some improvements to display info for users — change in the loop:

var label = LabelMgr.labelObject(" Normal motion , West to

East", " Mars", true, 16, color, "SE");

for (i=0; i<250; i++)

{

core.setDate("+ 1 days ");

if ((i % 10) == 0)

{

var strDate = "Day " + i;

LabelMgr.setLabelShow(apx, false);

var apx = LabelMgr.labelScreen(strDate, 20,

50, false, 16, color);

LabelMgr.setLabelShow(apx, true);

}

if (i == 75)

{

LabelMgr.deleteLabel(label);

label = LabelMgr.labelObject(" Retrograde or

17.7 More Examples 239

opposite motion begins", " Mars",

true, 16, color, "SE");

core.wait(2);

LabelMgr.deleteLabel(label);

label = LabelMgr.labelObject(" Retrograde

motion ", "Mars ", true, 16, color,

"SE");

}

if (i == 160)

{

LabelMgr.deleteLabel(label);

label = LabelMgr.labelObject(" Normal motion

returns", " Mars", true, 16, color,

"SE");

core.wait(2);

LabelMgr.deleteLabel(label);

label = LabelMgr.labelObject(" Normal motion",

"Mars ", true, 16, color, "SE");

}

core.wait(0.2);

}

17.7 More Examples

The best source of examples is the

scripts

sub-directory of the main Stellarium source tree. This directory

contains a sub-directory called

tests

which are not installed with Stellarium, but are nonetheless useful

sources of example code for various scripting features.

Practical Astronomy

18 Astronomical Concepts . . . . . . . . . . . . . 243

19 Astronomical Phenomena

. . . . . . . . . . 259

20 A Little Sky Guide

. . . . . . . . . . . . . . . . . . . 277

21 Exercises

. . . . . . . . . . . . . . . . . . . . . . . . . . . 287

18. Astronomical Concepts

BARRY GERDES, WITH ADDITIONS BY GEORG ZOTTI

This section includes some general notes on astronomy in an effort to outline some concepts that are helpful

to understand features of Stellarium. Material here is only an overview, and the reader is encouraged to get

hold of a couple of good books on the subject. A good place to start is a compact guide and ephemeris such

as the National Audubon Society Field Guide to the Night Sky

. Also recommended is a more complete

textbook such as Universe

. There are also some nice resources on the net, such as the Wikibooks Astronomy

book

18.1 The Celestial Sphere

The Celestial Sphere is a concept which helps us think about the positions of objects in the sky. Looking up

at the sky, you might imagine that it is a huge dome or top half of a sphere (a hemisphere), and the stars

are points of light on that sphere. Visualizing the sky in such a manner, it appears that the sphere moves,

taking all the stars with it — it seems to rotate. Watching the movement of the stars we can see that they

seem to rotate around a static point about once a day (the diurnal motion). Stellarium is the perfect tool to

demonstrate this!

Open the location dialog (

). Set the location to be somewhere in mid-northern latitudes. (Just

click on the map to select a location, or ﬁne-tune with the settings.) The United Kingdom is an ideal

location for this demonstration.

Turn off atmospheric rendering

and ensure cardinal points are turned on (

). This will keep

the sky dark so the Sun doesn’t prevent us from seeing the motion of the stars when it is above the

horizon.

3. Pan round to point north, and make sure the ﬁeld of view is about 90°.

4. Pan up so the ‘N’ cardinal point on the horizon is at the bottom of the screen.

Now increase the time rate. Press

– this should set the time rate so the stars

can be seen to rotate around a point in the sky about once every ten seconds. If you watch Stellarium’s

clock you’ll see this is the time it takes for one day to pass at this accelerated rate.

The point which the stars appear to move around is one of the Celestial Poles.

The apparent movement of the stars is due to the rotation of the Earth. Our location as the observer on

the surface of the Earth affects how we perceive the motion of the stars. To an observer standing at Earth’s

North Pole, the stars all seem to rotate around the zenith (the point directly upward). As the observer moves

https://www.amazon.com/National-Audubon-Society-Field-Series/dp/0679408525

https://www.amazon.com/Universe-Definitive-Visual-Martin-Rees/dp/0756636701

https://en.wikibooks.org/wiki/Subject:Astronomy

244 Chapter 18. Astronomical Concepts

south towards the equator, the location of the celestial pole moves down towards the horizon. At the Earth’s

equator, the North Celestial Pole appears to be on the northern horizon.

Similarly, observers in the southern hemisphere see the Southern Celestial Pole at the zenith when they

are at the South Pole, and it moves to the horizon as the observer travels towards the equator.

Leave time moving on nice and fast, and open the conﬁguration window. Go to the location tab and

click on the map right at the top – i.e., set your location to the North Pole. See how the stars rotate

parallel to the horizon, around a point right at the top of the screen. With the ﬁeld of view set to

and the horizon at the bottom of the screen, the top of the screen is the zenith.

2. Now click on the map again, this time a little further south. You should see the positions of the stars

jump, and the center of rotation has moved a little further down the screen.

Click on the map even further towards and equator. You should see the centre of rotation having

moved down again.

To help with the visualization of the celestial sphere, turn on the equatorial grid by clicking the button

on the main toolbar or pressing the

key. Now you can see grid lines drawn on the sky. These lines are

like lines of longitude and latitude on the Earth, but drawn for the celestial sphere.

The Celestial Equator is the line around the celestial sphere that is half way between the celestial poles –

just as the Earth’s equator is the line half way between the Earth’s poles.

18.2 Coordinate Systems

18.2.1 Altitude/Azimuth Coordinates

The Horizontal Coordinate System (also called Altitude/Azimuth coordinate system) can be used to describe

a direction of view (the azimuth angle) and an angular height in the sky (the altitude angle). The azimuth

angle is measured clockwise round from due north

. Hence North itself is 0°, East

°, Southwest is

225

and so on. The altitude angle is measured up from the mathematical horizon, which is just halfway between

“straight up” and “straight down”, without regard to the landscape. Looking directly up (at the zenith) would

°, half way between the zenith and the horizon is

° and so on. The point opposite the zenith is called

the nadir.

The Altitude/Azimuth coordinate system is attractive in that it is intuitive – most people are familiar

with azimuth angles from bearings in the context of navigation, and the altitude angle is something most

people can visualise pretty easily.

However, the altitude/azimuth coordinate system is not suitable for describing the general position of

stars and other objects in the sky – the altitude and azimuth values for a celestial object change with time and

the location of the observer.

Stellarium can draw grid lines for altitude/azimuth coordinates. Use the button on the main toolbar

to activate this grid, or press the

key.

In addition, the cardinal points can be highlighted using the

button or

key.

There are a few great circles with special names which Stellarium can draw (see section 4.4.4).

Meridian

This is a great circle which runs through the North Pole towards the zenith and further to the

South Pole and nadir.

(Mathematical) Horizon This is the line exactly 90° away from the zenith.

First Vertical

This is the vertical circle perpendicular to the horizon and which runs from the East point

through the zenith, down the West point and to the nadir.

18.2.2 Right Ascension/Declination Coordinates

Like the Altitude/Azimuth system, the Right Ascension/Declination (RA/Dec) Coordinate System (or

Equatorial Coordinate System) uses two angles to describe positions in the sky. These angles are measured

from standard points on the celestial sphere. Right ascension

and declination

are to the celestial sphere

what longitude and latitude are to terrestrial map makers.

The Northern Celestial Pole has a declination of

δ = 90

°, the celestial equator has a declination of

δ = 0

°,

and the Southern Celestial Pole has a declination of δ = −90°.

Occasionally, instrument makers of the past may have engraved polar distance

instead:

p = 90

○

− δ

Stellarium can be conﬁgured to use this convention, see section 4.3.3.v 25.4

In some textbooks azimuth is counted from south. There is no global authority to decide upon this issue, just be

aware of this when you compare numbers with other sources.

18.2 Coordinate Systems 245

Figure 18.1: Altitude/Azimuth (Horizontal) Coordinate System

Right ascension is measured as an angle round from the vernal equinox, a point in the sky also known as

the First Point of Aries

, in the same way that longitude is measured around the Earth from Greenwich.

Figure 18.2 illustrates RA/Dec coordinates. The angle

is usually expressed as time with minute and

seconds, with 15° equaling one hour.

Unlike Altitude/Azimuth coordinates, RA/Dec coordinates of a star do not change when the observer

changes latitude, and do not change noticeably over the course of the day due to the rotation of the Earth.

RA/Dec coordinates are generally used nowadays in star catalogs such as the Hipparcos catalog.

However, the story is complicated a little by precession (section 18.8) and parallax (section 18.9).

Precession causes a slow drift of the coordinates almost parallel to the ecliptic, and therefore star catalogs

always have to specify their equinox of validity.

Current catalogs and atlases use coordinates for the standard epoch J2000.0. The currently best deﬁned

coordinate system, the International Celestial Reference Frame (ICRF), is one particular version described in

detail in the astronomical literature (Urban and Seidelmann, 2013). Other catalogs with data referring to

“J2000.0” may have to be slightly adjusted (usually in sub-arcsecond rotations) to match the ICRF coordinate

system (short ICRS).

Stars close to the celestial poles are permanently visible above the horizon and thus called circumpolar.

Those stars have observable upper and lower culminations when they pass the meridian arc spanning from

the celestial pole over the zenith to the opposite point on the horizon, or from the celestial pole to the horizon

246 Chapter 18. Astronomical Concepts

Figure 18.2: Equatorial Coordinates

below, respectively.

Those circumpolar stars which show their upper culmination between pole and zenith also have limits in

azimuth which they can reach in their daily course, the points of greatest digression. At these points they

move vertically upwards (in the east) or downwards (in the west), respectively.

Stellarium can draw grid lines for equatorial coordinates. Use the button on the main toolbar to

activate this grid, or press the

key to draw the equatorial grid for the simulation time. The Markings

dialog (4.4.4) allows you to set also the grid for J2000.0 standard coordinates.

There are again a few great circles with special names which Stellarium can draw in addition, both for

simulation time and for J2000.0 (see section 4.4.4).

Celestial Equator the line directly above the Earth’s (or more generally, the observer’s planet’s) equator.

Colures

These are lines similar to meridian and ﬁrst vertical in the azimuthal system. The Equinoctial

Colure runs from the North Celestial Pole NCP through the First Point of Aries

, South Celestial

Pole SCP and First Point of Libra

, while the Solstitial Colure runs from the NCP through First

Point of Cancer ã, SCP and First Point of Capricorn é.

In case you are observing from another celestial object, the equatorial coordinates use a system similar

to the one referring to the Earth-based coordinates, but parallel to the planet’s rotational axis.

18.2 Coordinate Systems 247

18.2.3 Fixed Equatorial Coordinates

The celestial sphere with its stars and other objects located in equatorial coordinates seems to rotate around

the celestial polar axis. When observing with a telescope, it proved useful to mount the instrument on an axis

which is aimed to be parallel to the earth’s axis, i.e., points to the celestial pole. In this case, after setting

the objects’s declination, it is enough to move the telescope around this polar axis to track its course over

time and keep the object in the ﬁeld of view. We can describe the Fixed Equatorial Coordinate System as an

intermediate coordinate system which uses the same equator and declination as the equatorial system, but

does not rotate as time goes by. The longitudinal coordinate is conventionally counted in 0. . . 24 hours from

the meridian (0h) along the celestial equator towards the west (6h) and is aptly named Hour Angle. A star

which has passed the meridian will reach hour angle of 1 hour one sidereal hour later. In some traditions,

decimal degrees may be preferred, and negative hour angles are used instead on the eastern half of the sky.

(See section 4.3.3 for settings.)

Stellarium can display the ﬁxed equatorial coordinates in the Markings dialog (4.4.4).

18.2.4 Ecliptical Coordinates

The Earth’s orbit around the Sun, i.e., the ecliptic, deﬁnes the “equatorial line” of this coordinate system,

which is traditionally used when computing the coordinates for planets because of their close proximity to

this line. Mirroring Earth’s motion, the Sun is seen to move along the ecliptic.

The zero point of ecliptical longitude

is the same as for equatorial coordinates (

), and the ecliptical

latitude β is counted positive towards the Northern Ecliptical Pole NEP in the constellation of Draco.

Moon and Sun (and to a much lesser extent, the other planets) pull on the equatorial bulge and try to

put Earth’s axis normal to its orbital plane. Earth acts like a spinning top and evades this pull in a sideways

motion, so that Earth’s axis seems to describe a small circle over a period of almost 26.000 years (see

section 18.8).

In addition, ecliptic obliquity against the equatorial coordinates, which mirrors the Earth’s axial tilt,

slowly changes.

Therefore, also for ecliptical coordinates it is required to specify which date (epoch) the coordinates

refer to. Stellarium can draw grids for two epochs. Use the

key to draw the ecliptic for the simulation

time. The Markings dialog (4.4.4) allows you to add date marks to the ecliptic line and also show a line for

v 23.1

epoch J2000.0 and grids for the ecliptical coordinates for current epoch and epoch J2000.0. You can assign

your own shortcut keys (section 4.8) if you frequently operate with these coordinates.

Since version 0.14.0 Stellarium can very accurately show the motions between the coordinate sys-

tems (Vondrák, Capitaine, and Wallace, 2011; Vondrák, Capitaine, and Wallace, 2012), and it is quite

interesting to follow these motions for several millennia. To support such demonstrations, Stellarium can also

draw the precession circles between celestial and ecliptical poles (activate them in the Markings dialog (4.4.4).

However, these circles are simply plotted centered on the instantaneous ecliptic pole by the instantaneous

value of obliquity. If you observe long enough, you will see that these circles vary in size, reﬂecting the

changes in ecliptic obliquity. The real track of where Earth’s axis is pointing forms an open helical loop.

The inner planets are best observed when their apparent distance from the Sun, or elongation, reaches a

maximum. Unfortunately there are two deﬁnitions for elongation, though:

ψ angular distance on the sphere. This is today the most widely used deﬁnition.

∆

difference between solar and the object’s ecliptical longitude. The advantage of using this deﬁnition

is that we can easily read opposition (

∆λ

= 180

○

) and conjunction (

∆λ

= 0

○

). We can also see

whether we have eastern elongation (

∆λ

> 0

) where the planet is visible in the evening sky, or

western elongation (

∆λ

< 0

) where the planet is visible in the morning sky. For the inner planets

Mercury and Venus we further discern superior conjunction, when the planet is “above”, or behind,

the Sun, and inferior conjunction, when the planet is “below”, or closer than, the Sun.

Many of the minor bodies are best observed around the times of their opposition. Stellarium can display

a great circle in the ecliptical coordinates which runs through the ecliptic poles and through the Sun, thereby

allowing to estimate opposition and conjunction. Activate display of this Opposition/Conjunction Line in the

Markings dialog (Labeled “O./C. longitude”; 4.4.4). The Markings dialog also provides the possibility to

visualize the antisolar point, which lies opposite of the Sun, on the intersection of the ecliptic and the O/C

line.

Another interesting aspect of planets is their quadrature from the Sun. Here their angular distance is

○

. You can activate display of the quadrature circle in the Markings dialog (4.4.4).

It is interesting to note that star catalogs before TYCHO BRAHE’s (1546–1601), most notably the one in

PTOLEMY’s Almagest, used ecliptical coordinates. The reason is simple: it was known since HIPPARCHUS

248 Chapter 18. Astronomical Concepts

that stellar coordinates slowly move along the ecliptic through precession, and the correction to coordinates

of a date of interest was a simple addition of a linear correction to the ecliptical longitude in the catalog.

Changes of ecliptic obliquity were discovered much later.

18.2.5 Galactic Coordinates

The Milky Way appears to run along a great circle over the sky, mirroring the fact that the Sun is a star in it.

Coordinates for non-stellar objects which belong to the Milky Way like pulsars or planetary nebulae are

often mapped in Galactic Coordinates, where galactic longitude

and galactic latitude

are usually given

in decimal degrees. Here, the zero point of galactic longitudes lies in the Galactic Center.

Stellarium can also draw a galactic grid and the galactic equator by activating the respective options

in the Markings dialog (see section 4.4.4). You can assign a keyboard shortcut if you frequently use these

coordinates (see 4.8).

18.2.6 Planet Coordinates

The larger objects in the Solar system are described as spheroids, sometimes ﬂattened into slightly ellipsoid

shape.

Just like the Prime Meridian on Earth has been deﬁned to run through Greenwich Observatory, each such

object in the Solar system for which any kind of rotation has been detected has a prime meridian deﬁned by

the IAU Working Group on Cartographic Coordinates and Rotational Elements (WGCCRE). On a rocky

planet this is usually deﬁned by some surface feature like a crater. For the Moon, it has traditionally been

the center of the Lunar disk. For the gas giant planets with ever-changing atmospheric features, there are

even several systems of rotation. Most notably on Jupiter, System I describes the rotation of its equatorial

area, while System II describes the mean atmospheric rotation north of the south component of the north

equatorial belt, and south of the north component of the south equatorial belt. Ofﬁcial sources prefer to list

the rotation of the magnetic ﬁelds (System III) for these planets. The most interesting feature on Jupiter for

most observers is the Great Red Spot (GRS), a huge storm that has been observed since the 19th, if not even

since the 17th century.

Astronomical almanacs and observing guides often list transit times when the GRS crosses the center of

Jupiter’s visible disk. Stellarium aims to show it at the right place. The storm moves in longitude, and to

adjust for this you can conﬁgure its System II longitude in the settings, see 4.4.2.

Like many planet moons, also Earth’s Moon shows one side towards its planet. However, given its

elliptical orbit and disturbations by Earth, Sun and other planets, the Moon seems to nod slightly in east-west

and north-south directions. This motion is called Libration. Stellarium gives geocentric libration in longitude

and latitude

, which are the coordinates of the apparent center of the Lunar disk. Another way to express

this shift is the total angle of libration and the direction into which the Moon’s mean center has been shifted.

This angle is given counterclockwise from the direction of the North pole on the Lunar disk. The larger this

shift is, the better you can observe the opposite side, which is therefore marked in brackets. If libration is

larger than 3/5/7 degrees, Stellarium shows 1, 2 or 3 exclamation marks to draw your attention further to this

lunar rim. However, you also need light on this edge.

Another interesting point for which Stellarium gives coordinates is the sub-solar point (L

, B

The Selenographic colongitude of the Sun

= 450

○

− L

is given for the Moon. This helps estimating

the terminator (Meeus, 1998):

•

The morning terminator is at 360

○

− c

•

The evening terminator is at 180

○

− c

•

When c

= 0

○

, the Sun rises at selenographic longitude L = 0

○

, near First Quarter.

•

When c

= 90

○

, the Sun rises at selenographic longitude L = 270

○

, near Full Moon.

•

When c

= 180

○

, the Sun rises at selenographic longitude L = 180

○

, near Last Quarter.

•

When c

= 270

○

, the Sun rises at selenographic longitude L = 90

○

, near New Moon.

is used to compute the Sun’s altitude

over a surface point, e.g. a crater on the Moon at position

(η, θ ), which is displayed when you select a surface feature.

sinh = sinB

sin

θ + cosB

cosθ sin(c

+ η) (18.1)

18.3 Distance

As DOUGLAS ADAMS (1952–2001) pointed out in The Hitchhiker’s Guide to the Galaxy (Adams, 1981),

18.4 Time 249

Space [. . . ] is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly

big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just

peanuts to space.[p.76]

Astronomers use a variety of units for distance that make sense in the context of the mind-boggling vastness

of space.

Astronomical Unit (AU)

This is the mean Earth-Sun distance. Roughly 150 million kilometers (

1.49598×

). The AU is used mainly when discussing the solar system – for example the distance of

various planets from the Sun.

Light year (LY) A light year is not, as some people believe, a measure of time. It is the distance that light

travels in a year. The speed of light being approximately 300,000 kilometers per second means a light

year is a very large distance indeed, working out at about 9.5 trillion kilometers (

9.46073× 10

Light years are most frequently used when describing the distance of stars and galaxies or the sizes of

large-scale objects like galaxies, nebulae etc.

Parsec (pc)

A parsec is deﬁned as the distance of an object that has an annual parallax of 1 second of

arc. This equates to 3.26156 light years (

3.08568× 10

). Parsecs (and derivatives: kiloparsec

kpc

, megaparsec

Mpc

) are most frequently used when describing the distance of stars or the sizes of

large-scale objects like galaxies, nebulae etc.

18.4 Time

Figure 18.3: Sidereal day

The length of a day is deﬁned as the amount of time that it takes for the Sun to travel from the highest

point in the sky at mid-day to the next high-point on the next day. In astronomy this is called a solar day.

The apparent motion of the Sun is caused by the rotation of the Earth. However, in this time, the Earth not

only spins, it also moves slightly round its orbit. Thus in one solar day the Earth does not spin exactly

360

on its axis. Another way to measure day length is to consider how long it takes for the Earth to rotate exactly

360°. This is known as one sidereal day.

Figure 18.3 illustrates the motion of the Earth as seen looking down on the Earth orbiting the Sun. The

red triangle on the Earth represents the location of an observer. The ﬁgure shows the Earth at four times:

1. The Sun is directly overhead - it is mid-day.

250 Chapter 18. Astronomical Concepts

Twelve hours have passed since 1. The Earth has rotated round and the observer is on the opposite

side of the Earth from the Sun. It is mid-night. The Earth has also moved round in its orbit a little.

3. The Earth has rotated exactly 360°. Exactly one sidereal day has passed since 1.

It is mid-day again – exactly one solar day since 1. Note that the Earth has rotated more than

360

since 1.

It should be noted that in ﬁgure 18.3 the sizes of the Sun and Earth and not to scale. More importantly, the

distance the Earth moves around its orbit is much exaggerated. The Earth takes a year to travel round the

Sun – 365

solar days. The length of a sidereal day is about 23 hours, 56 minutes and 4 seconds.

18.4.1 Sidereal Time

It takes exactly one sidereal day for the celestial sphere to make one revolution in the sky. Astronomers ﬁnd

sidereal time useful when observing. This is the Right Ascension which is currently passing the meridian

line, or, equivalent, the Hour Angle of the First Point of Aries à. When visiting observatories, look out for

doctored alarm clocks that have been set to run faster and show sidereal time!

18.4.2 Julian Day Number

In the 19th century, astronomer JOHN HERSCHEL (1792–1871) introduced the use of Julian Day numbers

(invented around the time of the Gregorian calendar reform). This is a simple continuous day count starting

on January 1, -4712 (4713 BC). There are no years, months etc., and the integral day number switches at

noon, so during a single night of observation (in Europe) the date never changes.

The fractional part of the number is just the fraction of day that has elapsed since last noon. Given that a

day has 86400 seconds, we should give a JD with 5 decimal places to capture the nearest second.

This causes a problem for modern computers: even a “double precision ﬂoat” can keep only about

13 decimal places. More than 2.4 million days have passed, so that e.g. January 1, 2000, 12:00UT is

2451545.0, which is an accurately storable number with 7 decimal places, but 12:34:56UT is computed

as 2451545.02426. A more accurate result would yield 2451545.024259259259... So, for a ﬁeld where

sub-second accuracy became crucial like spacecraft operations, the Modiﬁed Julian Day (MJD) has been

introduced. It is simply

MJD = JD − 2400000.5. (18.2)

This means, days start at midnight, and the (constant, in our era) decimal places of the “big numbers” at the

begin of the number have been traded in for more decimal places at the end.

Don’t put your expectations too high when you see MJD displayed (section 4.1): Stellarium uses a

double-precision ﬂoating point number for JD for internal timekeeping, and Stellarium’s display of MJD is

simply computed from it. So you cannot set temporal increments smaller than a second, and it hardly would

make sense to expect more accuracy from the simulation algorithms.

18.4.3 Delta T

Until around 1900, the Earth’s rotation was regarded as perfect standard of time. There were 86400 seconds

per mean solar day, and the accuracy of reproducing time with mechanical clocks only in this time started to

become as good as the Earth’s rotation itself.

Astronomers who computed solar eclipses reported in texts from antiquity wondered about a required

time shift which they originally attributed to a yet-unknown “secular acceleration of the lunar motion”.

However, it turned out that indeed the gravitational effect of the Moon which causes the tides also has effects

on Earth’s rotation: the tides slowly break Earth’s rotational speed. The energy is also transferred to the

Moon, and the acceleration leads to the Moon slowly moving away from the Earth

This led to the introduction of a time named Ephemeris Time (ET) with progresses in the speed of the

second in the year 1900, to be used for positional computation in our solar system, in addition to Greenwich

Mean Time (GMT), from which all zone times and “civil” clock times were derived.

The introduction of atomic clocks in the middle of the 20th century led to a redeﬁnition of the (temporal)

second, which has been de-coupled from Earth’s rotation. This time, the International Atomic Time TAI

, is

No need to worry, the Moon recedes from the Earth only a few centimeters per year as measured with the laser

reﬂectors left by the Apollo astronauts in the 1970s. In a very far future, however, there will only be annular solar

eclipses as a consequence!

From the French name temps atomique international

18.4 Time 251

the basis for Terrestrial Time TT which can be considered as constantly progressing at constant speed

, and

is used for computation of the planetary positions.

Still, people living on Earth prefer to have the mean solar noon governing the run of day and night.

Therefore all forms of civil time are linked to Coordinated Universal Time UTC. Seconds in UTC and

TAI are of equal length. The slow and irregular divergence between TAI and UTC is observed by a few

standardization institutes. When necessary, a leap second can be introduced to the UTC to bring the Earth’s

rotation back in sync so that the Mean Sun again culminates at noon.

The difference

∆T = T T − UT

(or “Delta T”) describes the temporal offset which amounts already to

more than a minute in the 21st century. There have been many attempts to properly model

∆T

, and Stellarium

offers several models you can choose from in the conﬁguration dialog (see section 4.3.4). “Espenak and

Meeus (2006, 2014)”, is a widely accepted standard. The default, “Modiﬁed Espenak and Meeus (2006,

2014, 2023)”, is created to make

∆T

closely in line with observed and predicted values between the years

2015-2050. But if you are a researcher and want to experiment with alternative models, you will hopefully

like this feature. you can even specify your own data for

and the secular term for lunar acceleration

n (actually ˙n = dndt in units of arcsecondscentury

) if you can model ∆T according to the formula

∆T = a + b ⋅ u + c ⋅ u

where (18.3)

u =

year− y

100

(18.4)

18.4.3.1 List of ∆T models in Stellar ium

The following list describes sources and a few details about the models for ∆T implemented in Stellarium.

Without correction. Correction is disabled. Use only if you know what you are doing!

Schoch (1931).

This historical formula was obtained by Schoch (1931) and was also used in “A New Test of

Einstein’s Theory of Relativity by Ancient Solar Eclipses” (Henriksson, 2009). See for more in Peters

(2010). ˙n = −29.68

′′

cy

Clemence (1948).

This empirical equation was published in “On the system of astronomical constants”

(Clemence, 1948). Valid range of usage: between years 1681 and 1900. ˙n = −22.44

′′

cy

IAU (1952).

This formula is based on a study of post-1650 observations of the Sun, the Moon and the

planets (Spencer Jones, 1939) and reproduced in Astronomical Formulae for Calculators (Meeus,

1988). It was also adopted in the PC program SunTracker Pro. Valid range of usage: between years

1681 and 1936. ˙n = −22.44

′′

cy

Astronomical Ephemeris (1960).

This is a slightly modiﬁed version of the IAU 1952 (Spencer Jones,

1939) formula which was adopted in the “Astronomical Ephemeris” (Wilkins, 1961) and in the Canon

of Solar Eclipses -2003 to +2526 (Mucke and Meeus, 1983). Valid range of usage: between years

-500 and 2000. ˙n = −22.44

′′

cy

Tuckerman (1962, 1964) & Goldstine (1973).

The famous tables (Tuckerman, 1962; Tuckerman, 1964)

list the positions of the Sun, the Moon and the planets at 5- and 10-day intervals from 601 BCE to

1649 CE. The same relation was also implicitly adopted in the syzygy tables of Goldstine (1973).

Valid range of usage: between years -600 and 1649.

Muller & Stephenson (1975).

This equation was published in “The accelerations of the earth and moon

from early astronomical observations” (Muller and F. R. Stephenson, 1975). Valid range of usage:

between years -1375 and 1975. ˙n = −37.5

′′

cy

Stephenson (1978).

This equation was published in “Pre-Telescopic Astronomical Observations” (F. R.

Stephenson, 1978). ˙n = −30.0

′′

cy

Schmadel & Zech (1979).

This 12th-order polynomial equation (outdated and superseded by Schmadel

and Zech (1988)) was published in “Polynomial approximations for the correction delta T E.T.-U.T. in

the period 1800-1975” (Schmadel and Zech, 1979) as ﬁt through data published by Brouwer (1952).

Valid range of usage: between years 1800 and 1975, with meaningless values outside this range.

˙n = −23.8946

′′

cy

Morrison & Stephenson (1982).

This algorithm Morrison and F. R. Stephenson, 1982 was adopted in

Planetary Programs and Tables from –4000 to +2800 (Pierre Bretagnon and Simon, 1986) and

in the PC planetarium program RedShift. Valid range of usage: between years -4000 and 2800.

˙n = −26.0

′′

cy

We don’t discuss relativity here. The advanced reader is referred to the presentation in the Wikipedia,

https:

//en.wikipedia.org/wiki/Delta_T.

252 Chapter 18. Astronomical Concepts

Stephenson & Morrison (1984).

This formula was published in “Long-term changes in the rotation of the

earth - 700 B.C. to A.D. 1980” (F. R. Stephenson and Morrison, 1984). Valid range of usage: between

years -391 and 1600. ˙n = −26.0

′′

cy

Stephenson & Houlden (1986).

This algorithm (Houlden and F. Stephenson, 1986) is used in the PC

planetarium program Guide 7. Valid range of usage: between years -600 and 1600.

˙n = −26.0

′′

cy

Espenak (1987, 1989).

This algorithm was given in Fifty Year Canon of Solar Eclipses: 1986 – 2035

(Espenak, 1987) and in Fifty Year Canon of Lunar Eclipses: 1986 – 2035 (Espenak, 1989). Valid

range of usage: between years 1950 and 2100.

Borkowski (1988).

This formula was obtained by Borkowski (1988) from an analysis of 31 solar eclipse

records dating between 2137 BCE and 1715 CE. Valid range of usage: between years -2136 and 1715.

˙n = −23.895

′′

cy

Schmadel & Zech (1988). This 12th-order polynomial equation was published in “Empirical Transforma-

tions from U.T. to E.T. for the Period 1800-1988” (Schmadel and Zech, 1988) as data ﬁt through

values given by F. R. Stephenson and Morrison (1984). Valid range of usage: between years 1800 and

1988, with a mean error of less than one second, max. error 1.9s, and meaningless values outside this

range. ˙n = −26.0

′′

cy

Chapront-Touze & Chapront (1991).

This formula was adopted by M. Chapront-Touze & J. Chapront

in the shortened version of the ELP 2000-85 lunar theory in their Lunar Tables and Programs from

4000 B.C. to A.D. 8000 (Chapront-Touzé and Chapront, 1991). The relations are based on those of

F. R. Stephenson and Morrison (1984), but slightly modiﬁed to make them compatible with the tidal

acceleration parameter of

˙n = −23.8946

′′

cy

adopted in the ELP 2000-85 lunar theory (Chapront-

Touzé and Chapront, 1988a).

Stephenson & Morrison (1995).

This equation was published in “Long-Term Fluctuations in the Earth’s

Rotation: 700 BC to AD 1990” (F. R. Stephenson and Morrison, 1995). Valid range of usage: between

years -700 and 1600. ˙n = −26.0

′′

cy

Stephenson (1997).

F. R. Stephenson published this formula in his book Historical Eclipses and Earth’s

Rotation (F. Richard Stephenson, 1997). Valid range of usage: between years -500 and 1600.

˙n = −26.0

′′

cy

Meeus (1998) (with Chapront, Chapront-Touze & Francou (1997)).

Used in Astronomical Algorithms

(Meeus, 1998), and elsewhere. Table for 1620..2000, and includes a variant of Chapront, Chapront-

Touze & Francou (1997) for dates outside 1620..2000. Valid range of usage: between years -400 and

2150. ˙n = −25.7376

′′

cy

JPL HORIZONS.

The JPL Solar System Dynamics Group of the NASA Jet Propulsion Laboratory use

this formula in their interactive website JPL HORIZONS

. Valid range of usage: between years -2999

and 1620, with zero values outside this range. ˙n = −25.7376

′′

cy

Meeus & Simons (2000).

This polynome was published in “Polynomial approximations to Delta T, 1620-

2000 AD” (Meeus and Simons, 2000). Valid range of usage: between years 1620 and 2000, with zero

values outside this range. ˙n = −25.7376

′′

cy

Montenbruck & Pﬂeger (2000).

The fourth edition of Astronomy on the Personal Computer (Montenbruck

and Pﬂeger, 2000) provides simple 3rd-order polynomial data ﬁts for the recent past. Valid range of

usage: between years 1825 and 2005, with a typical 1-second accuracy and zero values outside this

range.

Reingold & Dershowitz (2002, 2007, 2018).

E. M. Reingold & N. Dershowitz present this polynomial

data ﬁt in Calendrical Calculations: The Ultimate Edition (Reingold and Dershowitz, 2018) and in

their Calendrical Calculations (Reingold and Dershowitz, 2007), Calendrical Tabulations 1900-2200

(Reingold and Dershowitz, 2002). It is based on Astronomical Algorithms (Meeus, 1991).

Morrison & Stephenson (2004, 2005).

This important solution was published in “Historical values of the

Earth’s clock error

∆

T and the calculation of eclipses” (Morrison and F. R. Stephenson, 2004) with

addendum (Morrison and F. R. Stephenson, 2005). Valid range of usage: between years -1000 and

2000. ˙n = −26.0

′′

cy

Stephenson, Morrison & Hohenkerk (2016, 2021).

This important new solution was published in “Mea-

surement of the Earth’s rotation: 720 BC to AD 2015” (F. R. Stephenson, Morrison, and Hohenkerk,

2016). The solution combines a spline ﬁt to observations (used between the given limits) with a

parabolic ﬁt (used as fallback outside the range, but without smooth transitions at the limits, i.e.,

values for 2016 and later deviate notably from current estimates, and should not be used for dates after

https://ssd.jpl.nasa.gov/?horizons

18.5 Angles 253

2015). The solution was updated in “Addendum 2020 to ‘Measurement of the Earth’s rotation: 720

BC to AD 2015’” (Morrison, F. R. Stephenson, et al., 2021). Recommended range of usage: between

years -720.0 and 2019.0 ˙n = −25.82

′′

cy

Espenak & Meeus (2006, 2014).

This solution by F. Espenak and J. Meeus, based on Morrison and F. R.

Stephenson (2004) and a polynomial ﬁt through tabulated values for 1600-2000, is used for the NASA

Eclipse Web Site

, in their Five Millennium Canon of Solar Eclipses: -1900 to +3000 (Espenak

and Meeus, 2006) and Thousand Year Canon of Solar Eclipses 1501 to 2500 (Espenak, 2014). This

formula is also used in the solar, lunar and planetary ephemeris program SOLEX. Valid range of usage:

between years -1999 and 3000. ˙n = −25.858

′′

cy

Modiﬁed Espenak & Meeus (2006, 2014, 2023).

This solution

is a modiﬁcation from Espenak & Meeus

(2006, 2014). Values for 2015-2033 are interpolated from observations and predictions by IERS

Rapid Service/Prediction Center. A simple formula is used to connect with F. Espenak’s predicted

value at year 2050. Valid range of usage: between years -1999 and 3000. ˙n = −25.858

′′

cy

Reijs (2006).

From the Length of Day (LOD; as determined by Morrison and F. R. Stephenson (2004)),

Victor Reijs derived a

∆T

formula by using a Simplex optimization with a cosine and square function.

This is based on a possible periodicity described by Morrison and F. R. Stephenson (2004). Valid

range of usage: between years -1500 and 1100. ˙n = −26.0

′′

cy

Banjevic (2006).

This solution is based on F. R. Stephenson and Morrison (1984) and was published in

“Ancient eclipses and dating the fall of Babylon” (Banjevic, 2006). Valid range of usage: between

years -2020 and 1620, with zero values outside this range. ˙n = −26.0

′′

cy

Islam, Sadiq & Qureshi (2008, 2013).

This solution by S. Islam, M. Sadiq and M. S. Qureshi, based on

Meeus and Simons (2000), was published in “Error Minimization of Polynomial Approximation of

Delta T” (Islam, Sadiq, and Qureshi, 2008) and revisited by Sana Islam in 2013. Valid range of usage:

between years 1620 and 2007, with zero values outside this range.

Khalid, Sultana & Zaidi (2014).

This polynomial approximation with 0.6 seconds of accuracy was pub-

lished in “Delta T: Polynomial Approximation of Time Period 1620–2013” (Khalid, Sultana, and

Zaidi, 2014). Valid range of usage: between years 1620 and 2013, with zero values outside this range.

Henriksson (2017).

A solution which combines Schoch’s 1931 solution (parabolic ﬁt) with a discussion of

and correction for relativistic effects. The author claims an accurate ﬁt for solar eclipses probably

depicted in artifacts going back to the mid-fourth millennium BC. Also with this setting, the exact

times from his paper (Henriksson, 2017) cannot be reproduced probably because the author used a

different ephemeris, but the phenomena are plausibly reproduced. Recommended range of usage:

between years -4000.0 and 2000.0 ˙n = −30.128

′′

cy

Custom equation of ∆T .

This is the quadratic formula 18.3 for calculation of

∆T

with coefﬁcients deﬁned

by the user.

18.5 Angles

Astronomers typically use degrees to measure angles. Since many observations require very precise

measurement, the degree is subdivided into sixty minutes of arc also known as arc-minutes. Each minute of

arc is further subdivided into sixty seconds of arc, or arc-seconds. Thus one degree is equal to 3600 seconds

of arc. Finer grades of precision are usually expressed using the SI preﬁxes with arc-seconds, e.g. milli

arc-seconds (one milli arc-second is one thousandth of an arc-second).

18.5.1 Notation

Degrees are denoted using the ° symbol after a number. Minutes of arc are denoted with a

′

, and seconds of

arc are denoted using

′′

. Angles are frequently given in two formats:

DMS format — degrees, minutes and seconds. For example

′

′′

. When more precision is

required, the seconds component may include a decimal part, for example 90°15

′

12.432

′′

2. Decimal degrees, for example 90.2533°

18.5.2 Handy Angles

Being able to estimate angular distance can be very useful when trying to ﬁnd objects from star maps in the

sky. One way to do this with a device called a crossbow.

https://eclipse.gsfc.nasa.gov/eclipse.html

This solution is used by default.

254 Chapter 18. Astronomical Concepts

Crossbows are a nice way get an idea of angular distances, but carrying one about is a little cumbersome.

A more convenient alternative is to hold up an object such as a pencil at arm’s length. If you know the length

of the pencil,

, and the distance of it from your eye,

, you can calculate its angular size,

using this

formula:

θ = 2 ⋅ arctan

2⋅ D

 (18.5)

Another, more handy (ahem!) method is to use the size of your hand at arm’s length:

Tip of little ﬁnger About 1°

Middle three ﬁngers About 4°

Across the knuckles of the ﬁst About 10°

Open hand About 18°

Using your hand in this way is not very precise, but it’s close enough to give you some way to translate

an idea like “Mars will be

° above the southeastern horizon at 21:30”. Of course, there are variations from

person to person, but the variation is compensated for somewhat by the fact that people with long arms tend

to have larger hands. In exercise 21.2 you will work out your own “handy angles”.

18.6 The Magnitude Scale

When astronomers talk about magnitude, they are referring to the brightness of an object. How bright

an object appears to be depends on how much light it is giving out and how far it is from the observer.

Astronomers separate these factors by using two measures: absolute magnitude (Mag or

) which is a

measure of how much light is being given out by an object, and apparent magnitude (mag or

) which is

how bright something appears to be in the sky.

For example, consider two 100 watt lamps, one which is a few meters away, and one which is a kilometer

away. Both give out the same amount of light – they have the same absolute magnitude. However the

nearby lamp seems much brighter – it has a much greater apparent magnitude. When astronomers talk about

magnitude without specifying whether they mean apparent or absolute magnitude, they are usually referring

to apparent magnitude.

The magnitude scale has its roots in antiquity. The Greek astronomer HIPPARCHUS deﬁned the brightest

stars in the sky to be ﬁrst magnitude, and the dimmest visible to the naked eye to be sixth magnitude. In

the 19th century British astronomer NORMAN POGSON (1829–1891) quantiﬁed the scale more precisely,

deﬁning it as a logarithmic scale where a magnitude 1 object is 100 times as bright as a magnitude 6 object

(a difference of ﬁve magnitudes). The zero-point of the modern scale was originally deﬁned as the brightness

of the star Vega, however this was re-deﬁned more formally in 1982 (Aller et al., 1989). Objects brighter

than Vega are given negative magnitudes.

The absolute magnitude of a star is deﬁned as the magnitude a star would appear if it were 10 parsecs

from the observer.

Table 18.1 lists several objects that may be seen in the sky, their apparent magnitude and their absolute

magnitude where applicable (only stars have an absolute magnitude value. Planets nor Moon emit light like

a star does – they reﬂect the light from the Sun).

Object m M

The Sun -27 4.8

Vega 0.05 0.6

Betelgeuse 0.47 -7.2

Sirius (the brightest star) -1.5 1.4

Venus (at brightest) -4.4 —

Full Moon (at brightest) -12.6 —

Table 18.1: Magnitudes of a few objects

18.7 Luminosity 255

18.7 Luminosity

Luminosity is an expression of the total energy radiated by a star. It may be measured in watts, however,

astronomers tend to use another expression — solar luminosities where an object with twice the Sun’s

luminosity is considered to have two solar luminosities and so on. Luminosity is related to absolute

magnitude.

18.8 Precession

Figure 18.4: Ecliptic obliquity

As the Earth orbits the Sun throughout the year, the axis of rotation (the line running through the rotational

poles of the Earth) seems to point towards the same position on the celestial sphere, as can be seen in

ﬁgure 18.4. The angle between the axis of rotation and the perpendicular of the orbital plane is called the

obliquity of the ecliptic. It is currently about

′

and is the angle between equatorial plane (18.2.2) and

ecliptical plane (18.2.4).

Observed over very long periods of time the direction the axis of rotation points to does actually change.

The angle between the axis of rotation and the orbital plane stays fairly constant, but the direction the axis

points — the position of the celestial pole — transcribes a ﬁgure similar to a circle on the celestial sphere.

The motion is similar to the way in which a gyroscope slowly twists, as ﬁgure 18.5 illustrates. This process

is called precession. The circles can be shown in Stellarium: from the View menu (

), tab “Markings”,

switch on “Precession Circles” (4.4.4).

Precession is a slow process. The axis of rotation twists through a full

360

° about once every 26,000

years. However, over these long times other gravitational perturbations (“planetary precession”) play a role,

and what may be thought of as rigid “precession circle” can actually only show the instantaneous (current)

state. Over millennia the circle slightly varies.

Precession has some important implications:

RA/Dec coordinates change over time, albeit slowly. Measurements of the positions of stars recorded

using RA/Dec coordinates must also include a date (“equinox”) for those coordinates. Therefore the

current star catalogues list their objects for the epoch and equinox J2000.0.

Polaris, the Pole Star, won’t stay a good indicator of the location of the Northern Celestial Pole. In

14,000 years time Polaris will be nearly 47° away from the celestial pole!

The change in declination causes a shift in the rising and setting positions of the stars along the

horizon. Figure 18.6 shows part of the horizon for latitude

ϕ = 30

° north. For a given year (left vertical

labels), make a horizontal line to ﬁnd rising azimuth of the bright stars indicated by the twisting lines.

Depending on where on the celestial sphere a star is located, it may appear to move north or south, or

be almost stationary for several centuries.

18.9 Parallax

Parallax is the change of angular position of two stationary points relative to each other as seen by an

observer, due to the motion of said observer. Or more simply put, it is the apparent shift of an object against

a background due to a change in observer position.

256 Chapter 18. Astronomical Concepts

Figure 18.5: Precession

90 95 100 105 110 115 120 125 130 135

85 90 95 100 105 110 115 120 125 130 135

Azimuth

-1000

-900

-800

-700

-600

-500

-400

-300

-200

-100

Deneb Kaitos

Rigel

Gam Ori

Mintaka

Alnilam

Alnitak

Kap Ori

Betelgeuse

Bet CMa

Sirius

Eps CMa

Del CMa

Zet Pup

Lam Vel

Alphard

Gam Cen

Spica

The Cen

Antares

Lam Sco

The Sco

Eps Sgr

Sig Sgr

Precession Shift of Stars on the Horizon

Geograpical Latitude: 30°0’ 0’’. Stars to mag=2.25. Azimuths from North, without refraction.

Figure 18.6: Precession: Change of rising positions of the stars along the eastern horizon from

azimuths 85 to 135 degrees, between years 1000 BC and 0, for latitude ϕ = 30°.

18.9 Parallax 257

Figure 18.7: Stellar Parallax

This can be demonstrated by holding one’s thumb up at arm’s length. Closing one eye, note the position

of the thumb against the background. After swapping which eye is open (without moving), the thumb appears

to be in a different position against the background.

18.9.1 Geocentric and Topocentric Observations

When computing planetary positions was done manually by adding numbers tabulated in yearly almanacs,

computing the Earth’s position and, say, the position of a minor planet was usually good enough to ﬁnd

the object in the sky. In both cases, the exact numbers refer to the gravitational centers of the respective

bodies. However, we are sitting on Earth’s surface, so the observed planet will be seen in a slightly shifted

location. The amount for objects in the inner solar system is usually just a few arc-seconds and is mostly

negligible when we just want to ﬁnd an object. But it makes a difference when it comes to observations of

stellar occultations by planets or asteroids. Such a body may measure only a few tens of kilometers, and the

shadow track which it leaves on Earth’s surface is of approximately the same size.

A much closer and bigger object is the Moon, which can also occult stars. It can even occult the one big

star we call the Sun: this is a solar eclipse. And here it makes a huge difference where on the planet you are

located.

If you are interested in astronomical computing, you may still be interested in geocentric numerical

results. From the Settings panel (

), tab “Tools”, there is a checkbox for “Topocentric Coordinates”.

Switch it off to put yourself into the center of the planet you are located.

18.9.2 Stellar Parallax

A similar thing happens due to the Earth’s motion around the Sun. Nearby stars appear to move against more

distant background stars, as illustrated in ﬁgure 18.7. The movement of nearby stars against the background

is called stellar parallax, or annual parallax.

Since we know the radius of the Earth’s orbit around the Sun from other methods, we can use simple

geometry to calculate the distance of the nearby star if we measure annual parallax.

As can be seen from ﬁgure 18.7, the annual parallax

is half the angular distance between the apparent

positions of the nearby star. The distance of the nearby object is

. Astronomers use a unit of distance called

the parsec (pc) which is deﬁned as the distance at which a nearby star has p = 1

′′

Even the nearest stars exhibit very small movement due to parallax. The closest star to the Earth other

than the Sun is Proxima Centauri. It has an annual parallax of

0.77199

′′

, corresponding to a distance of

1.295pc

(4.22 light years). Currently, Gaia satellite is the most accurate instrument for measuring stellar

parallax. It can measure parallax at the precision level of sub milli-arcseconds for bright stars (

G < 15

measuring distance with ≈ 10% to stars up to 10,000 parsecs.

In Stellarium, the annual parallax can be listed in the object information for stars when available and is

Unfortunately Stellarium (as of v0.15.0) is not accurate enough to reliably compute such occultations. Even a

deviation of 0.5 arc-seconds is too much here.

258 Chapter 18. Astronomical Concepts

accounted for by default in the positional calculations on any Solar System objects including the Earth. You

can also exaggerate the parallax effect up to 10, 000× to make it more apparent.

18.10 Aberration of Light

When you are standing under a rainy but windless sky with an umbrella placed vertically over your head,

your feet will not be hit by raindrops. But when you are walking, raindrops which just missed the umbrella

may hit your feet. Relative to your umbrella and feet, it seems that the raindrops are coming not quite

vertically from above, but inclined from the direction you are heading into, and therefore you tilt the umbrella

slightly forward to fend off the raindrops from your feet.

Light propagates very fast compared to the motion of the planets, but still with a ﬁnite velocity. Therefore,

just like the raindrops mentioned above, light from all celestial objects seem to come in from a position

slightly distorted towards the point in space the observer is heading to.

In search for stellar parallax (see section 18.9.2), this effect of the aberration of light was fortuitously

discovered and then explained by JAMES BRADLEY (1693–1762) in 1725. This was also the ﬁnal proof for

Earth’s movement around the Sun. For an observer on the moving Earth, the apparent deviation of a star

from the mean coordinates can reach

20.4”

. As the months pass, Earth is changing its direction along its

orbit, and so the light distortion also changes, i.e., the direction towards the object moves against the ﬁxed

coordinate axes. The effect is signiﬁcant when we want to compute, for example, stellar occultations by the

Moon.

In Stellarium, you can observe a slight annual wobble in all objects’ positions against the ﬁxed celestial

grids. Just enable the equatorial grid, zoom in and run through the months. You can also exaggerate the

aberration effect up to 5× to make it more apparent.

18.11 Proper Motion

Proper motion is the change in the position of a star over time as a result of its motion through space relative

to the Sun. Stellarium also includes the apparent shift in position of star due to annual parallax. The star

v 25.1

exhibiting the greatest proper motion is Barnard’s Star which moves more than ten seconds of arc per year.

If you want to simulate the effect of proper motion with Stellarium, put the map into equatorial view

mode, switch off ground and cardinal marks, and set some high time lapse speed. You will see a few stars

change their locations quite soon, those are usually stars in our galactic neighbourhood (see section 21.12).

Note however some limitations:

Stellarium will stop at

±100, 000

years. This limit may be still suitable for most stellar locations. The

planetary locations are not trustworthy outside of a much narrower temporal window (see section F).

You cannot simulate the sky over the dinosaurs or such things.

For most bright stars (

V < 10.5

), their full 6D astrometry (2D sky positions, 2D proper motion,

parallax, radial velocity) computed by assuming straight-line motion at constant speed. Otherwise

proper motion are only modelled by linear components.

18.11.1 Binary Stars

Binary stars are listed in catalogs as two individual stars with their current proper motion which consists of a

common spatial motion and the orbital motion around their common center of gravity. Their orbital motion

around each other, where known, is now properly modelled in Stellarium.v 25.1

Exaggerating even more causes graphics defects and has been disabled for now.

19. Astronomical Phenomena

BARRY GERDES, WITH ADDITIONS BY GEORG ZOTTI

This chapter focuses on the observational side of astronomy — what we see when we look at the sky.

19.1 The Sun

Without a doubt, the most prominent object in the sky is the Sun. The Sun is so bright that when it is in

the sky, its light is scattered by the atmosphere to such an extent that almost all other objects in the sky are

rendered invisible.

The Sun is a star like many others but it is much closer to the Earth at approximately 150 million kilome-

tres (a distance also called 1 Astronomical Unit). The next nearest star, Proxima Centauri is approximately

260,000 times further away from us than the Sun! The Sun is also known by its Latin name, Sol.

Over the course of a year, the Sun appears to move round the celestial sphere in a great circle known as

the ecliptic. Stellarium can draw the ecliptic on the sky. To toggle drawing of the ecliptic, press the

key.

WARNING: Looking at the Sun with even the smallest telescope or binoculars can permanently damage

the eye. Never look at the Sun without using the proper ﬁlters attached to the front end (objective lens)

of your instrument! Never use screw-in ocular ﬁlters, they may break in the heat and expose your eye to

damaging amounts of energy. By far the safest way to observe the Sun is to look at it on a computer screen,

courtesy of Stellarium!

19.1.1 Twilight

The sunlight is scattered in Earth’s atmosphere even if the Sun is below the horizon. The period after sunset

when the Sun is higher than

−6

° is called civil twilight. The sky is generally bright enough for outdoor

activity or reading the newspaper.

As time progresses, the ﬁrst stars will appear. The phase where the Sun is between

−6

° and

−12

° below

the (mathematical) horizon is called nautical twilight: before the invention of satellite navigation, celestial

navigation was used to ﬁnd a ship’s position on the oceans. This required that it was still bright enough so

that the horizon line was visible, but already dark enough to see enough stars to clearly identify them and

measure the altitude of a few of them. (See also section 14.7.)

The twilight phase when the Sun is between

−12

° and

−18

° is called astronomical twilight. Only the

western horizon shows some brightening, but else the natural sky is “almost” as dark as it can get.

In the morning the game is reversed. Dawn starts with astronomical twilight, progresses to nautical and

civil twilight, and sunrise ends the night.

In Stellarium, you can set the time when the Sun reaches a conﬁgured altitude. See section 4.8.1 about

how to conﬁgure the program.

260 Chapter 19. Astronomical Phenomena

Figure 19.1: Ursa Major

19.2 Stars

The Sun is just one of billions of stars. Even though many stars have a much greater absolute magnitude than

the Sun (they give out more light), they have an enormously smaller apparent magnitude due to their large

distance. Stars have a variety of forms — different sizes, brightnesses, temperatures, and colours. Measuring

the position, distance and attributes of the stars is known as astrometry, and is a major part of observational

astronomy.

19.2.1 Multiple Star Systems

Many stars have stellar companions. As many as six stars can be found orbiting one-another in close

associations known as multiple star systems — binary systems being the most common with two stars.

Multiple star systems are more common than solitary stars, putting our Sun in the minority group.

Sometimes multiple stars orbit each other in a way that means one will periodically eclipse the other.

These are eclipsing binaries or Algol variables.

19.2.1.1 Optical Doubles & Optical Multiples

Sometimes two or more stars appear to be very close to one another in the sky, but in fact have great

separation, being aligned from the point of view of the observer but of different distances. Such pairings are

known as optical doubles and optical multiples.

19.2.2 Constellations

The constellations are groupings of stars that are visually close to one another in the sky. The actual groupings

are fairly arbitrary — different cultures have grouped stars together into different constellations. In many

cultures, the various constellations have been associated with mythological entities. As such people have

often projected pictures into the skies as can be seen in ﬁgure 19.1 which shows the constellation of Ursa

Major. On the left is a picture with the image of the mythical Great Bear, on the right only a line-art version

(or stick ﬁgure) is shown. The seven bright stars of Ursa Major are widely recognised, known variously as

“the plough”, the “pan-handle”, and the “big dipper”. This sub-grouping is known as an asterism — a distinct

grouping of stars. On the right, the picture of the bear has been removed and only a constellation diagram

remains.

Stellarium can draw both constellation diagrams and artistic representations of the constellations.

Multiple sky cultures are supported: Western, Polynesian, Egyptian, Chinese, and several other sky cultures

are available, although at time of writing the non-Western constellations are not complete, and as yet there

are no artistic representations of these sky-cultures.

Aside from historical and mythological value, to the modern astronomer the constellations provide a

way to segment the sky for the purposes of describing locations of objects, indeed one of the ﬁrst tasks for

an amateur observer is learning the constellations — the process of becoming familiar with the relative

positions of the constellations, at what time of year a constellation is visible, and in which constellations

observationally interesting objects reside. The International Astronomical Union has adopted 88 “Western”

constellations as a common system for segmenting the sky (Table 19.1). They are based on Greek/Roman

19.2 Stars 261

Abbr. Name Genitive Abbr. Name Genitive

And Andromeda Andromedae Lac Lacerta Lacertae

Ant Antlia Antliae Leo Leo Leonis

Aps Apus Apodis LMi Leo Minor Leonis Minoris

Aqr Aquarius Aquarii

Lep Lepus Leporis

Aql Aquila Aquilae Lib Libra Librae

Ara Ara Arae Lup Lupus Lupi

Ari Aries Arietis Lyn Lynx Lyncis

Aur Auriga Aurigae Lyr Lyra Lyrae

Boo Bootes Bootis Men Mensa Mensae

Cae Caelum Caeli Mic Microscopium Microscopii

Cam Camelopardalis Camelopardalis Mon Monoceros Monocerotis

Cnc Cancer Cancri Mus Musca Muscae

Cvn Canes Venatici Canum Venaticorum Nor Norma Normae

CMa Canis Maior Canis Maioris Oct Octans Octantis

CMi Canis Minor Canis Minoris

Oph Ophiuchus Ophiuchi

Cap Capricornus Capricorni Ori Orion Orionis

Car Carina Carinae Pav Pavo Pavonis

Cas Cassiopeia Cassiopeiae Peg Pegasus Pegasi

Cen Centaurus Centauri Per Perseus Persei

Cep Cepheus Cephei Phe Phoenix Phoenicis

Cet Cetus Ceti Pic Pictor Pictoris

Cha Chamaeleon Chamaeleonis Psc Pisces Piscium

Cir Circinus Circini PsA Piscis Austrinus Piscis Austrini

Col Columba Columbae Pup Puppis Puppis

Com Coma Berenices Comae Berenicis

Pyx Pyxis Pyxidis

CrA Corona Australis Coronae Australis Ret Reticulum Reticuli

CrB Corona Borealis Coronae Borealis Sge Sagitta Sagittae

Crt Crater Crateris Sgr Sagittarius Sagittarii

Crv Corvus Corvi Sco Scorpius Scorpii

Cru Crux Crucis Scl Sculptor Sculptoris

Cyg Cygnus Cygni

Sct Scutum Scuti

Del Delphinus Delphini

Ser Serpens Serpentis

Dor Dorado Doradus Sex Sextans Sextantis

Dra Draco Draconis Tau Taurus Tauri

Equ Equuleus Equulei Tel Telescopium Telescopii

Eri Eridanus Eridani

Tri Triangulum Trianguli

For Fornax Fornacis TrA Triangulum Australe Trianguli Australis

Gem Gemini Geminorum Tuc Tucana Tucanae

Gru Grus Gruis UMa Ursa Maior Ursae Maioris

Her Hercules Herculis UMi Ursa Minor Ursae Minoris

Hor Horologium Horologii Vel Vela Velae

Hya Hydra Hydrae Vir Virgo Virginis

Hyi Hydrus Hydri Vol Volans Volantis

Ind Indus Indi Vul Vulpecula Vulpeculae

Table 19.1: The ofﬁcial 88 IAU constellation names and abbreviations

α alpha ε epsilon ι iota ν nu ρ rho ϕ phi

β beta ζ zeta κ kappa ξ xi σ sigma χ chi

γ gamma η eta λ lambda o omicron τ tau ψ psi

δ delta θ theta µ mu π pi υ upsilon ω omega

Table 19.2: The Greek alphabet used by Bayer

262 Chapter 19. Astronomical Phenomena

mythology, but with several additions from Renaissance and later centuries. As such some formalisation has

been adopted, each constellation having a proper name, which is in Latin, and a three letter abbreviation

of that name. For example, Ursa Major has the abbreviation UMa. Also, the “Western” constellation have

clearly deﬁned boundaries (Delporte, 1930), which you can draw in Stellarium when you press the

key

The IAU constellation a selected object is placed in is also available in the object information data (Roman,

1987), regardless of the currently active sky culture. On the other hand, the shapes of mythological ﬁgures,

and also stick ﬁgures, have not been canonized, so you will ﬁnd deviations between Stellarium and printed

atlases.

19.2.3 Star Names

The brighter stars often have one or more common names relating to mythical characters from the various

traditions. For example the brightest star in the sky, Sirius is also known as The Dog Star (the name Canis

Major — the constellation Sirius is found in — is Latin for “The Great Dog”).

Most bright names have been given names in antiquity. PTOLEMY’s most inﬂuential book, the Syntaxis,

was translated to the Arab language in the age of early Muslim scientists. When, centuries later, the

translation, called Almagest, was re-introduced to the re-awakening European science, those names, which

often only designated the position of the star within the ﬁgure, were taken from the books, often misspelled,

and used henceforth as proper names.

A few more proper names have been added later, sometimes dedicatory names added by court as-

tronomers into their maps. There are also 3 stars named after the victims of the Apollo 1 disaster in 1967.

Today, the International Astronomical Union (IAU) is the only scientiﬁcally accepted authority which can

give proper names to stars. Some companies offer a paid name service for commemoration or dedication of

a star for deceased relatives or such, but all you get here is a piece of paper with coordinates of (usually) an

unremarkably dim star only visible in a telescope, and a name to remember, stored (at best) in the company’s

database.

There are several more formal naming conventions that are in common use.

19.2.3.1 Bayer Designation

The German astronomer JOHANN BAYER (1572–1625) devised one such system for his atlas, the Ura-

nographia, ﬁrst published in 1603. His scheme names the stars according to the constellation in which they

lie preﬁxed by a lower case Greek letter (see Tab. 19.2), starting at

for (usually) the brightest star in the

constellation and proceeding with β , γ, . . . in descending order of apparent magnitude. For example, such a

Bayer Designation for Sirius is “

Canis Majoris” (note that the genitive form of the constellation name

is used, refer to Table 19.1; today also the short form

CMa is in use). There are some exceptions to the

descending magnitude ordering, and some multiple stars (both real and optical) are named with a numerical

superscript after the Greek letter, e.g. π

...

Orionis.

19.2.3.2 Flamsteed Designation

English astronomer JOHN FLAMSTEED (1646–1719) numbered stars in each constellation in order of

increasing right ascension followed by the genitive form of the constellation name, for example “61 Cygni”

(or short: “61 Cyg”).

19.2.3.3 Hipparcos

Hipparcos (for High Precision Parallax Collecting Satellite) was an astrometry mission of the European

Space Agency (ESA) dedicated to the measurement of stellar parallax and the proper motions of stars. The

project was named in honour of the Greek astronomer HIPPARCHUS.

Ideas for such a mission dated from 1967, with the mission accepted by ESA in 1980. The satellite was

launched by an Ariane 4 on 8 August 1989. The original goal was to place the satellite in a geostationary

orbit above the earth, however a booster rocket failure resulted in a highly elliptical orbit from 500 to

35,800 km (310 to 22,240 miles) altitude. Despite this difﬁculty, all of the scientiﬁc goals were accomplished.

Communications were terminated on 15 August 1993.

The program was divided in two parts: the Hipparcos experiment whose goal was to measure the ﬁve

astrometric parameters of some 120,000 stars to a precision of some 2 to 4 milli arc-seconds and the Tycho

experiment, whose goal was the measurement of the astrometric and two-colour photometric properties of

some 400,000 additional stars to a somewhat lower precision.

The ﬁnal Hipparcos Catalogue (120,000 stars with 1 milli arc-second level astrometry) and the ﬁnal

Tycho Catalogue (more than one million stars with 20-30 milli arc-second astrometry and two-colour

These boundaries or borders have been drawn using star maps from 1875. Due to the effect of precession, these

borders are no longer parallel to today’s coordinates.

19.2 Stars 263

photometry) were completed in August 1996. The catalogues were published by ESA in June 1997. The

Hipparcos and Tycho data have been used to create the Millennium Star Atlas: an all-sky atlas of one million

stars to visual magnitude 11, from the Hipparcos and Tycho Catalogues and 10,000 non-stellar objects

included to complement the catalogue data.

Figure 19.2: Star Names and Data

There were questions over whether Hipparcos has a systematic error of about 1 milli arc-second in at

least some parts of the sky. The value determined by Hipparcos for the distance to the Pleiades is about 10%

less than the value obtained by some other methods. By early 2004, the controversy remained unresolved.

Stellarium uses the Hipparcos Catalogue for star data, as well as having traditional names for many of

the brighter stars. The stars tab of the search window allows for searching based on a Hipparcos Catalogue

number (as well as traditional names), e.g. the star Sadalmelik in the constellation of Aquarius can be found

by searching for the name, or its Hipparcos number, 109074.

Figure 19.2 shows the information Stellarium displays when a star is selected. At the top, the common

name, Bayer/Flamsteed designations and Hipparcos number are shown, followed by the RA/Dec coordinates,

apparent magnitude, distance and other data.

19.2.4 Spectral Type & Luminosity Class

Stars have many different colours. Seen with the naked eye most appear to be white, but this is due to the

response of the eye — at low light levels the eye is not sensitive to colour. Typically the unaided eye can

start to see differences in colour only for stars that have apparent magnitude brighter than 1. Betelgeuse, for

example has a distinctly red tinge to it, and Sirius appears to be blue, while Vega is the prototype “white”

star.

By splitting the light from a star using a prism attached to a telescope and measuring the relative

intensities of the colours of light the star emits — the spectrum — a great deal of interesting information

can be discovered about a star including its surface temperature, and the presence of various elements in its

atmosphere.

Astronomers groups stars with similar spectra into spectral types, denoted by one of the following letters:

O, B, A, F, G, K and M.

Type O stars have a high surface temperature (up to around 50,000 K) while the at

other end of the scale, the M stars are red and have a much cooler surface temperature, typically 3000 K. The

Sun is a type G star with a surface temperature of around 5,500 K. Spectral types may be further sub-divided

using a numerical sufﬁx ranging from 0-9 where 0 is the hottest and 9 is the coolest. Table 19.3 shows the

details of the various spectral types.

For about 90% of stars, the absolute magnitude increases as the spectral type tends to the O (hot) end of

the scale. Thus the whiter, hotter stars tend to have a greater luminosity. These stars are called main sequence

stars. There are however a number of stars that have spectral type at the M end of the scale, and yet they

The classic mnemonic for students of astrophysics says: “Oh, Be A Fine Girl, Kiss Me”.

264 Chapter 19. Astronomical Phenomena

Spectral Type Surface Temperature (K) Star Colour

O 28,000—50,000 Blue

B 10,000—28,000 Blue-white

A 7,500—10,000 White-blue

F 6,000—7,500 Yellow-white

G 4,900—6,000 Yellow

K 3,500—4,900 Orange

M 2,000—3,500 Red

Table 19.3: Spectral Types

Luminosity class Description

Ia, Ib Super-giants

II Bright giants

III Normal giants

IV Sub-giants

V Main sequence

VI Sub-dwarfs

VII White-dwarfs

Table 19.4: Luminosity Classiﬁcation

have a high absolute magnitude. These stars are close to the ends of their lives and have a very large size,

and consequently are known as giants, the largest of these known as super-giants.

There are also stars whose absolute magnitude is very low regardless of the spectral class. These are

known as dwarf stars, among them white dwarfs (dying stars) and brown dwarfs (“failed stars”).

The luminosity class is an indication of the type of star — whether it is main sequence, a giant or a

dwarf. Luminosity classes are denoted by a number in roman numerals, as described in table 19.4.

Plotting the luminosity of stars against their spectral type/surface temperature gives a diagram called a

Hertzsprung-Russell diagram (after the two astronomers EJNAR HERTZSPRUNG (1873–1967) and HENRY

NORRIS RUSSELL (1877–1957) who devised it). A slight variation of this is shown in ﬁgure 19.3 (which is

technically a colour/magnitude plot).

19.2.5 Variable Stars

Most stars are of nearly constant luminosity. The Sun is a good example of one which goes through relatively

little variation in brightness (usually about 0.1% over an 11 year solar cycle). Many stars, however, undergo

signiﬁcant variations in luminosity, and these are known as variable stars. There are many types of variable

stars falling into two categories, intrinsic and extrinsic.

Intrinsic variables are stars which have intrinsic variations in brightness, that is, the star itself gets

brighter and dimmer. There are several types of intrinsic variables, probably the best-known and most

important of which is the Cepheid variable whose luminosity is related to the period with which its brightness

varies. Since the luminosity (and therefore absolute magnitude) can be calculated, Cepheid variables may be

used to determine the distance of the star when the annual parallax is too small to be a reliable guide. This is

especially welcome because they are giant stars, and so they are even visible in neighboring galaxies.

Extrinsic variables are stars of constant brightness that show changes in brightness as seen from the

Earth. These include rotating variables, stars whose apparent brightness change due to rotation, and eclipsing

binaries.

Stellarium’s catalogs include many kinds variable stars. See section C.3 for more details.

19.3 Our Moon

The Moon is the large satellite which orbits the Earth approximately every 28 days. It is seen as a large bright

disc in the early night sky that rises later each day and changes shape into a crescent until it disappears near

the Sun. After this it rises during the day then gets larger until it again becomes a large bright disc again.

19.3 Our Moon 265

Figure 19.3: Hertzsprung-Russell Diagram

266 Chapter 19. Astronomical Phenomena

New Moon

The moon’s disc is fully in shadow, or there is just a slither of illuminated surface on

the edge.

Waxing Crescent

Less than half the disc is illuminated, but more is illuminated each night.

First Quarter

Approximately half the disc is illuminated, and increasing each night.

Waxing Gibbous

More than half of the disc is illuminated, and still increasing each night.

Full Moon

The whole disc of the moon is illuminated.

Waning Gibbous

More than half of the disc is illuminated, but the amount gets smaller each night.

Last Quarter

Approximately half the disc is illuminated, but this gets less each night.

Waning Crescent

Less than half the disc of the moon is illuminated, and this gets less each night.

Table 19.5: Lunar Phases

19.3.1 Phases of the Moon

As the moon moves round its orbit, the amount that is illuminated by the sun as seen from a vantage point on

Earth changes. The result of this is that approximately once per orbit, the moon’s face gradually changes

from being totally in shadow to being fully illuminated and back to being in shadow again. This process is

divided up into various phases as described in table 19.5.

19.3.2 The Lunar Magnitude

The eastern half of the Moon has more dark maria, therefore careful studies (Russell, 1916) have shown

that in the waxing phases the Moon is slightly brighter than in the waning phase of the same degree of

illumination.

Around Full Moon, the Moon shows an opposition surge, a strong increase in brightness which Krisciunas

and B. Schaefer (1991) describe as a 35% increase in luminous ﬂux over the curve extrapolated from

measurements when the phase angle α< 7

○

Of course, just at Full Moon when the opposition is near-perfect, the Moon will also move through

Earth’s shadow during a Lunar eclipse.

The Moon reﬂects not only sunlight which directly hits it, but also sunlight reﬂected from Earth to the

Moon (Agrawal, 2016). This earthshine, also known as ashen glow, is brightest when the Moon is most

strongly illuminated by the Earth, i.e., when the Moon as seen from Earth shows only a thin crescent. In these

days around the New Moon, the thin crescent can often be seen complemented into a softly glowing full disk.

Stellarium’s estimate for visual magnitude is based on the mentioned references and a new standard value

for the solar illumination constant of 133.1 klx (Ashdown, 2019).

19.4 The Major Planets

Unlike the stars whose relative positions remain more or less constant, the planets seem to move across the

sky over time (the word “planet” comes from the Greek for “wanderer”). The planets are siblings of the

Earth, massive bodies that are in orbit around the Sun. Until 2006 there was no formal deﬁnition of a planet,

leading to some confusion about the classiﬁcation for some bodies traditionally regarded as being planets,

but which didn’t seem to ﬁt with the others.

In 2006 the International Astronomical Union (IAU) deﬁned a planet as a celestial body that, within the

Solar System:

1. is in orbit around the Sun

has sufﬁcient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic

equilibrium (nearly round) shape; and

3. has cleared the neighbourhood around its orbit

or within another system:

1. is in orbit around a star or stellar remnants

2. has a mass below the limiting mass for thermonuclear fusion of deuterium; and

3. is above the minimum mass/size requirement for planetary status in the Solar System.

Moving from the Sun outwards, the 8 major planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn,

Uranus and Neptune. Since the formal deﬁnition of a planet in 2006 Pluto has been relegated to having the

status of dwarf planet, along with bodies such as Ceres and Eris. See ﬁgure 19.4.

19.5 The Minor Bodies 267

Figure 19.4: The Planets

19.4.1 Terrestrial Planets

The planets closest to the sun are called collectively the terrestrial planets. The terrestrial planets are:

Mercury, Venus, Earth and Mars.

The terrestrial planets are relatively small, comparatively dense, and have solid rocky surface. Most of

their mass is made from solid matter, which is mostly rocky and/or metallic in nature.

19.4.2 Jovian Planets

Jupiter, Saturn, Uranus and Neptune make up the Jovian planets, also called gas giants. They are much more

massive than the terrestrial planets, and do not have a solid surface. Jupiter is the largest of all the planets

with a diameter of about 12, and mass over 300 times that of the Earth!

The Jovian planets do not have a solid surface – the vast majority of their mass being in gaseous form

(although they may have rocky or metallic cores). Because of this, they have an average density which is

much less than the terrestrial planets. Saturn’s mean density is only about

0.7gcm

– it would ﬂoat in water!

19.4.3 Apparent Magnitudes of the Planets

The apparent magnitude of the planets can be found in astronomical almanachs. Over time, several scientiﬁc

studies have reﬁned these models. A few of them have been implemented in Stellarium:

Müller 1893

G. Müller formulated visual magnitudes for the planets from visual observations of 1877–1891.

They can be found in Meeus (1998) and Wilkins (1961). They give notably lower brightness estimates

than the later models, which however provide instrumental magnitudes in the Johnson V photometric

system. Several important historical studies from the early 20th century are based on these estimates.

Astronomical Almanac 1984

This model was used in the Astronomical Almanac starting in 1984. The

expressions are allegedly “due to D. L. Harris”, but J. Meeus (1998, p.286) denies this origin.

Explanatory Supplement 1992 Expressions from Seidelmann (1992).

Explanatory Supplement 2013 Expressions from Urban and Seidelmann (2013).

Mallama & Hilton 2018

The currently most modern expressions include e.g. a model for Mars which takes

the brightening and dimming of albedo features into account (Mallama and J. L. Hilton, 2018).

Generic A simple model based on albedo, size and distance.

19.5 The Minor Bodies

As well as the Major Planets, the solar system also contains innumerable smaller bodies in orbit around

the Sun. These are generally the dwarf planets (Ceres, Pluto, Eris), the other minor planets, also known as

planetoids or asteroids, and comets.

While the positions of the major planets can meanwhile be computed for many millennia in the past and

268 Chapter 19. Astronomical Phenomena

future, the minor bodies have only been systematically observed since the beginning of the 19th century.

The small masses occasionally pass by the larger planets which exert gravitational forces, so that the orbits

of the minor bodies are not stable and cannot be computed for long periods. The positions are computed by

using osculating orbital elements, which describe the motions on instantaneous Kepler orbits

. If you want

to compute positions of these objects with Stellarium, you need to have valid (current) orbital elements. See

Solar System Editor plugin (section 13.8) and Appendix D.2.2 for more details.

19.5.1 Asteroids

Asteroids are celestial bodies orbiting the Sun in more or less regular orbits mostly between Mars and Jupiter.

They are generally rocky bodies like the inner (terrestrial) planets, but of much smaller size. They are

countless in number ranging in size from about ten meters to hundreds of kilometres.

19.5.2 Comets

A comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or

atmosphere) and/or a tail.

Most comets have a very eccentric orbit (featuring a highly ﬂattened ellipse, or even a parabolic track),

and as such spend most of their time a very long way from the Sun. Comets are composed of rock, dust and

ices. When they come close to the Sun, the heat evaporates the ices, causing a gaseous release. This gas and

loose material which comes away from the body of the comet is swept away from the Sun by the Solar wind,

forming the tail. The outgassing may also change the orbit of the comet, so that its orbital elements should

be used only for a few months around their epoch.

Most larger comets exhibit two kinds of tail: a straight gas tail (often blue-green in photographs), and a

wider, occasionally curved dust tail (reﬂecting whitish sunlight).

Comets whose orbit brings them close to the Sun more frequently than every 200 years are considered

to be short period comets, the most famous of which is probably Comet Halley, named after the British

astronomer EDMUND HALLEY (1656–1741/42

), which has an orbital period of roughly 76 years.

19.6 Meteoroids

These objects are small pieces of space debris left over from the early days of the solar system or which

crumbled off a comet when it came close to the sun. These particles orbit the Sun and come in a variety of

shapes, sizes an compositions, ranging from microscopic dust particles up to about ten meters across.

Sometimes these objects collide with the Earth. The closing speed of these collisions is generally

extremely high (tens of kilometres per second). When such an object ploughs through the Earth’s atmosphere,

a large amount of kinetic energy is converted into heat and light, and a visible ﬂash or streak can often be

seen with the naked eye. Even the smallest particles can cause these events which are commonly known as

shooting stars.

While smaller objects tend to burn up in the atmosphere, larger, denser objects can penetrate the

atmosphere and strike the surface of the planet, sometimes leaving meteor craters.

Sometimes the angle of the collision means that larger objects pass through the atmosphere but do not

strike the Earth. When this happens, spectacular ﬁreballs are sometimes seen.

To clarify some terminology:

Meteoroids are the objects when they are ﬂoating in space.

Meteor is the name given to the visible atmospheric phenomenon.

Shooting Star colloquial term for a small meteor

Fireball, Bolide

term for a very bright meteor. These illuminate the landscape, sometimes for several

seconds, and occasionally even cause sounds. These are also candidates for

Meteorites , the objects that penetrate the atmosphere and land (or impact) on the surface.

In some nights over the year you can observe increased meteorite activity. Those meteors seem to come

from a certain point in the sky, the Radiant. But what we see is similar to driving through a mosquito swarm

The ﬁrst discovered asteroid, (1) Ceres, was in fact discovered on January 1, 1801.

The mathematician and astronomer JOHANN ES KEPLER (1571–1630) discovered that planets do not move on

circles (which had been postulated since antiquity), but on “conical sections”, i.e., ellipses, parabolae or even hyperbolae.

The latter two can be observed for far-out comets and recently even interstellar objects passing the Sun.

EDMUND HALLEY lived in a time when Great Britain still used the Julian calendar and started the years in March.

He died on January 14th, 1741 (British Julian), which was called January 25th 1742 (Gregorian) in most other European

countries.

19.7 Zodiacal Light and Gegenschein 269

which all seem to come head-on. Earth itself moves through space, and sweeps up a dense cloud of particles

which originates from a comet’s tail. Stellarium’s Meteor Shower plugin (see section 14.6) can help you

planning your next meteor observing night.

19.7 Zodiacal Light and Gegenschein

In very clear nights on the best observing sites, far away from the light pollution of our cities, you can

observe a feeble glow also known as “false twilight” after evening twilight in the west, or before dawn in the

east. The glow looks like a wedge of light along the ecliptic. Exactly opposite the sun, there is another dim

glow that can be observed with dark-adapted eyes in perfect skies: the Gegenschein (counterglow).

This is sunlight reﬂected off the same dust and meteoroids in the plane of our solar system which is the

source of meteors. Stellarium’s sky can show the Zodiacal light (Kwon, Hong, and Weinberg, 2004), but

observe how quickly light pollution kills its visibility!

19.8 The Milky Way

There is a band of very dense stars running right round the sky in huge irregular stripe. Most of these stars

are very dim, but the overall effect is that on very dark clear nights we can see a large, beautiful area of

diffuse light in the sky. It is this for which we name our galaxy the Milky Way.

The reason for this effect is that our galaxy is somewhat like a disc, and we are off to one side. Thus

when we look towards the centre of the disc, we see more a great concentration of stars (there are more star

in that direction). As we look out away from the centre of the disc we see fewer stars - we are staring out

into the void between galaxies!

It’s a little hard to work out what our galaxy would look like from far away, because when we look up at

the night sky, we are seeing it from the inside. All the stars we can see are part of the Milky Way, and we can

see them in every direction. However, there is some structure. There is a higher density of stars in particular

places.

19.9 Nebulae

Seen with the naked eye, binoculars or a small telescope, a nebula (plural nebulae) is a fuzzy patch on the

sky. Historically, the term referred to any extended object, but the modern deﬁnition excludes some types of

object such as galaxies.

Observationally, nebulae are popular objects for amateur astronomers – they exhibit complex structure,

spectacular colours (in most cases only visible in color photography) and a wide variety of forms. Many

nebulae are bright enough to be seen using good binoculars or small to medium sized telescopes, and are a

very photogenic subject for astro-photographers.

Nebulae are associated with a variety of phenomena, some being clouds of interstellar dust and gas in

the process of collapsing under gravity, some being envelopes of gas thrown off during a supernova event

(so called supernova remnants), yet others being the remnants of dumped outer layers around dying stars

(planetary nebulae).

Examples of nebulae for which Stellarium has images include the Crab Nebula (M1), which is a

supernova remnant, and the Dumbbell Nebula (M27) and the Ring Nebula (M57) which are planetary

nebulae.

19.9.1 The Messier Objects

The Messier objects are a set of astronomical objects catalogued by CHARLES MESSIER (1730–1817) in his

catalogue of Nebulae and Star Clusters ﬁrst published in 1774. The original motivation behind the catalogue

was that Messier was a comet hunter, and he was frustrated by objects which resembled but were not comets.

He therefore compiled a list of these annoying objects.

The ﬁrst edition covered 45 objects numbered M1 to M45. The total list consists of 110 objects, ranging

from M1 to M110. The ﬁnal catalogue was published in 1781 and printed in the Connaissance des Temps in

1784. Many of these objects are still known by their Messier number.

Because the Messier list was compiled by astronomers in the Northern Hemisphere, it contains only

objects from the north celestial pole to a celestial latitude of about

−35

°. Many impressive Southern objects,

such as the Large and Small Magellanic Clouds are excluded from the list. Because all of the Messier objects

are visible with binoculars or small telescopes (under favourable conditions), they are popular viewing

270 Chapter 19. Astronomical Phenomena

objects for amateur astronomers. In early spring, astronomers sometimes gather for “Messier Marathons”,

when all of the objects can be viewed over a single night.

Stellarium includes images of many Messier objects.

19.9.2 The Caldwell catalogue

The Caldwell catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation

by amateur astronomers. The list was compiled by PATRICK MOORE (1923–2012) as a complement to the

Messier catalogue (O’Meara, 2003).

While the Messier catalogue is used by amateur astronomers as a list of deep-sky objects for observation,

Moore noted that Messier’s list was not compiled for that purpose and excluded many of the sky’s brightest

deep-sky objects (O’Meara, 2003), such as the Hyades, the Double Cluster (NGC 869 and NGC 884), and

the Sculptor Galaxy (NGC 253). The Messier catalogue was actually compiled as a list of known objects that

might be confused with comets. Moore also observed that since Messier compiled his list from observations

in Paris, it did not include bright deep-sky objects visible in the Southern Hemisphere, such as Omega

Centauri, Centaurus A, the Jewel Box, and 47 Tucanae (O’Meara, 2003). Moore compiled a list of 109

objects to match the commonly accepted number of Messier objects (he excluded M110 (Moore, 1995)), and

the list was published in Sky & Telescope in December 1995 (Moore, 1995).

Moore used his other surname – Caldwell – to name the list, since the initial of “Moore” is already

used for the Messier catalogue (O’Meara, 2003). Entries in the catalogue are designated with a “C” and the

catalogue number (1 to 109).

Unlike objects in the Messier catalogue, which are listed roughly in the order of discovery by Messier

and his peers, the Caldwell catalogue is ordered by declination, with C1 being the most northerly and C109

being the most southerly (O’Meara, 2003), although two objects (C 26=NGC 4244 and C 41, the Hyades)

are listed out of sequence (O’Meara, 2003). Other errors in the original list have since been corrected: it

incorrectly identiﬁed the S Norma Cluster (C 89=NGC 6087) as NGC 6067 and incorrectly labelled the

Lambda Centauri Cluster (C 100=IC 2944) as the Gamma Centauri Cluster (O’Meara, 2003).

19.10 Galaxies

Stars, it seems, are gregarious – they like to live together in groups. These groups are called galaxies. The

number of stars in a typical galaxy is literally astronomical – many billions – sometimes over hundreds of

billions of stars!

Our own star, the sun, is part of a galaxy. When we look up at the night sky, all the stars we can see are

in the same galaxy. We call our own galaxy the Milky Way (or sometimes simply “the Galaxy”

Other galaxies appear in the sky as dim fuzzy blobs. Only four are normally visible to the naked eye.

The Andromeda galaxy (M31) visible in the Northern hemisphere, the two Magellanic clouds, visible in the

Southern hemisphere, and the home galaxy Milky Way, visible in parts from north and south under dark

skies.

There are thought to be billions of galaxies in the universe comprised of an unimaginably large number

of stars.

The vast majority of galaxies are so far away that they are very dim, and cannot be seen without large

telescopes, but there are dozens of galaxies which may be observed in medium to large sized amateur

instruments. Stellarium includes images of many galaxies, including the Andromeda galaxy (M31), the

Pinwheel Galaxy (M101), the Sombrero Galaxy (M104) and many others.

Astronomers classify galaxies according to their appearance. Some classiﬁcations include spiral galaxies,

elliptical galaxies, lenticular galaxies and irregular galaxies.

19.11 Eclipses and Transits

Eclipses occur when an apparently large celestial body (planet, moon etc.) moves between the observer and

a more distant object – the more distant object being eclipsed by the nearer one.

19.11.1 Solar Eclipses

Solar eclipses occur when our Moon moves between the Earth and the Sun. This happens when the inclined

orbit of the Moon causes its path to cross the ecliptic and our line of sight to the Sun. In essence it is the

observer falling under the shadow of the Moon.

Which means closely the same thing, the word deriving from Greek gala=milk.

19.11 Eclipses and Transits 271

By a wonderful coincidence, Sun and Moon appear of almost identical size in Earth’s sky, but the Moon’s

elliptical orbit sometimes causes it to appear just a bit smaller than the Sun.

There are therefore three types of solar eclipses:

Partial

The Moon only covers part of the Sun’s surface which, for higher eclipse magnitudes, appears as

crescent.

Total The Moon completely obscures the Sun’s surface.

Annular

The Moon is at or close to apogee (furthest from Earth in its elliptic orbit) and its disc is too small

to completely cover the Sun. In this case most of the Sun’s disc is obscured – all except a thin ring

around the edge.

Sometimes the eclipse starts annular, but when the shadow reaches the part of the globe closest to the Moon,

it becomes just large enough to cover the sun totally, and when receding, it may go back to the annular

characteristic. This is called annular-total in the classical literature, or hybrid in more recent works.

19.11.2 Lunar Eclipses

Lunar eclipses occur when the Earth moves between the Sun and the Moon, and the Moon is in the Earth’s

shadow. They occur under the same basic conditions as the solar eclipse but appear to occur more often

because the Earth’s shadow is so much larger than the Moon’s, and a Lunar eclipse is observable from more

than half the Earth’s surface, while a Solar eclipse is limited to a smaller region.

The geometrical begin of a Lunar eclipse is totally unobservable: Seen from a point near the observable

edge of the Lunar surface, the large black disk of Earth just touches the Solar disk. While the time of this

event can be determined, the effect on the apparent brightness of the Moon’s surface as observed from Earth

is close to zero. Only as more of the Solar disk is occulted by Earth, this spot on the Lunar surface will

receive less sunlight and will appear darker when observed from Earth. A rule of thumb says that 70% of

the Moon must enter the Earth’s penumbra (partial shadow) before a light defect can be noted by attentive

human observers.

The Earth’s umbra (deep shadow) is then much darker. As soon as an observer on the Lunar edge

experiences a Total Solar eclipse, observers on Earth see the begin of the partial eclipse.

Total lunar eclipses are more noticeable than partial eclipses because the Moon moves fully into the

Earth’s shadow and there is very noticeable darkening. However, the Earth’s atmosphere refracts light (bends

it) in such a way that some sunlight can still fall on the Moon’s surface even during total eclipses. The

blue parts of sunlight are scattered and ﬁltered away, so that there is a marked reddening of the light as it

passes through the atmosphere, and this makes the Moon appear in a deep red colour. The darkness and

colors are notably inﬂuenced by atmospheric clarity and clouds. After big volcanic eruptions eclipses are

often reported to appear darker. ANDRÉ DAN JON (1890–1967) has introduced a scale for the apparent

brightness of the fully eclipsed Moon, where 0 is given for extremely dark eclipses and 4 for very bright ones.

These unpredictable brightness differences make accurate simulation of the exact appearance impossible, but

Stellarium’s display gives a pretty good impression for eclipses given as 2-3 on this Danjon scale.

Earth’s atmosphere also makes the shadow slightly larger than what can be derived by the geometrical

sizes and distances of the involved objects. The Astronomical Almanac uses a traditional enlargement by 2%

after WILLIAM CHAUVENET (1820–1870) while recent eclipse experts prefer another formulation which

leads to a slightly smaller enlargement after ANDRÉ DANJON (Espenak and Meeus, 2009). You can select

which formulation you prefer (see section 4.4.2).

19.11.3 Transits

The term “transit” generally describes the passage of one object in front of another

. The most prominent

examples are the passages of the inferior planets Mercury or Venus between the Sun and Earth, where they

appear as tiny black disks on the glaringly bright Solar disk. The disk of Venus can be seen with the unaided

eye

, while Mercury is too small to be discernible.

Observing the transits of Venus from various locations on Earth was an important scientiﬁc endeavour in

previous centuries. It allows a direct determination of the distance scale in the Solar System. Unfortunately,

these transits are rare events: After two such transits 8 years apart, there is a gap lasting more than a century.

The last such transits occurred in 2004 and 2012. Mercury’s transits are much more frequent.

In the telescope age, this also can be a passage of a Jovian Moon in front of Jupiter, or even the passage

of a shadow of such a moon over Jupiter’s disk, or, more recently, the passage of an artiﬁcial satellite in front

of the Sun or Moon.

Another “transit” means the crossing of the meridian by the object.

Never look into the Sun without proper ﬁlters!

272 Chapter 19. Astronomical Phenomena

19.11.4 Contact Times

Eclipse and transit observers like to prepare tables of precomputed contact times for which they use

terminology shown in Tables 19.6-19.8.

19.12 Observing Hints

When stargazing, there’s a few little things which make a lot of difference, and are worth taking into account.

Dark skies

For many people getting away from light pollution isn’t an easy thing. At best it means a drive

away from the towns, and for many the only chance to see a sky without signiﬁcant glow from street

lighting is on vacation. If you can’t get away from the cities easily, make the most of it when you are

away.

Wrap up warm

The best observing conditions are the same conditions that make for cold nights, even in

the summer time. Observing is not a strenuous physical activity, so you will feel the cold more than

if you were walking around. Wear a lot of warm clothing, don’t sit/lie on the ﬂoor (at least use a

camping mat, better take a deck-chair), and take a ﬂask of hot drink.

Dark adaptation

The true majesty of the night sky only becomes apparent when the eye has had time to

become accustomed to the dark. This process, known as dark adaptation, can take up to half an hour,

and as soon as the observer sees a bright light they must start the process over. Red light doesn’t

compromise dark adaptation as much as white light, so use a red torch if possible (and one that is as

dim as you can manage with). A dim single red LED light is ideal, also to have enough light to take

notes.

The Moon

Unless you’re particularly interested in observing the Moon on a given night, it can be a

nuisance—it can be so bright as to make observation of dimmer objects such as nebulae impossible.

When planning what you want to observe, take the phase and position of the Moon into account. Of

course Stellarium is the ideal tool for ﬁnding this out!

Averted vision

A curious fact about the eye is that it is more sensitive to dim light towards the edge of

the ﬁeld of view. If an object is slightly too dim to see directly, looking slightly off to the side but

concentrating on the object’s location can often reveal it.

Angular distance

Learn how to estimate angular distances. Learn the angular distances described in

section 18.5.2. If you have a pair of binoculars, ﬁnd out the angular distance across the ﬁeld of view

and use this as a standard measure.

19.13 Atmospheric effects

19.13.1 Atmospheric Extinction

Atmospheric Extinction is the attenuation of light of a celestial body by Earth’s atmosphere. In the last

split-second of its travel into our eyes or detectors, light from outer space has to pass our atmosphere, through

layers of mixed gas, water vapour and dust. If a star is in the zenith, its light must pass one air mass and is

reduced by whatever amount of water and dust is above you. When the star is on the horizon, it has to pass

about 40 times longer through the atmosphere: 40 air masses (Fig. 19.5). The number of air masses increases

fast in low altitudes, this is why we see so few stars along the horizon. Usually blue light is extinguished

more, this is why the sun and moon (and brighter stars) appear reddish on the horizon.

Stellarium can simulate extinction, and you can set the opacity of your atmosphere with a global factor

, the magnitude loss per airmass (see section 4.4.1.2). The best mountaintop sites may have

k = 0.15

, while

k = 0.25 seems a value usable for good locations in lower altitudes.

19.13.2 Atmospheric Refraction

Atmospheric Refraction is a lifting effect of our atmosphere which can be observed by the fact that objects

close to the horizon appear higher than they should be if computed only with spherical trigonometry.

Stellarium simulates refraction for terrestrial locations when the atmosphere is switched on. Refraction

depends on air pressure and temperature. Figure 19.6 has been created from the same formulae that are

employed in Stellarium. You can see how fast refraction grows very close to the mathematical horizon.

Note that these models can only give approximate conditions. There are many weird effects in the real

atmosphere, when temperature inversion layers can create light ducts, double sunsets etc.

Also note that the models give meaningful results only for altitudes above approximately

−2

°. Below

that, in nature, there is always ground which blocks our view. In Stellarium you can switch off the ground,

and you can observe a sunset with a strange egg-shaped sun below the horizon. This is of course nonsense.

19.13 Atmospheric effects 273

Contact Name Description

First Begin of partial eclipse Moon ﬁrst touches Sun from the outside

Second Begin of totality Moon completely covers the Sun

Mid-eclipse central time

Third End of totality Bright Solar edge re-appears from complete occultation

Fourth End of partial eclipse Moon leaves Sun completely

Table 19.6: Contact terminology for Total Solar eclipses.

Contact Name, Description

First Penumbral Begin of (penumbral) eclipse. Unobservable.

Moon ﬁrst touches Earth’s geometrical shadow cone from the outside.

Second Penumbral Begin of total immersion in penumbra

Moon shows a notable darkening

First Umbral Begin of partial eclipse

Moon ﬁrst touches the central dark shadow

Second Umbral Begin of totality

Moon completely immersed in Earth’s umbra (dark shadow)

Maximum Mid-eclipse, central time

Third Umbral End of totality

A bright Lunar edge re-appears from complete occultation

Fourth Umbral End of partial eclipse

Moon leaves umbra completely

Third Penumbral End of total penumbral phase

Lunar edge leaves penumbra. The opposide side is still darkened

Fourth Penumbral End of (penumbral) eclipse. Unobservable.

Moon leaves penumbra completely.

Table 19.7: Contact terminology for Lunar eclipses. Depending on shadow geometry, the second

penumbral contact may occur only after the ﬁrst umbral, and third penumbral contact before fourth

umbral.

Contact Name Description

First Exterior Ingress Planet/Moon ﬁrst touches Sun from the outside

Second Interior Ingress Planet/Moon starts to be visible completely inside Sun

Mid-transit central time

Third Interior Egress Planet/Moon ﬁrst touches Sun from the inside

Fourth Exterior Egress Planet/Moon leaves Sun completely

Table 19.8: Contact terminology for Transits and Annular Solar eclipses.

274 Chapter 19. Astronomical Phenomena

0 10 20 30 40 Airmass

−2 −1 0 1 2 3 4 5 6

mag =

0°

5°

10°

15°

0.4

0.3

0.25

0.2

0.175

0.15

0.125

Star invisible at k_v

0.4

0.3

0.25

0.2

0.175

0.15

0.125

Absorption [Dmag] k_v

Airmass, Absorption and Extinction Angle (m_z=6.5; apparent altitudes)

(Model: Schaefer, S&T4/1987; Airmass: Rozenberg 1966; Observations: Müller 1970)

Figure 19.5: Airmass and Extinction. The ﬁgure shows Airmass (blue) along the line of sight in the

altitude labeled on the left side. The green curves show how many magnitudes an object is dimmed

down, depending on extinction factor

(called

in the ﬁgure). The red curves indicate at which

altitude a star of given magnitude can be seen with good eyesight, again depending on

. The black

dots are observed values found in the literature.

19.13 Atmospheric effects 275

−1.3° −1.2° −1.1° −1.0° −0.9° −0.8° −0.7° −0.6° −0.5° −0.4° −0.3° −0.2° −0.1° 0.0° 0.1° 0.2° 0.3° 0.4° 0.5° 0.6° 0.7° 0.8° 0.9°

Dalt

−10°

−5°

0°

5°

10°

15°

20°

25°

1013.25 mbar, 10°C

Temperature: −60..10..50°C

Pressure: −500..100..1100 mbar

Bennett’s Formula

Correction of observed altitudes

Sæmundsson’s Formula

Correction of geometric altitudes

Refraction

(Model: Meeus, Astr.Alg.1994)

Figure 19.6: Refraction. The ﬁgure shows corrective values (degrees) which are subtracted from observed altitudes (left side) to reach geometric altitudes, or

values to be added to computed values (right side). The models used are not directly inverse operations.

276 Chapter 19. Astronomical Phenomena

Stellarium is also not able to properly recreate the atmospheric distortions as seen from a stratosphere balloon,

where the height of earth’s surface is several degrees below the mathematical horizon.

19.13.2.1 Scintillation

Scintillation is the scientiﬁc name of the twinkling which stars show in turbulent atmosphere. The twinkling

is caused by moving pockets of air with different temperature. Observe a star low on the horizon with a

telescope, and you will note it does not stand still but dances around a bit, often also changing color to show

red or blue hues. While the twinkling of stars may look ﬁne and comforting to the naked eye on a nice warm

summer evening, telescopic observers and astrophotographers don’t like it at all. They rather complain about

“bad seeing”, because it deteriorates the optical resolution of their instruments and photographs.

Just like extinction and refraction are stronger along the horizon, stars in low altitude in general show

more twinkling than stars higher up in the sky.

Note that planets seem to be affected less by scintillation: they are not point sources, but little disks,

and so the effect of the turbulent pockets of air distorting different parts of the disks cancels out a bit when

observing with the naked eye: planets appear to be more stable. Of course, the view in a telescope will still

be deteriorated by the turbulent atmosphere.

While bad seeing was one key motivation of sending telescopes into earth orbit since the 1970s, the

latest generation of ground-based giant telescopes is able to compensate for the turbulent motion by rapidly

deforming their secondary mirror.

19.13.3 Light Pollution

An ugly side effect of civilisation is a steady increase in outdoor illumination. Many people think it increases

safety, but while this statement can be questioned, one deﬁnite result, aside from environmental issues

like dangers for the nocturnal fauna, are ever worsening conditions for astronomical observations or just

enjoyment of the night sky.

Stellarium can simulate the effect of light pollution on the visibility of celestial objects. This is controlled

from the light pollution section of the Sky tab of the View window (see section 4.11). Light pollution levels

are set using a numerical value between 1 and 9 which corresponds to the Bortle Dark Sky Scale (see

Appendix B). Given that public lighting became bright enough to cause adverse effects on observability only

during the 19th century, Stellarium presents an unpolluted sky for dates before 1825. Note that of course

light pollution was not switched on over night, but became gradually noticeable over decades, but you have

to estimate the appropriate level.

In addition, local variations of the amount of light pollution can be included in a light pollution layer in

the landscapes, see section 7 for details. This foreground layer may include all kinds of light, e.g. campﬁres,

so this is also available for earlier dates.

20. A Little Sky Guide

PAUL ROBINSON, WITH ADDITIONS BY ALEXANDER WOLF

This chapter lists some astronomical objects that can be located using Stellarium. All of them can be seen

with the naked eye or binoculars. Since many astronomical objects have more than one name (often having a

“proper name”, a “common name” and various catalogue numbers), the chapter lists the name as it appears

in Stellarium — use this name when using Stellarium’s search function — and any other commonly used

names.

The Location Guide entry gives brief instructions for ﬁnding each object using nearby bright stars or

groups of stars when looking at the real sky — a little time spent learning the major constellations visible

from your latitude will pay dividends when it comes to locating fainter (and more interesting!) objects. When

trying to locate these objects in the night sky, keep in mind that Stellarium displays many stars that are too

faint to be visible without optical aid, and even bright stars can be dimmed by poor atmospheric conditions

and light pollution.

20.1 Dubhe and Merak, The Pointers

Type: Stars

Magnitude: 1.83, 2.36

Location Guide: The two “rightmost” of the seven stars that form the main shape of “The Plough” (or

“Big Dipper”, part of Ursa Major).

Northern hemisphere observers are very fortunate to have two stars that point towards Polaris, which lies

very close to the Northern Celestial Pole. Whatever the time of night or season of the year, they are always

an immediate clue to the location of Polaris, the Pole Star.

20.2 M31, Messier 31, The Andromeda Galaxy

Type: Spiral Galaxy

Magnitude: 3.4

Location Guide: Find the three bright stars that constitute the main part of the constellation of Andromeda.

From the middle of these look toward the constellation of Cassiopeia.

M31 is the most distant object visible to the naked eye, and among the few nebulae that can be seen

without a telescope or powerful binoculars. Under good conditions it appears as a large fuzzy patch of light.

It is a galaxy containing billions of stars whose distance is roughly 2.5 million light years from Earth.

278 Chapter 20. A Little Sky Guide

20.3 The Garnet Star, µ Cephei

Type: Variable Star

Magnitude: 4.25 (Avg.)

Location Guide: Cephius lies “above” the W-shape of Cassiopeia. The Garnet Star lies slightly to one side

of a point halfway between 5 Cephei and 21 Cephei.

A “supergiant” (1035 solar radii) of spectral class M with a strong red colour. Given its name by Sir

William Herschel in the 18th century, the colour is striking in comparison to its blue-white neighbours.

20.4 4 and 5 Lyrae, ε Lyrae

Type: Double Star

Magnitude: 4.7

Location Guide: Close to Vega (α Lyrae), one of the brightest stars in the sky.

In binoculars

Lyrae is resolved into two separate stars. Remarkably, each of these is also a double star

(although this will only be seen with a telescope) and all four stars form a physical system.

20.5 M13, Hercules Cluster

Type: Globular Cluster

Magnitude: 5.8

Location Guide: Located approximately 1/3 of the way along a line from 44 (η) to 40 (ζ ) Herculis.

This cluster of hundreds of thousands of mature stars appears as a circular “cloud” using the naked eye

or binoculars (a large telescope is required to resolve individual stars). Oddly the cluster appears to contain

one young star and several areas that are almost devoid of stars.

20.6 M45, The Pleiades , The Seven Sisters

Type: Open Cluster

Magnitude: 1.2 (Avg.)

Location Guide: Lies on the Bull’s back, about 1/3 between Aldebaran in Taurus and Almaak in Andromeda.

Depending upon conditions, 6 to 9 of the blueish stars in this famous cluster will be visible to someone

with average eyesight, and in binoculars it is a glorious sight. The cluster has more than 500 members in

total, many of which are shown to be surrounded by nebulous material in long exposure photographs.

20.7 C41, The Hyades

Type: Open Cluster

Magnitude: 0.5 (Avg.)

Location Guide: Lies near Aldebaran in Taurus.

The Hyades span about 6° of sky because they are one of the nearest open clusters, being about 153 light

years away. The age of the Hyades is estimated to be about 625 million years. The ﬁve brightest member

stars of the Hyades have consumed their hydrogen fuel in their cores and are now evolving into giant stars.

Four of these stars, with Bayer designations

, and

Tauri, form an asterism that is traditionally

identiﬁed as the head of Taurus, the Bull.

20.8 Algol, The Demon Star, β Persei

Type: Variable Star

Magnitude: 3.0 (Avg.)

Location Guide: Halfway between Aldebaran in Taurus and the middle star of the “W” of Cassiopeia.

Once every three days or so, Algol’s brightness changes from 2.1 to 3.4 and back within a matter of

hours. The reason for this change is that Algol has a dimmer giant companion star, with an orbital period of

about 2.8 days, that causes a regular partial eclipse. Although Algol’s ﬂuctuations in magnitude have been

known since at least the 17th century, it was the ﬁrst to be proved to be due to an eclipsing companion — it

is therefore the prototype Eclipsing Variable.

20.9 Sirius, α Canis Majoris 279

20.9 Sirius, α Canis Majoris

Type: Star

Magnitude: -1.47

Location Guide: Sirius is easily found by following the line of three stars in Orion’s belt southwards.

Sirius is a white dwarf star at a comparatively close 8.6 light years. This proximity and its high innate

luminance makes it the brightest star in our sky. Sirius is a double star; its companion is a white dwarf, much

dimmer but very hot, and is believed to be smaller than Earth.

20.10 M44, The Beehive, Praesepe

Type: Open Cluster

Magnitude: 3.7

Location Guide: Cancer lies about halfway between the twins (Castor & Pollux) in Gemini and Regulus,

the brightest star in Leo. The Beehive can be found between Asellus Borealis and Asellus Australis.

There are probably 350 or so stars in this cluster, although it appears to the naked eye simply as a misty

patch. It contains a mixture of stars from red giants to white dwarf and is estimated to be some 700 million

years old.

20.11 27 Cephei, δ Cephei

Type: Variable Star

Magnitude: 4.0 (Avg.)

Location Guide: Locate the four stars that form the square of Cepheus. One corner of the square has two

other bright stars nearby forming a distinctive triangle —

is at the head of this triangle in the direction of

Cassiopeia.

Cephei gives its name to a whole class of variables, all of which are pulsating high-mass stars in the

later stages of their evolution.

Cephei is also a double star with a companion of magnitude 6.3 visible in

binoculars.

20.12 Betelgeuse, α Orionis, 58 Orionis

Type: Star

Magnitude: 0.45

Location Guide: The distinctly reddish star in the constellation of Orion – one of the shoulders of Orion.

Betelgeuse is a distinctly reddish, semiregular variable star whose apparent magnitude varies between

0.0 and 1.3. It is classiﬁed as a red supergiant of spectral type M1-2, and is one of the largest stars visible

to the naked eye. If Betelgeuse were at the center of the Solar System, its surface would extend past the

asteroid belt, completely engulﬁng the orbits of Mercury, Venus, Earth, Mars, and possibly Jupiter.

In 1920, Betelgeuse became the ﬁrst extrasolar star to have the angular size of its photosphere measured.

Subsequent studies have reported an angular diameter (apparent size) ranging from 0.042 to 0.056 arcseconds,

with the differences ascribed to the non-sphericity, limb darkening, pulsations, and varying appearance at

different wavelengths. It is also surrounded by a complex, asymmetric envelope roughly 250 times the size

of the star, caused by mass loss from the star itself.

20.13 M42, The Great Or ion Nebula

Type: Nebula

Magnitude: 4.0

Location Guide: Almost in the middle of the area bounded by Orion’s belt and lower stars, Saiph and Rigel.

The Great Orion Nebula is the brightest nebula visible in the night sky and lies at about 1.500 light years

from Earth. It is a truly gigantic gas and dust cloud that extends for several hundred light years, reaching

almost halfway across the constellation of Orion. The nebula contains a cluster of hot young stars known as

the Trapezium, and more stars are believed to be forming within the cloud.

20.14 La Superba, Y Canum Venaticorum, HIP 62223

Type: Star

Magnitude: 5.4 (Avg.)

280 Chapter 20. A Little Sky Guide

Location Guide: Almost the center of the arch of stars of Ursa Major’s tail. Forms a neat triangle with

Phekda (γ) and Alkaid (η, tail tip) in Ursa Major towards Canes Venatici.

La Superba (215 solar radii) is a “Carbon Star” — a group of relatively cool gigantic (usually variable)

stars that have an outer shell containing high levels of carbon. This shell is very efﬁcient at absorbing the

short wavelengths of blue light, giving carbon stars a distinctive red or orange tint. It is one of the coolest

and reddest known stars.

20.15 52 and 53 Bootis, ν

and

Bootis

Type: Double Star

Magnitude: 5.0, 5.0

Location Guide: Follow a line from Seginus (

Boo, left shoulder) to Nekkar (

Boo, the head) and then

continue for the same distance again to arrive at this double star.

This optical double star consists of a pair of different spectral types. 52 Bootis, at approximately 800

light years, is twice as far away as 53 Boo.

20.16 Almach, γ Andromedae

Type: Multiple Star

Magnitude: 2.15 (Avg.)

Location Guide: The bright star located in the “legs” of Andromeda.

In 1778, JOHANN TOBIAS MAYER discovered that

Andromedae was a double star. When examined in

a small telescope, it appears to be a bright, golden-yellow star (

Andromedae) next to a dimmer, indigo-blue

star (

Andromedae), separated by approximately

′′

. It is often considered by stargazers to be a beautiful

double star with a striking contrast of color. It was later discovered that

Andromedae is itself a triple star

system. What appears as a single star to the naked eye is thus a quadruple star system.

20.17 Algieba, γ Leonis, 41 Leonis

Type: Double Star

Magnitude: 2.20 (Avg.)

Location Guide: The third brightest star in the constellation Leo – located on the “neck” of Leo.

The bright binary system in Leo with orange-red and yellow or greenish-yellow components is visible

through a modest telescope under good atmospheric conditions. To the naked eye, the Algieba system shines

at mid-second magnitude, but a telescope easily splits the pair. On November 6, 2009, the discovery of a

planetary companion around primary star γ

Leonis (

γ Leonis A) was announced.

20.18 Castor, α Geminorum

Type: Multiple Star

Magnitude: 1.9 (Avg.)

Location Guide: Castor is the second-brightest object in the constellation of Gemini.

Castor is a multiple star system made up of six individual stars; there are three visual components, all of

which are spectroscopic binaries. Appearing to the naked eye as a single star, Castor was ﬁrst recorded as a

double star in 1718 by JAMES POUND, but it may have been resolved into at least two sources of light by

Cassini as early as 1678. The separation between Castor A and Castor B has increased from about

′′

arcseconds) in 1970 to about 6

′′

in 2017. These two binary pairs have magnitudes of 1.9 and 3.0.

Both components have much fainter companions, Castor Aa and Ba, and both have orbits of a few days.

Castor C, or YY Geminorum, was discovered to vary in brightness with a regular period. It is an

eclipsing binary with additional variations due to areas of different brightness on the surface of one or both

stars, as well as irregular ﬂares. The Castor C components orbit each other in less than a day. Castor C is

believed to be in orbit around Castor AB, but with an extremely long period of several thousand years. It is

′′

distant from the bright components.

20.19 PZ Cas, HIP 117078

Type: Variable Star

Magnitude: 8.2 (Avg.)

20.20 VV Cephei, HIP 108317 281

Location Guide: Lies about 1/3 between Caph (

Cas, the top right star of “W”) in Cassiopeia and

Cephei (32 Cep, top left star in “rectangle” of Cepheus).

This faint red star is one of the biggest known stars — its average size parameter is 1565 solar radii (the

true value is from 1340 to 1940 solar radii). PZ Cas is a pulsating variable star located in a region with heavy

dust extinction.

20.20 VV Cephei, HIP 108317

Type: Variable Star, Double Star

Magnitude: 5.1 (Avg.)

Location Guide: Lies near the center of the “rectangle” of Cepheus).

This is an interesting eclipsing binary system — VV Cep A (1457 solar radii) is a highly distorted star in

a binary system, losing mass to its B-type companion VV Cephei B (10 solar radii) for at least part of its

orbit.

20.21 AH Scorpii, HIP 84071

Type: Variable Star

Magnitude: 7.1 (Avg.)

Location Guide: Lies in Scorpius, about 1

of a continuation of the Scorpion’s “tail”.

AH Sco (1411 solar radii) is variable by nearly 3 magnitudes in the visual range, and an estimated 20%

in total luminosity. The variation in diameter is not clear because the temperature also varies.

20.22 Albireo, β Cygni

Type: Double Star

Magnitude: 3.4, 5.1

Location Guide: The “head” of Cygni.

When viewed with the naked eye, it appears to be a single star. However, in a telescope it readily resolves

into a double star, consisting of Albireo A (amber), and Albireo B (blue-green). Separated by

′′

, the two

components provide one of the best contrasting double stars in the sky due to their different colors.

Figure 20.1: Albireo: A Bright and Beautiful Double. Credit & Copyright: Richard Yandrick.

20.23 31 and 32 Cygni, o

and o

Cygni

Type: Multiple Star

Magnitude: 3.8, 4.0

Location Guide: The two bright stars about 1/2 between Deneb (

Cygni, “tail” of Cygnus) and Rukh (

Cygni, middle of the left “wing” of Cygnus).

282 Chapter 20. A Little Sky Guide

The wide binary

Cygni and

Cygni is separated 61

′

(NNE), and this star is an easy naked-eye

double.

Cygni with 30 Cyg and HD 192579 (HIP 99676) is a moderately difﬁcult triple system. And

surprise — each of o

Cyg and o

Cyg are also Algol-type eclipsing binaries!

20.24 The Coathanger, Brocchi’s Cluster, Cr 399

Type: Asterism

Location Guide: It is best found by slowly sweeping across the Milky Way along an imaginary line from the

bright star Altair toward the even brighter star Vega (around 1/3 between Altair and Vega).

The asterism is made up of 10 stars ranging from 5th to 7th magnitude which form the conspicuous

“coathanger”, a straight line of 6 stars with a “hook” of 4 stars on the south side. Under a dark sky, Collinder

399 can be seen with the naked eye as an unresolved patch of light; binoculars or a telescope at very low

power are usually needed in order to view the “coathanger” asterism.

20.25 Kemble’s Cascade

Type: Asterism

Location Guide: The asterism lies in the constellation Camelopardalis, about 1/3 between CS Cam and

Cam — HIP 18505 has magnitude 5 and can be found in the center of the chain.

Kemble’s Cascade is a chain of stars which are visible in binoculars, even in light-polluted skies.

20.26 The Double Cluster, χ and h Persei, NGC 884 and NGC 869

Type: Open Clusters

Location Guide: The two open clusters near stars

χ and h in the constellation Perseus.

The Double Cluster (also known as Caldwell 14 or C14) is the common name for the naked-eye open

clusters NGC 869 and NGC 884 (often designated h Persei and

Persei, respectively). The Double Cluster

is approximately the radiant of the Perseid meteor shower, which peaks annually around August 12 or 13.

Although easy to locate in the northern sky, observing the Double Cluster in its two parts requires optical aid.

They are described as being an “awe-inspiring” and “breathtaking” sight, and are often cited as targets in

astronomical observers’ guides.

20.27 Large Magellanic Cloud, PGC 17223

Type: Dwarf Spiral Galaxy

Magnitude: 0.9

Location Guide: It is visible as a faint “cloud” in the night sky of the southern hemisphere straddling the

border between the constellations of Dorado and Mensa, and it appears from Earth more than 20 times the

width of the full moon.

The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way. The Large Magellanic Cloud

is usually considered an irregular galaxy. However, it shows signs of a bar structure, and has more recently

been reclassiﬁed as a Magellanic-type dwarf spiral galaxy. At a distance of 50 kiloparsecs, the LMC is

the third closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal (~16 kiloparsecs) and the

putative Canis Major Dwarf Galaxy (~12.9 kiloparsecs, though its status as a galaxy is under dispute) lying

closer to the center of the Milky Way. The LMC has a diameter of about 14,000 light-years (~4.3 kpc) and a

mass of approximately 10 billion (

) solar masses, making it roughly 1/100 as massive as the Milky Way.

The LMC has a wide range of galactic objects and phenomena — surveys of the galaxy have found roughly

60 globular clusters, 400 planetary nebulae, and 700 open clusters, along with hundreds of thousands of

giant and supergiant stars.

20.28 Tarantula Nebula, C 103, NGC 2070

Type: Nebula

Magnitude: 7.3

Location Guide: Part of Large Magellanic Cloud.

The Tarantula Nebula (also known as 30 Doradus) is an H II region in the Large Magellanic Cloud

(LMC). 30 Doradus has at its centre the star cluster NGC 2070 which includes the compact concentration of

stars known as R136 that produces most of the energy that makes the nebula visible. The estimated mass of

20.29 Small Magellanic Cloud, NGC 292, PGC 3085 283

Figure 20.2: Small and Large Magellanic Clouds over Paranal Observatory. Credit: ESO/J.

Colosimo.

the cluster is 450,000 solar masses, suggesting it will likely become a globular cluster in the future (Bosch,

E. Terlevich, and R. Terlevich, 2009). The closest supernova observed since the invention of the telescope,

Supernova 1987A, occurred in the outskirts of the Tarantula Nebula.

20.29 Small Magellanic Cloud, NGC 292, PGC 3085

Type: Dwarf Irregular Galaxy

Magnitude: 2.2

Location Guide: It is located mostly in the constellation of Tucana and appears as a hazy, light patch in the

night sky about 3° across, looking like a detached piece of the Milky Way. Since it has a very low surface

brightness, it is best viewed from a dark site away from city lights.

The Small Magellanic Cloud (SMC) is a dwarf galaxy near the Milky Way. It is classiﬁed as a dwarf

irregular galaxy. It has a diameter of about 7,000 light-years and has a total mass of approximately 7 billion

times the mass of the Sun. The SMC contains a central bar structure and it is speculated that it was once a

barred spiral galaxy that was disrupted by the Milky Way to become somewhat irregular. At a distance of

about 200,000 light-years, it is one of the Milky Way’s nearest neighbors. It is also one of the most distant

objects that can be seen with the naked eye.

20.30 ω Centauri cluster, C 80, NGC 5139

Type: Globular Cluster

Magnitude: 5.3

Location Guide: It is located around 1/3 between

ζ and γ Centauri.

Omega Centauri (

Cen), or NGC 5139, is a globular cluster in the constellation of Centaurus that was

ﬁrst identiﬁed as a non-stellar object by Edmond Halley in 1677. Located at a distance of 15,800 light-years

(4,850 pc), it is the largest globular cluster in the Milky Way at a diameter of roughly 150 light-years. It is

estimated to contain approximately 10 million stars and a total mass equivalent to 4 million solar masses.

Omega Centauri is so distinctive from the other galactic globular clusters that it is thought to have an alternate

origin as the core remnant of a disrupted dwarf galaxy (Noyola, Gebhardt, and Bergmann, 2008).

284 Chapter 20. A Little Sky Guide

20.31 47 Tucanae, C 106, NGC 104

Type: Globular Cluster

Magnitude: 4.1

Location Guide: It can be seen with the naked eye near Small Magellanic Cloud.

It is the one of brightest globular cluster in the sky, and is noted for having a very bright and dense core.

It is also one of the most massive globular clusters in the Milky Way Galaxy, containing millions of stars.

The cluster appears roughly the size of the full moon in the sky under ideal conditions.

20.32 The Coalsack Nebula, C 99

Type: Dark Nebula

Location Guide: Dark region between

α and β Crux.

The Coalsack Nebula is the most prominent dark nebula in the skies, easily visible to the naked eye as a

dark patch silhouetted against the southern Milky Way. It is located at a distance of approximately 600 light

years away from Earth. The Coalsack is important in Australian Aboriginal astronomy, and forms the head

of the Emu in the sky in several Aboriginal cultures.

Figure 20.3: The Coalsack Nebula taken by the Wide Field Imager on the MPG/ESO 2.2-metre

telescope. Credit: ESO.

20.33 Mira, o Ceti, 68 Cet

Type: Variable Star

Magnitude: 2.0–10.1

Location Guide: It is located around 1/3 between

δ and θ Ceti.

Mira (

Ceti) is a star estimated 200–400 light years away in the constellation Cetus. Mira is a binary

star system that consists of a red giant (Mira A) undergoing mass loss and a high temperature white dwarf

companion (Mira B) that is accreting mass from the primary. Such an arrangement of stars is known as

a symbiotic system, and this is the closest such symbiotic pair to the Sun. Mira is the brightest periodic

20.34 α Persei Cluster, Cr 39, Mel 20 285

variable in the sky that is not visible to the naked eye for part of its cycle. Its distance is uncertain. Mira A is

a well-known example of a category of long-period variable stars known as Mira variables, which are named

after it.

20.34 α Persei Cluster, Cr 39, Mel 20

Type: Open Cluster

Magnitude: 1.2

Location Guide: Around the white-yellow supergiant Mirfak, also known as

Persei in direction to

Persei.

The Alpha Persei Cluster, also known as Melotte 20 or Collinder 39, is an open cluster in the constellation

of Perseus. To the naked eye, the cluster consists of several blue (spectral class B) stars.

20.35 M7, The Ptolemy Cluster

Type: Open Cluster

Magnitude: 3.3

Location Guide: The cluster is easily detectable with the naked eye, close to the “sting” of Scorpius — near

the center of the line between Shaula (λ Scorpii) and Kaus Media (δ Sagittarii).

M7 has been known since antiquity — it was ﬁrst recorded by the 2nd-century Greek-Roman astronomer

Ptolemy, who described it as a nebula in 130 AD. Telescopic observations of the cluster reveal about 80 stars

within a ﬁeld of view of 1.3 ° across. At the cluster’s estimated distance of 980 light years this corresponds to

an actual diameter of 25 light years.

20.36 M22, NGC 6656, The Great Sagittarius Cluster

Type: Globular Cluster

Magnitude: 5.1

Location Guide: Located just south of the Ecliptic, and northwest of

Sagittarii (Kaus Borealis), the

northernmost star of the “Teapot” asterism.

M22 is an elliptical globular cluster of stars in the constellation Sagittarius, near the Galactic bulge

region. It is one of the brightest and nearest globular clusters that is visible in the night sky. M22 is very

unusual in that it is one of only four globulars that are known to contain a planetary nebula. In 2012 two

black holes of between 10 and 20 solar masses each have been discovered in this globular cluster, initially

with the Very Large Array radio telescope in New Mexico, and corroborated by the Chandra X-ray telescope.

The angular size of M22 is over 0.5°.

20.37 M24, The Sagittarius Star Cloud

Type: Star Cloud

Magnitude: 4.6

Location Guide: In the Milky Way region near Polis (

µ Sagittarii).

The Sagittarius Star Cloud is a star cloud in the constellation of Sagittarius, approximately 600 light years

wide. The stars, clusters and other objects comprising M24 are part of the Sagittarius or Sagittarius-Carina

arms of the Milky Way galaxy. Messier described M24 as a “large nebulosity containing many stars” and

gave its dimensions as being some 1.5° across.

20.38 IC 4665, The Summer Beehive Cluster

Type: Open Cluster

Magnitude: 4.2

Location Guide: Visible to the naked eye near Cebalrai (

β Ophiuchi).

IC 4665 is an open cluster in the constellation Ophiuchus which is easily visible in the smallest of

telescopes and also with binoculars. From a sufﬁciently dark place it is also visible to the naked eye.

286 Chapter 20. A Little Sky Guide

20.39 The E Nebula, Bar nard 142 and 143

Type: Dark Nebula

Location Guide: A well-deﬁned dark area on a background of Milky Way near Tarazed (

γ Aquilae).

The “E” or “Barnard’s E” Nebula (ofﬁcially designated as B142 and B143) is a pair of dark nebulae in

the constellation Aquila. It is a well-deﬁned dark area on a background of the Milky Way. The size of the

nebula is roughly 0.5°, and its distance from Earth is estimated at about 2000 light years.

21. Exercises

PAUL ROBINSON, WITH ADDITIONS BY ALEXANDER WOLF

21.1 Find M31 in Binoculars

M31 – the Andromeda Galaxy – is the most distant object visible to the naked eye. Finding it in binoculars is

a rewarding experience for new-comers to observing.

21.1.1 Simulation

Set the location to a mid-Northern latitude if necessary (M31 isn’t always visible for Southern

hemisphere observers). The UK is ideal.

Find M31 and set the time so that the sky is dark enough to see it. The best time of year for this at

Northern latitudes is Autumn/Winter, although there should be a chance to see it at some time of night

throughout the year.

Set the ﬁeld of view to

° (or the ﬁeld of view of your binoculars if they’re different.

° is typical for

7x50 binoculars).

Practice ﬁnding M31 from the bright stars in Cassiopeia and the constellation of Andromeda. Learn

the chain of stars that extends from Andromeda’s central star perpendicular to her body.

21.1.2 For Real

This part is not going to be possible for many people. First, you need a good night and a dark sky. In urban

areas with a lot of light pollution it’s going to be very hard to see Andromeda.

21.2 Handy Angles

As described in section 18.5.2, your hand at arm’s length provides a few useful estimates for angular size.

It’s useful to know whether your handy angles are typical, and if not, what they are. The method here below

is just one way to do it – feel free to use another method of your own construction!

Hold your hand at arm’s length with your hand open – the tips of your thumb and little ﬁnger as far apart

as you can comfortably hold them. Get a friend to measure the distance between your thumb and your eye,

we’ll call this

. There is a tendency to over-stretch the arm when someone is measuring it – try to keep the

thumb-eye distance as it would be if you were looking at some distant object.

Without changing the shape of your hand, measure the distance between the tips of your thumb and little

ﬁnger. It’s probably easiest to mark their positions on a piece of paper and measure the distance between

the marks, we’ll call this

. Using some simple trigonometry, we can estimate the angular distance

using

equation (18.5).

Repeat the process for the distance across a closed ﬁst, three ﬁngers and the tip of the little ﬁnger.

For example, for one author D = 72cm, d = 21cm, so:

288 Chapter 21. Exercises

θ = 2 ⋅ arctan

144

≈ 16

° (21.1)

Remember that handy angles are not very precise – depending on your posture at a given time the values

may vary by a fair bit.

21.3 Find a Lunar Eclipse

Stellarium comes with two scripts for ﬁnding lunar eclipses, but can you ﬁnd one on a different date?

21.4 Find a Solar Eclipse

Find a Solar Eclipse using Stellarium and take a screenshot of it. Use the location panel and see how the

eclipse look on different locations at the same time. Don’t forget to have “Topocentric coordinates” enabled

in the settings (see section 18.9.1).

21.5 Find a retrograde motion of Mars

Find Mars using Stellarium and take a series of screenshots of its position at different times. Use the date

and time panel and see how the motion of Mars changes over the time. Find periods of direct and retrograde

motion of Mars (see also section 17.6).

21.6 Analemma

Set a time around noon and set time rate to pause, turn on the azimuthal grid. Find the Sun and check its

horizontal coordinates. Use the date and time panel and see how the horizontal coordinates of the Sun

change over time (please use one time step for simulation — look at the position of the Sun every 7 days for

example). Use the location panel and see how the positions of the Sun look from different location at the

same times. Check the change of positions of the Sun on Mars at the same times.

21.7 Transit of Venus

Set date to

of June, 2012, ﬁnd Venus near the Sun and change scale of the view (zoom in). Find time of

all four contacts and maximum of transit for your location. Because the Sun appears to rotate as it crosses

the sky, Venus will appear to move on some curve — for example it will be an inverted “U” shape for eastern

states of Australia. Check difference of path shape of Venus for equatorial and azimuthal mounts. Find a

few dates and times for transit of Venus in past and in future. Notice how they usually come in pairs 8 years

apart, with gaps of over 100 years between pairs.

21.8 Transit of Mercury

Set date to

of May, 2016, ﬁnd Mercury near the Sun and change scale of the view (zoom in). Find time

of all four contacts and maximum of transit for your location. Because the Sun appears to rotate as it crosses

the sky, Mercury will appear to move on some curve — for example it will be an inverted “U” shape for

observers from Europe. Check difference of path shape of Mercury for equatorial and azimuthal mounts.

Find few dates and times for transit of Mercury in past and in future.

21.9 Triple shadows on Jupiter

Set date to

of January, 2015, ﬁnd Jupiter and change scale of the view (zoom in). Find the time when

three shadows will be visible on the disk of Jupiter. Which moons cast those shadows? Check which moons

cause triple shadows on Jupiter at 3 June 2014. Details for this phenomenon you can ﬁnd in the book

Mathematical Astronomy Morsels (Meeus, 1997).

21.10 Jupiter without satellites 289

21.10 Jupiter without satellites

Set date to

November, 2019, ﬁnd Jupiter and change scale of the view (zoom in). Find time limits for the

disappearance of the moons. Which moons are on the back of the planet, and which — in front of it? Please

give answer on the same questions for 3 September 2009. Details for this phenomenon you can ﬁnd in the

book Mathematical Astronomy Morsels (Meeus, 1997)

21.11 Mutual occultations of planets

Set date to

October, 1590, ﬁnd Venus and change scale of the view (zoom in). Find time of minimal

separation of Venus and Mars on this date. Set typical scale of view for visual observation and check Venus

and Mars again. What would the typical observer of that time had said? Find the minimal separation between

Venus and Saturn near end of August 1771. What would the typical observer on Earth had said? Find the

minimal separation between Mars and Mercury in ﬁrst half of August 2079.

Find mutual occultation of Earth and Mercury as seen from Mars near the end of November 2022. Find

mutual occultation of Saturn and Mercury as seen from Venus near the middle of May 1967.

Details for this phenomenon you can ﬁnd in the books More Mathematical Astronomy Morsels (Meeus,

2002) and Mathematical Astronomy Morsels III (Meeus, 2004)

21.12 The proper motion of stars

Turn off ground and atmosphere, set time rate on pause, ﬁnd the star HIP 87937 and change the scale of

the view to better see Barnard’s Star. Use the date and time panel and see how the location of the star is

changing in time (please try use one time step for simulation — look at the position of the star every year for

example). When will Barnard’s star cross the border of constellation? When has Barnard’s star crossed the

border of constellation in the past?

Please check the proper motions of Sirius (HIP 32349), Procyon (HIP 37279), 61 Cyg (HIP 104214)

and

Cet (HIP 8102). Which star has the fastest proper motion? Which star has the slowest rate of proper

motion?

When will observers see Arcturus and HIP 68706 as close optical binary? Find the minimal angular

separation between θ and ε Ind in the past.

How will the appearance of following constellations change over a wide range of time (

−100000..100000

years for example): Ursa Major, Orion, Bootes?

Appendices

A Default Hotkeys . . . . . . . . . . . . . . . . . . . . 293

B The Bortle Scale of Light Pollution

. . . . 301

C Star Catalogues

. . . . . . . . . . . . . . . . . . . . 305

D Conﬁguration Files

. . . . . . . . . . . . . . . . . . 333

E Planetary nomenclature

. . . . . . . . . . . . 365

F Accuracy

. . . . . . . . . . . . . . . . . . . . . . . . . . 375

G GNU Free Documentation License

. . . 385

H Acknowledgements

. . . . . . . . . . . . . . . . 391

Bibliography . . . . . . . . . . . . . . . . . . . . . . . 407

Index

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417

A. Default Hotkeys

The currently conﬁgured hotkeys are visible in the Help dialog (

). Here is the default list for reference.

WARNING: The list of hotkeys in this Guide uses notation for standard PC-compatible keyboards. Not

all keyboards are PC-compatible – for example Apple’s computers use keyboards with their own speciﬁc keys

–

Option

and

Command

. The

Option

key is equivalent to the

Alt

key on the PC-compatible keyboards.

The Haiku operating system is the successor of BeOS, and it swaps behaviour for

Ctrl

and

Alt

keys – e.g.

PC’s

Ctrl

will be

Alt

in Haiku.

A.1 Mouse actions with combination of the keyboard keys

Actions Description

Arrow keys & left mouse drag Pan view around the sky

Page Up/Down

Ctrl

Page Up/Down

Zoom in/out

Ctrl

& left mouse drag Time dragging

Ctrl

& mouse wheel Time scrolling: minutes

Ctrl

& mouse wheel Time scrolling: hours

Ctrl

Alt

& mouse wheel Time scrolling: days

Ctrl

Alt

& mouse wheel Time scrolling: years

Left click Select object

Right click Clear selection

& left click Add custom marker

& right click Delete the one closest marker to mouse cursor

Alt

& right click Delete all custom markers

294 Appendix A. Default Hotkeys

A.2 Display Options

Shortcut key Description

Planets

Alt

Planet labels

Ctrl

Planet markers

Planet orbits

Planet trails

Ctrl

Planet selection marker

Alt

Nomenclature labels

Stars

Alt

Star labels

Deep-sky objects (symbols)

Deep-sky objects background images

Ctrl

Reload the deep-sky objects background images

Ctrl

Alt

Toggle Hierarchical Progressive Surveys (experimental)

Milky Way

Ctrl

Zodiacal Light

Ground

Fog

Landscape Illumination

Ctrl

Landscape Labels

Atmosphere

Cardinal points

Ecliptic line

Equator line

Equatorial grid

Azimuthal grid

Horizon line

;

Meridian line

Constellation lines

Constellation labels

Constellation art

Constellation boundaries

Ctrl

Alt

Select single constellation

Tab

Remove selection of constellations

Ctrl

Native planet names (from sky culture)

Alt

Asterism labels

Alt

Asterism lines

Alt

Ray helpers

Ctrl

Alt

Reload the sky culture

Remove selection of constellations

Alt

Select all constellations

F11

Full-screen mode

Ctrl

Night mode

Ctrl

Flip scene horizontally

Ctrl

Flip scene vertically

A.3 Miscellaneous 295

A.3 Miscellaneous

Shortcut key Description

Ctrl

Copy selected object information to clipboard

Ctrl

Quit

Ctrl

Save screenshot

Ctrl

Switch between equatorial and azimuthal mount

Ctrl

Toggle visibility of GUI

Ctrl

Reload shaders (for development)

A.4 Movement and Selection

Shortcut key Description

Center on selected object

Ctrl

Go to home

Ctrl

Set home planet to selected planet (“go there”)

Look towards East

Look towards North

Look towards South

Look towards West

Look towards Zenith

Alt

Look towards North Celestial pole

Alt

Look towards South Celestial pole

Track object

Zoom in on selected object

Zoom out

Ctrl

Alt

Set FOV to 180°

Ctrl

Alt

Set FOV to 90°

Ctrl

Alt

Set FOV to 60°

Ctrl

Alt

Set FOV to 45°

Ctrl

Alt

Set FOV to 20°

Ctrl

Alt

Set FOV to 10°

Ctrl

Alt

Set FOV to 5°

Ctrl

Alt

Set FOV to 2°

Ctrl

Alt

Set FOV to 1°

Ctrl

Alt

Set FOV to 0.5°

296 Appendix A. Default Hotkeys

A.5 Date and Time

Shortcut key Description

Add 1 solar day

Subtract 1 solar day

Ctrl

Add 1 solar hour

Ctrl

Subtract 1 solar hour

Alt

Add 1 sidereal day

Alt

Subtract 1 sidereal day

]

Add 7 solar days

[

Subtract 7 solar days

Ctrl

Alt

]

Add 1 sidereal year

Ctrl

Alt

[

Subtract 1 sidereal year

Decrease time speed

Decrease time speed (a little)

Set normal time rate

Increase time speed

Increase time speed (a little)

Set time rate to zero

Set time to now

Set reverse time direction

Ctrl

Pause script execution

Ctrl

Resume script execution

Ctrl

Stop script execution

A.6 Scripts

Shortcut key Description

Ctrl

Run script “Solar System Screensaver”

Ctrl

Run script “Western Constellations Tour”

Ctrl

Run script “Sky Culture Tour”

Ctrl

Run script “Screensaver”

Ctrl

Run script “Skybox Tiles”

Ctrl

Run script “Jupiter and triple shadow phenomena”

Ctrl

Run script “Jupiter without Galilean satellites”

Ctrl

Run script “Occultations of bright stars by planets”

Ctrl

Run script “Mutual occultations of planets”

A.7 Windows

Shortcut key Description

Toggle Help window

Toggle Conﬁguration window

Toggle Search window

Toggle Sky and viewing options window

Toggle Date/time window

Toggle Location window

Toggle Shortcuts window

F10

Toggle Astronomical calculations window

F12

Toggle Script Console window

Alt

Toggle Bookmarks window

A.8 Plugins 297

A.8 Plugins

A.8.1 Angle Measure

Shortcut key Description

Ctrl

Toggle angle measurement

A.8.2 ArchaeoLines

Shortcut key Description

Ctrl

Toggle archaeolines

Ctrl

Toggle archaeolines dialog

A.8.3 Calendars

Shortcut key Description

Alt

Toggle Calendars display

Alt

Toggle Calendars dialog

A.8.4 Equation of Time

Shortcut key Description

Ctrl

Alt

Show solution for Equation of Time

A.8.5 Exoplanets

Shortcut key Description

Ctrl

Alt

Show exoplanets

Alt

Toggle Exoplanets conﬁguration window

A.8.6 Meteor Showers

Shortcut key Description

Ctrl

Toggle meteor showers

Toggle radiant labels

Ctrl

Alt

Show search dialog

Ctrl

Alt

Show settings dialog

A.8.7 Oculars

Shortcut key Description

Ctrl

Ocular view

Alt

Oculars popup menu

Alt

Show crosshairs

Ctrl

Telrad sight

A.8.8 Pulsars

Shortcut key Description

Ctrl

Alt

Show pulsars

298 Appendix A. Default Hotkeys

A.8.9 Quasars

Shortcut key Description

Ctrl

Alt

Show quasars

A.8.10 Satellites

Shortcut key Description

Ctrl

Toggle satellite hints

Alt

Toggle satellite labels

Alt

Toggle Satellites conﬁguration window

A.8.11 Scenery3d: 3D landscapes

Shortcut key Description

Ctrl

Toggle 3D landscape

Ctrl

Show settings dialog

Ctrl

Alt

Show viewpoint dialog

Ctrl

Toggle location text

Ctrl

Toggle shadows

Ctrl

Toggle torchlight

Ctrl

Toggle debug information

Ctrl

Reload shaders

A.8.12 Solar System Editor

Shortcut key Description

Ctrl

Alt

Import orbital elements in MPC format...

A.8.13 Telescope Control

Shortcut key Description

Ctrl

Move a telescope to a given set of coordinates (shows dialog)

Ctrl

Move telescope #1 to selected object

Ctrl

Move telescope #2 to selected object

Ctrl

Move telescope #3 to selected object

Ctrl

Move telescope #4 to selected object

Ctrl

Move telescope #5 to selected object

Ctrl

Move telescope #6 to selected object

Ctrl

Move telescope #7 to selected object

Ctrl

Move telescope #8 to selected object

Ctrl

Move telescope #9 to selected object

Alt

Move telescope #1 to the point currently in the center of the screen

Alt

Move telescope #2 to the point currently in the center of the screen

Alt

Move telescope #3 to the point currently in the center of the screen

Alt

Move telescope #4 to the point currently in the center of the screen

Alt

Move telescope #5 to the point currently in the center of the screen

Alt

Move telescope #6 to the point currently in the center of the screen

Alt

Move telescope #7 to the point currently in the center of the screen

Alt

Move telescope #8 to the point currently in the center of the screen

Alt

Move telescope #9 to the point currently in the center of the screen

A.9 Special local keys 299

Ctrl

+ +

Move a telescope to a given set of coordinates (shows dialog)

Ctrl

Sync telescope #1 to selected object

Ctrl

Sync telescope #2 to selected object

Ctrl

Sync telescope #3 to selected object

Ctrl

Sync telescope #4 to selected object

Ctrl

+ +

Sync telescope #5 to selected object

Ctrl

Sync telescope #6 to selected object

Ctrl

Sync telescope #7 to selected object

Ctrl

Sync telescope #8 to selected object

Ctrl

Sync telescope #9 to selected object

Ctrl

Alt

Abort last slew command of telescope #1

Ctrl

Alt

Abort last slew command of telescope #2

Ctrl

Alt

Abort last slew command of telescope #3

Ctrl

Alt

Abort last slew command of telescope #4

Ctrl

Alt

Abort last slew command of telescope #5

Ctrl

Alt

Abort last slew command of telescope #6

Ctrl

Alt

Abort last slew command of telescope #7

Ctrl

Alt

Abort last slew command of telescope #8

Ctrl

Alt

Abort last slew command of telescope #9

A.8.14 Text User Interface (TUI)

Shortcut key Description

Alt

Activate TUI

A.9 Special local keys

All these hotkeys are locally available to run when a speciﬁc window or tab is opened.

Shortcut key Description

Script console

Ctrl

Load script from ﬁle

Ctrl

Save script to ﬁle

Ctrl

Return

Run script

Astronomical calculations

F10

Update positions

F10

Calculate ephemeris

F10

Calculate transits

F10

Calculate phenomena

B. The Bortle Scale of Light Pollution

The Bortle scale is a nine-level numeric scale that measures the night sky’s brightness of a particular location.

It quantiﬁes the astronomical observability of celestial objects and the interference caused by light pollution.

JOHN E. BORTLE created the scale and published it in Sky & Telescope magazine (Bortle, 2001) to help

amateur astronomers evaluate the darkness of an observing site, and secondarily, to compare the darkness

of observing sites. The scale ranges from Class 1, the darkest skies available on Earth, through Class 9,

inner-city skies. It gives several criteria for each level beyond naked-eye limiting magnitude (NELM). The

accuracy and utility of the scale have been questioned in recent research (Crumey, 2014).

Figure B.1: Light Pollution Simulation / Bortle Scale

302 Appendix B. The Bortle Scale of Light Pollution

B.1 Excellent dark sky site

Level: 1

Naked-eye limiting magnitude: 7.6 – 8.0

Approx. SQM mag/arcsec

: 21.7 – 22.0

Zodiacal light, gegenschein, zodiacal band visible; M33 direct vision naked-eye object; Scorpius and

Sagittarius regions of the Milky Way cast obvious shadows on the ground; Airglow is readily visible; Jupiter

and Venus affect dark adaptation; surroundings basically invisible.

B.2 Typical truly dark site

Level: 2

Naked-eye limiting magnitude: 7.1 – 7.5

Approx. SQM mag/arcsec

: 21.5 – 21.7

Airglow weakly visible near horizon; M33 easily seen with naked eye; highly structured Summer Milky

Way; distinctly yellowish zodiacal light bright enough to cast shadows at dusk and dawn; clouds only visible

as dark holes; surroundings still only barely visible silhouetted against the sky; many Messier globular

clusters still distinct naked-eye objects.

B.3 Rural sky

Level: 3

Naked-eye limiting magnitude: 6.6 – 7.0

Approx. SQM mag/arcsec

: 21.3 – 21.5

Some light pollution evident at the horizon; clouds illuminated near horizon, dark overhead; Milky Way

still appears complex; M15, M4, M5, M22 distinct naked-eye objects; M33 easily visible with averted vision;

zodiacal light striking in spring and autumn, color still visible; nearer surroundings vaguely visible.

B.4 Rural/suburban transition

Level: 4

Naked-eye limiting magnitude: 6.1 – 6.5

Approx. SQM mag/arcsec

: 20.4 – 21.3

Light pollution domes visible in various directions over the horizon; zodiacal light is still visible, but

not even halfway extending to the zenith at dusk or dawn; Milky Way above the horizon still impressive,

but lacks most of the ﬁner details; M33 a difﬁcult averted vision object, only visible when higher than 55°;

clouds illuminated in the directions of the light sources, but still dark overhead; surroundings clearly visible,

even at a distance.

Dark Skies Awareness – http://www.darkskiesawareness.org/nomogram.php

B.5 Suburban sky 303

B.5 Suburban sky

Level: 5

Naked-eye limiting magnitude: 5.6 – 6.0

Approx. SQM mag/arcsec

: 19.1 – 20.4

Only hints of zodiacal light are seen on the best nights in autumn and spring; Milky Way is very weak or

invisible near the horizon and looks washed out overhead; light sources visible in most, if not all, directions;

clouds are noticeably brighter than the sky.

B.6 Bright suburban sky

Level: 6

Naked-eye limiting magnitude: 5.1 – 5.5

Approx. SQM mag/arcsec

: 18.0 – 19.1

Zodiacal light is invisible; Milky Way only visible near the zenith; sky within 35° from the horizon

glows grayish white; clouds anywhere in the sky appear fairly bright; surroundings easily visible; M33 is

impossible to see without at least binoculars, M31 is modestly apparent to the unaided eye.

B.7 Suburban/urban transition

Level: 7

Naked-eye limiting magnitude: 4.6 – 5.0

Approx. SQM mag/arcsec

: 18.0 – 19.1

Entire sky has a grayish-white hue; strong light sources evident in all directions; Milky Way invisible;

M31 and M44 may be glimpsed with the naked eye, but are very indistinct; clouds are brightly lit; even in

moderate-sized telescopes the brightest Messier objects are only ghosts of their true selves.

B.8 City sky

Level: 8

Naked-eye limiting magnitude: 4.1 – 4.5

Approx. SQM mag/arcsec

: <18.0

Sky glows white or orange — you can easily read; M31 and M44 are barely glimpsed by an experienced

observer on good nights; even with telescope, only bright Messier objects can be detected; stars forming

familiar constellation patterns may be weak or completely invisible.

B.9 Inner-city sky

Level: 9

Naked-eye limiting magnitude: 4.0 at best

Approx. SQM mag/arcsec

: <18.0

Sky is brilliantly lit with many stars forming constellations invisible and many weaker constellations

invisible; aside from Pleiades, no Messier object is visible to the naked eye; only objects to provide fairly

pleasant views are the Moon, the Planets and a few of the brightest star clusters.

C. Star Catalogues

This chapter provides technical descriptions on how Stellarium records its star catalogues, and the related

ﬁle formats.

C.1 Stellarium’s Sky Model

C.1.1 Zones

The celestial sphere is split into zones, which correspond to the triangular faces of a geodesic sphere. The

number of zones (faces) depends on the level of sub-division of this sphere plus one global zone for high

proper motion stars that can cross zones in the past/future or stars. The lowest level, 0, is an icosahedron (20

faces + 1 global zone), subsequent levels L of sub-division give the number of zones n as:

n = 20⋅ 4

+ 1 (C.1)

Stellarium uses levels 0 to 8 in the existing star catalogues. So the number of zones are 21 for level 0 to

1,310,721 for level 8. Stars within the global zone are always checked if they are visible or not without any

zone restriction, since stars can move out of their original zones due to proper motion and not drawn in the

sky. Only level 0 to level 2 star catalogs have their global zone populated (i.e. level 3-8 global zones are

empty).

For level 0, any stars who will move out of their original zones in

±200, 000

years are moved to the

global zone. For level 1 and 2, stars are moved to the global zone only if they move out of their original

zones and the bordering zones or brighter than 0.3 mag from their present apparent magnitude in

±200, 000

years.

C.2 Star Catalogue File Format

With version 25.1, Stellarium is adopting the currently most modern class of astrometrical data: Gaia DR3.

v 25.1

This astrometry satellite, operated by ESA, delivers unprecedented accuracy for millions of stars. However,

just those stars most important to human casual observers, naked-eye stars, are too bright for the sensitive

instruments. Therefore, for the brightest stars, data from the preceding Hipparcos mission are still used.

Most indexing is still based on Hipparcos numbers. In previous versions, dimmer stars were stored without

number. Now, you can use the long index from Gaia DR3 in descriptions of constellations, or search for the

number directly.

Information about the previous format is easiest found in the v24.4 User Guide.

C.2.1 General Description

Stellarium’s star catalogue data is kept in the

stars/hip_gaia3

sub-directory of the Installation Directory

v 25.1

306 Appendix C. Star Catalogues

and/or User Directory (see section 5.1).

The main catalogue data is split into several ﬁles:

stars_0_0v0_18.cat

stars_1_0v0_15.cat

stars_2_0v0_16.cat

stars_3_0v0_10.cat

stars_4_1v0_6.cat

stars_5_1v0_6.cat

stars_6_1v0_4.cat

stars_7_1v0_4.cat

stars_8_2v0_3.cat

There also exist some control and reference ﬁles:

object_types_v0_1.cat

stars_hip_sp_0v0_6.cat

gcvs.cat

wds_hip_part.dat

cross-id.cat

starsConfig.json

name.fab

binary_orbitparam.dat

When Stellarium starts, it reads the ﬁle

stars/hip_gaia3/starsConfig.json

, from which it de-

termines the names of the other ﬁles which it then loads. The ﬁle

stars_hip_sp_0v0_6.cat

contain

spectral type of HIP stars. The ﬁle

object_types_v0_1.cat

contain object type classiﬁcation name for

the main star catalogs. The ﬁle

gcvs.cat

contains data about variables stars (see section C.3) and ﬁle

wds_hip_part.dat

contains data about double stars (see section C.4) which again contains references into

the main catalogue ﬁles. The ﬁle

cross-id.cat

(see section C.5) contains cross-identiﬁcation data between

HIP, Gaia DR3, SAO, HD and HR designations. The ﬁle

binary_orbitparam.cat

(see section C.6)

contains binary star system orbital parameters.

A given catalogue ﬁle models stars for one and only one level (i.e. for a ﬁxed number of zones), which

is recorded in the header of the ﬁle. Individual star records do not contain full positional coordinates, instead

they contain coordinates relative to the central position of the zone they occupy. Thus, when parsing star

catalogues, it is necessary to know about the zone model to be able to extract positional data.

File Data Data Geodesic #Records Notes

Type Record Size Level

stars_0_0v0_18.cat 0 48 bytes 0 5,045 Hipparcos + Gaia

stars_1_0v0_15.cat 0 48 bytes 1 21,611 Hipparcos + Gaia

stars_2_0v0_16.cat 0 48 bytes 2 141,761 Hipparcos + Gaia

stars_3_0v0_10.cat 0 48 bytes 3 418,129 Gaia

stars_4_1v0_6.cat 1 32 bytes 4 1,741,849 Gaia

stars_5_1v0_6.cat 1 32 bytes 5 8,051,933 Gaia

stars_6_1v0_4.cat 1 32 bytes 6 29,879,734 Gaia

stars_7_1v0_4.cat 1 32 bytes 7 57,534,724 Gaia

stars_8_2v0_3.cat 2 16 bytes 8 122,908,184 Gaia

For a given catalogue ﬁle, there may be one of three formats for the actual star data. The variation comes

from the source of the data – the larger catalogues of fainter stars providing less data per star than the brighter

star catalogues. See tables Stellarium’s star catalogue and for details.

Stellarium’s star catalogues are based on Hipparcos (Anderson and Francis, 2012; ESA, 1997) and

Gaia (Gaia Collaboration and al., 2016) catalogues.

C.2.2 File Sections

The catalogue ﬁles are split into three main sections as described in table C.1.

The data has signiﬁcantly changed in version 25.1. The previous structure can be found in older guides.

Or stars/hip_gaia3/defaultStarsConfig.json ﬁle in Installation Directory

C.2 Star Catalogue File Format 307

Section Offset Description

File Header Record 0

Contains magic number, geodesic subdivision level, magnitude

and epoch information

Zone Records 28

A list of how many records there are for each zone. The length

of the zones section depends on the level value from the header

Star Data Records 28+ 4n

This section of the ﬁle contains ﬁxed-size star records, as de-

scribed below. Records do not contain zone information, which

must be inferred by counting how many records have been read

so far and switching zones when enough have been read to ﬁll

the number of stars for the zone, as speciﬁed in the zones sec-

tion above. The value of

used in the offset description is the

number of zones, as described above.

Table C.1: File sections

C.2.3 Record Types

C.2.3.1 File Header Record

The File Header Record describes ﬁle-wide settings. It also contains a magic number which servers as a ﬁle

type identiﬁer. See table C.2.

Name Offset Type Size Description

Magic 0 int 4

magic number which identiﬁes the ﬁle as a star

catalogue. 0x835f040a

Data Type 4 int 4

type of the ﬁle, which deﬁnes the size and struc-

ture of the Star Data record for the ﬁle.

Major Version 8 int 4 ﬁle format major version number

Minor Version 12 int 4 ﬁle format minor version number

Level 16 int 4

sets the level of sub-division of the geodesic

sphere used to create the zones. 0 means an

icosahedron (20 triangular faces + 1 global zone),

subsequent levels of sub-division lead to num-

bers of zones as described in section C.2.3.2

Magnitude Minimum 20 int 4

low bound of the magnitude of the catalog in

milli-mag unit.

Catalog Epoch 24 ﬂoat 4 Epoch of the catalog in Julian days.

Table C.2: Header Record

C.2.3.2 Zone Records

The Zone Records section of the ﬁle lists the number of star records there are per zone. The number of

zones is determined from the level value in the File Header Record, as described in section C.1.1. The Zones

section is simply a list of integer values which describe the number of stars for each zone. The total length of

the Zones section depends on the number of zones. See table C.3.

C.2.3.3 Star Data Records

After the Zones section, the actual star data starts. The star data records themselves do not contain the zone

in which the star belongs. Instead, the zone is inferred from the position of the record in the ﬁle. For example,

if the Zone Records section of the ﬁle says that the ﬁrst 100 records are for zone 0, the next 80 for zone 1 and

so on, it is possible to infer the zone for a given record by counting how many records have been read so far.

The actual record structure depends on the value of the Data Type, as found in the File Header Record.

See tables C.4, C.5 and C.6 for record structure details.

Details about vector algebra related to astrometric calculations can be found in (van Altena, 2013).

308 Appendix C. Star Catalogues

Name Offset Type Size Description

num stars in zone 0 0 int 4

number of records in this ﬁle which are in zone

num stars in zone 1 4 int 4

number of records is this ﬁle which are in zone

. . .

num stars in zone n − 1 4n − 4 int 4

number of records is this ﬁle which are in zone

num stars in zone n 4n int 4

number of records is this ﬁle which are in the

global zone

Table C.3: Zones section

Name Offset Type Size Description

gaia_id 0 int64_t 8 Gaia source id

x0 8 int 4

Cartesian x position of the star on an unit sphere

at the catalog epoch scaled by 2× 10

x1 12 int 4

Cartesian y position of the star on an unit sphere

at the catalog epoch scaled by 2× 10

x2 16 int 4

Cartesian z position of the star on an unit sphere

at the catalog epoch scaled by 2× 10

dx0 20 int 4

First component of the star’s proper motion vector

at the catalog epoch scaled by 1× 10

dx1 24 int 4

Second component of the star’s proper motion

vector at the catalog epoch scaled by 1× 10

dx2 28 int 4

Third component of the star’s proper motion vec-

tor at the catalog epoch scaled by 1× 10

b_v 32 short 2 B −V colour in milli-mag unit.

mag 34 short 2 V -band magnitude in milli-mag unit.

plx 36 unsigned short 2 parallax of the star in 0.02 mas unit.

plx_err 38 unsigned short 2 parallax error of the star in 0.01 mas unit.

rv 40 short 2 radial velocity of the star in 0.1 km/s unit.

sp_int 42 unsigned short 2

index into an array of spectral type descriptions

which is taken from the ﬁle

stars_hip_sp.cat

the index corresponds to the line number in the

ﬁle - 1

obtype 44 unsigned char 1

object type classiﬁcation index. The index

corresponds to the line number in the ﬁle

object_types_v*.cat - 1.

hip 45 int 3

Hipparcos catalogue number with component ID

(e.g. A, B, C...)

Table C.4: Star Data Record Type 0

C.2 Star Catalogue File Format 309

For the catalog with Star Data Record Type 0, in practice to convert

x0, x1, x2

to right ascension

and

declination δ , one can use the following formulas:

α = arctan2(x1, x0)

δ = arcsin(x2)

(C.2)

and to convert proper motion vector

(dx0, dx1, dx2)

to proper motion in right ascension

∗

and

declination µ

, one can use the following formulas:

xy =



+ x1

;



p = −

, 0.;



q = −

x0 ⋅ x2

, −

x1 ⋅ x2

, xy;

∗



p ⋅ (dx0, dx1, dx2);



q ⋅ (dx0, dx1, dx2);

(C.3)

where

∗

≡

cos(δ ).

Name Offset Type Size Description

gaia_id 0 int64_t 8 Gaia source id

x0 8 int 4 Right ascension

α of the star in mas unit.

x1 12 int 4 Declination δ of the star in mas unit.

dx0 16 int 4 Proper motion

of the star in µas/year

dx1 20 int 4 Proper motion

of the star in µas/year

b_v 24 short 2 B −V colour in milli-mag unit.

mag 26 short 2 V -band magnitude in milli-mag unit.

plx 28 unsigned short 2 parallax of the star in 0.01 mas unit.

plx_err 30 unsigned short 2 parallax error of the star in 0.01 mas unit.

Table C.5: Star Data Record Type 1

Name Offset Type Size Description

gaia_id 0 int64_t 8 Gaia source id

x0 8 int 3 Right ascension

α of the star in 0.1 arcsecond unit.

x1 11 int 3 Declination δ of the star in 0.1 arcsecond unit.

b_v 14 unsigned short 1 B −V colour in 25 milli-mag unit offset by +1 mag.

mag 15 unsigned short 1 V

-band magnitude in 20 milli-mag unit offset by

−16

mag.

Table C.6: Star Data Record Type 2

310 Appendix C. Star Catalogues

Name Type Description

HIP/Gaia int

This is the HIP or Gaia DR3 identiﬁer for the star. Used for reference to

the main star catalogue.

GCVS

string This is the GCVS designation for the variable star.

Type

string Type of variability.

Max ﬂoat Magnitude at maximum brightness.

MFlag

int

Magnitude ﬂag code (0=No ﬂag; 1="(" if max. magnitude is an amplitude;

2="<" if max. magnitude is a bright limit; 3=">" is max. magnitude is a

faint limit).

Min I

ﬂoat First minimum magnitude or amplitude.

Min II ﬂoat Second minimum magnitude.

char The photometric system for magnitudes.

Epoch

ﬂoat Epoch for maximum or minimum light (in Julian days).

Period

ﬂoat Period for the variable star (in days).

M-m

ﬂoat Rising time or duration of the eclipse (in percent).

Spectrum

string Spectral class of the variable star.

Table C.7: Variable Star Catalog File Format

C.3 Variable Stars

Since version 0.12.2 Stellarium supports the subset of variable stars from GCVS

which have HIP identiﬁers

(i.e., stars from the Hipparcos catalog). Stellarium’s Catalog of Variable Stars is based on the “General

catalogue of variable stars: Version GCVS 5.1” (Samus’ et al., 2017).

C.3.1 Variable Star Catalog File Format

C.3.1.1 General Description

Stellarium’s Variable Stars catalog data is kept in the

stars/hip_gaia3

sub-directory of the Installation

Directory and/or User Directory (see section 5.1).

C.3.1.2 File Format

The

gcvs.cat

ﬁle contains data about 49800+ Variable Stars (see section 19.2.5) which have HIP or Gaia

DR3 identiﬁers and are stored in a plain text format with tab delimiter (Table C.7).

C.3.2 GCVS Variability Types

An improved system of variability classiﬁcation is used in the fourth edition of the GCVS, based on recent

developments in classiﬁcation principles and taking into account the suggestions of a number of specialists.

Variability types are grouped according to the major astrophysical reasons for variability.

All of these classes include objects of a dissimilar nature that belong to different types of light variability.

On the other hand, an object may be variable because of almost all of the possible reasons or because of any

combination of them. If a variable belongs to several types of variability, the types are joined in the data ﬁeld

by a “+” sign, e.g., E+UG, UV+BY.

Despite considerable success in understanding stellar variability processes, the classiﬁcation adopted in

the Catalogue is far from perfect. This is especially the case for explosive, symbiotic and novalike variables;

X-ray sources; and peculiar objects.

The new variability types (ZZO, AM, R, BE, BLBOO, EP, SRS, LPB) have been added in the Name-Lists

67-77 and in the GCVS vol.V.

You can read about latest different types of variability at SAI GCVS page

C.3.2.1 Eruptive Variable Stars

Eruptive variables are stars varying in brightness because of violent processes and ﬂares occurring in their

chromospheres and coronae. The light changes are usually accompanied by shell events or mass outﬂow in

http://www.sai.msu.su/gcvs/gcvs/

http://www.sai.msu.su/gcvs/gcvs/vartype.htm

C.3 Variable Stars 311

the form of stellar winds of variable intensity and/or by interaction with the surrounding interstellar medium.

This class includes the following types:

It becomes more and more clear that, although the majority of Be stars are photometrically variable,

not all of them could be properly called GCAS variables. Quite a number of them show small-scale

variations not necessarily related to shell events; in some cases the variations are quasi-periodic. By

now we are not able to present an elaborated system of classiﬁcation for Be variables, but we adopt a

decision that in the cases when a Be variable cannot be readily described as a GCAS star we give

simply BE for the type of variability.

Orion variables of the FU Orionis type. Characterized by gradual increases in brightness by about 6

mag in several months, followed by either almost complete constancy at maximum that is sustained

for long periods of time or slow decline by 1-2 mag. Spectral types at maximum are in the range

Ae(alpha) - Gpe(alpha). After an outburst, a gradual development of an emission spectrum is observed

and the spectral type becomes later. These variables probably mark one of the evolutionary stages of

T Tauri-type Orion variables (INT), as evidenced by an outburst of one member, V1057 Cyg, but its

decline (2.5 mag in 11 years) commenced immediately after maximum brightness was attained. All

presently known FU Ori variables are coupled with reﬂecting cometary nebulae.

GCAS

Eruptive irregular variables of the Gamma Cas type. These are rapidly rotating B III-IVe stars

with mass outﬂow from their equatorial zones. The formation of equatorial rings or disks is often

accompanied by temporary fading. Light amplitudes may reach 1.5 mag in V.

Poorly studied irregular variables with unknown features of light variations and spectral types. This is a

very inhomogeneous group of objects.

IA Poorly studied irregular variables of early (O-A) spectral type.

IB Poorly studied irregular variables of intermediate (F-G) to late (K-M) spectral type.

Orion variables. Irregular, eruptive variables connected with bright or dark diffuse nebulae or

observed in the regions of these nebulae. Some of them may show cyclic light variations caused

by axial rotation. In the Spectrum-Luminosity diagram, they are found in the area of the main

sequence and subgiants. They are probably young objects that, during the course of further

evolution, will become light-constant stars on the zero-age main sequence (ZAMS). The range

of brightness variations may reach several magnitudes. In the case of rapid light variations

having been observed (up to 1 mag in 1-10 days), the letter “S” is added to the symbol for the

type (INS). This type may be divided into the following subtypes:

INA

Orion variables of early spectral types (B-A or Ae). They are often characterized by

occasional abrupt Algol-like fadings (T Ori);

INB

Orion variables of intermediate and late spectral types, F-M or Fe-Me (BH Cep, AH Ori).

F-type stars may show Algol-like fadings similar to those of many INA stars; K-M stars

may produce ﬂares along with irregular light variations;

INT,IT

Orion variables of the T Tauri type. Stars are assigned to this type on the basis of

the following (purely spectroscopic) criteria: spectral types are in the range Fe-Me. The

spectra of most typical stars resemble the spectrum of the solar chromosphere. The feature

speciﬁc to the type is the presence of the ﬂuorescent emission lines Fe II 4046, 4132 A

(anomalously intense in the spectra of these stars), emission lines [Si II] and [O I], as well

as the absorption line Li I 6707 A. These variables are usually observed only in diffuse

nebulae. If it is not apparent that the star is associated with a nebula, the letter “N” in the

symbol for the type may be omitted, e.g., IT (RW AUR);

IN(YY)

Some Orion variables (YY Ori) show the presence of absorption components on the

redward sides of emission lines, indicating the infall of matter toward the stars’ surfaces.

In such cases, the symbol for the type may be accompanied by the symbol “YY”.

Rapid irregular variables having no apparent connection with diffuse nebulae and showing light

changes of about 0.5 - 1.0 mag within several hours or days. There is no strict boundary between

rapid irregular and Orion variables. If a rapid irregular star is observed in the region of a diffuse

nebula, it is considered an Orion variable and designated by the symbol INS. To attribute a

variable to the IS type, it is necessary to take much care to be certain that its light changes are

really not periodic. Quite a number of the stars assigned to this type in the third edition of the

GCVS turned out to be eclipsing binary systems, RR Lyrae variables, and even extragalactic BL

Lac objects.

ISA Rapid irregular variables of the early spectral types, B-A or Ae;

ISB Rapid irregular variables of the intermediate and late spectral types, F-M and Fe-Me.

312 Appendix C. Star Catalogues

RCB

Variables of the R Coronae Borealis type. These are hydrogen-poor, carbon- and helium-rich, high-

luminosity stars belonging to the spectral types Bpe-R, which are simultaneously eruptive and

pulsating variables. They show slow nonperiodic fadings by 1-9 mag in V lasting from a month or

more to several hundred days. These changes are superposed on cyclic pulsations with amplitudes up

to several tenths of a magnitude and periods in the range 30-100 days.

Eruptive variables of the RS Canum Venaticorum type. This type is ascribed to close binary systems

with spectra showing Ca II H and K in emission, their components having enhanced chromospheric

activity that causes quasi-periodic light variability. The period of variation is close to the orbital one,

and the variability amplitude is usually as great as 0.2 mag in V (UX Ari). They are X-ray sources

and rotating variables. RS CVn itself is also an eclipsing system (see below).

SDOR

Variables of the S Doradus type. These are eruptive, high-luminosity Bpec-Fpec stars showing

irregular (sometimes cyclic) light changes with amplitudes in the range 1-7 mag in V. They belong

to the brightest blue stars of their parent galaxies. As a rule, these stars are connected with diffuse

nebulae and surrounded by expanding envelopes (P Cyg, Eta Car).

Eruptive variables of the UV Ceti type, these are K Ve-M Ve stars sometimes displaying ﬂare activity

with amplitudes from several tenths of a magnitude up to 6 mag in V. The amplitude is considerably

greater in the ultraviolet spectral region. Maximum light is attained in several seconds or dozens of

seconds after the beginning of a ﬂare; the star returns to its normal brightness in several minutes or

dozens of minutes.

UVN

Flaring Orion variables of spectral types Ke-Me. These are phenomenologically almost identical

to UV Cet variables observed in the solar neighborhood. In addition to being related to nebulae,

they are normally characterized by being of earlier spectral type and greater luminosity, with slower

development of ﬂares (V389 Ori). They are possibly a speciﬁc subgroup of INB variables with

irregular variations superimposed by ﬂares.

Eruptive Wolf-Rayet variables. Stars with broad emission features of He I and He II as well as C II-C

IV, O II-O IV, and N III-N V. They display irregular light changes with amplitudes up to 0.1 mag in V,

which are probably caused by physical processes, in particular, by nonstable mass outﬂow from their

atmospheres.

C.3.2.2 Pulsating Variable Stars

Pulsating variables are stars showing periodic expansion and contraction of their surface layers. The

pulsations may be radial or nonradial. A radially pulsating star remains spherical in shape, while in the case

of nonradial pulsations the star’s shape periodically deviates from a sphere, and even neighboring zones of

its surface may have opposite pulsation phases.

Depending on the period value, on the mass and evolutionary status of the star, and on the scale of

pulsational phenomena, the following types of pulsating variables may be distinguished:

ACYG

Variables of the Alpha Cygni type, which are nonradially pulsating supergiants of Bep-AepIa

spectral types. The light changes with amplitudes of the order of 0.1 mag often seem irregular, being

caused by the superposition of many oscillations with close periods. Cycles from several days to

several weeks are observed.

BCEP

Variables of the Beta Cephei type (Beta Cep, Beta CMa), which are pulsating O8-B6 I-V stars with

periods of light and radial-velocity variations in the range of 0.1 - 0.6 days and light amplitudes from

0.01 to 0.3 mag in V. The light curves are similar in shape to average radial-velocity curves but lag in

phase by a quarter of the period, so that maximum brightness corresponds to maximum contraction,

i.e., to minimum stellar radius. The majority of these stars probably show radial pulsations, but some

(V469 Per) display nonradial pulsations; multiperiodicity is characteristic of many of these stars.

BCEPS

A short-period group of Beta Cep variables. The spectral types are B2-B3 IV-V; periods and

light amplitudes are in the ranges 0.02 - 0.04 days and 0.015 - 0.025 days, respectively, i.e., an

order of magnitude smaller than the normally observed ones.

BLBOO

The so-called “anomalous Cepheids”, i.e. stars with periods characteristic of comparatively

long-period RRAB variables, but considerably brighter by luminosity (BL Boo = NGC 5466 V19).

CEP

Cepheids. Radially pulsating, high luminosity (classes Ib-II) variables with periods in the range of

1-135 days and amplitudes from several hundredths to 2 mag in V (in the B band, the amplitudes are

greater). Spectral type at maximum light is F; at minimum, the types are G-K. The longer the period

of light variation, the later is the spectral type. The maximum of the surface-layer expansion velocity

almost coinciding with maximum light.

CEP(B)

Cepheids (TU Cas, V 367 Sct) displaying the presence of two or more simultaneously

operating pulsation modes (usually the fundamental tone with the period P0 and the ﬁrst

C.3 Variable Stars 313

overtone P1). The periods P0 are in the range from 2 to 7 days, with the ratio P1/P0 approx.

0.71.

Variables of the W Virginis type. These are pulsating variables of the galactic spherical component (old

disk) population with periods of approximately 0.8 to 35 days and amplitudes from 0.3 to 1.2 mag in

V. They obey a period-luminosity relation different from that for Delta Cep variables (see DCEP). For

an equal period value, the W Vir variables are fainter than the Delta Cep stars by 0.7 - 2 mag. The

light curves of W Vir variables for some period intervals differ from those of Delta Cep variables for

corresponding periods either by amplitudes or by the presence of humps on their descending branches,

sometimes turning into broad ﬂat maxima. W Vir variables are present in globular clusters and at high

galactic latitudes. They may be separated into the following subtypes:

CWA W Vir variables with periods longer than 8 days (W Vir);

CWB W Vir variables with periods shorter than 8 days (BL Her).

DCEP

These are the classical cepheids, or Delta Cep-type variables. Comparatively young objects that

have left the main sequence and evolved into the instability strip of the Hertzsprung-Russell (H-R)

diagram, they obey the well-known Cepheid period-luminosity relation and belong to the young disk

population. DCEP stars are present in open clusters. They display a certain relation between the

shapes of their light curves and their periods.

DCEPS

These are Delta Cep variables having light amplitudes <0.5 mag in V (<0.7 mag in B) and

almost symmetrical light curves (M-m approx. 0.4 - 0.5 periods); as a rule, their periods do not

exceed 7 days. They are probably ﬁrst-overtone pulsators and/or are in the ﬁrst transition across

the instability strip after leaving the main sequence (SU Cas).

Traditionally, both Delta Cep and W Vir stars are quite often called Cepheids because it is

often impossible to discriminate between them on the basis of the light curves for periods

in the range 3 - 10 days. However, these are distinct groups of entirely different objects in

different evolutionary stages. One of the signiﬁcant spectral differences between W Vir stars

and Cepheids is the presence, during a certain phase interval, of hydrogen-line emission in the

former and of Ca II H and K emission in the latter.

DSCT

Variables of the Delta Scuti type. These are pulsating variables of spectral types A0-F5 III-V

displaying light amplitudes from 0.003 to 0.9 mag in V (usually several hundredths of a magnitude)

and periods from 0.01 to 0.2 days. The shapes of the light curves, periods, and amplitudes usually

vary greatly. Radial as well as nonradial pulsations are observed. The variability of some members

of this type appears sporadically and sometimes completely ceases, this being a consequence of

strong amplitude modulation with the lower value of the amplitude not exceeding 0.001 mag in some

cases. The maximum of the surface layer expansion does not lag behind the maximum light for

more than 0.1 periods. DSCT stars are representatives of the galactic disk (ﬂat component) and are

phenomenologically close to the SX Phe variables.

DSCTC

Low amplitude group of Delta Sct variables (light amplitude <0.1 mag in V). The majority

of this type’s representatives are stars of luminosity class V; objects of this subtype generally

are representative of the Delta Sct variables in open clusters.

GDOR

Gamma Doradus stars. Early type F dwarfs showing (multiple) periods from several tenths of a day

to slightly in excess of one day. Amplitudes usually do not exceed 0.1 mag. Presumably low degree

g-mode non-radial pulsators. Prototype: gamma Dor.

Slow irregular variables. The light variations of these stars show no evidence of periodicity, or any

periodicity present is very poorly deﬁned and appears only occasionally. Like for the type I, stars are

often attributed to this type because of being insufﬁciently studied. Many type L variables are really

semiregulars or belong to other types.

Slow irregular variables of late spectral types (K, M, C, S); as a rule, they are giants (CO Cyg).

This type is also ascribed, in the GCVS, to slow red irregular variables in the case of unknown

spectral types and luminosities.

Irregular variable supergiants of late spectral types having amplitudes of about 1 mag in V (TZ

Cas).

LPB The comparatively long-period pulsating B stars (periods exceeding (LBV) one day).

Mira (Omicron) Ceti-type variables. These are long-period variable giants with characteristic late-type

emission spectra (Me, Ce, Se) and light amplitudes from 2.5 to 11 mag in V. Their periodicity is

well pronounced, and the periods lie in the range between 80 and 1000 days. Infrared amplitudes

are usually less than in the visible and may be <2.5 mag. For example, in the K band they usually

do not exceed 0.9 mag. If the amplitudes exceed 1 - 1.5 mag , but it is not certain that the true light

314 Appendix C. Star Catalogues

amplitude exceeds 2.5 mag, the symbol “M” is followed by a colon, or the star is attributed to the

semiregular class with a colon following the symbol for that type (SR).

PVTEL

Variables of the PV Telescopii type. These are helium supergiant Bp stars with weak hydrogen

lines and enhanced lines of He and C. They pulsate with periods of approximately 0.1 to 1 days, or

vary in brightness with an amplitude of 0.1 mag in V during a time interval of about a year.

RPHS

Very rapidly pulsating hot (subdwarf B) stars. Typical periods are hundreds of seconds, amplitudes

are within several hundredths of a magnitude. Prototype: V361 Hya = EC 14026-2647.

Variables of the RR Lyrae type, which are radially-pulsating giant A-F stars having amplitudes from 0.2

to 2 mag in V. Cases of variable light-curve shapes as well as variable periods are known. If these

changes are periodic, they are called the Blazhko effect.

Traditionally, RR Lyrae stars are sometimes called short-period Cepheids or cluster-type variables. The

majority of these stars belong to the spherical component of the Galaxy; they are present, sometimes

in large numbers, in some globular clusters, where they are known as pulsating horizontal-branch stars.

Like Cepheids, maximum expansion velocities of surface layers for these stars practically coincide

with maximum light.

RR(B)

RR Lyrae variables showing two simultaneously operating pulsation modes, the fundamental

tone with the period P0 and the ﬁrst overtone, P1 (AQ Leo). The ratio P1/P0 is approximately

0.745;

RRAB

RR Lyrae variables with asymmetric light curves (steep ascending branches), periods from

0.3 to 1.2 days, and amplitudes from 0.5 to 2 mag in V;

RRC

RR Lyrae variables with nearly symmetric, sometimes sinusoidal, light curves, periods from

0.2 to 0.5 days, and amplitudes not greater than 0.8 mag in V (SX UMa).

Variables of the RV Tauri type. These are radially pulsating supergiants having spectral types F-G at

maximum light and K-M at minimum. The light curves are characterized by the presence of double

waves with alternating primary and secondary minima that can vary in depth so that primary minima

may become secondary and vice versa. The complete light amplitude may reach 3-4 mag in V. Periods

between two adjacent primary minima (usually called formal periods) lie in the range 30-150 days

(these are the periods appearing in the Catalogue). Two subtypes, RVA and RVB, are recognized:

RVA RV Tauri variables that do not vary in mean magnitude (AC Her);

RVB

RV Tauri variables that periodically (with periods from 600 to 1500 days and amplitudes up to

2 mag in V) vary in mean magnitude (DF Cyg, RV Tau).

Semiregular variables, which are giants or supergiants of intermediate and late spectral types showing

noticeable periodicity in their light changes, accompanied or sometimes interrupted by various

irregularities. Periods lie in the range from 20 to >2000 days, while the shapes of the light curves are

rather different and variable, and the amplitudes may be from several hundredths to several magnitudes

(usually 1-2 mag in V).

SRA

Semiregular late-type (M, C, S or Me, Ce, Se) giants displaying persistent periodicity and

usually small (<2.5 mag in V) light amplitudes (Z Aqr). Amplitudes and light-curve shapes

generally vary and periods are in the range of 35-1200 days. Many of these stars differ from

Miras only by showing smaller light amplitudes;

SRB

Semiregular late-type (M, C, S or Me, Ce, Se) giants with poorly deﬁned periodicity (mean

cycles in the range of 20 to 2300 days) or with alternating intervals of periodic and slow irregular

changes, and even with light constancy intervals (RR CrB, AF Cyg). Every star of this type may

usually be assigned a certain mean period (cycle), which is the value given in the Catalogue.

In a number of cases, the simultaneous presence of two or more periods of light variation is

observed;

SRC

Semiregular late-type (M, C, S or Me, Ce, Se) supergiants (Mu Cep) with amplitudes of about

1 mag and periods of light variation from 30 days to several thousand days;

SRD

Semiregular variable giants and supergiants of F, G, or K spectral types, sometimes with

emission lines in their spectra. Amplitudes of light variation are in the range from 0.1 to 4 mag,

and the range of periods is from 30 to 1100 days (SX Her, SV UMa).

SRS

Semiregular pulsating red giants with short period (several days to a month), probably high-

overtone pulsators. Prototype: AU Ari.

SXPHE

Phenomenologically, these resemble DSCT (Delta Sct) variables and are pulsating subdwarfs of

the spherical component, or old disk galactic population, with spectral types in the range A2-F5. They

may show several simultaneous periods of oscillation, generally in the range 0.04-0.08 days, with

variable-amplitude light changes that may reach 0.7 mag in V. These stars are present in globular

C.3 Variable Stars 315

clusters.

ZZ Ceti variables. These are nonradially pulsating white dwarfs that change their brightnesses with

periods from 30 s to 25 min and amplitudes from 0.001 to 0.2 mag in V. They usually show several

close period values. Flares of 1 mag are sometimes observed; however, these may be explained by the

presence of close UV Ceti companions.

These variables are divided into the following subtypes:

ZZA

ZZ Cet-type variables of DA spectral type (ZZ Cet) having only hydrogen absorption lines in

their spectra;

ZZB

ZZ Cet-type variables of DB spectral type having only helium absorption lines in their spectra.

ZZO

ZZ Cet-type variables of the DO spectral type showing HeII and and CIV absorption lines in

their spectra.

C.3.2.3 Rotating Variable Stars

Variable stars with nonuniform surface brightness and/or ellipsoidal shapes, whose variability is caused by

axial rotation with respect to the observer. The nonuniformity of surface brightness distributions may be

caused by the presence of spots or by some thermal or chemical inhomogeneity of the atmosphere caused

by a magnetic ﬁeld whose axis is not coincident with the rotation axis. These stars are subdivided into the

following types:

ACV

Alpha2 Canum Venaticorum variables. These are main-sequence stars with spectral types B8p-A7p

and displaying strong magnetic ﬁelds. Spectra show abnormally strong lines of Si, Sr, Cr, and rare

earths whose intensities vary with rotation. They exhibit magnetic ﬁeld and brightness changes

(periods of 0.5-160 days or more). The amplitudes of the brightness changes are usually within

0.01-0.1 mag in V.

ACVO

Rapidly oscillating Alpha2 CVn variables. These are nonradially pulsating, rotating magnetic

variables of Ap spectral type (DO Eri). Pulsation periods are in the range of 6-12 mmag

(0.004-0.01 days), while amplitudes of light variation caused by the pulsation are about 0.01

mag in V. The pulsational variations are superposed on those caused by rotation.

BY Draconis-type variables, which are emission-line dwarfs of dKe-dMe spectral type showing

quasiperiodic light changes with periods from a fraction of a day to 120 days and amplitudes from

several hundredths to 0.5 mag in V. The light variability is caused by axial rotation of a star with a

variable degree of nonuniformity of the surface brightness (spots) and chromospheric activity. Some

of these stars also show ﬂares similar to those of UV Cet stars, and in those cases they also belong to

the latter type and are simultaneously considered eruptive variables.

ELL

Rotating ellipsoidal variables (b Per, Alpha Vir). These are close binary systems with ellipsoidal

components, which change combined brightnesses with periods equal to those of orbital motion

because of changes in emitting areas toward an observer, but showing no eclipses. Light amplitudes

do not exceed 0.1 mag in V.

FKCOM

FK Comae Berenices-type variables. These are rapidly rotating giants with nonuniform surface

brightnesses, which have G-K spectral types with broad H and K Ca II emission and sometimes

Halpha. They may also be spectroscopic binary systems. Periods of light variation (up to several days)

are equal to rotational periods, and amplitudes are several tenths of a magnitude. It is not excluded

that these objects are the product of further evolution of EW (W UMa) close binary systems (see

below).

PSR

Optically variable pulsars (CM Tau), which are rapidly rotating neutron stars with strong magnetic

ﬁelds, radiating in the radio, optical, and X-ray regions. Pulsars emit narrow beams of radiation, and

periods of their light changes coincide with rotational periods (from 0.004 to 4 s), while amplitudes of

the light pulses reach 0.8 mag.

Close binary systems characterized by the presence of strong reﬂection (re-radiation) of the light of

the hot star illuminating the surface of the cooler companion. Light curves are sinusoidal with the

period equal to Porb, maximum brightness coinciding with the passage of the hot star in front of the

companion. The eclipse may be absent. The range of light variation is about 0.5-1.0mag V (KV Vel).

SXARI

SX Arietis-type variables. These are main-sequence B0p-B9p stars with variable-intensity He I

and Si III lines and magnetic ﬁelds. They are sometimes called helium variables. Periods of light

and magnetic ﬁeld changes (about 1 day) coincide with rotational periods, while amplitudes are

approximately 0.1 mag in V. These stars are high-temperature analogs of the ACV variables.

C.3.2.4 Cataclysmic (Explosive and Novalike) Variables

These are variable stars showing outbursts caused by thermonuclear burst processes in their surface layers

(novae) or deep in their interiors (supernovae). We use the term “novalike” for variables that show novalike

316 Appendix C. Star Catalogues

outbursts caused by rapid energy release in the surrounding space (UG-type stars - see below) and also

for objects not displaying outbursts but resembling explosive variables at minimum light by their spectral

(or other) characteristics. The majority of explosive and novalike variables are close binary systems, their

components having strong mutual inﬂuence on the evolution of each star. It is often observed that the hot

dwarf component of the system is surrounded by an accretion disk formed by matter lost by the other, cooler,

and more extended component. This category is subdivided into the following types:

Novae. Close binary systems with orbital periods from 0.05 to 230 days. One of the components of these

systems is a hot dwarf star that suddenly, during a time interval from one to several dozen or several

hundred days, increases its brightness by 7-19 mag in V, then returns gradually to its former brightness

over several months, years, or decades. Small changes at minimum light may be present. Cool

components may be giants, subgiants, or dwarfs of K-M type. The spectra of novae near maximum

light resemble A-F absorption spectra of luminous stars at ﬁrst. Then broad emission lines (bands)

of hydrogen, helium, and other elements with absorption components indicating the presence of a

rapidly expanding envelope appear in the spectrum. As the light decreases, the composite spectrum

begins to show forbidden lines characteristic of the spectra of gas nebulae excited by hot stars. At

minimum light, the spectra of novae are generally continuous or resemble the spectra of Wolf-Rayet

stars. Only spectra of the most massive systems show traces of cool components.

Some novae reveal pulsations of hot components with periods of approximately 100 s and amplitudes

of about 0.05 mag in V after an outburst. Some novae eventually turn out to be eclipsing systems.

According to the features of their light variations, novae are subdivided into fast (NA), slow (NB),

very slow (NC), and recurrent (NR) categories.

Fast novae displaying rapid light increases and then, having achieved maximum light, fading by

3 mag in 100 or fewer days (GK Per);

Slow novae that fade after maximum light by 3 mag in >= 150 days (RR Pic). Here the presence

of the well-known “dip” in the light curves of novae similar to T Aur and DQ Her is not taken

into account: The rate of fading is estimated on the basis of a smooth curve, its parts before and

after the “dip” being a direct continuation of one another;

Novae with a very slow development and remaining at maximum light for more than a decade,

then fading very slowly. Before an outburst these objects may show long-period light changes

with amplitudes of 1-2 mag in V (RR Tel); cool components of these systems are probably

giants or supergiants, sometimes semiregular variables, and even Mira variables. Outburst

amplitudes may reach 10 mag. High excitation emission spectra resemble those of planetary

nebulae, Wolf-Rayet stars, and symbiotic variables. The possibility that these objects are

planetary nebulae in the process of formation is not excluded;

Novalike variables, which are insufﬁciently studied objects resembling novae by the characteris-

tics of their light changes or by spectral features. This type includes, in addition to variables

showing novalike outbursts, objects with no bursts ever observed; the spectra of novalike

variables resemble those of old novae, and small light changes resemble those typical for old

novae at minimum light. However, quite often a detailed investigation makes it possible to

reclassify some representatives of this highly inhomogeneous group of objects into other types;

Recurrent novae, which differ from typical novae by the fact that two or more outbursts (instead

of a single one) separated by 10-80 years have been observed (T CrB).

Supernovae (B Cas, CM Tau). Stars that increase, as a result of an outburst, their brightnesses by 20

mag and more, then fade slowly. The spectrum during an outburst is characterized by the presence of

very broad emission bands, their widths being several times greater than those of the bright bands

observed in the spectra of novae. The expansion velocities of SN envelopes are in the thousands of

km/s. The structure of a star after outburst alters completely. An expanding emission nebula results

and a (not always observable) pulsar remains at the position of the original star. According to the light

curve shape and the spectral features, supernovae are subdivided into types I and II.

SNI

Type I supernovae. Absorption lines of Ca II, Si, etc., but no hydrogen lines are present in

the spectra. The expanding envelope almost lacks hydrogen. During 20-30 days following

maximum light, the brightness decreases by approximately 0.1 mag per day, then the rate of

fading slows and reaches a constant value of 0.014/day;

SNII

Type II supernovae. Lines of hydrogen and other elements are apparent in their spectra. The

expanding envelope consists mainly of H and He. Light curves show greater diversity than

those of type I supernovae. Usually after 40-100 days since maximum light, the rate of fading

is 0.1 mag per day.

C.3 Variable Stars 317

U Geminorum-type variables, quite often called dwarf novae. They are close binary systems consisting

of a dwarf or subgiant K-M star that ﬁlls the volume of its inner Roche lobe and a white dwarf

surrounded by an accretion disk. Orbital periods are in the range 0.05-0.5 days. Usually only small,

in some cases rapid, light ﬂuctuations are observed, but from time to time the brightness of a system

increases rapidly by several magnitudes and, after an interval of from several days to a month or

more, returns to the original state. Intervals between two consecutive outbursts for a given star may

vary greatly, but every star is characterized by a certain mean value of these intervals, i.e., a mean

cycle that corresponds to the mean light amplitude. The longer the cycle, the greater the amplitude.

These systems are frequently sources of X-ray emission. The spectrum of a system at minimum is

continuous, with broad H and He emission lines. At maximum these lines almost disappear or become

shallow absorption lines. Some of these systems are eclipsing, possibly indicating that the primary

minimum is caused by the eclipse of a hot spot that originates in the accretion disk from the infall of

a gaseous stream from the K-M star. According to the characteristics of the light changes, U Gem

variables may be subdivided into three types: SS Cyg, SU UMa, and Z Cam.

UGSS

SS Cygni-type variables (SS Cyg, U Gem). They increase in brightness by 2-6 mag in V in

1-2 days and in several subsequent days return to their original brightnesses. The values of the

cycle are in the range 10 days to several thousand;

UGSU

SU Ursae Majoris-type variables. These are characterized by the presence of two types of

outbursts called “normal” and “supermaxima”. Normal, short outbursts are similar to those of

UGSS stars, while supermaxima are brighter by 2 mag, are more than ﬁve times longer (wider),

and occur several times less frequently. During supermaxima the light curves show superposed

periodic oscillations (superhumps), their periods being close to the orbital ones and amplitudes

being about 0.2-0.3 mag in V. Orbital periods are shorter than 0.1 days; companions are of dM

spectral type;

UGZ

Z Camelopardalis-type stars. These also show cyclic outbursts, differing from UGSS variables

by the fact that sometimes after an outburst they do not return to the original brightness, but

during several cycles retain a magnitude between maximum and minimum. The values of cycles

are from 10 to 40 days, while light amplitudes are from 2 to 5 mag in V.

ZAND

Symbiotic variables of the Z Andromedae type. They are close binaries consisting of a hot star, a star

of late type, and an extended envelope excited by the hot star’s radiation. The combined brightness

displays irregular variations with amplitudes up to 4 mag in V. A very inhomogeneous group of

objects.

C.3.2.5 Close Binary Eclipsing Systems

We adopt a triple system of classifying eclipsing binary systems: according to the shape of the combined light

curve, as well as to physical and evolutionary characteristics of their components. The classiﬁcation based

on light curves is simple, traditional, and suits the observers; the second and third classiﬁcation methods take

into account positions of the binary-system components in the (MV ,B-V) diagram and the degree of inner

Roche lobe ﬁlling. Estimates are made by applying the simple criteria proposed by Svechnikov and Istomin

(1979). The symbols for the types of eclipsing binary systems that we use are given below.

C.3.2.6 Classiﬁcation based on the shape of the light curve

E Eclipsing binary systems. These are binary systems with orbital planes so close to the observer’s line of

sight (the inclination i of the orbital plane to the plane orthogonal to the line of sight is close to 90 deg)

that the components periodically eclipse each other. Consequently, the observer ﬁnds changes of the

apparent combined brightness of the system with the period coincident with that of the components’

orbital motion.

Algol (Beta Persei)-type eclipsing systems. Binaries with spherical or slightly ellipsoidal compo-

nents. It is possible to specify, for their light curves, the moments of the beginning and end of the

eclipses. Between eclipses the light remains almost constant or varies insigniﬁcantly because of

reﬂection effects, slight ellipsoidality of components, or physical variations. Secondary minima

may be absent. An extremely wide range of periods is observed, from 0.2 to >= 10000 days.

Light amplitudes are also quite different and may reach several magnitudes.

Beta Lyrae-type eclipsing systems. These are eclipsing systems having ellipsoidal components

and light curves for which it is impossible to specify the exact times of onset and end of eclipses

because of a continuous change of a system’s apparent combined brightness between eclipses;

secondary minimum is observed in all cases, its depth usually being considerably smaller than

that of the primary minimum; periods are mainly longer than 1 day. The components generally

belong to early spectral types (B-A). Light amplitudes are usually <2 mag in V.

318 Appendix C. Star Catalogues

EP Stars showing eclipses by their planets. Prototype: V0376 Peg.

W Ursae Majoris-type eclipsing variables. These are eclipsing binaries with periods shorter

than 1 days, consisting of ellipsoidal components almost in contact and having light curves for

which it is impossible to specify the exact times of onset and end of eclipses. The depths of the

primary and secondary minima are almost equal or differ insigniﬁcantly. Light amplitudes are

usually <0.8 mag in V. The components generally belong to spectral types F-G and later.

C.3.2.7 Classiﬁcation according to the components’ physical characteristics

Systems with one or both giant and supergiant components; one of the components may be a main

sequence star.

PN Systems having, among their components, nuclei of planetary nebulae (UU Sge).

RS Canum Venaticorum-type systems. A signiﬁcant property of these systems is the presence in their

spectra of strong Ca II H and K emission lines of variable intensity, indicating increased chromospheric

activity of the solar type. These systems are also characterized by the presence of radio and X-ray

emission. Some have light curves that exhibit quasi sine waves outside eclipses, with amplitudes and

positions changing slowly with time. The presence of this wave (often called a distortion wave) is

explained by differential rotation of the star, its surface being covered with groups of spots; the period

of the rotation of a spot group is usually close to the period of orbital motion (period of eclipses) but

still differs from it, which is the reason for the slow change (migration) of the phases of the distortion

wave minimum and maximum in the mean light curve. The variability of the wave’s amplitude (which

may be up to 0.2 mag in V) is explained by the existence of a long-period stellar activity cycle similar

to the 11-year solar activity cycle, during which the number and total area of spots on the star’s surface

vary.

WD Systems with white-dwarf components.

WR Systems having Wolf-Rayet stars among their components (V444 Cyg).

C.3.2.8 Classiﬁcation based on the degree of ﬁlling of inner Roche lobes

Detached systems of the AR Lacertae type. Both components are subgiants not ﬁlling their inner

equipotential surfaces.

D Detached systems, with components not ﬁlling their inner Roche lobes.

Detached main-sequence systems. Both components are main-sequence stars and do not ﬁll

their inner Roche lobes.

DS Detached systems with a subgiant. The subgiant also does not ﬁll its inner critical surface.

DW Systems similar to W UMa systems in physical properties (KW, see below), but not in contact.

K Contact systems, both components ﬁlling their inner critical surfaces.

Contact systems of early (O-A) spectral type, both components being close in size to their inner

critical surfaces.

Contact systems of the W UMa type, with ellipsoidal components of F0-K spectral type.

Primary components are main-sequence stars and secondaries lie below and to the left of the

main sequence in the (MV,B-V) diagram.

Semidetached systems in which the surface of the less massive component is close to its inner Roche

lobe.

The combination of the above three classiﬁcation systems for eclipsing binaries results in the assignment

of multiple classiﬁcations for object types. These are separated by a solidus (“/”) in the data ﬁeld. Examples

are: E/DM, EA/DS/RS, EB/WR, EW/KW, etc.

C.3.2.9

Optically Variable Close Binary Sources of Strong, Variable X-ray Radiation (X-ray Sources)

AM Her type variables; close binary systems consisting of a dK-dM type dwarf and of a compact object

with strong magnetic ﬁeld, characterized by variable linear and circular polarization of light. The total

range of light variations may reach 4-5 mag V.

Close binary systems that are sources of strong, variable X-ray emission and which do not belong to

or are not yet attributed to any of the above types of variable stars. One of the components of the

system is a hot compact object (white dwarf, neutron star, or possibly a black hole). X-ray emission

originates from the infall of matter onto the compact object or onto an accretion disk surrounding the

compact object. In turn, the X-ray emission is incident upon the atmosphere of the cooler companion

of the compact object and is reradiated in the form of optical high-temperature radiation (reﬂection

effect), thus making that area of the cooler companion’s surface an earlier spectral type. These effects

lead to quite a peculiar complex character of optical variability in such systems. These objects may be

subdivided into the following types:

X-ray bursters. Close binary systems showing X-ray and optical bursts, their duration being from

C.3 Variable Stars 319

several seconds to ten minutes, with amplitudes of about 0.1 mag in V (V 801 Ara, V 926 Sco);

Fluctuating X-ray systems showing rapid variations of X-ray (Cygnus X-1 = V1357 Cyg) and

optical (V821 Ara) radiation on time scales of dozens of milliseconds;

X-ray irregulars. Close binary systems consisting of a hot compact object surrounded by an

accretion disk and a dA - dM-type dwarf. These display irregular light changes on time scales

of minutes and hours, and amplitudes of about 1 mag in V. Superposition of a periodic variation

because of orbital motion is possible (V818 Sco);

X-ray binaries characterized by the presence of relativistic jets evident at X-ray and radio

wavelengths, as well as in the optical spectrum in the form of emission components showing

periodic displacements with relativistic velocities (V1343 Aql);

XND

X-ray, novalike (transient) systems containing, along with a hot compact object, a dwarf or

subgiant of G-M spectral type. These systems occasionally rapidly increase in brightness by

4-9 mag in V, in the visible simultaneously with the X-ray range, with no envelope ejected. The

duration of the outburst may be up to several months (V616 Mon);

XNG

X-ray, novalike (transient) systems with an early-type supergiant or giant primary component

and a hot compact object as a companion. Following the main component’s outburst, the

material ejected by it falls onto the compact object and causes, with a signiﬁcant delay, the

appearance of X rays. The amplitudes are about 1-2 mag in V (V725 Tau);

X-ray pulsar systems. The primary component is usually an ellipsoidal early-type supergiant. The

reﬂection effect is very small and light variability is mainly caused by the ellipsoidal primary

component’s rotation. Periods of light changes are between 1 and 10 days; the period of the

pulsar in the system is from 1 s to 100 min. Light amplitudes usually do not exceed several

tenths of a magnitude (Vela X-1 = GP Vel);

XPR

X-ray pulsar systems featuring the presence of the reﬂection effect. They consist of a dB-dF-

type primary and an X-ray pulsar, which may also be an optical pulsar. The mean light of the

system is brightest when the primary component is irradiated by X rays; it is faintest during a

low state of the X-ray source. The total light amplitude may reach 2-3 mag in V (HZ Her);

XPRM,XM

X-ray systems consisting of a late-type dwarf (dK-dM) and a pulsar with a strong

magnetic ﬁeld. Matter accretion on the compact object’s magnetic poles is accompanied by

the appearance of variable linear and circular polarization; hence, these systems are sometimes

known as “polars”. The amplitudes of the light changes are usually about 1 mag in V but,

provided that the primary component is irradiated by X rays, the mean brightness of a system

may increase by 3 mag in V. The total light amplitude may reach 4-5 mag in V (AM Her, AN

UMa).

If the beam of X-ray emission originating at the magnetic poles of the rotating hot compact object does

not pass through the observer’s position and the system is not observed as a pulsar, the letter “P” in the

above symbols for X-ray-system types is not used. If an X-ray system is also an eclipsing or an ellipsoidal

variable, the X-ray symbol is preceded by “E” or “ELL” joined with the X-ray symbol by a “+” sign (e.g.,

E+X, ELL+X).

C.3.2.10 Other Symbols

In addition to the variable-star types described above, certain other symbols that need to be explained will be

found in the Type data ﬁeld:

BLLAC

Extragalactic BL Lacertae-type objects. These are compact quasistellar objects showing almost

continuous spectra with weak emission and absorption lines and relatively rapid irregular light changes

with amplitudes up to 3 mag in V or more. Sources of strong X-ray radiation and radio waves, their

emission displays strong and variable linear polarization in the visible and infrared spectral regions.

Some objects of this type, considered erroneously to be variable stars and designated in the GCVS

system, will probably sometimes be included in the main table of the Catalogue in the future, too.

CST

Nonvariable stars, formerly suspected to be variable and hastily designated. Further observations have

not conﬁrmed their variability.

GAL

Optically variable quasistellar extragalactic objects (active galactic nuclei [AGNs]) considered to be

variable stars by mistake.

L: Unstudied variable stars with slow light changes.

QSO

Optically variable quasistellar extragalactic sources (quasars) that earlier were erroneously considered

to be variable stars.

S Unstudied variable stars with rapid light changes.

Unique variable stars outside the range of the classiﬁcations described above. These probably represent ei-

320 Appendix C. Star Catalogues

ther short stages of transition from one variability type to another or the earliest and latest evolutionary

stages of these types, or they are insufﬁciently studied members of future new types of variables.

If a variable star belongs to several types of light variability simultaneously, the types are joined in the

Type ﬁeld by a “+” sign (e.g., E+UG, UV+BY).

: Uncertainty ﬂag on Type of Variability

C.4 Double Stars

Since version 0.15.0 Stellarium supports the subset of double stars from WDS

which have HIP identiﬁers

(i.e., stars from the Hipparcos catalog). Stellarium’s Catalog of Double Stars is based on the “The 2001 US

Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog” (Mason et al., 2001).

Cross reference data for WDS and HIP designations is based on the XHIP catalog (Anderson and Francis,

2012) through the astronomical database SIMBAD (Wenger et al., 2000).

C.4.1 Double Star Ca talog File Format

Stellarium’s Double Stars catalog data is kept in the

stars/hip_gaia3

sub-directory of the Installation

Directory and/or User Directory (see section 5.1).

C.4.1.1 File Format

The

wds_hip_part.dat

ﬁle contains data about 16411 double stars which have HIP identiﬁers and stored

in plain text format with tab delimiters.

Name Type Description

HIP int

HIP identiﬁer for the star. Used for reference to the main star cata-

logue.

WDS string WDS designation for the double star.

Observation

int Date of last satisfactory observation (in years).

Position Angle

ﬂoat

Position Angle at date of last satisfactory observation (in decimal

degrees).

Separation

ﬂoat Separation at date of last satisfactory observation (in arcsec).

Table C.8: Format of wds_hip_part.dat

C.4.2 Designations

In version 0.20.4 we incorporated support for additional designations for double stars which have also HIP

identiﬁcation. All these designations were added especially for double star observers and people who use

Stellarium as reference software. The cross-identiﬁcation data for double stars were obtained from The

Cambridge Double Star Atlas (MacEvoy and Tirion, 2015; Mullaney and Tirion, 2009).

In version 0.21.1 we updated cross-identiﬁcation data according to The Washington Double Star Catalog

data (Mason et al., 2001).

Traditional ID Modern ID

Observer Active period

— A R. G. Aitken 1891—1937

—

ABH H.A. Abt 1961—2006

—

ABT G. Abetti 1911—1925

AC A. Clark 1857—1864

—

ACA A.C. Ashcraft 2005—2007

ACG

ACG Astrographic Catalog (Greenwich)

— ADA C. Adam 2014

—

ADM E.R. Adams 2012—2013

—

AG Astronomische Gesellschaft Katalog 1903

http://www.astro.gsu.edu/wds/ or https://www.stelledoppie.it/index2.php?section=1

Latinized and capitalized version of traditional ID

Note: * — Stellarium uses traditional designation of double star

C.4 Double Stars 321

AGC AGC A.G. Clark 1862

—

AHD A. Ahad 2010—2020

—

ALB Albany Observatory 1910–1936

—

ALC C. Allen 2000—2014

—

ALD H.L. Alden 1924—1957

—

ALI A. Ali 1949—1955

—

ALL R.M. Aller 1930—1960

—

ALP P.R. Allen 2007—2012

—

AMM M. Ammler-von Eiff 2016

—

AMS A. Amosse 2012—2020

—

ANJ J.A. Anderson 1920

—

ANT R. Anton 2001—

AOT

AOT Astronomical Observatory Torino

— ARA S. Aravamudan 1961—1963

Arg

ARG F.W.A. Argelander 1857—1865

—

ARI E. Aristidi 1997—1999

—

ARN D. Arnold 2001—2013

—

ARR S. Arribas 1998

—

ARU A.N. Argue 1984—1992

—

ARY R.W. Argyle 1977—2020

—

AST HST FGS Astrometry Science Team 1991—

—

AZC A.A. Azcona 2012—2020

— B W.H. van den Bos 1921—1968

—

BAG Yu.Yu. Balega 1977—2015

—

BAK G.A. Bakos 2006

—

BAL R. Baillaud 1924—1944

—

BAR E.E. Barnard 1884—1922

—

BAS M.A. Barstow 2001

BAT

BAT H. Batterman

— BAU C. Bauer 1994—2007

—

BAZ P. Baize 1927—1994

—

BDK Brown Dwarf Kinematic Project Catalog 2010

—

BDT T.D. Brandt 2014—

—

BED T.R. Bedding 1993—1994

—

BEU J.-L. Beuzit 2004

—

BEW U. Bastian, J. Eisloeffel, K. Wiese 1988

—

BGH S. van den Bergh 1958

—

BGR J.-P. Berger 2011

—

BHA T.P. Bhaskaran 1916—1938

—

BHJ A. Blaauw, W.A. Hiltner, H.L. Johnson 1959

—

BID W.P. Bidelman 1976—1980

Big

BIG G. Bigourdan 1883—1903

—

BIL B.A. Biller 2006—2014

—

BKO E. Berko 2002—2012

—

BLA A. Blazit 1877—1987

—

BLK D.R. Blackmore 1990

Bll

BLL R.S. Ball 1872—1884

—

BLM B.L. Morgan 1978—1982

—

BLO M. Bloch 1931

—

BNK A. Brandeker 2001—2006

—

BNS D. Baines 2006

—

BNU D. Bonneau 1979—2011

—

BNV M. Bonavita 2007—2020

—

BNW W.A. Baranov 1909

—

BOD A.F. Boden 1998—2012

— BOT G. Boettger 1958—1967

Bow

BOW W.M. Bowyer 1896—1921

322 Appendix C. Star Catalogues

— BPM Bordeaux PM2000 catalogue 2010

—

BRC C. Briceno 1998—2017

BRD

BRD F. Bird

— BRF F.L. Brown 1916—1927

—

BRG C. Bergfors 2010—2016

—

BRH W. Barth 1994

—

BRR W. Brandner 1995—2004

—

BRT S.G. Barton 1926—1957

BrsO

BSO Brisbane Observatory 1834—1851

—

BTG A. Bertoglio 2007—2010

—

BTM M. Bottom 2015

—

BTZ E. Bernewitz 1920—1963

β BU * S. Burnham 1873—1918

β pm BUP * (Proper motion pairs) 1873—1918

—

BVD R. Benavides 2003—2018

—

BWL B.P. Bowler 2012—2018

—

BYV V. Bailey 2014

— CAB J.A. Caballero 2005—2018

—

CAN S.M. Caballero-Nieves 2014—2020

—

CAR M. Carbillet 1996—1998

—

CAT C. Catala 2006

—

CBL R. Caballero 2008—2015

—

CHE Stanislas Chevalier 1908—1925

—

CHM J. Chaname 2004

—

CHN M. Cohen 1979—1983

—

CHR

Center for High Ang. Res. Astronomy

(speckle interferometry systems)

— CHT A.C. Cheetham 2015—2018

—

CIA

Center for High Angular Resolution As-

tronomy (CHARA Interferometric Array)

— CLL J.L. Comellas 2003

—

CLO L.P. Close 1997—2014

—

CLP P. Clark 2011

Cog

COG W.A. Cogshall 1896—1905

Com

COM G.C. Comstock 1894—1911

CorO

COO Cordoba Observatory 1883—1920

Cop

COP R. Copeland 1875—1886

—

COU P. Couteau 1952—1999

CpO, CapO

CPO Cape Observatory 1822—1938

—

CRB J.-L. Carballo 2009—2016

—

CRC M. Cortes-Contreras 2014—2017

—

CRE T. Currie 2010—2020

CRI

CRI F. Crifo

— CRJ J.P. Crepp 2010—2015

Cru

CRU L. Cruls 1884

—

CRZ K.L. Cruz 2007

—

CSE G. Csepany 2015—2017

—

CSI Sz. Csizmadia 2009

—

CSN J.C. Carson 2005—2013

—

CSR I. Coster 2006—2016

—

CSU O. Chesneau 2014

—

CTI P.S. Conti 1971—1980

—

CTT J.-F. Courtot 1995—

—

CTU J.C. Christou 2006—2009

—

CUD K.M. Cudworth 1973

— CUS F. Cusano 2012

—

CUY J. Cuypers 1997—1999

C.4 Double Stars 323

— CVE Z. Cvetkovic 2005—2020

—

CVN G. Chauvin 2002—2015

—

CVP R.J. Cava and R.A. Pascal, Jr. 2004

—

CVR J. Chivers 2011—2015

D D H. Dembowski 1856—1884

Dawes

DA W.R. Dawes 1831—1867

—

DAE S. Daemgen 2007—2015

—

DAL J.A. Daley 1998—2018

—

DAM F. Damm 2009—

—

DAN A. Danjon 1937—1956

δ DAW * B.H. Dawson 1918—1933

—

DBK M. De Becker 2004—2012

—

DCH G. Duchene 1999—2018

—

DEA N.R. Deacon 2005—2020

—

DEL X. Delfosse 1999—2000

—

DIC J. Dick 1921—1963

—

DJU P. Djurkovic 1953—1973

Dob

DOB W.A. Doberck 1875—1934

—

DOM J. Dommanget 1949—1979

—

DON H.F. Donner 1937—1964

—

DOO E. Doolittle 1901—1923

—

DOR Dorpat Observatory

— DRD P. Durand 1983—2011

—

DRS R.J. De Rosa 2011—2019

—

DSG DSSI-Gemini 2012

∆

DUN * J. Dunlop 1825—1846

—

DUQ A. Duquennoy 1987—1996

—

DVG M.J. del Valle Gonzalez 2015—

DYR

DYR E.R. Dyer, Jr.

— EBE J. Ebersberger 1979—1986

EDG

EDG D.W. Edgecomb

Egb EGB H.V. Egbert 1879—1906

—

EGG O.J. Eggen 1945—1982

—

EGN P. Eggenberger 2007—2008

—

EHR D. Ehrenreich 2010

—

EIS T. Eisenbeiss 2007

—

ELP P. Elliott 2015—2016

Eng

ENG R. Engelmann 1865—1887

Enh

ENH B. von Engelhardt 1887—1895

—

ENO European Network Observations

— ES T.E. Espin 1901—1933

—

ESG S. Els 2001

—

EVS N.R. Evans 1993—2020

—

EVT T.M. Evans 2012

— FAB C. Fabricius 2000

—

FAL J.L. Falin and F. Mignard 1999

—

FAR J. Farihi 2004—2013

—

FGL E.D. Feigelson 1996—2006

—

FGS HST Fine Guide Sensor 2015

φ FIN W.S. Finsen 1926—1978

—

FLE J. Fleckenstein 1956—1958

—

FMR F.M. Rica Romero 1996—

—

FOR L. Forgeron 1911

—

FOX P. Fox 1909—1946

— FRH R. Furuhjelm 1932

— FRK W.S. Franks 1914—1919

324 Appendix C. Star Catalogues

— FRT W.J. Forrest 1988—1990

—

FYM M. Fay 2013—2017

— GAA A. Gallenne 2014—2019

—

GAL J. Gallo 1912—1914

GAn

GAN G. Anderson 1888—1897

—

GAT G.D. Gatewood 1973—2019

—

GAU P.L. Gauchet 1923—1928

—

GDM B. Goldman 2010

—

GHE A.M. Ghez 1991—2016

—

GIC H. Giclas 1961—1978

—

GII R. Gili 1991—2020

—

GIR P.M. Girard 1992—1994

—

GIZ J.E. Gizis 2000—2006

—

GJ W. Gliese and H. Jahreiss 1988

—

GKI D.A. Golimowski 1993—2004

Gale

GLE W.F. Gale 1897

Gli

GLI J.M. Gilliss 1850—1868

Glp

GLP S. Glasenapp 1888—1899

—

GMC G. Micello 2011—2019

—

GNS C. Ginski 2012—2016

GNT

GNT Grant

— GOE K.-D. Goecking 1994

GOL

GOL H. Goldschmidt

— GRB S. Groombridge 1913

—

GRE J. Gregorio-Hetem 1992

—

GRF R.F. Grifﬁn 1975—2019

—

GRV J. Greaves 2004—

—

GRY C.A. Grady 2004

—

GSH J. Glaisher 1906—1908

—

GTB K. Gottlieb 1948

—

GUE E.W. Guenther 2001—2005

—

GUI J. Guillaume 1912—1931

—

GUL K. Gullikson 2016

—

GVT GRAVITY collaboration 2018—

—

GWP Garraf Wide Pairs 2012—2016

—

GYL A.N. Goyal 1958—1970

—

GZA B. Gauza 2012—2015

H I to VI, H N H 1 to 6, H N W. Herschel 1777—1821

—

HAT P. Hartigan 1994—2003

—

HAU H. Haupt 1964—1966

Hd, HdO

HDO Harvard Observatory 1866—1911

—

HDS Hipparcos Double Star Catalog c. 1991

—

HEG E.K. Hege 1983—1991

—

HEI W.D. Heintz 1954—2001

—

HEL K. Helminiak 2009—2016

—

HER G.H. Herbig 1950—1998

HJ J.F.W. Herschel 1826—1870

—

HJL J.L. Halbwachs 1981—2020

HL A. Hall 1866—1894

—

HLA L.A. Hirsch 2019

Hld

HLD E.S. Holden 1874—1884

—

HLG G. Hill 1970—1988

—

HLM E. Holmes 1906

—

HLN F. Holden 1963—1979

—

HMM C.A. Hummel 2001—2017

— HNK S. Hinkley 2010—2015

C.4 Double Stars 325

Ho HO G.W. Hough 1883—1907

—

HOM F. Hormuth 2007

Hrg

HRG L. Hargrave 1871—1892

—

HRS D.L. Harris 1947

—

HSL J.N. Heasley 2002

—

HSW R. Harshaw 1990—1993

HTG

HTG C.S. Hastings

Hu HU W.J. Hussey 1896—1914

—

HUB S. Hubrig 2001

—

HUE N. Huelamo 2009—2015

—

HWD A.W. Howard 2010

Howe

HWE H.A. Howe 1876—1882

—

HZE A. Heinze 2009—2010

—

HZG E. Hertzsprung 1907—1958

— I R.T.A. Innes 1895—1948

—

INN P.A. Ianna 1974—1988

—

IOT IOTA Array 1995—2011

—

ISO S. Isobe 1990—1992

—

ITF I.T. Falcon 2011—2020

—

ITO Y. Itoh 1999—2011

—

ISM R.M. Ismailov 1998—2020

— J R. Jonckheere 1908—1958

—

JAY R. Jayawardhana 2001—2006

JC W.S. Jacob 1847—1860

JCT

JCT J.-C. Thorel

— JEF H.M. Jeffers 1945—1978

—

JKA K.A. Janes 2017

JKS

JKS M.P. Jenniskens

— JNN M. Janson 2006—2020

—

JOD E. Jodar 2013

—

JOH E.L. Johnson 1916—1948

—

JOY A.H. Joy 1941—1949

—

JRN A. Jorissen 1988

—

JSP M.K. Jessup 1937—1964

— KAL P. Kalas 2008

—

KAM P. van de Kamp 1929—1969

—

KAR M. Karovska 1986—1997

—

KEL A. Kellerer 2007

—

KIR J.D. Kirkpatrick 1995—2014

—

KNG B. Koenig 2002—2005

—

KNP G.F.G. Knipe 1959—1969

Knott

KNT G. Knott 1865—1881

KO Koenigstuhl (Max Planck Institute)

— KOE L. Koechlin 1979—1983

—

KOH R. Koehler 1998—2016

—

KOI Kepler Object of Interest 2011—2018

—

KON Q.M. Konopacky 2007—2010

—

KOU M.B.N. Kouwenhoven 2005

—

KPP W. Knapp 2015—

—

KPR K.W. Kamper 1976—1992

—

KR A. Kruger

KRO KRO G. Kron

— KRS C.D. Koresko 1991—2002

—

KRU E.C. Kruger 1936—1937

— KRV P. Kervella 2009—2019

— KRW Carlos A. Krawczenko 2009—2020

326 Appendix C. Star Catalogues

— KSS S. Kraus 2007—2012

—

KST J.H. Kastner 2012

KU F. Kustner 1884—1902

—

KUI G.P. Kuiper 1929—1961

Kza

KZA S.M. Kazeza 1984

L L T. Lewis 1891—1921

—

LAB A. Labeyrie 1974

—

LAD T. Ladanyi 2003—2007

—

LAF D. Lafreniere 2007—2014

Lal

LAL J.-J. de Lalande 1825—1877

Lam

LAM J. Lamont 1849

—

LAU H.E. Lau 1905—1917

—

LAW N.M. Law 2006—2010

—

LBZ P. Labitzke 1925—1929

Lcl

LCL N.L. Lacaille 1750

—

LCS P.W. Lucas 2005

—

LDS, LPM Luyten p.m. catalog

— LEC J. Lecacheux 2000—2007

LEE

LEE O.J. Lee

— LEI Ch. Leinert 1986—2001

—

LEO F.C. Leonard 1918—1943

—

LEP S. Lepine 2001—2011

—

LFR L. Ferrero 2009

—

LGR A.-M. Lagrange 2006—2009

—

LI W. Li 1994

—

LIC G. Li Causi 2013

—

LIM M.C. Liu 1996—2012

—

LIN J.F. Ling 1983—2020

—

LLO J.P. Lloyd 2002—2007

—

LMP P. Lampens 2001—2016

—

LNA A. Luna 2020

—

LOC G. Locatelli 2013—2019

—

LOS F. Losse 2005—2010

—

LOU N.P. Loutrel 2011

—

LPL N. La Palombara 2012

LpO

LPO La Plata Observatory

— LSC

Lowell-Southern Connecticut Collabora-

tion

— LUH K.L. Luhman 2002—2013

—

LUY W.J. Luyten 1933—1969

LV F.P. Leavenworth 1887—1930

—

LWR P.J. Lowrance 1999—2005

—

LYS L. Louys 1987

Mad MAD J.H. Maedler 1835—1859

—

MAJ J. Manfroid 1987

—

MAM E.E. Mamajek 2010—2017

—

MAR C. Marois 2008—2010

—

MBA B.A. Macintosh 2001—2003

—

MCA H.A. McAlister 1976—1996

—

MCD M. Michaud 2012

—

MCN L. Maccarini 2015—2019

—

MCT C. McCarthy 2001

—

MCY D.W. McCarthy 1982—1993

—

MEL E.L. Martin 1998—2006

—

MET S.A. Metchev 2003—2009

— MFL F.L. Martinez 2018—2019

C.4 Double Stars 327

— MGN G.N. Mace 2013

—

MIL J.A. Miller 1903—1907

—

MIU N. Miura 1992—1995

—

MKR V.V. Makarov 2005—2010

—

MKT Mark III Interferometer 1988—2006

—

MLB W. Milburn 1918—1939

—

MLD A. Meilland 2008—2011

MlF

MLF F. Muller 1889

MlbO

MLO Melbourne Observatory 1873—1898

—

MLR P. Muller 1938—1997

—

MOC C. Moutou 2017

—

MRI E.R. Masa Martin 2005—2015

—

MRN L. Marion 2014

—

MRZ W. Markowitz 1956—1969

—

MSH T. Meshkat 2015

—

MUA A. Muller 2011

—

MUG M. Mugrauer 2004—2020

—

MWT D. Mawet 2011—2015

—

MZA J. Maiz-Apellaniz 2007—2020

— NAJ T. Nakajima 1989—1995

—

NHR R. Neuhauser 2000—2011

—

NLS E.L. Nielsen 2010—2016

—

NOI

Navy Prototype/Precision Optical Interfer-

ometer

1997—2019

—

NOR J.R. North 2007

—

NOV B. Novakovic 2005—2008

—

NSE P. Nisenson 1985

—

NSN J. Nanson 2013—2018

—

NVL I. Novalbos 2009—2016

—

NYS O. Nys 1963—1983

NZO

NZO New Zealand Observatory 1911

— OCC Occult. Doubles Cat. 1971—

—

ODE M. Odenkirchen 1995—1997

—

OL C.P. Olivier 1907—1957

—

OLE D. Olevic 1970—2006

—

ONL Occult. News Letters

— OPI E. Opik 1927—1932

—

ORL V.G. Orlov 2007—

—

OSO M.R. Zapatero Osorio 2004—2010

—

OSV V. Osvalds 1957—1964

—

OSW T.D. Oswalt 1988—2012

—

OUD R.D. Oudmaijer 2010

— PAR J.A. Parkhurst 1932

—

PAT J. Patience 1998—2008

—

PBL T. Pribulla 2006—2018

—

PBS T. Preibisch 1999—2014

Pck

PCK E. Pickering 1879—1912

—

PEA F.G. Pease 1925—1927

Per

PER J. Perrotin 1883—1887

—

PES S. Peretti 2019

—

PET D. Peter 2012

—

PIC W.H. Pickering 1900—1937

—

PIN D.J. Pinﬁeld 2006—2012

—

PKO Pulkova Observatory 1965—

— PLQ E. Paloque 1923—1939

— PLT L. Plaut 1934—1940

328 Appendix C. Star Catalogues

— PNT L.R. de Pont 2012—

Pol

POL J.A. Pollock 1887

—

POP G.M. Popovic 1967—2007

—

POT D. Potter 2002

—

POU M.A. Pourteau 1933

—

PRB R.G. Probst 2006

Prn

PRN C.D. Perrine 1899—1900

PrO

PRO Perth Observatory 1913

—

PRU J.-L. Prieur 2001—2017

Pry

PRY J.J.M. Perry 1880—1886

—

PRZ E. Przbyllok 1908—1926

—

PSF Project Sixteen Forty

— PTI Palomar Testbed Interferometer 2001—2004

—

PTR M.G. Petr 1998

Pwl

PWL E.B. Powell 1854—1892

—

PWS T. Pauwels and P. Lampens 1993

PZ G. Piazzi 1814

R R H.C. Russell 1871—1892

—

RAG D. Raghavan 2004—2010

—

RAO Robo AO project 2014—2020

—

RAS D.A. Rastegaev 2007—2014

—

RBR L.C. Roberts, Jr. 2002—2018

—

RBT J.G. Robertson 1991—1999

—

RCH A. Richichi 1994—2020

—

RDR D.R. Rodriguez 2011—2015

—

RED I.N. Reid 1982—2008

REI

REI K. Reinmuth

— REP B. Reipurth 1986—2015

—

REU D. Reuyl 1931—1945

—

RGS T.J. Rodigas 2014—2016

Rhd

RHD Father Richaud 1729

—

RIZ A.C. Rizzuto 2013—2020

—

RJJ J. Rajagopal 2010

Rmk

RMK C. Rumker 1825—1837

—

RMU J. Rameau 2013

—

ROE E.D. Roe 1908—1919

—

ROL T. Roell 2012

—

RSS J.M. Rousseau 1996

—

RST R.A. Rossiter 1933—1964

—

RUC S.M. Rucinski 2007—2010

S S J. South 1826—1825

—

SAN R.F. Sanford 1921—1940

—

SAO Special Astrophysical Observatory 2017

—

SBK G.M. Seabroke 1881—1910

—

SBN E. Serabyn 2006—2010

—

SCA M. Scardia 1979—2020

—

SCE A. Schneider 2011

—

SCJ H. Schjellerup 1906

—

SCO M. Scholler 1996—2020

—

SCP C. Schnupp 2010

—

SCZ A.B. Schultz 1998

—

SDK N. Sanduleak 1990

—

SDR W.L. Sanders 1966

—

SDT T.O.B. Schmidt 2008—2013

SE A. Secchi 1855—1865

λ SEE * T.J.J. See 1892—1900

C.4 Double Stars 329

— SEI J. Scheiner 1908

Shb

SHB J.M. Schaeberle 1893—1897

SHJ J. South and J. Herschel 1821—1840

—

SHN G. Schneider 1993—2004

—

SHT N.I. Shatsky 1998—2014

—

SHY E.J. Shaya 2011

—

SIN D. Sinachopoulos 1988—2007

—

SKF B.A. Skiff 2000—

Ski

SKI A.N. Skinner 1872—1911

—

SLE G. Soulie 1966—2007

Slr

SLR R.P. Sellors 1892—1910

—

SMA W.M. Smart 1931—1932

—

SMK P.C. Schmidtke 1984—2011

—

SML L.C. Smith 2015

—

SMR J. Schlimmer 2007—

—

SMW G.V. Simonov 1937—1951

Smyth

SMY W.H. Smyth 1833—1860

—

SNA H. Sana 2006—2014

—

SOZ R.-D. Scholz 2003—2017

SP J.V. Schiaparelli 1876—1909

—

SPM Springbook Middle School 2021

—

SRT R. Shuart 2005

—

SRW R.W. Sinnott 1999

—

SS S. Sharpless 1954

—

ST C.L. Stearns 1936—1939

—

STA G.A. Starikova 1962—1985

—

STE C.B. Stephenson 1965—1988

STF * F. Wilhelm von Struve 1814—1843

Σ I, Σ II

STFA, STFB * (Supplemental catalogs) 1814—1843

—

STG G. Struve 1932—1963

—

STH H. Struve 1901—1913

—

STI J. Stein 1926

—

STJ J. Serot 2009—2019

Stone

STN O. Stone 1867—1882

OΣ

STT * O. von Struve 1832—1878

OΣΣ

STTA * (Supplemental catalogs) 1832—1878

—

STU K. Sturdy 1984—1994

—

STZ M.F. Sterzik 1997—2005

—

SUB J.P. Subasavage 2005—2017

—

SUN G. Sun 2020

SWI

SWI L. Swift

— SWR J. Stock 1972—1997

SyO

SYO Sydney Observatory 1927—1986

—

SZA T.B. Souza 2020

— TAM V.S. Tamazian 1999—2008

Tar

TAR K.J. Tarrant 1886—1893

—

TDS, TDT Tycho Double Star

— THA C. Thalmann 2009

—

THB F. Thiebaut 1995

—

THP B. Thompson 2006—2014

—

TKA V.V. Tel’nyuk-Adamchuk 1966

—

TNG W.J. Tango 1979—2009

—

TNN A.M. Tanner 2010

—

TOB T. Tobal 2000—2016

—

TOI TOI Numbers from Stassun et al. 2010

— TOK A.A. Tokovinin 1979—

—

TOR Torino Observatory 1978—1992

330 Appendix C. Star Catalogues

— TRA V. Trajkovska 1999

—

TRN N.H. Turner 1999—2010

—

TRR G. Torres 1985—2020

Tuc

TUC R.H. Tucker 1893

—

TVB T.V. Bryant 2014—2019

— UC

USNO CCD Astrographic Catalog

(UCAC1, UCAC2, UCAC3, UCAC4)

2013—2015

Upt

UPT W. Upton 1877—1878

—

USNO Robotic Astrometric Telescope

(URAT)

2015—2016

—

USD US Numbers from Esplin et al. 2005—2018

— VAS G. Vaskuti 2011—2012

—

VBS G. Van Biesbroeck 1904—1965

—

VDK J. Vanderdonck 1909—1944

—

VGT N. Vogt 2012—2015

—

VIG A. Vigan 2012—2016

—

VKI E. Vilkki 1984—1989

—

VLM W. Vollmann 2006—2016

—

VOU J.G. Voute 1908—1956

—

VSP VLT + SPHERE 2019—

VVO

VVO Van Vleck Observatory 1962—1993

—

VVV Vista Variables in Via Lactea

— VYS A.N. Vyssotsky 1927—1956

— WAK R.L. Walker 1966—1985

—

WAL A. Wallenquist 1934—1958

—

WCK W.C. Wickes 1973—1975

—

WDK K. Patience Ward-Duong 2015

Webb

WEB T.W. Webb

— WEI M. Weisse 1906

—

WFC

Washington Fundamental Cat. - astro-

graphs

1939—1999

—

WG R.W. Wrigley 1911

—

WGA G.A.H. Walker 1994

—

WGK K. Wagner 2016—2018

—

WGT G.P. Weigelt 1978—2002

WHC

WHC H.C. Wilson 1890

—

WHI G.L. White 1991—2019

—

WIL J.C. Wilson 2001

—

WIR C.A. Wirtanen 1941—1981

—

WIS Wide-ﬁeld Infrared Survey Explorer 2010—2016

—

WLF Wolf 1913

Wnc

WNC F.A. Winnecke 1855—1909

WNO

WNO Washington Naval Observatory 1866—1896

—

WOR C.E. Worley 1956—2001

Wrd

WRD I.W. Ward 1876—1878

—

WRH R.H. Wilson 1933—1982

—

WRS K. Wierzchos 2017—2019

WS J.M. Wilson 1875—1877

—

WSI Washington Speckle Interferometer 1997—

—

WTT J.M. Wittrock 2016—2017

—

WZ C. Wirtz 1912—1923

— XMI X. Miret 2007—2016

Yng YNG C.A. Young 1881—1887

—

YR Yale-Rochester Collaboration

— YSC Yale-Southern Connecticut Collaboration

C.5 Cross-Identiﬁcation Data 331

— YSJ Yale-San Juan Collaboration

— ZHN Z.H. Zhang 2010—2013

—

ZUC B. Zuckerman 1992—2001

—

ZUL D.J. Zulevic 1967—2000

Table C.9: Additional designations for double stars

C.5 Cross-Identiﬁcation Data

Stellarium supports cross-identiﬁcation between stars from Hipparcos (HIP) (Anderson and Francis, 2012),

Smithsonian Astrophysical Observatory (SAO) Star Catalog J2000.0 (SAO Staff, 1995), Henry Draper

Catalogue and Extension (HD) (Cannon and Pickering, 1993) and Catalogue of bright stars (Hofﬂeit, 1964)

(BSC5 or HR) catalogues.

C.5.1 Cross-Identiﬁcation Catalog File Format

Stellarium’s Cross-Identiﬁcation catalog data is kept in the

stars/hip_gaia3

sub-directory of the Installa-

tion Directory and/or User Directory (see section 5.1).

C.5.1.1 File Format

The ﬁle

cross-id.cat

contains cross reference data for catalogues HIP, SAO, HD and HR, which are

stored in a binary format.

Name Type Description

HIP uint64_t

HIP or Gaia identiﬁer for the star. Used for reference to the main

star catalogue.

Component

unsigned char Component of the star in the multiple star system.

SAO

int SAO identiﬁer for the star.

HD int HD identiﬁer for the star.

int HR identiﬁer for the star.

Table C.10: Format of cross-id.cat

C.6 Binary Star System Orbital Parameters

Since version 25.1 Stellarium supports modelling orbital motion of a handful of binary stars. These include

v 25.1

•

α Centauri A & B

•

Sirius A & B

•

61 Cygni A & B

•

γ Virginis A & B

•

Alula Australis A & B

•

Achird A & B

•

ε1 Lyr A & B

•

ε2 Lyr A & B

•

β Mus A & B

•

Dalim A & B

•

ψ Vel A & B

•

ρ Oph A & B

•

ζ Her A & B

•

η Oph A & B

C.6.1 Binary Star System Orbital Parameters Catalog File Format

Stellarium’s Binary Star System Orbital Parameters catalog data is kept in the

stars/hip_gaia3

sub-

directory of the Installation Directory and/or User Directory (see section 5.1).

C.6.1.1 File Format

The ﬁle

binary_orbitparam.dat

contains binary system orbital parameter data, which are stored in plain

text format (C.11).

332 Appendix C. Star Catalogues

Name Type Description

binary period p double Orbital period [days]

eccentricity e

ﬂoat Eccentricity

inclination i

ﬂoat Orbit inclination [rad]

big omega Ω

ﬂoat Position angle of ascending node [rad]

small omega ω ﬂoat Argument of periastron [rad]

periastron epoch JD

double Julian Date at periastron passage

semi major a

double Angular semi-major axis [arcsec]

bary distance ∆

double distance [parsec]

data epoch E

double Julian Date of the data

bary ra

α double Right Ascension of the barycenter [rad]

bary dec δ double Declination of the barycenter [rad]

bary rv RV

double Barycenter radial velocity [km/s]

primary mass m

ﬂoat Primary star mass [solar mass]

secondary mass m

ﬂoat Secondary star mass [solar mass]

bary pmra

α double Barycenter RA proper motion [mas/yr]

bary pmdec

δ double Barycenter DEC proper motion [mas/yr]

Table C.11: Format of binary_orbitparam.dat

D. Conﬁgura tion Files

D.1 Program Conﬁguration

First, see 5.4 (The Main Conﬁguration File) for information about the ﬁle

config.ini

, including its default

installed location, and command line options that can affect how it is processed.

The ﬁle

config.ini

(or a ﬁle which you can load instead with the

--config <file>

option) is

structured into the following parts. In addition, plugins can add a section named like the plugin (Exception:

The Text User Interface plugin’s section is named [tui] for historical reasons).

D.1.1

[

astro

]

This section includes settings for the commonly displayed objects.

ID Type Default Description

apparent_magnitude_algorithm string Mallama2018

Set algorithm for computation of appar-

ent magnitude of the planets. Possible

values: Mallama2018, ExpSup2013, Ex-

pSup1992, AstrAlm1984, Mueller1893

and Generic.

nebula_magnitude_limit

ﬂoat 8.5

Value of limiting magnitude for the

deep-sky objects.

star_magnitude_limit

ﬂoat 6.5

Value of limiting magnitude for the stars.

Sometimes you don’t want to display

more stars when zooming in.

planet_magnitude_limit

ﬂoat 6.5

Value of limiting magnitude for the plan-

ets. Sometimes you don’t want to dis-

play more planets when zooming in.

planets_orbits_color_style

string one_color

Set the style of orbits color. Possible

values: one_color, groups and max.

ﬂag_nebula_magnitude_limit

bool false

Set to true to activate limit for showing

deep-sky objects.

ﬂag_star_magnitude_limit

bool false

Set to true to activate limit for showing

stars

ﬂag_planet_magnitude_limit

bool false

Set to true to activate limit for showing

planets.

extinction_mode_below_horizon string zero

Set extinction mode for atmosphere be-

low horizon. Possible values: zero, mir-

ror and max.

334 Appendix D. Conﬁguration Files

twilight_altitude ﬂoat -6.0

Solar altitude for going to previous/next

twilight.

ﬂag_stars bool true Set to false to hide the stars on start-up

ﬂag_star_name

bool true

Set to false to hide the star labels on

start-up

ﬂag_star_additional_names

bool true

Set true to use all available proper

names for stars.

ﬂag_star_designation_usage bool false

If true, use designations of stars on the

sky (on-screen labels) instead of their

common names.

ﬂag_star_designation_dbl

bool false

If true, and star doesn’t have common

name and Bayer or Flamsteed designa-

tions then use ﬁrst of traditional desig-

nations of double stars to the on-screen

labels.

ﬂag_star_designation_var

bool false

If true, and star doesn’t have common

name or Bayer, Flamsteed or double star

designation then use designation of vari-

able stars as the on-screen label.

ﬂag_star_designation_hip

bool false

If true, use HIP designations of stars for

the on-screen labels if common name or

traditional designations do not exist for

star.

ﬂag_planets bool true

Set to false to hide the planet labels on

start-up

ﬂag_planets_hints

bool true

Set to false to hide the planet hints on

startup (names and circular highlights)

ﬂag_planets_orbits

bool false

Set to true to show the planet orbits on

startup

ﬂag_permanent_orbits

bool false

Set to true to show the orbit of planet,

when planet is out of the viewport also.

ﬂag_planets_pointers bool false

Set to true to show the planet pointer

markers on startup

ﬂag_planets_nomenclature

bool false

Set to true to show the planetary nomen-

clature markers and labels

ﬂag_planets_nomenclature_. . .

bool false Set to true to show only items

terminator_only

along the terminator

planet_nomenclature_. . .

solar_altitude_min int -5

minimum solar altitude for the termina-

tor setting above

solar_altitude_max

int 40

maximum solar altitude for the termina-

tor setting above

ﬂag_hide_local_nomenclature

bool true

Set to true to hide the planetary nomen-

clature items on the observer’s celestial

body

ﬂag_light_travel_time bool true

Should be true to improve accuracy in

the movement of the planets by com-

pensating for the time it takes for light

to travel. This has a slight impact on

performance, but is essential e.g. for

Jupiter’s moons.

ﬂag_object_trails

bool false

Turns on and off drawing of object trails

(which show the movement of the plan-

ets over time).

D.1 Program Conﬁguration 335

ﬂag_nebula bool true Set to false to hide the nebulae on start-

up.

ﬂag_nebula_name bool false

Set to true to show the nebula labels on

start-up.

ﬂag_nebula_display_no_texture

bool false

Set to true to suppress displaying of neb-

ula textures.

nebula_texture_decimation

int 1

Reduce nebula texture size by this fac-

tor [1. . . 8]. May help on very limited

systems.

nebula_hints_amount

ﬂoat 3.0 Sets the amount of hints [0. . . 10].

nebula_labels_amount

ﬂoat 3.0 Sets the amount of labels [0. . . 10].

ﬂag_milky_way

bool true Set to false to hide the Milky Way.

milky_way_color Color 1.0,1.0,1.0 Base color of the Milky Way.

milky_way_intensity

ﬂoat 1.0

Sets the relative brightness with which

the milky way is drawn. Typical [1. . . 3].

milky_way_saturation ﬂoat 1.0

Sets the color saturation with which the

milky way is drawn [0. . . 1].

ﬂag_zodiacal_light

bool true Set to false to hide the zodiacal light

zodiacal_light_color

Color 1.0,0.0,1.0 Base color of the Zodiacal Light.

zodiacal_light_intensity

ﬂoat 1.0

Sets the relative brightness with which

the zodiacal light is drawn.

max_mag_nebula_name

ﬂoat 8.0

Sets the magnitude of the nebulae

whose name is shown.

ﬂag_nebula_hints_proportional

bool false

Enables/disables proportional markers

for deep-sky objects.

ﬂag_surface_brightness_usage

bool false

Enables/disables usage surface bright-

ness for markers for deep-sky objects.

ﬂag_size_limits_usage bool false

Enables/disables usage angular size ﬁl-

ter for markers for deep-sky objects.

size_limit_min

int 1

Minimal angular size of visible deep-

sky objects in arcminutes.

size_limit_max

int 600

Maximum angular size of visible deep-

sky objects in arcminutes.

ﬂag_use_type_ﬁlter bool false

Enables/disables usage of the type ﬁlters

for deep-sky objects.

ﬂag_nutation bool true Enables/disables usage nutation.

ﬂag_topocentric_coordinates bool true

Enables/disables usage topocentric co-

ordinates.

shadow_enlargement_danjon bool false

Earth shadow enlargement (see

19.11.2).

ﬂag_dso_designation_usage bool false

If true, use designations of deep-sky ob-

jects on the sky instead of their common

names.

ﬂag_dso_outlines_usage

bool false

If true, use outlines for big deep-sky

objects on the sky instead of their hints.

ﬂag_dso_additional_names bool true

Set true to use additional names (also

known as) for deep-sky objects.

ﬂag_dso_show_only_named bool false

If true, only show deep-sky objects with

names, hiding those with only designa-

tions.

grs_longitude int 216

Longitude (System II) of Great Red

Spot on Jupiter in degrees.

336 Appendix D. Conﬁguration Files

grs_drift ﬂoat 15.0

Annual drift of Great Red Spot on

Jupiter in degrees.

grs_jd

ﬂoat 2456901.5

Initial JD for calculation of position of

Great Red Spot on Jupiter.

grs_measurements_url

string

URL of recent measurements of GRS’

position

meteor_zhr int 10 ZHR for sporadic meteors.

de430_path string Path to JPL DE430 ephemerides ﬁle.

ﬂag_use_de430

bool false

Enables/disables usage JPL DE430

ephemerides (if available).

de431_path

string Path to JPL DE431 ephemerides ﬁle.

ﬂag_use_de431

bool false

Enables/disables usage JPL DE431

ephemerides (if available).

ﬂag_toast_survey bool false

Enables/disables Digitized Sky Survey

in TOAST format.

toast_survey_host

string

Host of Digitized Sky Survey storage

data.

toast_survey_directory

string results

Directory name of Digitized Sky Survey

storage data.

toast_survey_levels

int 11

Count of levels for Digitized Sky Survey

storage data.

D.1.2

[

astrocalc

]

This section includes settings for the Astronomical Calculations feature.

ID Type Default Description

ﬂag_ephemeris_markers bool true

Set to true to show the calculated ephemeris

markers for Solar system bodies.

ﬂag_ephemeris_line

bool false

Set to true to show the connecting line between

the ephemeris markers.

ﬂag_ephemeris_dates

bool false

Set to true to show the dates of calculated

ephemeris for Solar system bodies.

ﬂag_ephemeris_magnitudes

bool false

Set to true to show the magnitude of Solar sys-

tem body for the calculated ephemeride.

ﬂag_ephemeris_horizontal

bool false

Set to true to use horizontal coordinates for

ephemerides.

ﬂag_ephemeris_skip_data

bool false

Set to true to skip the showing data near

ephemeris markers.

ﬂag_ephemeris_smart_dates

bool true

Set to true to use smart format for dates, who

showing near ephemeris markers.

ﬂag_ephemeris_scale_markers

bool false

Set to true to use small ephemeris markers,

when line is enabled.

ephemeris_celestial_body

string Moon

Default celestial body for computation of

ephemerides.

ephemeris_time_step

int 6 Identiﬁcator for time step category.

ephemeris_data_step

int 0

Value of skipping step when skipping option is

enabled (label each N steps, where N is step).

celestial_magnitude_limit

ﬂoat 6.0

Value of limiting magnitude for the celestial

objects in computation of their positions.

celestial_category

int 200

Identiﬁcator for default category of celestial

bodies.

Default value is http://jupos.privat.t-online.de/rGrs.htm

D.1 Program Conﬁguration 337

ﬂag_horizontal_coordinates bool false

Set to true to use horizontal coordinates for

compute of positions for the celestial objects.

ﬂag_phenomena_opposition

bool false

Set to true to compute of opposition phe-

nomenon between the Solar system bodies.

ﬂag_phenomena_perihelion

bool false

Set to true to compute perihelion and aphelion

for Solar system bodies (except moons).

phenomena_angular_separation

ﬂoat 1.0

Allowed angular separation between celestial

bodies for computation of phenomena.

phenomena_celestial_body

string Venus

Default celestial body for computation of phe-

nomena.

phenomena_celestial_group

int 0

Identiﬁcator for group of celestial bodies for

computation of phenomena.

wut_magnitude_limit

ﬂoat 10.0

Value of limiting magnitude for calculations

within What’s Up Tonight feature.

wut_time_interval

int 0

Identiﬁcator for time interval within What’s Up

Tonight feature computations.

wut_angular_limit_ﬂag

bool false Set to true to use the angular size ﬁlter.

wut_angular_limit_min

ﬂoat 1.0 Minimal allowed angular size, arcminutes.

wut_angular_limit_max

ﬂoat 600.0 Maximal allowed angular size, arcminutes.

wut_altitude_min

ﬂoat 0.0

Minimal allowed altitude for compute rise and

set times, degrees.

graphs_celestial_body

string Moon Default celestial body for draw of graphs.

graphs_duration

int 1

How much years account into calculation of

graphs.

graphs_ﬁrst_id

int 1 Identiﬁcator for left graph (blue line).

graphs_second_id

int 2 Identiﬁcator for right graph (yellow line).

D.1.3

[

audio

]

This section includes settings for Audio features.

ID Type Default Description

enabled bool true Enable sound output

D.1.4

[

color

]

This section deﬁnes the RGB colors for the various objects, lines, grids, labels etc. Values are given in ﬂoat

from 0 to 1. e.g. 1.0,1.0,1.0 for white, or 1,0,0 for red. Leave no whitespace between the numbers!

ID Default Colour of the. . .

default_color 0.5,0.5,0.7 default colour.

daylight_text_color 0.0,0.0,0.0 info text at daylight.

info_text_color 1.0,1.0,1.0

info text color when overwrite mode for

text color is enabled.

sky_background_color 0.0,0.0,0.0

sky background (non-black is useful for

artists only).

ecliptical_J2000_color 0.4,0.1,0.1 ecliptical grid (J2000.0 frame).

ecliptic_J2000_color

0.7,0.2,0.2 ecliptic line (J2000.0 frame).

equinox_J2000_points_color

0.7,0.2,0.2 equinox points (J2000.0 frame).

solstice_J2000_points_color

0.7,0.2,0.2 solstice points (J2000.0 frame).

ecliptic_J2000_poles_color 0.7,0.2,0.2 ecliptic poles (J2000.0 frame).

ecliptical_color 0.6,0.3,0.1 ecliptical grid (of date).

338 Appendix D. Conﬁguration Files

ecliptic_color 0.9,0.6,0.2 ecliptic line (of date).

equinox_points_color

0.9,0.6,0.2 equinox points (of date).

solstice_points_color 0.9,0.6,0.2 solstice points (of date).

ecliptic_poles_color

0.9,0.6,0.2 ecliptic poles (of date).

precession_circles_color

0.9,0.6,0.2 precession circles.

equator_J2000_color 0.2,0.2,0.6 equator line (J2000.0 frame).

equatorial_J2000_color

0.1,0.1,0.5 equatorial grid (J2000.0 frame).

celestial_J2000_poles_color 0.2,0.2,0.6 celestial poles (J2000.0 frame).

equator_color 0.3,0.5,1.0 equator line (of date).

equatorial_color

0.2,0.3,0.8 equatorial grid (of date).

celestial_poles_color

0.3,0.5,1.0 celestial poles (of date).

circumpolar_circles_color 0.3,0.5,1.0 circumpolar circles.

ﬁxed_equator_color 0.5,0.5,0.7 ﬁxed equator (hour angle) line.

ﬁxed_equatorial_color

0.5,0.5,0.7 ﬁxed equatorial grid.

galactic_color 0.3,0.2,0.1 galactic grid.

galactic_equator_color

0.5,0.3,0.1 galactic equator line.

galactic_poles_color

0.5,0.3,0.1 galactic poles.

supergalactic_color 0.2,0.2,0.2 supergalactic grid.

supergalactic_equator_color

0.4,0.4,0.4 supergalactic equator line.

supergalactic_poles_color

0.4,0.4,0.4 supergalactic poles.

azimuthal_color 0.0,0.3,0.2 azimuthal grid.

horizon_color

0.2,0.6,0.2 horizon line.

meridian_color 0.2,0.6,0.2 meridian line.

prime_vertical_color

0.2,0.5,0.2 prime vertical.

zenith_nadir_color

0.2,0.6,0.2 zenith and nadir.

cardinal_color

0.8,0.2,0.1 cardinal points.

colures_color 0.5,0.0,0.5 colures.

antisolar_point_color 0.9,0.3,0.5 antisolar point.

apex_points_color

0.8,0.2,0.3 apex points.

oc_longitude_color

0.6,0.2,0.4 opposition/conjunction longitude.

quadrature_color

0.6,0.2,0.4 quadrature circle.

const_lines_color 0.2,0.2,0.6 constellation lines.

const_names_color 0.4,0.6,0.9 constellation names.

const_boundary_color

0.8,0.3,0.3 constellation boundaries.

const_hulls_color

0.6,0.2,0.2 constellation areas (convex hulls).

asterism_lines_color

0.4,0.4,0.8 asterism lines.

asterism_names_color 0.4,0.4,0.8 asterism names.

rayhelper_lines_color

1.0,1.0,0.0 the ray helper lines.

skyculture_zodiac_color

1.0,1.0,0.0 Zodiac band.

skyculture_lunarsystem_color

0.0,1.0,0.5

Band/boundaries of Lunar sta-

tions / mansions.

dso_label_color 0.2,0.6,0.7 deep-sky objects labels.

dso_circle_color 1.0,0.7,0.2

deep-sky objects symbols, if not of the

types below.

dso_region_color

0.7,0.7,0.2 regions symbols.

dso_galaxy_color 1.0,0.2,0.2 galaxies symbols.

dso_radio_galaxy_color 0.3,0.3,0.3 radio galaxies symbols.

D.1 Program Conﬁguration 339

dso_active_galaxy_color 1.0,0.5,0.2 active galaxies symbols.

dso_interacting_galaxy_color

0.2,0.8,1.0 clusters of galaxies symbols.

dso_galaxy_cluster_color 0.2,0.5,1.0 interacting galaxies symbols.

dso_quasar_color

1.0,0.2,0.2 quasars symbols.

dso_possible_quasar_color

1.0,0.2,0.2 possible quasars symbols.

dso_bl_lac_color

1.0,0.2,0.2 BL Lac objects symbols.

dso_blazar_color 1.0,0.2,0.2 blazars symbols.

dso_nebula_color

0.1,1.0,0.1 nebulae symbols.

dso_planetary_nebula_color

0.1,1.0,0.1 planetary nebulae symbols.

dso_reﬂection_nebula_color

0.1,1.0,0.1 reﬂection nebulae symbols.

dso_bipolar_nebula_color 0.1,1.0,0.1 bipolar nebulae symbols.

dso_emission_nebula_color

0.1,1.0,0.1 emission nebulae symbols.

dso_dark_nebula_color

0.3,0.3,0.3 dark nebulae symbols.

dso_hydrogen_region_color

0.1,1.0,0.1 hydrogen regions symbols.

dso_supernova_remnant_color

0.1,1.0,0.1 supernovae remnants symbols.

dso_supernova_candidate_color 0.1,1.0,0.1 supernova candidates symbols.

dso_supernova_remnant_cand_color

0.1,1.0,0.1

supernova remnant candidates symbols.

dso_interstellar_matter_color 0.1,1.0,0.1 interstellar matter symbols.

dso_molecular_cloud_color

0.1,1.0,0.1 molecular clouds symbols.

dso_possible_planetary_nebula_color 0.1,1.0,0.1 possible planetary nebulae symbols.

dso_protoplanetary_nebula_color

0.1,1.0,0.1 protoplanetary nebulae symbols.

dso_cluster_color

1.0,1.0,0.1 star clusters symbols.

dso_open_cluster_color

1.0,1.0,0.1 open star clusters symbols.

dso_globular_cluster_color

1.0,1.0,0.1 globular star clusters symbols.

dso_stellar_association_color 1.0,1.0,0.1 stellar associations symbols.

dso_star_cloud_color

1.0,1.0,0.1 star clouds symbols.

dso_star_color

1.0,0.7,0.2 star symbols.

dso_symbiotic_star_color

1.0,0.7,0.2 symbiotic star symbols.

dso_emission_star_color 1.0,0.7,0.2 emission-line star symbols.

dso_emission_object_color

1.0,0.7,0.2 emission objects symbols.

dso_young_stellar_object_color

1.0,0.7,0.2 young stellar objects symbols.

planet_names_color 0.5,0.5,0.7 planet names.

planet_pointers_color

1.0,0.3,0.3 planet pointers.

planet_nomenclature_color 0.1,1.0,0.1

planetary nomenclature hints and labels.

sso_orbits_color 0.7,0.2,0.2 default orbits.

major_planet_orbits_color

0.7,0.2,0.2 major planet orbits.

minor_planet_orbits_color

0.7,0.5,0.5 minor planet orbits.

dwarf_planet_orbits_color

0.7,0.5,0.5 dwarf planet orbits.

moon_orbits_color 0.7,0.2,0.2 moon of planet orbits.

cubewano_orbits_color

0.7,0.5,0.5 cubewano orbits.

plutino_orbits_color

0.7,0.5,0.5 plutino orbits.

sdo_orbits_color

0.7,0.5,0.5 scattered disk object orbits.

oco_orbits_color 0.7,0.5,0.5 Oort cloud object orbits.

sednoid_orbits_color

0.7,0.5,0.5 Sednoid object orbits.

interstellar_orbits_color

1.0,0.6,1.0

Interstellar object “orbits” (trajectories).

comet_orbits_color 0.7,0.8,0.8 comet orbits.

mercury_orbit_color

0.5,0.5,0.5 orbit of Mercury.

venus_orbit_color

0.9,0.9,0.7 orbit of Venus.

earth_orbit_color 0.0,0.0,1.0 orbit of Earth.

mars_orbit_color

0.8,0.4,0.1 orbit of Mars.

340 Appendix D. Conﬁguration Files

jupiter_orbit_color 1.0,0.6,0.0 orbit of Jupiter.

saturn_orbit_color

1.0,0.8,0.0 orbit of Saturn.

uranus_orbit_color 0.0,0.7,1.0 orbit of Uranus.

neptune_orbit_color

0.0,0.3,1.0 orbit of Neptune.

object_trails_color 1.0,0.7,0.0 planet trails.

custom_marker_color 0.1,1.0,0.1 custom marker.

script_console_keyword_color 1.0,0.0,1.0

syntax highlight for keywords in the

script console.

script_console_module_color

0.0,1.0,1.0

syntax highlight for modules in the

script console.

script_console_comment_color

1.0,1.0,0.0

syntax highlight for comments in the

script console.

script_console_function_color

0.0,1.0,0.0

syntax highlight for functions in the

script console.

script_console_constant_color

1.0,0.5,0.5

syntax highlight for constants in the

script console.

fov_center_marker_color 0.5,0.5,0.7 FOV Center marker.

fov_circular_marker_color

0.5,0.5,0.7 circular marker of FOV.

fov_rectangular_marker_color 0.5,0.5,0.7 rectangular marker of FOV.

compass_marks_color

0.5,0.5,0.7 compass marks.

D.1.5

[

custom_selected_info

]

You can ﬁne-tune the bits of information to display for the selected object in this section. Set the entry to

true to display it.

ID Type Description

ﬂag_show_name bool common name for object.

ﬂag_show_catalognumber

bool catalog designations for objects.

ﬂag_show_type

bool type of object.

ﬂag_show_magnitude

bool magnitude for object.

ﬂag_show_absolutemagnitude

bool absolute magnitude for objects.

ﬂag_show_radecj2000

bool equatorial coordinates (J2000.0 frame) of object.

ﬂag_show_radecofdate

bool equatorial coordinates (of date) of object.

ﬂag_show_hourangle

bool hour angle for object.

ﬂag_show_altaz

bool horizontal coordinates for objects.

ﬂag_show_eclcoordj2000

bool ecliptic coordinates (J2000.0 frame) of object.

ﬂag_show_eclcoordofdate

bool ecliptic coordinates (of date) of object.

ﬂag_show_galcoord

bool galactic coordinates (System II) of object.

ﬂag_show_supergalcoord

bool supergalactic coordinates of object.

ﬂag_show_othercoord

bool other coordinates of object (from plugins).

ﬂag_show_constellation

bool show 3-letter IAU constellation label.

ﬂag_show_sidereal_time

bool sidereal time.

ﬂag_show_elongation

bool elongation from the Sun for solar system objects.

ﬂag_show_distance

bool distance to object.

ﬂag_show_velocity

bool velocity of object.

ﬂag_show_propermotion

bool proper motion of object.

ﬂag_show_size

bool size of object.

ﬂag_show_rts_time bool rise, transit and set times.

ﬂag_show_solar_lunar bool horizontal coordinates for Sun and Moon.

ﬂag_show_extra

bool extra info for object.

D.1 Program Conﬁguration 341

D.1.6

[

custom_time_correction

]

Stellarium allows experiments with ∆T . See 18.4.3 for details.

ID Type Description

coefﬁcients [ﬂoat,ﬂoat,ﬂoat] Coefﬁcients a, b, c for custom equation of ∆T

ndot

ﬂoat n-dot value for custom equation of ∆T

year

int Year for custom equation of ∆T

D.1.7

[

devel

]

This section is for developers only.

ID Type Description

check_loading_constellation_data bool

Set to true to check loading constellation data. This option

is needed to debug new sky cultures. Default value: false.

convert_locations_list

bool

Set to true to convert ﬁle

base_locations.txt

into ﬁle

base_locations.bin

. Default value: false.

convert_dso_catalog

bool

Set to true to convert ﬁle

catalog.txt

into ﬁle

catalog.dat. Default value: false.

convert_dso_decimal_coord

bool

Set to true to use decimal values for coordinates in source

catalog. Default value: true.

markers_to_logﬁle bool

Write marker coordinates to logﬁle. Useful when developing

dark constellations. See p. 115

D.1.8

[

dso_catalog_ﬁlters

]

In this section you can ﬁne-tune which of the deep-sky catalogs should be selected on startup.

ID Type Default Description

ﬂag_show_ngc bool true New General Catalogue (NGC).

ﬂag_show_ic

bool true Index Catalogue (IC).

ﬂag_show_m

bool true Messier Catalog (M).

ﬂag_show_c

bool false Caldwell Catalogue (C).

ﬂag_show_b

bool false Barnard Catalogue (B).

ﬂag_show_sh2

bool false Sharpless Catalogue (SH2).

ﬂag_show_vdb

bool false Van den Bergh Catalogue of reﬂection nebulae (vdB).

ﬂag_show_rcw

bool false

The RCW catalogue of H

-emission regions in the southern

Milky Way (RCW).

ﬂag_show_lbn

bool false Lynds’ Catalogue of Bright Nebulae (LBN).

ﬂag_show_ldn

bool false Lynds’ Catalogue of Dark Nebulae (LDN).

ﬂag_show_cr

bool false Collinder Catalogue (Cr or Collinder).

ﬂag_show_mel

bool false Melotte Catalogue of Deep Sky Objects (Mel or Melotte).

ﬂag_show_pgc

bool false HYPERLEDA. I. Catalog of galaxies (PGC).

ﬂag_show_ced

bool false Cederblad Catalog of bright diffuse Galactic nebulae (Ced).

ﬂag_show_ugc

bool false The Uppsala General Catalogue of Galaxies (UGC).

ﬂag_show_arp

bool false Atlas of Peculiar Galaxies (Arp).

ﬂag_show_vv

bool false The Catalogue of Interacting Galaxies (VV).

ﬂag_show_pk

bool false The Catalogue of Galactic Planetary Nebulae (PK).

ﬂag_show_png

bool false

The Strasbourg-ESO Catalogue of Galactic Planetary Nebulae

(PN G).

ﬂag_show_snrg

bool false A catalogue of Galactic supernova remnants (SNR G).

ﬂag_show_aco

bool false A Catalog of Rich Clusters of Galaxies (Abell or ACO).

ﬂag_show_hcg

bool false A Hickson Compact Group (HCG).

ﬂag_show_eso

bool false ESO/Uppsala Survey of the ESO(B) Atlas (ESO).

ﬂag_show_vdbh

bool false Catalogue of southern stars embedded in nebulosity (vdBH).

To get the standard packed

base_locations.bin.gz

ﬁle please run the command

gzip -nc base_locations.bin > base_locations.bin.gz.

342 Appendix D. Conﬁguration Files

ﬂag_show_dwb bool false

Catalogue and distances of optically visible H II regions (DWB).

ﬂag_show_tr bool false Trumpler Catalogue (Tr or Trumpler).

ﬂag_show_st

bool false Stock Catalogue (St or Stock).

ﬂag_show_ru

bool false Ruprecht Catalogue (Ru or Ruprecht).

ﬂag_show_vdbha

bool false van den Bergh-Hagen Catalogue (vdB-Ha).

ﬂag_show_other

bool true All objects without identiﬁers.

D.1.9

[

dso_type_ﬁlters

]

In this section you can ﬁne-tune which types of the deep-sky objects should be selected on startup.

ID Type Default Description

ﬂag_show_galaxies bool true display galaxies.

ﬂag_show_active_galaxies

bool true display active galaxies.

ﬂag_show_interacting_galaxies

bool true display interacting galaxies.

ﬂag_show_open_clusters

bool true display open star clusters.

ﬂag_show_globular_clusters

bool true display globular star clusters.

ﬂag_show_bright_nebulae

bool true display bright nebulae.

ﬂag_show_dark_nebulae

bool true display dark nebulae.

ﬂag_show_planetary_nebulae

bool true display planetary nebulae.

ﬂag_show_hydrogen_regions

bool true display hydrogen regions.

ﬂag_show_supernova_remnants

bool true display supernovae remnants.

ﬂag_show_galaxy_clusters

bool true display clusters of galaxies.

ﬂag_show_other

bool true display other deep-sky objects.

D.1.10

[

fov

]

In this section you can ﬁne-tune 10 predeﬁned values of ﬁeld of view in degrees (all FOV may be set through

keyboard hotkeys, see section 3.2).

ID Type Default Description

quick_fov_1 ﬂoat 180 predeﬁned value for FOV 1.

quick_fov_2

ﬂoat 90 predeﬁned value for FOV 2.

quick_fov_3

ﬂoat 60 predeﬁned value for FOV 3.

quick_fov_4

ﬂoat 45 predeﬁned value for FOV 4.

quick_fov_5

ﬂoat 20 predeﬁned value for FOV 5.

quick_fov_6

ﬂoat 10 predeﬁned value for FOV 6.

quick_fov_7

ﬂoat 5 predeﬁned value for FOV 7.

quick_fov_8

ﬂoat 2 predeﬁned value for FOV 8.

quick_fov_9

ﬂoat 1 predeﬁned value for FOV 9.

quick_fov_0

ﬂoat 0.5 predeﬁned value for FOV 0.

D.1.11

[

gui

]

This section includes settings for the graphical user interface. See sections 4.3.3–4.3.5 for most of these keys.

ID Type Default Description

ﬂag_show_gui bool true If true, display GUI.

screen_font_size int 13

Sets the font size for screen texts. Typi-

cal value: 13..15

gui_font_size

int 13

Sets the dialog font size. Typical value:

10..20

base_font_name

string Verdana Selects the name

(Windows) for base font

DejaVu Sans

(others)

base_font_ﬁle string

Selects the name for font ﬁle, e.g. De-

jaVuSans.ttf

D.1 Program Conﬁguration 343

ﬂag_font_selection bool false Show GUI elements for font selection.

immediate_save_details bool false

Set to true to store some detail settings

in the conﬁguration dialog immediately,

instead of having to press “Save settings”

explicitly.

ﬂag_mouse_cursor_timeout bool true

Set to false if you want to have cursor

visible at all times.

mouse_cursor_timeout

ﬂoat 10

Set to 0 if you want to keep the mouse

cursor visible at all times. non-0 values

mean the cursor will be hidden after that

many seconds of inactivity

ﬂag_show_boundaries_button bool false

Show a button to toggle constellation

boundaries

ﬂag_show_asterism_lines_button

bool false Show a button to toggle asterism lines

ﬂag_show_asterism_labels_button

bool false

Show a button to toggle asterism labels

ﬂag_show_ecliptic_grid_button bool false Show a button to toggle ecliptic grid

ﬂag_show_icrs_grid_button

bool false

Show a button to toggle ICRS (equato-

rial J2000.0) grid

ﬂag_show_galactic_grid_button

bool false Show a button to toggle galactic grid

ﬂag_show_goto_selected_button

bool true

Show a button to center to selected ob-

ject

ﬂag_show_nightmode_button

bool true Show a button to toggle night mode

ﬂag_show_nebulae_

background_button

bool false

Show a button to toggle images for deep-

sky objects

ﬂag_show_ﬂip_buttons

bool false

Show the image ﬂipping buttons in the

main toolbar

ﬂag_show_dss_button

bool false

Show a button to toggle Digitized Sky

Survey (DSS)

ﬂag_show_hips_button

bool false

Show a button to toggle HiPS survey

display

ﬂag_show_bookmark_button

bool false

Show a button to show and edit book-

marks

ﬂag_show_fullscreen_button

bool true

Show a button to toggle fullscreen view

ﬂag_show_quit_button bool true Show a button to quit via button press

ﬂag_show_cardinal_button

bool true

Show a button to toggle cardinals via

button press

ﬂag_show_compass_button

bool false

Show a button to toggle compass marks

via button press

ﬂag_show_buttons_background

bool true

If true, use background under buttons

on bottom bar.

ﬂag_overwrite_info_color bool false

Set true to use one color for test in info

panel for all objects.

ﬂag_info_shadow

bool false

Set true to apply a slight shadow behind

the infotext for increased readability.

pixmaps_brightness

ﬂoat 1.0

Brighten the gray of GUI buttons. Us-

able: [1. . . 1.8]

selected_object_info string all

Values: default, all, short, none, and

custom (see 4.3.2).

custom_marker_size ﬂoat 5.0 Size of custom marker.

custom_marker_radius_limit

int 15

Limit the click radius for mouse cursor

position in any direction for removing

of closest custom marker.

auto_hide_horizontal_toolbar bool true

Set to true if you want auto hide the

horizontal toolbar.

344 Appendix D. Conﬁguration Files

auto_hide_vertical_toolbar bool true

Set to true if you want auto hide the

vertical toolbar.

ﬂag_use_window_transparency

bool false If false, show menu bars opaque

ﬂag_show_datetime

bool true display date and time in the bottom bar

ﬂag_time_jd

bool false

use JD format for time in the bottom bar

ﬂag_show_tz bool false show time zone info in the bottom bar

ﬂag_show_location

bool true display location in the bottom bar

ﬂag_show_fps

bool true

show at how many frames per second

Stellarium is rendering

ﬂag_show_fov

bool true

show how many degrees your vertical

ﬁeld of view is

ﬂag_fov_dms

bool false

use DMS format for FOV in the bottom

bar

ﬂag_show_decimal_degrees bool false

If true, use decimal degrees for coordi-

nates

ﬂag_use_azimuth_from_south bool false

If true, calculate azimuth from south

towards west (as in some astronomical

literature)

ﬂag_use_negative_hour_angles

bool false If true, use hour angles -12h. . . 12h

ﬂag_use_polar_distance

bool false

Use distance from North Celestial Pole,

not declination from equator

ﬂag_surface_brightness_arcsec bool false

Toggle usage the measure unit

mag



◻

′

(

mag

arcmin

) or

mag



◻

′′

(

mag

arcsec

)

for the surface brightness of deep-sky

objects.

ﬂag_surface_brightness_short

bool false

Toggle usage the short notation for the

surface brightness of deep-sky objects.

ﬂag_enable_kinetic_scrolling bool true

If true, use kinetic scrolling in the GUI

pointer_animation_speed ﬂoat 1.0 Animation speed of pointers.

gpsd_hostname string localhost

hostname of server running gpsd (non-

Windows only)

gpsd_port

int 2947

port number of gpsd (non-Windows

only)

gps_interface

string COM3

Port number of serial/USB GPS device.

(May look like

ttyUSB0

on Linux, if

you really don’t run gpsd.)

gps_baudrate

int 4800

baudrate of serial/USB GPS device (for

direct serial connection only)

D.1.12

[

init_location

]

ID Type Description

landscape_name string

Sets the landscape you see. Built-in options are garching, geneva, grossmugl,

guereins, hurricane, jupiter, mars, moon, neptune, ocean, saturn, trees,

uranus, zero.

location

string Name of location on which to start stellarium.

last_location

string Coordinates of last used location in stellarium.

D.1.13

[

landscape

]

Scroll by dragging in the window directly, not a slider handle. Scrolling stops after a short time.

D.1 Program Conﬁguration 345

ID Type Description

atmosphere_fade_duration ﬂoat

Sets the time (seconds) it takes for the atmosphere

to fade when de-selected

ﬂag_landscape

bool

Set false if you don’t want to see the landscape at

start-up

ﬂag_fog

bool Set false if you don’t want to see fog on start-up

ﬂag_atmosphere

bool

Set false if you don’t want to see atmosphere on

start-up

ﬂag_landscape_sets_location

bool

Set true if you want Stellarium to modify the ob-

server location when a new landscape is selected

(changes planet and longitude/latitude/altitude if

location data is available in the landscape.ini ﬁle)

minimal_brightness ﬂoat

Set minimal brightness for landscapes. [0. . . 1]

Typical value: 0.01

atmosphereybin

int

Atmosphere tessellation coefﬁcient for Y axis.

Default=44.

ﬂag_minimal_brightness

bool

Set true to use minimal brightness for landscape.

ﬂag_landscape_sets_minimal_brightness bool

Set true to use value for minimal brightness for

landscape from landscape settings.

ﬂag_enable_illumination_layer

bool Set true to use illumination layer for landscape.

ﬂag_enable_labels

bool

Set true to use landscape labels from gazetteer

layer.

label_font_size

int Font size for landscape labels.

label_color

0.0,1.0,0.0 Color for the labels

label_angle

int Angle to display landscape labels [0. . . 90].

polyline_thickness

int

Thickness to draw polygon line, if one is deﬁned

[0. . . 5]

polyline_color

1.0,0.0,0.0 Color for the polygon line, if one is deﬁned

ﬂag_transparency

bool Set true to show landscape semitransparent.

transparency

ﬂoat

Use this transparency for landscapes. [0... 1]

Typical value: 0.5

atmospheric_extinction_coefﬁcient

ﬂoat

Set atmospheric extinction coefﬁcient

[mag/air-

mass]

temperature_C

ﬂoat Set atmospheric temperature [Celsius]

pressure_mbar

ﬂoat Set atmospheric pressure [mbar]

cache_size_mb

int

Set the cache size for landscapes [megabytes].

Default: 100

D.1.14

[

localization

]

ID Type Description

sky_culture string

Sets the sky culture to use. E.g. western, polynesian, egyptian, chinese,

lakota, navajo, inuit, korean, norse, tupi, maori, aztec, sami.

sky_locale

string

Sets language used for names of objects in the sky (e.g. planets). The

value is a short locale code, e.g. en, de, en_GB

app_locale

string

Sets language used for Stellarium’s user interface. The value is a short

locale code, e.g. en, de, en_GB.

time_zone

string

Sets the time zone. Valid values: system_default, or some region/location

combination, e.g. Paciﬁc/Marquesas

ﬂag_dst

bool Set true to apply daylight saving time as required by time zone.

time_display_format

string time display format: can be system_default, 24h or 12h.

date_display_format

string

date display format: can be system_default, mmddyyyy, ddmmyyyy,

yyyymmdd (ISO8601), wwmmddyyyy, wwddmmyyyy, wwyyyymmdd.

D.1.15

[

main

]

346 Appendix D. Conﬁguration Files

ID Type Description

invert_screenshots_colors bool

If true, Stellarium will save the screenshots with in-

verted colors.

screenshot_dir

string Path for saving screenshots

screenshot_format

string

File format. One of

png|jpg|jpeg|tif|tiff|

webp|pbm|pgm|ppm|xbm|xpm|ico

screenshot_custom_size

bool true if you want to specify particular dimensions next:

screenshot_custom_width

int

custom width of screenshots. Max. available size is

hardware dependent!

screenshot_custom_height

int

custom height of screenshots. Max. available size is

hardware dependent!

screenshot_dpi

int DPI setting for screenshots.

observinglists_dir string

Default path for saving and loading observing lists. De-

faults to the user’s home dir.

version

string

Version of Stellarium. This parameter may be used to

detect necessary changes in conﬁg.ini ﬁle, do not edit.

use_separate_output_ﬁle

bool

Set to true if you want to create a new ﬁle for script

output for each start of Stellarium

restore_defaults

bool

If true, Stellarium will restore default settings at

startup. This is equivalent to calling Stellarium with

the –restore-defaults option.

ignore_opengl_warning

bool

Set to true if you don’t want to see OpenGL warnings

for each start of Stellarium.

check_requirements

bool

Set to false if you want to disable and permanently ig-

nore checking hardware requirements at startup. Expect

problems if hardware is below requirements!

geoip_api_url

string URL for JSON interface of GeoIP service.

D.1.16

[

navigation

]

This section controls much of the look&feel of Stellarium. Be careful if you change something here.

ID Type Description

preset_sky_time ﬂoat

Preset sky time used by the dome version. Unit is Julian

Day. Typical value: 2451514.250011573

startup_time_mode

string

Set the start-up time mode, can be actual (start with

current real world time), or Preset (start at time deﬁned

by preset_sky_time)

ﬂag_enable_zoom_keys

bool Set to false if you want to disable the zoom

ﬂag_manual_zoom

bool

Set to false for normal zoom behaviour as described in

this guide. When set to true, the auto zoom feature only

moves in a small amount and must be pressed many

times

ﬂag_enable_move_keys

bool Set to false if you want to disable the arrow keys

ﬂag_enable_mouse_navigation

bool

Set to false if you want to disable the mouse pan (drag).

ﬂag_enable_mouse_zooming bool

Set to false if you want to disable the mouse zooming

(mousewheel).

init_fov

ﬂoat Initial ﬁeld of view, in degrees. Typical value: ”60”.

min_fov

ﬂoat

Minimal ﬁeld of view, in degrees. Typical value:

”0.001389” (5").

max_fov

ﬂoat

Maximal ﬁeld of view, in degrees. Typical value:

”360.0”.

D.1 Program Conﬁguration 347

init_view_pos ﬂoats

Initial viewing direction. This is a vector with x,y,z-

coordinates. x being N-S (S +ve), y being E-W (E +ve),

z being up-down (up +ve). Thus to look South at the

horizon use 1,0,0. To look Northwest and up at

°, use

-1,-1,1 and so on.

auto_move_duration

ﬂoat

Duration (seconds) for the program to move to point at

an object when the space bar is pressed. Typical value:

1.4

return_home_duration

ﬂoat

Duration (seconds) of movement of returning to a home

location (for a demo). Default value: 0.

return_fov_duration

ﬂoat

Duration (seconds) of zooming to an initial ﬁeld of view

value (for a demo). Default value: 1.

mouse_zoom

ﬂoat Sets the mouse zoom amount (mouse-wheel)

move_speed

ﬂoat Sets the speed of movement

zoom_speed

ﬂoat Sets the zoom speed

viewing_mode

string

If set to horizon, the viewing mode simulate an alt/azi

mount, if set to equator, the viewing mode simulates an

equatorial mount

auto_zoom_out_resets_direction

bool

Set to true if you want to auto-zoom restoring direction.

time_correction_algorithm string Algorithm of DeltaT correction.

D.1.17

[

plugins_load_at_startup

]

This section lists which plugins are loaded at startup (those with true values). Each plugin can add another

section into this ﬁle with its own content, which is described in the respective plugin documentation, see 12.

You activate loading of plugins in the

settings dialog, tab “Plugins”. After selection of which plugins to

load, you must restart Stellarium.

ID Type Description

AngleMeasure bool 13.1 Angle Measure plugin

ArchaeoLines

bool 14.9 ArchaeoLines plugin

Calendars

bool 13.10 Calendars plugin

EquationOfTime

bool 13.2 Equation of Time plugin

Exoplanets

bool 14.3 Exoplanets plugin

MeteorShowers

bool 14.6 Meteor Showers plugin

NebulaTextures

bool 13.9 Nebula Textures plugin

Novae

bool 14.1 Bright Novae plugin

Observability

bool 16.3 Observability Analysis

Oculars

bool 16.1 Oculars plugin

Pulsars

bool 14.4 Pulsars plugin

Quasars

bool 14.5 Quasars plugin

RemoteControl

bool 13.5 Remote Control plugin

RemoteSync

bool 13.6 Remote Sync plugin

Satellites

bool 14.8 Satellites plugin

Scenery3d

bool 15 Scenery 3D plugin

SolarSystemEditor

bool 13.8 Solar System Editor plugin

Supernovae

bool 14.2 Historical Supernovae plugin

TelescopeControl

bool 16.2 Telescope Control plugin

TextUserInterface

bool 13.4 Text User Interface plugin

D.1.18

[

projection

]

This section contains the projection of your choice and several advanced settings important if you run

Stellarium on a single screen, multi-projection, dome projection, or other setups.

ID Type Description

348 Appendix D. Conﬁguration Files

type string

Sets projection mode. Values: ProjectionPerspective, Pro-

jectionEqualArea, ProjectionStereographic, Projection-

Fisheye, ProjectionHammer, ProjectionCylinder, Projec-

tionCylinderFill, ProjectionMercator, ProjectionOrtho-

graphic, ProjectionMiller, or ProjectionSinusoidal.

ﬂip_horz

bool

ﬂip_vert bool

viewport string

How the view-port looks. Values: none (regular rectangu-

lar screen), disk (circular screen, useful for planetarium

setup).

viewportMask

string How the view-port looks. Values: none.

viewport_fov_diameter

ﬂoat

viewport_x ﬂoat Usually 0.

viewport_y

ﬂoat Usually 0.

viewport_width

ﬂoat

viewport_height ﬂoat

viewport_center_x ﬂoat Usually half of viewport_width.

viewport_center_y

ﬂoat Usually half of viewport_height.

viewport_center_offset_x

ﬂoat [-0.5. . . +0.5] Usually 0.

viewport_center_offset_y

ﬂoat

[-0.5. . .+0.5] Use negative values to move the horizon

lower.

D.1.19

[

proxy

]

This section has setting for connection to network through proxy server (proxy will be using when host of

proxy is ﬁlled).

ID Type Description

host_name string Name of host for proxy. E.g. proxy.org

type

string Type of proxy. E.g. socks

port

int Port of proxy. E.g. 8080

user

string Username for proxy. E.g. michael_knight

password

string Password for proxy. E.g. xxxxx

D.1.20

[

scripts

]

ID Type Default Description

startup_script string startup.ssc name of script executed on program start

ﬂag_allow_screenshots_dir

bool false Allow scripts to set a target directory.

ﬂag_allow_write_absolute_path

bool false

set true to let scripts store output ﬁles to abso-

lute pathnames. This may pose a security risk

if you run scripts from other authors without

checking what they are doing.

D.1.21

[

]

ID Type Description

ﬂag_search_online bool If true, Stellarium will be use SIMBAD for search.

simbad_server_url

string URL for SIMBAD mirror

ﬂag_start_words

bool If false, Stellarium will be search phrase only from start of words

coordinate_system

string

Speciﬁes the coordinate system. Possible values: equatorialJ2000, equato-

rial, horizontal, galactic. Default value: equatorialJ2000.

D.1.22

[

spheric_mirror

]

Stellarium can be used in planetarium domes. You can use a projector with a hemispheric mirror with

geometric properties given in this section. Note: These functions are only rarely used or tested, some may

not work as expected.

D.1 Program Conﬁguration 349

ID Type Default Description

ﬂip_horz bool true Flip the projection horizontally

ﬂip_vert

bool false Flip the projection vertically

projector_alpha

ﬂoat 0

This parameter controls the properties of the

spheric mirror projection mode.

projector_gamma

ﬂoat

This parameter controls the properties of the

spheric mirror projection mode.

projector_delta

ﬂoat -1e100

This parameter controls the properties of the

spheric mirror projection mode.

projector_phi

ﬂoat 0

This parameter controls the properties of the

spheric mirror projection mode.

projector_position_x

ﬂoat 0

projector_position_y ﬂoat 1

projector_position_z ﬂoat -0.2

mirror_position_x ﬂoat 0

mirror_position_y ﬂoat 2

mirror_position_z ﬂoat 0

image_distance_div_height ﬂoat -1e100

mirror_radius ﬂoat 0.25

dome_radius ﬂoat 2.5

custom_distortion_ﬁle string

texture_triangle_base_length ﬂoat

zenith_y ﬂoat 0.125 deprecated

scaling_factor

ﬂoat 0.8 deprecated

distorter_max_fov

ﬂoat 175.0

Set the maximum ﬁeld of view for the spheric

mirror distorter in degrees. Typical value: 180

viewportCenterWidth

ﬂoat projected image width, pixels

viewportCenterHeight

ﬂoat projected image height, pixels

viewportCenterX

ﬂoat projected image center X, pixels

viewportCenterY

ﬂoat projected image center Y, pixels

D.1.23

[

stars

]

This section controls how stars are rendered.

ID Type Description

relative_scale ﬂoat

relative size of bright and faint stars. Higher values mean that bright

stars are comparatively larger when rendered. Typical value: 1.0

absolute_scale

ﬂoat

Changes how large stars are rendered. larger value lead to larger

depiction. Typical value: 1.0

star_twinkle_amount

ﬂoat amount of twinkling. Typical value: 0.3

ﬂag_star_twinkle

bool true to allow twinkling (but only when atmosphere is active!).

ﬂag_forced_twinkle

bool

true to allow twinkling stars even without atmosphere. This is obvious

nonsense and contrary to nature, but some users seem to like it.

ﬂag_star_halo

bool

false to not draw a halo around the brightest stars. This looks poor,

but some users seem to prefer it.

mag_converter_max_fov

ﬂoat

maximum ﬁeld of view for which the magnitude conversion routine

is used. Typical value: 90.0.

mag_converter_min_fov

ﬂoat

minimum ﬁeld of view for which the magnitude conversion routine

is used. Typical value: 0.001.

labels_amount

ﬂoat amount of labels. Typical value: 3.0

init_bortle_scale

int initial value of light pollution on the Bortle scale. Typical value: 3.

D.1.24

[

tui

]

The built-in text user interface (TUI) plugin (see chapter 13.4) is most useful for planetariums. You can even

conﬁgure a system shutdown command. For historical reasons, the section is not called

[TextUserInterface]

350 Appendix D. Conﬁguration Files

but simply [tui].

ID Type Default Description

tui_font_size ﬂoat 15 Font size for TUI.

tui_font_color

ﬂoatRGB 0.3,1,0.3 Font color for TUI.

ﬂag_show_gravity_ui

bool false

Set to true to enable gravity mode for UI (for

dome projection)

ﬂag_show_tui_datetime

bool false

Set to true if you want to see a date and time

label suited for dome projections

ﬂag_show_tui_short_obj_info

bool false

Set to true if you want to see object info

suited for dome projections

tui_admin_shutdown_command

string e.g. for Linux: shutdown –poweroff +2

D.1.25

[

video

]

ID Type Description

fullscreen bool

If true, Stellarium will start up in full-screen mode, else

windowed mode

screen_w

int

Display width when in windowed mode. Value in pixels,

e.g. 1024

screen_h

int

Display height when in windowed mode. Value in pixels,

e.g. 768

screen_x

int

Horizontal position of the top-left corner in windowed

mode. Value in pixels, e.g. 0

screen_y

int

Vertical position of the top-left corner in windowed mode.

Value in pixels, e.g. 0

viewport_effect

string

This is used when the spheric mirror display mode is acti-

vated. Values include none and sphericMirrorDistorter.

minimum_fps

int

Sets the minimum number of frames per second to display

at (hardware performance permitting)

maximum_fps

int

Sets the maximum number of frames per second to display

at. This is useful to reduce power consumption in laptops.

min_time_bewteen_frames int

Sets the minimum time (in milliseconds) between the end

of rendering and the start of the next frame. Only takes

effect on Macs. Used to work around

https://github

.com/Stellarium/stellarium/issues/2778.

multisampling

int

Sets the number of samples to use for multisampling an-

tialiasing. 0 disables antialiasing, 1 is no-op (single sample

per pixel), higher values increase smoothness and degrade

performance. Too high a value may result in excessive

blurriness of the GUI. A good starting value to try is 4.

planet_shadows_supersampling

bool

Improves quality of shadows on the Moon by evaluating

the color for each multisampling sample, rather than once

per pixel. Level of improvement (and performance cost)

depends on multisampling setting. Default is false, i.e.

disabled.

anisotropic_ﬁltering

int

Improves quality of rendering of inclined textured surfaces

like e.g. planetary surface near the limb. Modern (and

even quite old, like from 2010) GPUs can handle high

anisotropy with no noticeable performance drop, so it

should be ﬁne to set this value as high as 16. If this setting

value is higher than the GPU is capable of, the maximum

value supported is used. The default is 16. To disable

anisotropic ﬁltering, set this value to 0.

D.1 Program Conﬁguration 351

D.1.26

[

viewing

]

This section deﬁnes which objects, labels, lines, grids etc. you want to see on startup. Set those to true. Most

items can be toggled with hotkeys or switched in the GUI. Entries ending with

_line

..._lines

usually

also have entries ..._parts and ..._labels which govern partitions and labels, respectively.

ID Type Description

ﬂag_asterism_drawing bool Display asterism line drawing

ﬂag_asterism_name

bool Display asterism names

ﬂag_rayhelper_drawing

bool Display the ray helper line drawing

ﬂag_constellation_drawing

bool Display constellation line drawing

ﬂag_constellation_name

bool Display constellation names

ﬂag_constellation_art

bool Display constellation art

ﬂag_constellation_boundaries

bool Display constellation boundaries

ﬂag_constellation_isolate_selected

bool

If true, constellation lines, boundaries and art will be

limited to the constellation of the selected star, if that

star is “on” one of the constellation lines, adding more

constellations as you click more

ﬂag_constellation_pick

bool

If ﬂag_constellation_isolate_selected is also true, set to

true if you only want to see the line drawing, art and

name of the currently selected constellation

ﬂag_isolated_trails bool

Set to true if you only want to see the trail line drawn

for the selected planet (asteroid, comet, moon)

number_isolated_trails

int

Number of isolated trails for latest selected Solar system

bodies [1..5].

max_trail_points

int

Limit maximum length of trails. Trails are drawn for 1

year or this number of computing steps. Default 5000,

reduce if drawing trails slows down the program too

much.

ﬂag_planets_orbits_only

bool

Set to true if you want to suppress orbits of minor bodies

and moons.

ﬂag_isolated_orbits

bool

Set to true if you want to see orbits only for selected

planet.

ﬂag_orbits_with_moons

bool

Set to true if you want to see also orbits of the selected

planet.

line_thickness int

Set the line thickness for grids and lines. Typical value:

part_thickness

int

Set the line thickness for line partitions. Typical value:

ﬂag_azimutal_grid bool Display azimuthal grid

ﬂag_equatorial_grid

bool Display equatorial grid (of date)

ﬂag_equatorial_J2000_grid

bool Display equatorial grid (J2000)

ﬂag_ecliptic_grid

bool Display ecliptic grid (of date)

ﬂag_ecliptic_J2000_grid

bool Display ecliptic grid (J2000)

ﬂag_galactic_grid

bool Display galactic grid (System II)

ﬂag_galactic_equator_line

bool Display galactic equator line

ﬂag_supergalactic_grid

bool Display supergalactic grid

ﬂag_supergalactic_equator_line

bool Display supergalactic equator line

ﬂag_equator_line

bool Display celestial equator line (of date)

ﬂag_ﬁxed_equatorial_grid

bool Display ﬁxed equatorial (hour angle) grid

ﬂag_ﬁxed_equator_line

bool Display ﬁxed equator (hour angle) line

ﬂag_equator_J2000_line

bool Display celestial equator line (J2000)

ﬂag_ecliptic_line

bool Display ecliptic line (of date)

ﬂag_ecliptic_J2000_line

bool Display ecliptic line (J2000)

ﬂag_longitude_line bool Display opposition/conjunction circle

ﬂag_quadrature_line

bool Display quadrature circle

352 Appendix D. Conﬁguration Files

ﬂag_meridian_line bool Display meridian line

ﬂag_prime_vertical_line

bool Display Prime Vertical line (East-Zenith-West)

ﬂag_colure_lines

bool Display colure lines (Celestial Pole-à/ã/æ/é)

ﬂag_cardinal_points bool Display cardinal points

ﬂag_ordinal_points

bool Display intercardinal (or ordinal) points

ﬂag_16wcr_points

bool Display secondary intercardinal points

ﬂag_32wcr_points

bool Display tertiary intercardinal points

cardinal_font_size

int Font size for cardinal points. Typical value: 24

ordinal_font_size

int

Font size for intercardinal (or ordinal) points. Typical

value: 18

16wcr_font_size

int

Font size for secondary intercardinal points. Typical

value: 16

ﬂag_gravity_labels bool

Set to true if you want labels to undergo gravity (top

side of text points toward zenith). Useful with dome

projection.

ﬂag_moon_scaled bool Keep it false if you want to see the real moon size

moon_scale

ﬂoat

Sets the moon scale factor, sometimes useful to correlate

to our perception of the moon’s size. Typical value: 4

ﬂag_planets_scaled

bool Keep it false if you want to see the real planet size

planets_scale

ﬂoat

Sets the planet scale factor, sometimes useful to show

planets symbolically. Typical value: 150

ﬂag_sun_scaled

bool Keep it false if you want to see the real sun size

sun_scale

ﬂoat

Sets the sun scale factor, sometimes useful to correlate

to our perception of the sun’s size. Typical value: 4

ﬂag_minorbodies_scaled

bool Set to true if you want to see minor bodies enlarged

minorbodies_scale

ﬂoat

Set scale factor for minor bodies, to see them in unnatu-

ral detail. Typical value: 10

ﬂag_draw_moon_halo bool Display halo around the Moon

ﬂag_draw_sun_halo

bool Display Sun’s glare

ﬂag_draw_sun_corona

bool Display Sun’s corona when atmosphere is disabled

ﬂag_fov_center_marker bool

Set to true to enable drawing a ﬁeld of view center

marker

ﬂag_fov_circular_marker

bool Set to true to enable drawing a circular FOV marker

size_fov_circular_marker

ﬂoat size of the circular FOV marker, degrees

ﬂag_fov_rectangular_marker

bool

Set to true to enable drawing a rectangular FOV marker

width_fov_rectangular_marker ﬂoat width of the rectangular FOV marker, degrees

height_fov_rectangular_marker

ﬂoat height of the rectangular FOV marker, degrees

rot_fov_rectangular_marker

ﬂoat rotation angle of the rectangular FOV marker, degrees

ﬂag_compass_marks

bool Set to true to enable drawing compass marks

constellation_art_intensity ﬂoat

brightness [0. . . 1] of the constellation art images. Typi-

cal value: 0.5

constellation_art_fade_duration

ﬂoat

time the constellation art takes to fade in or out, in

seconds. Typical value: 1.5

constellation_font_size

int font size for constellation labels

constellation_line_thickness

int

thickness of constellation lines [1. . . 5]. Typical value: 1

asterism_font_size int font size for asterism labels

asterism_line_thickness

int

thickness of the asterism lines [1. . . 5]. Typical value: 1

rayhelper_line_thickness int

thickness of the ray helper lines [1. . . 5]. Typical value:

ﬂag_night bool Enable night mode (red-only mode) on startup

light_pollution_luminance ﬂoat Sets the level of the light pollution simulation

use_luminance_adaptation bool Enable dynamic eye adaptation

D.1 Program Conﬁguration 353

sky_brightness_label_threshold ﬂoat Sky brightness [cdm

] to show infotext in black

ﬂag_landscape_autoselection bool

load ﬁtting landscape after changing planet (use zero

landscape when no ﬁtting found).

ﬂag_environment_auto_enable

bool

Enable/disable atmosphere, fog and cardinals for ob-

server location when switching planet.

ﬂag_show_selection_marker

bool

Enable/disable visibility of pointers for selected objects.

D.1.27

[

DialogPositions

]

By default, GUI panels appear centered in the screen. You can move them to your favorite location, and

on next start they will appear on that location instead. The entries in this section deﬁne the upper left pixel

coordinate where panels are stored.

Examples:

ID Type Example Description

Help int,int 58,39 Position of Help panel

DateTime

int,int 1338,944 Position of time panel

D.1.28

[

DialogSizes

]

GUI panels can be resized by dragging on their lower corners or borders. Enlarged sizes are stored here, and

on next start they will appear in this size. The entries in this section deﬁne the size.

Examples:

ID Type Example Description

Help int,int 895,497 Size of Help panel

AstroCalc

int,int 913,493 Size of AstroCalc panel

D.1.29

[

hips

]

This section deﬁnes the source list of the HiPS surveys, as well as other HiPS related options.

ID Type Description

show bool show HiPS at startup?

sources/size

int Number of HiPS survey sources

sources/n/url

string uri of the nth source hipslist ﬁle (n ∈ [1. . . sourcessize])

visible/url

bool HiPS conﬁgured to be displayed. (Stores current setting on program exit)

354 Appendix D. Conﬁguration Files

D.2 Solar System Conﬁguration Files

The ﬁles

ssystem_major.ini

and

ssystem_minor.ini

(in the

data/

subdirectory of the program

directory, contain orbital and rotational data from which Stellarium conﬁgures the Solar System objects.

The minor bodies can be modiﬁed by placing a privately modiﬁed copy of

ssystem_minor.ini

into

your own

data/

directory (see Chapter 5). You can edit the ﬁle either manually or with the Solar System

Editor plugin (see Section 13.8). The private user ﬁle is automatically created by the Solar System Editor

plugin.

Each object’s data are described in its own section which is typically named after the object name. Some

section names (e.g. those using diacriticals, spaces or other problematic characters) appear a bit mangled.

We list here examples for the major planets, larger moons with special coordinate functions, minor

moons with generic orbital elements, minor planets and comets with elliptical and parabolic orbit elements.

All elements are stored in alphabetic order in the ﬁles, however it makes more sense to present the

elements in another sequence which better reﬂects the meaning. The actual order of the objects in the ﬁles,

and order of entries inside an object section, is irrelevant, but in case of duplicate entries the later entry is

used.

D.2.1 File ssystem_major.ini

D.2.1.1 Planet section

Example:

[ jupiter ]

name = Jupiter

type = planet

coord_func = jup it er_sp ec ial

orbi t_ Pe riod =4331.87

atmosphere =1

albedo =0.51

color =1. , 0.983 , 0.934

ab solut e_mag nit ud e = -9.40

radius =71492

oblateness =0 .0 64874

tex_map = jup iter . png # texture court esy of Bj \ xf6rn J \ xf 3nsson

# deprecated rotational elemen ts

ro t_e qua tor _as cen din g_nod e = -22.203

ro t_ ob liquity =2.222461

rot_peri od e =9.92 491

ro t_r ot ati on_of fse t = -1 # use J up it erGRS patch

# WGCCRE rotational elements

rot_pole _r a =2 68 .0 56 59 5

rot_ po le _ra1 = -0.006499

rot_pole _d e =64.495303

rot_ po le _de1 =0. 002413

rot_pole _w 0 =28 4.95

rot_pole _w 1 =8 70 .5360000

where

name English name of the planet. May appear translated.

type Mandatory for planets:

parent =Sun. The body which this object is running around. Default: Sun

coord_func The planet positions are all computed with a dedicated function (VSOP87 or DE43x).

Before v0.16, there was a single ﬁle, ssystem.ini, with slightly different rules.

D.2 Solar System Conﬁguration Files 355

orbit_Period

number of (earth) days for how long the orbit should be made visible. Typically Stellarium

shows one orbit line. The orbit slowly drifts, however.

atmosphere (0 or 1) ﬂag to indicate whether observer locations should enable atmosphere drawing.

radius Equator radius, km.

oblateness Flattening of the polar diameter. (1− r

pole

r

)

albedo

total albedo (reﬂectivity) of the planet. Used for “generic” magnitude computation, but the major

planets usually have dedicated magnitude formulas, so the value is not evaluated unless you are

observing from a location outside Earth.

color Used to colorize halo. At least one of the components should be 1.

tex_map File name of texture map in textures folder.

halo

Should be true to draw a halo (simple light disk) when object too small to draw a sphere. Default:

true

Elements for the Physical Ephemeris

Where known, Stellarium can properly model axis rotation with the

rot_...

entries in the element sets.

Versions prior to 0.21 had rotational elements deﬁned with respect to the equator of the parent object. While

writing this documentation the origin and accuracy of this model is unfortunately untraceable. However, the

IAU Working Group on Cartographic Coordinates and Rotational Elements (WGCCRE) and modern sources

like Urban and Seidelmann (2013) use rotational elements with respect to the ICRF (see section 18.2.2).

Therefore, starting with version 0.21, Stellarium uses these more modern data and can now also show axes

with precessional or other motions. Data for some planet moons are unfortunately still not available in this

WGCCRE format, and therefore the old format can still be used, but should not be used for new entries.

rot_equator_ascending_node deprecated

rot_obliquity deprecated

rot_rotation_offset

deprecated longitude of prime meridian. For Planets, this used to be counted from the

ascending node of the equator over the ecliptical plane at J2000.0. For moons, it is the longitude of

the prime meridian counted from the ascending node of the moon’s equator over the planet equator. A

special value here indicates special treatment for the Great Red Spot.

rot_periode deprecated Duration of one sidereal rotation, in earth hours.

rot_pole_ra constant of axis right ascension in ICRF, degrees

rot_pole_ra1 change per century of axis right ascension in ICRF, degrees

rot_pole_de constant of axis declination in ICRF, degrees

rot_pole_de1 change per century of axis declination in ICRF, degrees

rot_pole_w0

longitude of the prime meridian counted from the ascending node of the objects’s equator

through the ICRF equator, degrees

rot_pole_w1 change per day of axis rotation, degrees

In many cases, the attitude/rotation formulae for the North (or “positive”) pole (

)are given like

= rot_pole_ra + T ∗ rot_pole_ra1 (D.1)

= rot_pole_de + T ∗ rot_pole_de1 (D.2)

W = rot_pole_w0 + d ∗ rot_pole_w1 (D.3)

These cases are fully covered by the data in

ssystem_major.ini

. Corrections for solar system objects

given by Archinal, A’Hearn, Bowell, et al. (2010), Archinal, A’Hearn, Conrad, et al. (2011), Archinal, Acton,

A’Hearn, et al. (2018), Archinal, Acton, Conrad, et al. (2019), and Urban and Seidelmann (2013) have been

implemented in the program.

D.2.1.2 Moon section

All planet moons are deﬁned only in ssystem_major.ini.

Moons are special in that they orbit another planet. Therefore, the rotational elements used to be

speciﬁed relative to the equatorial plane of the parent planet, and

orbit_SemiMajorAxis

are speciﬁed in

kilometers. However, as for the planets (see section D.2.1.1 above), current IAU reference material gives

axis orientation with right ascension and declination values for the pole in ICRF coordinates, with some of

them in motion. So again, if one of the

rot_pole_...

values exist, we assume the current standard, but

keep the old elements available until we ﬁnd new data. For more complicated motion, again some special

functions are applied.

356 Appendix D. Conﬁguration Files

[ ama lthea ]

name = Amalthea

type = moon

parent = Jupiter

ia u_ moon_ number = JV

or bit _A sce nding Nod e =141. 55215 207 94 674

or bit_E ccent ric it y = 0. 006 175 74440 294 970 1

orbit_Ep oc h =2 454619. 50000

or bit_I nclin ation = 0.3 86457 610 34 045 82

or bit _Long OfP eri cente r = 245.4 222 355 15 012 000 0

or bit _M ean Longi tud e =22 4.792 489 35525 500 00

orbi t_ Pe riod =0 .5016 37046 211 6355

or bit _S emi Major Axi s =1819 94.86 583 58 799

ab solut e_mag nit ud e =7.4

albedo =0.09

color =1. , 0.627 , 0.492

radius =83.5

tex_map = amalt hea . png

model = j5am al thea_ MLfix . obj

ro t_e qua tor _as cen din g_nod e =213.7

ro t_ ob liquity =15.5

# rot_periode = 12.03 928 91 090 79252

ro t_r ot ati on_of fse t =235.50

rot_pole _r a =26 8.05

rot_ po le _ra1 = -0.009

rot_pole _d e =64.49

rot_ po le _de1 =0.003

rot_pole _w 0 =23 1.67

rot_pole _w 1 =7 22 .6314560

where

name English name of planet moon. No number, just the name. May be translated.

type moon

parent English name of planet or parent body.

iau_moon_number

a short label (string) consisting of the planet’s initial and the moon’s Roman number in

order of discovery.

coord_func

Must be

kepler_orbit

(default, can be left away) for moons with orbital elements given, or

<name>_special for

orbit_AscendingNode Ω

orbit_Eccentricity e

orbit_Epoch

orbit_Inclination i [degrees]

orbit_LongOfPericenter

orbit_MeanLongitude

orbit_Period [days]

orbit_SemiMajorAxis a [km]

radius Equator radius, km.

oblateness

Flattening of the polar diameter. (

1− r

pole

r

) Bodies with non-ellipsoid shape, e.g. tri-axial

geometry, cannot be modelled with this simple approach, but a 3D solid model can be shown, see

below.

albedo total reﬂectivity [0..1]

color for drawing halo (default: 1,1,1)

D.2 Solar System Conﬁguration Files 357

halo [=true|false] to draw a simple diffuse dot when zoomed out. Default: true

tex_map

name of spherical texture map. Many moons have been mapped by visiting spacecraft! For many

other moons, Stellarium applies an inverted Lunar texture image.

model

(optional) name of a 3D model for a non-spherical body in the

model

subdirectory of the program

directory.

rot_equator_ascending_node deprecated

rot_obliquity deprecated

rot_rotation_offset deprecated longitude of prime meridian at J2000.0.

rot_periode

deprecated Duration of one sidereal rotation, in earth hours. For moons in bound rotation

(which always show one face towards their parent planet), it is best to omit this value: it defaults to

orbit_Period * 24.

rot_pole_ra constant of axis right ascension in ICRF, degrees

rot_pole_ra1 change per century of axis right ascension in ICRF, degrees

rot_pole_de constant of axis declination in ICRF, degrees

rot_pole_de1 change per century of axis declination in ICRF, degrees

rot_pole_w0

longitude of the prime meridian counted from the ascending node of the objects’s equator

through the ICRF equator, degrees

rot_pole_w1 change per day of axis rotation, degrees

D.2.1.3 Observers

Stellarium is great for excursions to the surface of any object with known orbital elements. Conﬁguring a

viewpoint away from a planet requires a special kind of location.

Solar System Observer

The Solar System Observer has been provided in earlier versions as a neutral view location high above the

North pole of the Solar System. Meanwhile the location can be changed by keyboard interaction. See

section 4.2.3.

[ so lar _sy st em_ obs erver ]

name = Solar System Obse rver

parent = Sun

halo = false

hidden = true

or bit _S emi Major Axi s =30

type = observer

Note that it is

hidden

and has no

halo

. The observer is attached to the Sun, therefore the value for distance

orbit_SemiMajorAxis is given in AU.

Planet Observers

There are other “observer” locations for all planets which have moons: Earth, Mars, Jupiter, Saturn, Uranus,

and Neptune. For example:

[ ea rt h_obs er ver ]

name = Earth Ob server

parent = Earth

halo = false

hidden = true

or bit _S emi Major Axi s =1 49600000

type = observer

The distance

orbit_semiMajorAxis

has been preconﬁgured with a distance that gives a good view of

v 23.1

the planet with its moons. Like for moons, the units are km from the planet.

D.2.2 File ssystem_minor.ini

Orbital elements for minor bodies are always given for a particular equinox like J2000.0 (which indicates the

coordinate reference system) and epoch (date). The other planets pull on the objects and change their orbits,

most usually leading to the objects appearing too early or too late in their orbits, but also changing the other

orbital elements. In addition, outgassing events of comets can act like jet propulsion and change orbits in

unpredictable ways. It is heavily recommended to update the orbital elements on a regular basis (

2×

/year?),

358 Appendix D. Conﬁguration Files

or at least before you go out and are actually observing minor bodies. Use the Solar System Editor plugin for

this task (section 13.8).

You may ﬁnd element sets for different equinoxes, like B1950.0. These have to be converted to equinox

J2000.0 data before being useful in Stellarium. The conversion is outside Stellarium’s scope.

coord_func

kepler_orbit

by default. For compatibility and interoperability with older versions we

will keep the old default of comet_orbit for some longer time.

parent defaults to Sun and can be omitted.

orbit_Epoch JDE when these elements are valid. Defaults to 2451545.0 = the J2000.0 standard epoch.

orbit_good

can be given in days to limit computation of the object to the time range

epoch ± orbit_good

If speciﬁed as

there is no check for out-of-range dates. If speciﬁed as

-1

, half the orbital period

is used. The main purpose of this parameter is to avoid an element clash or the inadvertent use of

outdated comet orbit elements when a periodic comet reappears.

orbit_ArgOfPericenter

ω [degrees]

orbit_AscendingNode Ω [degrees]

orbit_Eccentricity e = 0 circular, 0 < e < 1 elliptic, e = 1 parabolic, e > 1 hyperbolic

orbit_Inclination i [degrees] inclination against J2000 ecliptic

orbit_SemiMajorAxis a [AU]

The other parameters are like those for the major planets.

D.2.2.1 Minor Planet section

[4 vesta ]

type = asteroid

mi nor _p lan et_nu mbe r =4

name = Vesta

coord_func = comet_orbit

parent = Sun

orbit_Ep oc h =2457000.5

or bit_M eanAn omaly =20.86389

or bit_M ea nMoti on =0.27154465

or bit _ArgO fPe ricen ter = 15 1.19843

or bit _A sce nding Nod e =1 03.85141

or bit_E ccent ric it y =0.0887401

or bit_I nclin ation =7.14043

or bit _S emi Major Axi s =2 .3617933

orbit_good =1 325.46

color =1. , 1. , 1.

halo = true

oblateness =0.0

albedo =0.423

radius =280

ab solut e_mag nit ud e =3.2

sl op e_par ameter =0.32

tex_map = vesta . png

model =4 ves ta_21_M Lf ix . obj

type

can be

asteroid, dwarf planet, cubewano, plutino, scattered disc object, Oort cloud

object

. With the exception of Pluto (which is included in

ssystem_major.ini

and cannot be

changed), all positions for minor bodies are computed with the orbiting elements given in this way.

Minor planets further specify

orbit_Epoch , JDE when these elements are valid. Defaults to J2000.0, i.e., 2451545.0.

orbit_MeanAnomaly M mean anomaly, degrees.

Previous editions used the name

comet_orbit

. Now the

coord_func

line can be left away, defaulting to

kepler_orbit.

D.2 Solar System Conﬁguration Files 359

orbit_MeanMotion n mean motion [degrees/day].

Visual magnitude is modelled from

absolute_magnitude H

slope_parameter G.

Elements for rotational axis may be given just like for planets when they are known. It is recommended

to use the modern speciﬁcation (elements rot_pole_...).

model

A few asteroids have been visited by spacecraft, and for many other asteroids visual observations

of stellar occultations by asteroids and light curve measurements have enabled researchers to derive

3D shape models of asteroids. If a model is available in the

models

subdirectory of the program

directory, this can be conﬁgured with a model entry.

D.2.2.2 Comet section

Comets are tiny, and their outgassing and close approaches to the major planets cause fast changes in their or-

bital elements, so that each apparition should be speciﬁed with a dedicated section in

ssystem_minor.ini

Naming schemes

Over just the past decades, the naming of comets has changed considerably. Starting in the 19th century,

comets are usually named after their discoverer(s). In addition, they are given a catalog number. Traditionally,

comets observations published by scientiﬁc organisations were sorted and labelled with Roman numerals

after date of perihelion. When scientiﬁc communication became faster, comet discoveries were circulated by

telegraphs, and a preliminary immediate labelling by sequence of discovery was used. After the year was

over, the comet received again the Roman number indicating the position in the sequence of perihelon dates

in that year.

In 1994, a new scheme has been introduced

: When a comets is discovered, the discovery date governs

a unique label: The 12 months of the year are split into half-months, for which 24 of the 26 letters of the

alphabet are used (I and Z are omitted). After the letter, discoveries are enumerated in sequence. A letter

before this number indicates what kind of comet the element set describes: C indicates a regular comet, P a

periodic (recurring) comet, D is defunct (lost). X is one for which no reliable orbital elements can be given.

I labels an interstellar object (an object on an orbit, or more accurately, a hyperbolic trajectory which only

swings around the Sun one time). After a return, periodic comets receive a serial number before the P.

This new scheme is also applied for old comets. However, for the sake of compatibility with older

literature, Stellarium can use several optional entries in addition to the name: v 23.2

name

1P/Halley (First periodic comet, named after EDMUND HALLEY, the astronomer who identiﬁed its

recurrent nature)

iau_designation 1982 U1 (First comet discovered in 2nd half of October 1982)

discovery_code 1982i (9th comet discovered in 1982)

perihelion_code 1986 III (Third comet to go through perihelion in 1986)

There is unfortunately divergent information about use of the new IAU discovery code for periodical

comets like 1P/Halley. Some lists provide such codes for previous observations, while others use the modern

code for Halley’s own observation (P/1682 Q1) for every apparition, in which case identiﬁcation of the

proper apparition from just the name becomes impossible. IAU simply uses a periodic number with P and

optional name (for comet Halley, “1P/Halley”. Almost all periodic comets have names) to identify such a

recurring object. While this can be used for predicted future passages through the inner Solar system, there

cannot be a modern “discovery code” based label when the comet was at least in theory followed through

aphelion. But also this format, using only periodic number, prevents disambiguation between apparitions. To

make life simpler for us, we prefer to use a name entry like “1P/Halley (1986)” with year of perihel passage

in brackets. A numbered comet may come without a discoverer name. In this case it is just shown with

perihel year like “396P (2019)”. The ini ﬁle should include a periodic number in front of the P in the name,

however some data ﬁles are incomplete. Unnumbered comets follow the new IAU code, e.g., “C/1996 B2

(Hyakutake)”. You can also provided separate

name

and

iau_designation

entries, in which case they will

be combined.

Most other elements are similar to minor planets. But note the speciﬁcation of

orbit_PericenterDistance q [AU]

orbit_TimeAtPericenter T JDE of closest approach to the Sun

orbit_Epoch JDE when these elements are valid (optional).

which is more typical for comets which may have no orbital period when they are on parabolic or hyperbolic

orbits. Frequently orbital elements are given for a date very close to perihelion so that the perihel date

https://minorplanetcenter.net/iau/lists/CometResolution.html

360 Appendix D. Conﬁguration Files

is used wherever

orbit_Epoch

is not given. However, this assumption does not always hold, so we

recommend to state orbit_Epoch explicitly.

ref Reference, e.g. some MPC Circular (optional). May be used in future versions.

Comet magnitudes

Like for minor planets, visual magnitude is modelled from

absolute_magnitude H

slope_parameter G

but with a modiﬁed expression:

mag = H + 5⋅ log∆ + 2.5⋅ G ⋅ logr (D.4)

The term

slope_parameter

may be a misnomer in case of comets. From the literature (Meeus, 1998)

(equation 33.13) we ﬁnd

mag = g + 5log∆ + κ logr (D.5)

from which

κ = 2.5 ⋅ G

. In any case,

is typically [5. . . 15] and speciﬁc for each comet. The standard value

for G is 4 (therefore κ = 10).

Estimating and predicting comet magnitudes is very difﬁcult, and values for

and

often differ

between data sources like the Minor Planetary Center

and NASA/JPL Horizon

. When you think some

comet magnitude is off, consider searching for other sources than MPC

You can ﬁnetune the appearance of the comet, both when zooming in all the way to the core, or how the

tails are represented.

albedo (default: 0.075) is used to set the brightness for rendering the body, if you are close enough.

model

Some comets have been visited by spacecraft so that shape models of their cores may be available

and can be conﬁgured with this entry.

outgas_intensity

(default:0.1) Intensity of a pseudo-outgas effect on the core, based on an inverse exponen-

tial Lambert shading, with the light at the viewing position.

outgas_falloff (default:0.1) Exponent for falloff of outgas effect, should probably stay < 1.

dust_brightnessfactor (default: 1.5) brightness of dust tail relative to the gas tail.

dust_lengthfactor (default: 0.4) length of dust tail relative to the gas tail.

dust_widthfactor (default: 1.5) width of dust tail relative to the gas tail.

Some historical depictions show huge comets. If painted correctly, you can try to recreate such paintings.

A large number of elements for historical comets is provided in the ﬁle

ssystem_1000comets.ini

the installation directory. You can copy&paste what you need into your

ssystem_minor.ini

or add all

with the Solar System Editor plugin (section 13.8).

With a clever combination of elements and

orbit_good

entries, it is possible to specify several sets of

orbital elements for different epochs of one apparition.

Periodic Comet

[1 phalley ]

type = comet

name =1 P / Halley

ia u_ desig nation =1982 U1

di sc overy _c ode =1982 i

pe ri helio n_code =1986 III

or bit _ArgO fPe ricen ter =111.7154

or bit _A sce nding Nod e =58.8583

or bit_E ccent ric it y =0.9 68004

or bit_I nclin ation =162.2453

or bit _Pe ric enter Dis tan ce =0. 57136

https://www.minorplanetcenter.net/data

https://ssd.jpl.nasa.gov/horizons/

One interesting website is

http://www.aerith.net/index.html

which provides magnitude predictions

in terms of D.5 for current comets, sometimes even in intervals from perihel date as comets evolve. Just extract

absolute_magnitude = g and slope_parameter = κ/2.5.

D.2 Solar System Conﬁguration Files 361

or bit _Time AtP eri cente r = 24 464 63 .12 97 916 7

orbit_good =780

color =1.0 , 1.0 , 1.0

du st_ brigh tne ssfac tor =1.5

du st_le ngthf actor =0.4

du st_wi dt hfact or =1.5

albedo =0.1

radius =5

ab solut e_mag nit ud e =5.5

sl op e_par ameter =3.2

model =1682 q1 halley_ ML fix . obj [ opti onal ]

Note a rather short duration of

orbit_good

, which means the comet is only displayed 780 days before

and after perihelion. (Actually, before and after

orbit_Epoch

, but this is not given explicitly, so it defaults

to orbit_TimeAtPericenter.)

Parabolic/Hyperbolic Comet

[ c2013us 10 %28 catalina %29]

type = comet

name = Catalina

ia u_ desig nation =C /2013 US10

or bit _ArgO fPe ricen ter =340.3533

or bit _A sce nding Nod e =186.141

or bit_E ccent ric it y =1.0 00372

or bit_I nclin ation =148.8766

or bit _Pe ric enter Dis tan ce =0.82 29 58

or bit _Time AtP eri cente r = 24 573 42 .20 74 884 3

orbit_good =1000

...

ab solut e_mag nit ud e =4.4

sl op e_par ameter =4

This has basically the same format. Note that eccentricity is larger than 1, this means the comet is follow-

ing a slightly hyperbolic orbit. Stellarium shows data for this comet for almost 3 years (

orbit_good=1000

days) from the epoch (defaults to pericenter time).

D.2.3 JPL Horizons

The JPL Horizons

on-line solar system data and ephemeris computation service provides access to key

solar system data and ﬂexible production of highly accurate ephemerides for solar system objects (Late 2023:

1,334,683 asteroids, 3,904 comets, 290 planetary satellites includes satellites of Earth and dwarf planet Pluto,

8 planets, the Sun, L1, L2, select spacecraft, and system barycenters). Horizons is provided by the Solar

System Dynamics Group of the Jet Propulsion Laboratory.

D.2.3.1 How to manually look up a body

A comet discovered in early 2023, C/2023 A3 (Tsuchinshan-ATLAS), may become bright in October 2024.

Let’s ﬁnd out its orbital elements for the most interesting time!

We use the Horizons web interface to look up the body we are interested in and ﬁnd its orbital elements.

The Horizons web interface will display something like this:

https://ssd.jpl.nasa.gov/horizons/

362 Appendix D. Conﬁguration Files

1 Ephemeris Type:

Osculating Orbital Elements

Edit

Target Body: C/2023 A3 (Tsuchinshan-ATLAS)

Edit

Coordinate Center: Sun (body center) [500@10]

Edit

Time Speciﬁcation: Start=2024-07-03 TDB, Stop=2024-12-02, Step=5 (days)

Edit

Table Settings: custom

Generate Ephemeris

1. Ephemeris Type must be set to

Osculating Orbital Elements

2. Target Body is the body you want to add to Stellarium. Click

Edit

to look it up.

3. Center should be set to Sun for all heliocentric trajectories.

Time Speciﬁcation: Use a short interval or discrete dates near the time you are most interested. The

returned JDE date (Julian Day number) will be used as epoch in Stellarium.

Table Settings: We must

Edit

and select Output units:

au and days

to create data compatible with

the appropriate ﬁelds in ssystem_minor.ini

The result begins with listing osculating elements for a certain epoch in the past and its own initial conditions

and settings. Horizons then applies numerical integration and simulates the movement and gravitational

interaction between all its solar system objects, including our comet. Then, for each requested time, orbital

elements are listed. Here you could see the slight changes these elements undergo over weeks. However, in

Stellarium, we can only use one particular element set and show the comet’s movement under the assumption

that these elements do not change. When we have read it will be brightest in October, let’s take this section.

The ﬁrst number is the date (JDE) where these elements are valid, i. e., the element epoch.

2460584.50 0 0 0 0 0 0 0 = A. D . 2024 - Oct -01 00:00:00.0000 TDB

EC = 1.00008 6 7 7 9 0 1 3 4 3 6 E +00 QR = 3.914011809 3 4 8 2 4 7 E -01 IN = 1.391089 3 1 2 5 7 0 2 8 7 E +02

OM = 2.15604 9 2 8 7 7 5 9 3 6 4 E +01 W = 3.0849559434 2 9 2 1 9 E +02 Tp = 2 4 6 0 5 8 1 .2 48 5 32 14 99 41

N = 3 . 2 5 3 8 1 56 1 56 0 7 08 3 E -06 MA = 1. 05 7 9 67 6 86 4 5 70 9 1 E -05 TA = 1.819722055 1 6 0 8 3 7 E +01

A = -4.510320 7 0 3 5 32996 E +03 AD = 9 . 9 9 9 9 99 9 9 99 9 99 9 8 E +99 PR = 9.9999999 9 9 9 9 9 9 9 8 E +99

Below you also ﬁnd the keys:

Symbol meaning :

JDTDB Julian Day Number , Bary ce nt ri c Dynam ical Time

EC Eccentricity , e

QR Periap si s distance , q ( km )

IN Inclinati on w.r . t X -Y plane , i ( degrees )

OM Longit ud e of A sc ending Node , OMEGA , ( degrees )

W Argument of Perifocus , w ( degrees )

Tp Time of periapsis ( Julian Day Number )

N Mean motion , n ( degrees / sec )

MA Mean anomaly , M ( degrees )

TA True anomaly , nu ( degrees )

A Semi - major axis , a ( km )

AD Apoa psis distance ( km )

PR Side real orbit period ( sec )

Now we can add an entry into our

ssystems_minor.ini

. We can leave the exponential writing style

(trailing “E+02” etc.) or convert to the more human-readable as shown here. Symbols

and

are given

only in the top list of initial elements. The symbols in brackets refer to the above table, do not enter those!

[ c20 2 3A3 ( t s u c h in s h an a t l as )]

iau_designation = C /2023 A3

name = C /20 23 A3 ( T such inshan - ATLAS )

type = comet

orbit_ E p o c h = 246058 4 . 5

orbit_A r g O f P er ic en te r = (W ) 308.495594 3 4 2 9 2 1 9

orbit_As c e n d i n gN o de = ( OM ) 21 . 5 6 04 9 28 7 7 59 3 64

orbit_Ecc e n t r i c i ty = ( EC ) 1 . 0 0 0 0 8 67 7 9 01 3 43 6

orbit_Incl i n a t i o n = ( IN ) 13 9 . 1 0 89 3 12 5 70 2 8 7

orbit_ P e r i ce nterDist a n c e = ( QR ) 0.3 9 1 4 0 1 1 8 09 3 48 24 7

orbit_ T i m e A tP er ic en te r = ( Tp ) 2 4 6 0 58 1. 2 48 53 21 4 99 41

D.2 Solar System Conﬁguration Files 363

absolute_ m a g n i t u de = ( M1 ) 6.1

slope_parameter = ( k1 /2.5) 3.4

orbi t _ g o o d = 1000

dis c o v ery = 2023 -01 -09 [ Not giv en by JPL Ho r i zons ]

ref = JPL Horiz o n s : JPL # 25

JPL Horizons can also deliver osculating elements for a number of interplanetary spacecraft. To visualize

them, you should assign

type=interstellar object

(to make the orbit line stand out a bit more than

with

asteroid

) and invent your own magnitude, e.g.,

absolute_magnitude=0

or even brighter, to make

them visible. Obviously, the shown trajectory is valid only around the given epoch and changes signiﬁcantly

whenever a spacecraft encounters a larger solar system object or when operators ﬁre its engines. An Example

for the Voyager 2 spacecraft may look like:

[ voya g e r2 ]

name = Voyag er 2 ( a fter Neptun e )

iau_designation = Voyager 2

type = i nterstellar obje ct

orbit_A r g O f P er ic en te r = 1 . 3 0 0 8 7 2 3 8 88 6 32 4 4 E +02

orbit_As c e n d i n gN o de = 1.0178405119 7 1 1 7 4 E +02

orbit_Ecc e n t r i c i ty = 6 .2 9 4 33 8 89 1 6 86 2 61 E +00

orbit_ E p o c h = 246055 4 . 5 [ Sept 1, 202 4]

orbit_Incl i n a t i o n = 7. 8 9 53 4 20 3 8 40 0 21 4 E +01

orbit_ P e r i ce nterDist a n c e = 2 . 1 3 0 8 18 1 95 9 68 9 7 4 E +01

orbit_ T i m e A tP er ic en te r = 2445446. 8 6 8 6 6 56 16 9 59

orbi t _ g o o d = 1 2797

ref = JPL Horiz o n s

absolute_ m a g n i t u de = 0

slope_parameter = 4

The displayed trajectory should start at Voyager 2’s encounter with Neptune on August 18, 1989 (JD

2447757.5). The value of orbit_good= (2460554.5− 2447757.5 =) 12797 fulﬁlls this idea.

E. Planetary nomenclature

Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the

surface of a planet or natural satellite so that the features can be easily located, described, and discussed.

Since the invention of the telescope, astronomers have given names to the surface features they have discerned,

especially on the Moon and Mars. To standardize planetary nomenclature, the International Astronomical

Union (IAU) was assigned in 1919 the task of selecting ofﬁcial names for features on solar system bodies

Figure E.1: Feature nomenclature of the Moon.

Since version 0.17.0 Stellarium supports planetary nomenclature, which allows using the planetarium

for educational and informative purposes on the one hand, and as tool for recognition and targeting of the

planetary features for advanced amateurs on the other hand, avoiding the need for additional cartographic

software in the ﬁeld.

All planetary nomenclature items are stored in a dedicated internal format, and all names are translatable

to provide better understanding of those names by average users and newbies – for example in schools or

universities. Of course all nomenclature items are available for ﬁnding in the Search Tool after enabling the

History of Planetary Nomenclature – https://planetarynames.wr.usgs.gov/Page/History

366 Appendix E. Planetary nomenclature

display of nomenclature (this feature is rather costly in terms of computing power and therefore is by default

disabled in the GUI).

The information in sections E.3–E.6, included here for reference, has been taken from the “Gazetteer

of Planetary Nomenclature” website by the International Astronomical Union (IAU) Working Group for

Planetary System Nomenclature (WGPSN)

E.1 Format of nomenclature data ﬁle

File data/nomenclature.fab is a plain text ﬁle in UTF-8 encoding and has a very simple data format:

•

One item per line;

•

Each item contains seven elements with white space (“space” or “tab” character) as delimiter.

File

data/nomenclature.dat

is a zipped

data/nomenclature.fab

ﬁle and used to minimize time of

loading the data and reduce size of the installation package.

Item Type Comment

planet name string

English name of the planet, moon or minor body car-

rying the named feature

ID of planetary feature

integer

unique integer, equal to Feature ID obtained from

Gazetteer of Planetary Nomenclature

translatable name of planetary feature

string English name, containing context data for translators

type of planetary feature

string

2-char code (see designation column in table in sec-

tion E.6)

center latitude of planetary feature

ﬂoat decimal degrees

center longitude of planetary feature

ﬂoat decimal degrees

size of planetary feature

ﬂoat kilometers

Example:

Vesta 15201 _ (" Caesonia "," crater " ) AA 31.20117 249.93457 104.23

E.2 Planetary Coordinate Systems

When we observe the Moon or another planet from Earth (or actually from anywhere), we can see only

about half of the surface of the spheroid body at any time. Foreshortening further prevents us from observing

surface features along the planet’s visible limb. Therefore it is important to know the coordinates of the

center of the apparent disk, given by the central meridian and latitude. In addition, we can also compute

the subsolar point, where the sun is visible in the zenith, and which provides the center of the illuminated

hemisphere. This is not the center of the visible disk! A part of the illuminated hemisphere is generally on

the far side of the planet.

The north pole of the planets is the pole of rotation directed towards the north of the invariable plane

(near the ecliptic) of the Solar system. Most planets are rotating in the same sense as they are moving around

the sun. This is called prograde. Seen from the north side of the ecliptic, they rotate counterclockwise. Only

a few objects, most notable Venus, are rotating clockwise, i.e., retrograde.

For historical reasons, there are several ways to count longitudes. Just like the terrestrial zero meridian

has been deﬁned as that one running through Greenwich observatory

, the zero meridian on rocky bodies

like the Moon or Mars is usually deﬁned by some surface feature like a small crater. For the gas planets,

the rotation of the magnetic ﬁeld is usually given to deﬁne the central meridian. Starting from this central

meridian, we can count longitudes in both directions. For the Moon, which shows always (almost, see

18.2.6) the same side towards Earth, we count western and eastern longitudes from the central meridian

towards the trailing or leading edge of its daily motion, respectively. (Seeing the Moon through an unguided

telescope, we ﬁrst see the eastern longitudes from

≈ 90

○

, then the western longitudes from

○

≈ 90

○

Alternatively we can count the western longitudes as negative. The counting continues to the (invisible) far

side of the Moon where one meridian has an Eastern longitude of +180

○

= −180

○

https://planetarynames.wr.usgs.gov, visited on 2022-04-04

In earlier times, at least each seafaring nation had its own zero meridian, usually running through an ofﬁcial

observatory.

E.3 How names are approved by the IAU 367

For other objects, historically, Mars was the ﬁrst planet to be mapped with cartographic coordinates. Its

rotational period of just over 24.5 hours allows to follow its rotation and observe only a slight change in

appearance every day. It appeared natural to count the central meridian so that central longitude increased as

time passed. Just like on Earth, as time passes, increasingly western longitudes receive sunlight and also

become visible. Therefore these planetographic longitudes are counted towards the west on planets with

prograde rotation. On planets with retrograde rotation like Venus, these longitudes are counted eastward.

In contrast, current convention on Earth is to count geographic longitudes eastward.

The information about coordinates for center and subsolar points in the information displayed for a

planet is counted in this planetographic sense.

Another convention are planetocentric coordinates where longitudes are always counted positively

towards the east. East is deﬁned as going counterclockwise as seen from the north pole, which is itself

deﬁned as the one pole more closely aligned with Earth’s north pole. The latest maps and data for Mars are

using planetocentric data, i.e., eastern longitudes.

For clarity, therefore coordinates are often explicitly written with “E” and “W” instead of signed numbers.

Another difference between planetographic and planetocentric coordinates is that the latter model the

planet as simple sphere, ignoring the (usually small) ﬂattening of the planet bodies.

The surface coordinate systems deﬁned by the WGPSN

and used in Stellarium follows are shown

in table E.1

. However, given that the WGPSN publishes their data only with planetocentric latitudes,

Stellarium provides planetocentric latitudes in the information panel for surface features.

E.3 How names are approved by the IAU

When images are ﬁrst obtained of the surface of a planet or satellite, a theme for naming features is chosen

and a few important features are named, usually by members of the appropriate IAU task group (a commonly

accepted planet-naming group). Later, as higher resolution images and maps become available, additional

features are named at the request of investigators mapping or describing speciﬁc surfaces, features, or

geologic formations. Anyone may suggest that a speciﬁc name be considered by a task group. If the members

of the task group agree that the name is appropriate, it can be retained for use when there is a request from a

member of the scientiﬁc community that a speciﬁc feature be named. Names successfully reviewed by a

task group are submitted to the IAU Working Group for Planetary System Nomenclature (WGPSN). Upon

successful review by the members of the WGPSN, names are considered provisionally approved and can be

used on maps and in publications as long as the provisional status is clearly stated. Provisional names are

then presented for adoption to the IAU’s General Assembly, which met triennially in the past, and which

now adopts nomenclature for planetary surface features as required. A name is not considered to be ofﬁcial –

that is, “adopted” – until the General Assembly has given its approval.

E.4 IAU rules and conventions

Names adopted by the IAU must follow various rules and conventions established and amended through the

years by the Union. These include:

Nomenclature is a tool and the ﬁrst consideration should be to make it simple, clear, and unambiguous.

In general, ofﬁcial names will not be given to features whose longest dimensions are less than 100

meters, although exceptions may be made for smaller features having exceptional scientiﬁc interest.

The number of names chosen for each body should be kept to a minimum. Features should be named

only when they have special scientiﬁc interest, and when the naming of such features is useful to the

scientiﬁc and cartographic communities at large.

Duplication of the same surface feature name on two or more bodies, and of the same name for

satellites and minor planets, is discouraged. Duplications may be allowed when names are especially

appropriate and the chances for confusion are very small.

Individual names chosen for each body should be expressed in the language of origin. Transliteration

for various alphabets should be given, but there will be no translation from one language to another.

Where possible, the themes established in early solar system nomenclature should be used and

expanded on.

Solar system nomenclature should be international in its choice of names. Recommendations sub-

mitted to the IAU national committees will be considered, but ﬁnal selection of the names is the

IAU Working Group for Planetary System Nomenclature – https://planetarynames.wr.usgs.gov/

https://planetarynames.wr.usgs.gov/TargetCoordinates, visited Jan.5, 2022

368 Appendix E. Planetary nomenclature

Target Coordinate Systems Control Networks

Amalthea Planetographic +West 0. . . +360

Ariel Planetocentric +East 0. .. +360

Callisto Planetographic +West 0. . . +360

Charon Planetocentric +East 0. .. +360 Charon

Deimos Planetographic +West 0. . . +360

Dione Planetographic +West 0. . . +360

Enceladus Planetographic +West 0. . . +360

Epimetheus Planetographic +West 0. . .+360

Europa Planetographic +West 0. . . +360

Ganymede Planetographic +West 0. .. +360

Hyperion Planetographic +West 0. . . +360

Iapetus Planetographic +West 0. . . +360

Io Planetographic +West 0. . . +360 Voyager/Galileo SSI

Janus Planetographic +West 0. . .+360

Mars Planetocentric +East 0. .. +360 MDIM 2.1

Mercury Planetographic +West 0. . . +360 MESSENGER Team

Mimas Planetographic +West 0. . . +360

Miranda Planetocentric +East 0. .. +360

Moon Planetographic +East −180. . .+180 LOLA 2011, ULCN 2005

Oberon Planetocentric +East 0. . .+360

Phobos Planetographic +West 0. . .+360

Phoebe Planetographic +West 0. . .+360

Pluto Planetocentric +East 0. . . +360 Pluto

Proteus Planetographic +West 0. .. +360

Puck Planetocentric +East 0. .. +360

Rhea Planetographic +West 0. . .+360

Tethys Planetographic +West 0. .. +360

Thebe Planetographic +West 0. .. +360

Titan Planetographic +West 0. .. +360

Titania Planetocentric +East 0. . . +360

Triton Planetographic +East 0. . .+360

Umbriel Planetocentric +East 0. . .+360

Venus Planetocentric +East 0. . . +360

Table E.1: Coordinate systems used by the WGPSN

E.5 Naming conventions 369

responsibility of the International Astronomical Union. Where appropriate, the WGPSN strongly

supports an equitable selection of names from ethnic groups, countries, and gender on each map;

however, a higher percentage of names from the country planning a landing is allowed on landing site

maps.

No names having political, military or religious signiﬁcance may be used, except for names of political

ﬁgures prior to the 19th century.

Commemoration of persons on planetary bodies should not normally be a goal in itself, but may be

employed in special circumstances and is reserved for persons of high and enduring international

standing. Persons being so honored must have been deceased for at least three years, before a proposal

may be submitted.

10.

When more than one spelling of a name is extant, the spelling preferred by the person, or used in an

authoritative reference, should be used. Diacritical marks are a necessary part of a name and will be

used.

11.

Ring and ring-gap nomenclature and names for newly discovered satellites are developed in joint

deliberation between WGPSN and IAU Commission X2. Names will not be assigned to satellites until

their orbital elements are reasonably well known or deﬁnite features have been identiﬁed on them.

12.

Accessible and authoritative sources, including Internet sources, are required for adopted names.

Wikipedia is not sufﬁcient as a source, but may be useful for identifying appropriate sources.

In addition to these general rules, each task group develops additional conventions as it formulates an

interesting and meaningful nomenclature for individual planetary bodies. Most of these conventions are self

evident from study of the appendixes that follow.

E.5 Naming conventions

Names for all planetary features include a descriptor term, with a few exceptions. For craters, the descriptor

term is implicit. Some features named on Io and Triton do not carry a descriptor term because they are

ephemeral.

In general, the naming convention for a feature type remains the same regardless of its size. Exceptions

to this rule are channels (valles) on Mars and Venus, and craters on the Moon, Mars, and Venus; naming

conventions for these features differ according to size. The categories for naming features on each planet

or satellite (and the exceptions) are listed in Categories for Naming Features on Planets and Satellites

One feature classiﬁcation, regio, was originally used on early maps of the Moon and Mercury (drawn from

telescopic observations) to describe vague albedo features. It is now also used to delineate a broad geographic

region.

Named features on bodies so small that coordinates have not yet been determined are identiﬁed on

drawings or images of the body that are included in the IAU Transactions volume of the year when the

names were adopted. Satellite rings and gaps in the rings are named for scientists who have studied these

features; drawings that show these names are also included in the pertinent Transactions volume. Names for

atmospheric features are informal at present; a formal system will be chosen in the future.

The boundaries of many large features (such as terrae, regiones, planitiae, and plana) are not topographi-

cally or geomorphically distinct; the coordinates of these features are identiﬁed from an arbitrarily chosen

center point. Boundaries (and thus coordinates) may be determined more accurately from geochemical and

geophysical data obtained by future missions.

During active missions, small surface features are often given informal names. These may include

landing sites, spacecraft impact sites, and small topographic features, such as craters, hills, and rocks. Such

names will not be given ofﬁcial status by the IAU, except as provided for by Rule 2 above. As for the larger

objects, ofﬁcial names for any such small features would have to conform to established IAU rules and

categories.

When a satellite has been discovered through the efforts of a large scientiﬁc team, the list of individual

team members may be too long to include all contributors. In such cases, credit for the discovery will go to

the science team.

Surface Feature Categories – https://planetarynames.wr.usgs.gov/Page/Categories

370 Appendix E. Planetary nomenclature

E.6 Descriptor terms (feature types)

Descriptor terms are intended to represent morphological characteristics, not geological origin. The WGPSN

does not endorse any speciﬁc scientiﬁc hypotheses when assigning descriptors.

Feature Designation Description

Albedo Feature AL

Geographic area distinguished by amount of re-

ﬂected light

Arcus, arc

AR Arc-shaped feature

Astrum, astra

AS Radial-patterned features on Venus

Catena, catenae CA Chain of craters

Cavus, cavi

Hollows, irregular steep-sided depressions usually

in arrays or clusters

Chaos, chaoses

CH Distinctive area of broken terrain

Chasma, chasmata

CM A deep, elongated, steep-sided depression

Collis, colles

CO Small hills or knobs

Corona, coronae

CR Ovoid-shaped feature

Crater, craters

AA A circular depression

Dorsum, dorsa DO Ridge

Eruptive center ER Active volcanic centers on Io

Facula, faculae FA Bright spot

Farrum, farra

FR Pancake-like structure, or a row of such structures

Flexus, ﬂex

A very low curvilinear ridge with a scalloped pattern

Fluctus, ﬂuct

us FL Flow terrain

Flumen, ﬂumina

FM Channel on Titan that might carry liquid

Fossa, fossae

FO Long, narrow depression

Fretum, freta

Strait, a narrow passage of liquid connecting two

larger areas of liquid

Insula, insulae IN

Island (islands), an isolated land area (or group of

such areas) surrounded by, or nearly surrounded by,

a liquid area (sea or lake)

Labes, lab

es LA Landslide

Labyrinthus, labyrinthi

LB Complex of intersecting valleys or ridges

Lacuna, lacunae

Irregularly shaped depression on Titan having the

appearance of a dry lake bed

Lacus, lac

“Lake” or small plain; on Titan, a “lake” or small,

dark plain with discrete, sharp boundaries

Landing site name

LF Lunar features at or near Apollo landing sites

Large ringed feature

LG Cryptic ringed features

Lenticula, lenticulae

LE Small dark spots on Europa

Linea, lineae

A dark or bright elongate marking, may be curved

or straight

Lingula, lingulae

Extension of plateau having rounded lobate or

tongue-like boundaries

Macula, maculae MA Dark spot, may be irregular

Mare, maria

“Sea”; on the Moon, low albedo, relatively smooth

plain, generally of large extent; on Mars, dark albedo

areas of no known geological signiﬁcance; on Titan,

large expanses of dark materials thought to be liquid

hydrocarbons

Mensa, mensae

MN A ﬂat-topped prominence with cliff-like edges

Mons, montes

MO Mountain

Oceanus, oceani OC A very large dark area on the moon

E.6 Descriptor terms (feature types) 371

Palus, paludes PA “Swamp”; small plain

Patera, paterae

An irregular crater, or a complex one with scalloped

edges

Planitia, planitiae

PL Low plain

Planum, plana

PM Plateau or high plain

Plume, plumes

PU Cryo-volcanic features on Triton

Promontorium, promontoria

PR “Cape”; headland promontoria

Regio, regiones RE

A large area marked by reﬂectivity or color distinc-

tions from adjacent areas, or a broad geographic

region

Reticulum, reticula

RT Reticular (netlike) pattern on Venus

Rima, rimae

RI Fissure

Rupes, rup

RU Scarp

Satellite Feature SF

A feature that shares the name of an associated fea-

ture. For example, on the Moon the craters referred

to as “Lettered Craters” are classiﬁed in the gazetteer

as “Satellite Features”

Saxum, saxa

SA Boulder or rock

Scopulus, scopuli

SC Lobate or irregular scarp

Serpens, serpentes

Sinuous feature with segments of positive and nega-

tive relief along its length

Sinus, sin

“Bay”; small plain; on Titan, bays within seas or

lakes of liquid hydrocarbons

Sulcus, sulci

SU Subparallel furrows and ridges

Terra, terrae TA Extensive land mass

Tessera, tesserae

TE Tile-like, polygonal terrain

Tholus, tholi

TH Small domical mountain or hill

Unda, undae UN Dunes

Vallis, valles VA Valley

Vastitas, vastitates

VS Extensive plain

Virga, virgae

VI A streak or stripe of color

E.6.1 Chart of landform types

The graphical examples of some landform types were taken from a chart of landform types created in 1979

by Anne Gifford, then at the Air and Space Museum, Smithsonian Institution, Washington, D.C.

Lacus [LC] and Mare [ME] Oceanus [OC] and Palus [PA]

Planitia [PL] and Planum [PM]

https://planetarynames.wr.usgs.gov/images/Farouk_drawings_composite.pdf

372 Appendix E. Planetary nomenclature

“lake” (small irregular patch of

dark, smooth material of the

Moon) and “sea” (large, often

circular, region of dark smooth

material of the Moon)

“ocean” (vast, irregular, dark,

smooth region – Oceanus Procel-

larum only) and “swamp” (small

irregular area, on the Moon a

mixture of mare and highland

material)

low plain or large level expanse

of lowlands and high plain or a

plateau

Catena [CA] Cavus [CB] Chaos [CH]

chain; a string of closely spaced

depressions

cavities; irregular steep-sided de-

pressions usually in clusters

chaos; area of distinctive broken

or jumped terrain

Chasma [CM] Crater [AA] Dorsum [DO]

chasm; steep-walled trough;

large canyon

crater; any roughly circular de-

pression resulting from impact

or volcanic activity

ridge; elongate raised structure;

wrinkle ridge

Fossa [FO] Labyrinthus [LB] Mensa [MN]

ditch; narrow linear trench (on

the Moon called Rima)

labyrinth; an expanse of inter-

secting canyon-like troughs

mesa; ﬂat-topped elevation with

steep walls

Mons [MO] Patera [PE] Promontorium [PR]

E.6 Descriptor terms (feature types) 373

mountain

“saucer”; shallow, complex

crater with scalloped walls

promontory; extension of lunar

mountains into mare

Rima [RI] Rupes [RU] Scopulus [SC]

channel; long narrow valley, ﬁs-

sure or channel on the Moon

linear scarp of cliff face

cliff; lobate or highly irregular

scarp

Sinus [SI] Sulcus [SU] Terra [TA]

“bay”; semi-enclosed dark area

opening into a mare on the Moon

complex area of sub-parallel fur-

rows and ridges

uplands or highlands

Tholus [TH] Vallis [VA] Vastitas [VS]

dome; isolated domical moun-

tain or hill

valley; canyon-like, often sinu-

ous trough

“wasteland”; extensive plains of

lowlands, only on Mars

Author and Acknowledgement

The nomenclature feature has been implemented by Teresa Huertas Roldán supported by the “ESA Summer

of Code in Space 2017” programme.

F. Accuracy

Stellarium originally was developed to present a beautiful simulation of the night sky, mostly to understand

what is visible in the sky when you leave your house, i.e., for present times. To save computation time, some

concessions were made in astronomical accuracy by using simpliﬁed models which seemed acceptable at

that time which was also close to the standard epoch of J2000.0. However, time is progressing, precession

becomes noticeable when pointing telescopes to J2000.0 coordinates, and some users also started to overstress

Stellarium’s capabilities to simulate the historical sky of many centuries in the past, and found — or even

worse: did not ﬁnd, but simply published — the resulting inconsistencies and errors. Unfortunately, celestial

motions are indeed more complicated than a simple clockwork, and the process of retroﬁtting detailed and

accurate models which started around v0.11.0 (in 2011) has only recently (2021) come to a state where

we as developers are beginning to be satisﬁed. Now, after implementation of annual aberration, Stellarium

appears to deviate from reference solutions in the present time only by fractions of arcseconds, and by a

few arcseconds in the remote past. Greater accuracy, including relativistic effects or the deﬂection of light

by the Solar gravity ﬁeld, may still be required for critical observations of stellar occultations by asteroids,

grazing occultations of stars by the Moon or similar things. Stellarium does not compute these effects, and

is deﬁnitely not usable for detailed planning of your spacecraft missions to the planets. There are more

specialized programs for these topics, please use them.

Therefore, when using Stellarium for scientiﬁc work like eclipse simulation to illustrate records found

in Cuneiform tablets, always also use some other reference to compare, and of course specify the program

version you used for your work. (Use at least version 25.1 of Stellarium, which introduced the much improved

star catalog!) You can of course contact us if you bring a solid background in fundamental astronomy and

are willing and able to help improving Stellarium’s accuracy even further!

F.1 Date Range

The calendar dates are limited to a very wide interval of years,

−200, 000. . . + 200, 000

. If you want to

v 25.3

observe the other planets, this is way beyond what current ephemeris models are able to show, as explained

in section F.3! Observe for example the Moon: you will ﬁnd that it seems to run on a polar orbit around

+78.000 and even retrograde on a highly elongated orbit a few millennia after that. A quick check in -180.000

places it in a highly elongated orbit beyond Jupiter that takes it through the solar system at up to more than

10% the speed of light. This is obvious nonsense, caused by excessively extrapolating mathematical models

in inappropriate ways.

The extended date range is only useful to visualize the effect of stellar proper motions and the wobbling

motion of Earth’s axis known as precession. All other components of Stellarium have not made for this

extended date range.

Before version 25.3, the date range was −100, 000. . . + 100, 000.

376 Appendix F. Accuracy

Object(s) Method Notes

Mercury, Venus, Earth-Moon barycen-

ter, Mars

VSOP87

Accuracy is 1 arc-second from 2000

B.C. – 6000 A.D.

Jupiter, Saturn

VSOP87

Accuracy is 1 arc-second from 0 A.D.

– 4000 A.D.

Uranus, Neptune VSOP87

Accuracy is 1 arc-second from 4000

B.C. – 8000 A.D.

Pluto

Pluto’s position is valid only from

1885 A.D. – 2099 A.D.

Earth’s Moon

ELP2000-82B

Fit against JPL DE200, which pro-

vides date range 1850–2050. Posi-

tions should be usable for some (un-

speciﬁed) longer interval.

Galilean satellites

L2 Valid from 500 A.D. – 3500 A.D.

Table F.1: Orbit-centric accuracy of used algorithms

F.2 Stellar Astrometry

Even though you can follow movements of stars on the sky for tens of thousands of years, please note that

the precision of these predictions are limited by the precision of the data we have at the present time provided

by Hipparcos for bright stars and Gaia. Most of the stars brighter than magnitude 10.5 have 3D position

v 25.1

and 3D velocity data (i.e., 6D astrometry) in our star catalogs, thus their 6D astrometry are computed at

any epoch by assuming linear motion with constant velocity. These calculation provides arcseconds level

accuracy of stellar position, arcseconds per year level accuracy of proper motions, arcseconds level accuracy

of parallax and km/s level accuracy of radial velocity in the previous and next tens of thousands of years.

For stars fainter than magnitude 10.5 but brighter than magnitude 16.75, 2D computation is performed such

that RA/DEC positions are computed from RA/DEC proper motions separately and assume constant proper

motion. For stars fainter than magnitude 16.75, no astrometry propagation is performed hence their RA/DEC

stay constant at any epoch.

The study of De Lorenzis and Oroﬁno (2018) emphasized sky position errors with bright high proper

motion stars like Arcturus, Dubhe, Sirius, Toliman and Vega which deviate noticeably from their correct

locations even at around 2500BC with Stellarium 0.17.0 released on 21 Dec 2017. The star catalogs and

astrometry propagation algorithms have been signiﬁcantly improved since Stellarium 25.1, which has solved

the problem outlined in the study.

A quick estimate: For Barnard’s Star which is nearby and moving fast, the sky position uncertainty

on the sky would be

≈ 0.05

○

(200000 mas) at year 200,000 using Gaia DR3 astrometries and associated

uncertainies. The 2015 DR3 sky position uncertainty is ≈ 0.04 mas.

F.3 Planetary Positions

Stellarium uses by default the widespread VSOP87 theory (P. Bretagnon and Francou, 1988) to calculate the

positions of the planets over time. This is an analytical ephemeris modeled to match the numerical integration

run DE200 from NASA JPL, which by itself gives positions for 1850. . . 2050. Its use is recommended for the

years

−4000. . . + 8000

. You can observe the sun leaving the “ecliptic of date” and running on the “ecliptic

J2000” outside this date range. This is obviously a mathematical trick to keep continuity. Still, positions may

be somewhat useful outside this range, but don’t expect anything reliable 50,000 years in the past!

The optionally usable JPL DE431 and DE441 (see 5.5.3) deliver planet positions strictly for the year

range -13000. . . +17000 only, and nothing outside, but likely with higher accuracy. Outside of this range,

positions from VSOP87 will be shown again.

As far as Stellarium is concerned, the user should bear in mind the limits of the VSOP87 and other

models (Table F.1). Accuracy values for VSOP87 are heliocentric as given by P. Bretagnon and Francou

(1988).

F.4 Minor Bodies 377

F.4 Minor Bodies

Positions for the Minor Bodies (Dwarf Planets, Asteroids, Comets) are computed with standard algorithms

found in astronomical text books. The generally used method of orbital elements allows computing the

positions of the respective object on an undisturbed Kepler orbit around the sun. However, gravitational,

and in the case of comets, non-gravitational (outgassing) disturbances slowly change these orbital elements.

Therefore an epoch is given for such elements, and computation of positions for times far from this epoch

will lead to positional errors. Therefore, when searching for asteroids or comets, always update your orbital

elements (See section 13.8), and use elements with an epoch as close to your time of observation as possible!

Stellarium does not simulate gravitational perturbances and orbital changes of minor bodies passing major

planets.

F.5 Precession and Nutation

Since v0.14.0, Stellarium computes the orientation of earth’s axis according to the IAU2006 Precession in a

long-time variant developed by Vondrák, Capitaine, and Wallace (2011) and Vondrák, Capitaine, and Wallace

(2012), and IAU2000B Nutation (McCarthy and Luzum, 2003). This also now allows proper depiction of

the changes in ecliptic obliquity and display of “instantaneous precession circles” around the ecliptic poles.

These circles are indeed varying according to ecliptical obliquity. Nutation is only computed for about 6000

years around J2000.0. Nobody could have observed it before 1609, and it is unclear for how long this model

is applicable.

F.6 Planet Axes

Where available, Stellarium uses axis orientation and rotation data from the IAU Working Group on

Cartographic Coordinates and Rotational Elements (WGCCRE). Orientation for some small moons is still

simpliﬁed and based on the model originally available. (See section D.2.1.1)

F.7 Eclipses

The moon’s motion is very complicated, and eclipse computations can be tricky. One aspect which every

student of history, prehistory and archaeology should know, but as it seems not every does, is at least a basic

understanding of the irregular slow-down of earth’s rotation known as ∆T (see section 18.4.3).

Eclipse records on cuneiform tablets go back to the 8th century BC, some Chinese records go back a

bit further. Experts on Earth rotation have provided models for

∆T

based on such observations. These are

usually given as parabolic ﬁt, with some recommended time span. Extrapolating parabolic ﬁts to erratic

curves too far into the past is dangerous, pointless and inevitably leads to errors or invalid results. Models

differ by many hours (exceeding a whole day!) when applied too far in the past. This means, there was

certainly an eclipse, and latitude will be OK, but you cannot say which longitude the eclipse was covering.

The probability to have seen a total eclipse at a certain interesting location will be very small and should by

itself not be used as positive argument for any reasonable statement. This is not a problem of Stellarium, but

of current knowledge. To repeat, you may ﬁnd a solar eclipse in the 6th millennium BC, but you cannot even

be sure which side of Earth could have observed it!

WANTED: A model for ∆T that works in the Mesolithic!

F.8 The Calendar

Stellarium follows the widely accepted convention that dates before the Gregorian calendar reform are given

in the Julian calendar, introduced by JULIUS CAESAR in 46 BC. This calendar introduces a leap day every

fourth year, which is a bit too much. If you want to show summer solstice in the year

−2500

, you will notice

it is not on June 21st. This is not an error of Stellarium – the Gregorian reform had a reason! In prehistoric

times, it may be more useful to work with solar ecliptic longitudes. For example, summer solstice is when

the Sun is at λ = 90°.

JULIUS CAESAR introduced a Solar calendar to the Roman empire in 46 BC but was assassinated in

March 44 BC=

−43

(see below). His simple 4-year leap rule was then misapplied by the high priests of Rome

by adding a leap day every third year. A UGUSTUS ﬁxed the calendar by omitting a few leap days, and only

8 AD was the ﬁrst correctly applied leap year as we know them (Ginzel, 1908, §186, §189). Be careful if

you are working in Augustean and earlier times in the Roman world, maybe even related to named dates in

378 Appendix F. Accuracy

the pre-Julian Roman calendar: Stellarium, also its Calendars plugin (see section 13.10), does not model

these issues!

Some authors (esp. for Mesoamerican dates) give dates in the proleptic Gregorian calendar (which means

that they apply the Gregorian leap year rules before 1582). This is a convention, they may of course do that,

but you must do the conversion to the Julian calendar to visualize the sky with Stellarium. If they also give

Julian Day numbers (JD), you can use them with Stellarium as JD numbers are independent from calendar

systems. Otherwise, you can utilize the Calendars plugin (see section 13.10).

Some users have noted and expressed confusion about a difference of one between dates given as

BC (or BCE) versus Stellarium’s negative years. Note that historical chronology does not know a year

Zero! (Try to write this date in Roman numbers!) Year AD 1 (1 CE) was preceded by year 1 BC (1 BCE).

Astronomers want to simplify computations and therefore use a year

(equivalent to 1 BC). It is simple:

1 BC=

, 2 BC=

−1

, . . . 100 BC=

−99

(Fig. F.1). Stellarium is an astronomy program and uses astronomical

counting. Other programs may behave differently in this respect, e.g. may even use negative signs to indicate

years BC. However, the Calendars plugin (see section 13.10) even allows displaying both counting systems.

⇐Ô negative 0 positive Ô⇒

Astronomical

. . . -3 -2 -1 0 1 2 3 . . .

Historical . . . 4 BC 3 BC 2 BC 1 BC AD 1 AD 2 AD 3 . . .

⇐Ô Before Christ After Christ Ô⇒

Figure F.1: Counting years around the beginning of the Common Era.

F.9 Comparison to Reference Data

Tables F.2 and F.3 provide comparison data between JPL Horizons

and Stellarium. The JPL data were

fetched in July 2021 by our attentive user Atque. These are apparent geocentric coordinates provided by

JPL’s solutions DE440/DE441 in J2000.0 equatorial coordinates, including JPL’s corrections for nutation,

light time, aberration, light deﬂection in the Solar gravity ﬁeld, and other relativistic effects. The right part

provides the respective values computed by Stellarium from DE440/DE441 ﬁles, with the current state of

corrections for nutation, light time and aberration. The

∆T

model was set to “JPL Horizons”, but when using

DE* ﬁles a slightly different model specialized to the DE ephemeris is used

, resulting in differences in the

effective value of ∆T . Among the causes for differences we must take into account:

•

Stellarium does not provide corrections for diurnal aberration (should not matter for geocentric

positions)

•

Stellarium does not provide corrections for light deﬂection in the Sun’s gravitational ﬁeld

•

JPL Horizons uses slightly different models than Stellarium for precession and nutation

The ﬁrst item should not make a difference. The next two may cause differences in the range of a few

arcseconds. The apparent drift that we can observe in the remote past may stem from different assumptions

regarding ∆T (see 18.4.3) or from other reasons yet to be identiﬁed. Competent help welcome!

WANTED

If you can trace down hitherto unknown reasons for remaining inaccuracies and either provide a ﬁx or a

decisive hint to us, we can offer a reward in the EUR200–500 range from our donation fund. We, the

developers, will judge and evaluate relevance, legal recourse is excluded.

https://ssd.jpl.nasa.gov/horizons.cgi

For experts: The value for secular acceleration of the Moon in ELP2000-82B,

˙n = −23.8946

, is replaced by

˙n = −25.8.

https://ssd.jpl.nasa.gov/?horizons_doc#specific_quantities

F.9 Comparison to Reference Data 379

Table F.2: An ephemeris comparison between Stellarium and JPL Horizons. Both are

showing geocentric apparent coordinates from the JPL DE440/441 ephemerides (with

slightly different models for precession, nutation and aberration; JPL results are also

corrected for light deﬂection). While results for present times agree very well, results

for the past seem to diverge a bit, presumably caused by differences in ∆T handling.

JPL Horizons (DE440/441) Stellarium 0.21.2β

UT Date Time RA J2000.0 DE J2000.0 α

J2000.0

∆T

SUN

b2500-Jan-01 00:00

17h 24m 24.70s -23° 43’ 11.8” 17h 24m 23.52s -23° 43’ 13.2” 57938.45s

b2500-Jun-02 00:00

03h 06m 17.57s +17° 54’ 00.7” 03h 06m 16.61s +17° 53’ 58.6” 57927.29s

b2500-Nov-01 00:00

13h 11m 48.12s -07° 48’ 17.2” 13h 11m 47.07s -07° 48’ 11.5” 57916.12s

b2499-Apr-02 00:00

23h 26m 28.14s -03° 42’ 34.9” 23h 26m 27.30s -03° 42’ 40.9” 57904.96s

b0500-Jan-01 00:00

18h 25m 28.83s -23° 37’ 22.2” 18h 25m 28.82s -23° 37’ 23.4” 16704.77s

b0500-Jun-02 00:00

04h 09m 13.48s +21° 17’ 20.8” 04h 09m 13.50s +21° 17’ 21.9” 16698.78s

b0500-Nov-01 00:00

14h 04m 26.18s -12° 48’ 35.8” 14h 04m 26.15s -12° 48’ 36.3” 16692.79s

b0499-Apr-02 00:00

00h 21m 10.51s +02° 19’ 31.0” 00h 21m 10.52s +02° 19’ 31.1” 16686.79s

0500-Jan-01 00:00

18h 53m 06.08s -23° 04’ 11.0” 18h 53m 06.04s -23° 04’ 11.8” 5413.20s

0500-Jun-01 00:00

04h 39m 16.40s +22° 19’ 46.7” 04h 39m 16.39s +22° 19’ 47.4” 5409.79s

0500-Oct-31 00:00

14h 29m 26.81s -14° 52’ 19.2” 14h 29m 26.77s -14° 52’ 19.5” 5406.38s

0501-Apr-01 00:00

00h 46m 23.08s +05° 01’ 37.5” 00h 46m 23.07s +05° 01’ 37.6” 5402.97s

0501-Aug-31 00:00

10h 41m 17.14s +08° 22’ 56.8” 10h 41m 17.14s +08° 22’ 57.2” 5399.56s

1600-Jan-01 00:00

18h 43m 28.07s -23° 06’ 56.6” 18h 43m 28.33s -23° 06’ 56.5” 141.31s

1600-Jun-01 00:00

04h 35m 37.18s +22° 04’ 25.0” 04h 35m 37.43s +22° 04’ 25.6” 140.84s

1600-Oct-31 00:00

14h 21m 56.45s -14° 09’ 38.9” 14h 21m 56.68s -14° 09’ 40.1” 140.37s

1601-Apr-01 00:00

00h 41m 18.48s +04° 27’ 19.4” 00h 41m 18.70s +04° 27’ 20.8” 139.90s

1601-Aug-31 00:00

10h 36m 30.29s +08° 48’ 10.8” 10h 36m 30.52s +08° 48’ 09.6” 139.44s

2021-Jan-01 00:00

18h 46m 53.59s -22° 59’ 57.2” 18h 46m 53.59s -22° 59’ 57.2” 65.79s

2021-Jun-02 00:00

04h 40m 40.91s +22° 11’ 09.1” 04h 40m 40.90s +22° 11’ 09.1” 66.11s

2021-Nov-01 00:00

14h 25m 34.78s -14° 25’ 31.0” 14h 25m 34.78s -14° 25’ 30.9” 66.43s

2022-Apr-02 00:00

00h 45m 00.07s +04° 50’ 03.8” 00h 45m 00.07s +04° 50’ 03.7” 66.76s

MERCURY

b2500-Jan-01 00:00

17h 07m 28.00s -25° 22’ 36.2” 17h 07m 24.54s -25° 22’ 33.7” 57938.45s

b2500-Jun-02 00:00

04h 57m 29.05s +22° 59’ 25.2” 04h 57m 28.40s +22° 59’ 34.3” 57927.29s

b2500-Nov-01 00:00

11h 56m 15.20s +03° 10’ 47.5” 11h 56m 14.50s +03° 10’ 55.1” 57916.12s

b2499-Apr-02 00:00

23h 03m 07.53s -07° 14’ 26.7” 23h 03m 04.03s -07° 14’ 56.6” 57904.96s

b0500-Jan-01 00:00

18h 40m 28.21s -25° 26’ 38.0” 18h 40m 27.54s -25° 26’ 40.0” 16704.77s

b0500-Jun-02 00:00

05h 38m 48.42s +22° 19’ 54.2” 05h 38m 49.11s +22° 19’ 58.7” 16698.78s

b0500-Nov-01 00:00

12h 56m 45.19s -03° 57’ 14.5” 12h 56m 44.96s -03° 57’ 12.2” 16692.79s

b0499-Apr-02 00:00

00h 21m 09.78s +01° 53’ 27.6” 00h 21m 08.99s +01° 53’ 20.6” 16686.79s

0500-Jan-01 00:00

18h 23m 39.86s -25° 14’ 04.0” 18h 23m 39.46s -25° 14’ 04.4” 5413.20s

0500-Jun-01 00:00

06h 29m 34.30s +24° 32’ 58.8” 06h 29m 34.21s +24° 33’ 00.8” 5409.79s

0500-Oct-31 00:00

13h 28m 10.47s -06° 51’ 07.8” 13h 28m 10.93s -06° 51’ 11.8” 5406.38s

0501-Apr-01 00:00

23h 55m 15.72s -02° 45’ 50.1” 23h 55m 15.30s -02° 45’ 53.7” 5402.97s

0501-Aug-31 00:00

12h 03m 40.27s -01° 48’ 53.7” 12h 03m 40.10s -01° 48’ 51.4” 5399.56s

1600-Jan-01 00:00

19h 16m 55.37s -24° 27’ 04.8” 19h 16m 55.69s -24° 27’ 04.5” 141.31s

1600-Jun-01 00:00

05h 27m 00.75s +22° 06’ 49.9” 05h 27m 00.88s +22° 06’ 49.8” 140.84s

1600-Oct-31 00:00

13h 24m 30.87s -06° 45’ 17.1” 13h 24m 31.13s -06° 45’ 18.8” 140.37s

1601-Apr-01 00:00

00h 45m 30.34s +03° 58’ 05.0” 00h 45m 30.64s +03° 58’ 07.2” 139.90s

1601-Aug-31 00:00

12h 08m 26.65s -04° 19’ 14.8” 12h 08m 26.83s -04° 19’ 16.2” 139.44s

2021-Jan-01 00:00

19h 17m 59.43s -24° 20’ 58.1” 19h 17m 59.41s -24° 20’ 58.2” 65.79s

2021-Jun-02 00:00

05h 35m 35.59s +22° 40’ 50.7” 05h 35m 35.59s +22° 40’ 50.7” 66.11s

2021-Nov-01 00:00

13h 25m 55.55s -06° 47’ 18.8” 13h 25m 55.54s -06° 47’ 18.7” 66.43s

2022-Apr-02 00:00

00h 43m 05.35s +03° 21’ 44.7” 00h 43m 05.34s +03° 21’ 44.7” 66.76s

VENUS

b2500-Jan-01 00:00

14h 38m 40.01s -10° 33’ 46.3” 14h 38m 40.01s -10° 33’ 46.8” 57938.45s

b2500-Jun-02 00:00

01h 31m 36.91s +08° 30’ 50.3” 01h 31m 35.42s +08° 30’ 41.0” 57927.29s

b2500-Nov-01 00:00

14h 04m 33.57s -13° 23’ 07.7” 14h 04m 31.93s -13° 22’ 58.4” 57916.12s

b2499-Apr-02 00:00

02h 07m 22.90s +16° 14’ 49.7” 02h 07m 21.78s +16° 14’ 43.3” 57904.96s

b0500-Jan-01 00:00

15h 15m 48.26s -13° 58’ 19.4” 15h 15m 48.35s -13° 58’ 20.3” 16704.77s

b0500-Jun-02 00:00

02h 41m 50.72s +14° 49’ 02.0” 02h 41m 50.54s +14° 49’ 01.5” 16698.78s

b0500-Nov-01 00:00

15h 14m 41.57s -18° 52’ 17.3” 15h 14m 41.35s -18° 52’ 16.9” 16692.79s

b0499-Apr-02 00:00

03h 10m 27.71s +21° 27’ 17.2” 03h 10m 27.72s +21° 27’ 17.6” 16686.79s

0500-Jan-01 00:00

20h 18m 43.11s -15° 30’ 09.1” 20h 18m 43.83s -15° 30’ 09.4” 5413.20s

0500-Jun-01 00:00

02h 11m 10.44s +11° 10’ 10.0” 02h 11m 10.33s +11° 10’ 09.7” 5409.79s

0500-Oct-31 00:00

14h 33m 32.68s -14° 39’ 03.4” 14h 33m 32.50s -14° 39’ 02.8” 5406.38s

0501-Apr-01 00:00

03h 03m 13.09s +18° 47’ 05.5” 03h 03m 12.97s +18° 47’ 05.1” 5402.97s

0501-Aug-31 00:00

09h 10m 52.83s +08° 18’ 44.4” 09h 10m 53.44s +08° 18’ 40.8” 5399.56s

1600-Jan-01 00:00

17h 09m 26.57s -18° 08’ 55.1” 17h 09m 26.71s -18° 08’ 55.3” 141.31s

1600-Jun-01 00:00

02h 28m 53.12s +12° 50’ 48.1” 02h 28m 53.37s +12° 50’ 49.4” 140.84s

1600-Oct-31 00:00

14h 54m 13.53s -16° 15’ 03.3” 14h 54m 13.79s -16° 15’ 04.6” 140.37s

1601-Apr-01 00:00

03h 18m 37.64s +20° 06’ 01.5” 03h 18m 37.90s +20° 06’ 02.6” 139.90s

380 Appendix F. Accuracy

JPL Horizons (DE440/441) Stellarium 0.21.2β

UT Date Time RA J2000.0 DE J2000.0 α

J2000.0

∆T

1601-Aug-31 00:00 07h 48m 52.93s +16° 06’ 13.5” 07h 48m 53.14s +16° 06’ 13.3” 139.44s

2021-Jan-01 00:00

17h 18m 28.43s -22° 26’ 01.6” 17h 18m 28.42s -22° 26’ 01.5” 65.79s

2021-Jun-02 00:00

05h 57m 01.46s +24° 21’ 39.2” 05h 57m 01.45s +24° 21’ 39.2” 66.11s

2021-Nov-01 00:00

17h 40m 41.73s -27° 05’ 05.3” 17h 40m 41.73s -27° 05’ 05.3” 66.43s

2022-Apr-02 00:00

21h 52m 25.36s -12° 04’ 41.5” 21h 52m 25.35s -12° 04’ 41.5” 66.76s

MOON

b2500-Jan-01 00:00

00h 13m 40.60s -00° 43’ 59.3” 00h 13m 13.41s -00° 47’ 44.2” 57938.45s

b2500-Jun-02 00:00

12h 48m 51.83s -04° 50’ 11.6” 12h 48m 20.00s -04° 45’ 50.3” 57927.29s

b2500-Nov-01 00:00

02h 49m 20.95s +19° 57’ 17.4” 02h 48m 49.83s +19° 54’ 22.0” 57916.12s

b2499-Apr-02 00:00

15h 45m 48.47s -25° 00’ 31.4” 15h 45m 11.61s -24° 58’ 11.1” 57904.96s

b0500-Jan-01 00:00

02h 14m 28.99s +14° 10’ 37.4” 02h 14m 20.11s +14° 10’ 05.8” 16704.77s

b0500-Jun-02 00:00

15h 02m 34.83s -16° 05’ 08.5” 15h 02m 24.07s -16° 04’ 39.3” 16698.78s

b0500-Nov-01 00:00

05h 18m 41.70s +19° 00’ 42.7” 05h 18m 32.17s +19° 00’ 41.6” 16692.79s

b0499-Apr-02 00:00

18h 10m 41.75s -18° 33’ 49.1” 18h 10m 31.22s -18° 33’ 56.3” 16686.79s

0500-Jan-01 00:00

05h 33m 09.71s +28° 18’ 25.7” 05h 33m 02.93s +28° 18’ 25.0” 5413.20s

0500-Jun-01 00:00

19h 39m 46.24s -24° 36’ 20.7” 19h 39m 38.25s -24° 36’ 48.8” 5409.79s

0500-Oct-31 00:00

08h 41m 09.22s +19° 42’ 14.7” 08h 41m 03.32s +19° 42’ 46.3” 5406.38s

0501-Apr-01 00:00

22h 26m 23.71s -07° 51’ 05.2” 22h 26m 17.20s -07° 51’ 54.1” 5402.97s

0501-Aug-31 00:00

11h 28m 24.37s -00° 41’ 25.5” 11h 28m 19.05s -00° 40’ 44.2” 5399.56s

1600-Jan-01 00:00

07h 04m 55.02s +24° 04’ 37.3” 07h 04m 56.39s +24° 04’ 33.9” 141.31s

1600-Jun-01 00:00

19h 54m 15.59s -20° 26’ 36.3” 19h 54m 16.89s -20° 26’ 31.4” 140.84s

1600-Oct-31 00:00

10h 11m 24.53s +07° 13’ 09.4” 10h 11m 25.66s +07° 13’ 02.2” 140.37s

1601-Apr-01 00:00

22h 46m 21.63s -02° 54’ 30.7” 22h 46m 22.87s -02° 54’ 22.4” 139.90s

1601-Aug-31 00:00

12h 52m 10.20s -10° 52’ 36.0” 12h 52m 11.39s -10° 52’ 43.0” 139.44s

2021-Jan-01 00:00

08h 23m 36.67s +23° 01’ 21.2” 08h 23m 36.54s +23° 01’ 21.5” 65.79s

2021-Jun-02 00:00

22h 46m 54.03s -13° 27’ 21.8” 22h 46m 53.93s -13° 27’ 22.4” 66.11s

2021-Nov-01 00:00

11h 18m 43.58s +09° 57’ 42.8” 11h 18m 43.49s +09° 57’ 43.4” 66.43s

2022-Apr-02 00:00

01h 21m 51.21s +05° 40’ 00.7” 01h 21m 51.14s +05° 40’ 00.1” 66.76s

MARS

1601-Jan-01 00:00

19h 26m 56.21s -23° 01’ 42.7” 19h 26m 56.45s -23° 01’ 42.4” 140.18s

1601-Jun-02 00:00

02h 59m 06.93s +16° 41’ 21.5” 02h 59m 07.15s +16° 41’ 22.6” 139.71s

1601-Nov-01 00:00

09h 48m 48.55s +15° 01’ 38.0” 09h 48m 48.75s +15° 01’ 37.2” 139.25s

1602-Apr-02 00:00

10h 25m 38.57s +13° 17’ 29.7” 10h 25m 38.70s +13° 17’ 29.0” 138.78s

2021-Jan-01 00:00

01h 40m 18.14s +11° 20’ 41.2” 01h 40m 18.14s +11° 20’ 41.1” 65.79s

2021-Jun-02 00:00

07h 45m 03.73s +22° 37’ 21.0” 07h 45m 03.72s +22° 37’ 21.0” 66.11s

2021-Nov-01 00:00

13h 55m 54.00s -11° 22’ 08.1” 13h 55m 54.00s -11° 22’ 08.1” 66.43s

2022-Apr-02 00:00

21h 31m 33.53s -15° 56’ 58.5” 21h 31m 33.53s -15° 56’ 58.5” 66.76s

JUPITER

1601-Jan-01 00:00

11h 33m 23.43s +04° 18’ 09.3” 11h 33m 23.58s +04° 18’ 08.4” 140.18s

1601-Jun-02 00:00

10h 59m 49.52s +07° 52’ 18.0” 10h 59m 49.67s +07° 52’ 17.1” 139.71s

1601-Nov-01 00:00

12h 39m 41.32s -03° 02’ 14.3” 12h 39m 41.47s -03° 02’ 15.3” 139.25s

1602-Apr-02 00:00

13h 08m 44.17s -05° 35’ 33.6” 13h 08m 44.30s -05° 35’ 34.4” 138.78s

2021-Jan-01 00:00

20h 20m 44.62s -20° 00’ 44.3” 20h 20m 44.62s -20° 00’ 44.4” 65.79s

2021-Jun-02 00:00

22h 15m 51.65s -11° 42’ 45.3” 22h 15m 51.65s -11° 42’ 45.3” 66.11s

2021-Nov-01 00:00

21h 41m 29.27s -15° 01’ 08.9” 21h 41m 29.27s -15° 01’ 08.9” 66.43s

2022-Apr-02 00:00

23h 30m 29.23s -04° 17’ 08.2” 23h 30m 29.24s -04° 17’ 08.2” 66.76s

SATURN

1750-Jan-01 00:00

15h 46m 12.27s -17° 54’ 37.7” 15h 46m 12.37s -17° 54’ 38.1” 22.71s

1750-Jun-02 00:00

15h 44m 23.78s -17° 34’ 00.9” 15h 44m 23.87s -17° 34’ 01.3” 22.52s

1750-Nov-01 00:00

15h 59m 19.00s -18° 50’ 41.0” 15h 59m 19.10s -18° 50’ 41.4” 22.34s

1751-Apr-02 00:00

16h 49m 11.72s -20° 39’ 30.2” 16h 49m 11.82s -20° 39’ 30.5” 22.15s

2021-Jan-01 00:00

20h 15m 50.41s -20° 10’ 28.7” 20h 15m 50.41s -20° 10’ 28.7” 65.79s

2021-Jun-02 00:00

21h 04m 25.24s -17° 24’ 46.6” 21h 04m 25.24s -17° 24’ 46.6” 66.11s

2021-Nov-01 00:00

20h 39m 27.72s -19° 14’ 59.7” 20h 39m 27.72s -19° 14’ 59.7” 66.43s

2022-Apr-02 00:00

21h 39m 14.50s -15° 01’ 42.2” 21h 39m 14.50s -15° 01’ 42.2” 66.76s

URANUS

1600-Jan-01 00:00

01h 41m 51.34s +10° 01’ 26.1” 01h 41m 51.49s +10° 01’ 26.9” 141.31s

1600-Jun-01 00:00

02h 05m 21.58s +12° 13’ 45.6” 02h 05m 21.73s +12° 13’ 46.4” 140.84s

1600-Oct-31 00:00

02h 04m 09.95s +12° 05’ 39.9” 02h 04m 10.09s +12° 05’ 40.7” 140.37s

1601-Apr-01 00:00

02h 07m 08.63s +12° 25’ 31.5” 02h 07m 08.78s +12° 25’ 32.4” 139.90s

1601-Aug-31 00:00

02h 28m 09.10s +14° 11’ 23.3” 02h 28m 09.24s +14° 11’ 24.1” 139.44s

2021-Jan-01 00:00

02h 18m 27.82s +13° 21’ 27.5” 02h 18m 27.83s +13° 21’ 27.5” 65.79s

2021-Jun-02 00:00

02h 40m 37.83s +15° 11’ 44.7” 02h 40m 37.84s +15° 11’ 44.7” 66.11s

2021-Nov-01 00:00

02h 42m 31.60s +15° 19’ 13.5” 02h 42m 31.60s +15° 19’ 13.5” 66.43s

2022-Apr-02 00:00

02h 42m 25.31s +15° 22’ 19.7” 02h 42m 25.31s +15° 22’ 19.7” 66.76s

NEPTUNE

1801-Jan-01 00:00

15h 07m 04.41s -15° 44’ 47.2” 15h 07m 04.49s -15° 44’ 47.6” 5.51s

1801-Jun-02 00:00

15h 01m 57.08s -15° 18’ 05.9” 15h 01m 57.15s -15° 18’ 06.2” 5.42s

1801-Nov-01 00:00

15h 07m 02.36s -15° 46’ 26.5” 15h 07m 02.43s -15° 46’ 26.9” 5.33s

1802-Apr-02 00:00

15h 17m 01.46s -16° 20’ 15.8” 15h 17m 01.54s -16° 20’ 16.2” 5.24s

F.9 Comparison to Reference Data 381

JPL Horizons (DE440/441) Stellarium 0.21.2β

UT Date Time RA J2000.0 DE J2000.0 α

J2000.0

∆T

2021-Jan-01 00:00 23h 19m 18.38s -05° 33’ 12.4” 23h 19m 18.39s -05° 33’ 12.4” 65.79s

2021-Jun-02 00:00

23h 36m 13.26s -03° 46’ 42.9” 23h 36m 13.26s -03° 46’ 42.9” 66.11s

2021-Nov-01 00:00

23h 27m 30.35s -04° 46’ 19.7” 23h 27m 30.35s -04° 46’ 19.7” 66.43s

2022-Apr-02 00:00

23h 38m 17.59s -03° 34’ 19.0” 23h 38m 17.59s -03° 34’ 19.0” 66.76s

IO(JI)

1601-Jan-01 00:00

11h 33m 30.36s +04° 17’ 19.7” 11h 33m 30.51s +04° 17’ 18.9” 140.18s

1601-Jun-02 00:00

10h 59m 55.45s +07° 51’ 35.7” 10h 59m 55.61s +07° 51’ 34.8” 139.71s

1601-Nov-01 00:00

12h 39m 41.63s -03° 02’ 20.8” 12h 39m 41.81s -03° 02’ 22.0” 139.25s

1602-Apr-02 00:00

13h 08m 39.94s -05° 35’ 12.3” 13h 08m 40.11s -05° 35’ 13.4” 138.78s

2021-Jan-01 00:00

20h 20m 41.43s -20° 00’ 57.7” 20h 20m 41.43s -20° 00’ 57.7” 65.79s

2021-Jun-02 00:00

22h 15m 44.01s -11° 43’ 33.2” 22h 15m 44.01s -11° 43’ 33.2” 66.11s

2021-Nov-01 00:00

21h 41m 21.65s -15° 01’ 52.3” 21h 41m 21.65s -15° 01’ 52.3” 66.43s

2022-Apr-02 00:00

23h 30m 27.92s -04° 17’ 20.4” 23h 30m 27.93s -04° 17’ 20.4” 66.76s

EUROPA(JII)

1601-Jan-01 00:00

11h 33m 16.17s +04° 19’ 07.1” 11h 33m 16.29s +04° 19’ 06.3” 140.18s

1601-Jun-02 00:00

10h 59m 53.24s +07° 51’ 59.3” 10h 59m 53.37s +07° 51’ 58.7” 139.71s

1601-Nov-01 00:00

12h 39m 49.09s -03° 03’ 11.4” 12h 39m 49.26s -03° 03’ 12.3” 139.25s

1602-Apr-02 00:00

13h 08m 40.13s -05° 35’ 20.4” 13h 08m 40.28s -05° 35’ 21.3” 138.78s

2021-Jan-01 00:00

20h 20m 34.16s -20° 01’ 24.9” 20h 20m 34.16s -20° 01’ 24.9” 65.79s

2021-Jun-02 00:00

22h 15m 55.57s -11° 42’ 23.5” 22h 15m 55.57s -11° 42’ 23.5” 66.11s

2021-Nov-01 00:00

21h 41m 41.68s -14° 59’ 58.2” 21h 41m 41.68s -14° 59’ 58.2” 66.43s

2022-Apr-02 00:00

23h 30m 29.10s -04° 17’ 03.2” 23h 30m 29.11s -04° 17’ 03.3” 66.76s

GANYMEDE(JIII)

1601-Jan-01 00:00

11h 33m 29.35s +04° 17’ 17.1” 11h 33m 29.49s +04° 17’ 16.2” 140.18s

1601-Jun-02 00:00

11h 00m 04.63s +07° 50’ 38.0” 11h 00m 04.78s +07° 50’ 37.2” 139.71s

1601-Nov-01 00:00

12h 39m 41.91s -03° 02’ 07.8” 12h 39m 42.07s -03° 02’ 08.7” 139.25s

1602-Apr-02 00:00

13h 08m 24.28s -05° 33’ 17.7” 13h 08m 24.40s -05° 33’ 18.6” 138.78s

2021-Jan-01 00:00

20h 20m 33.16s -20° 01’ 30.9” 20h 20m 33.15s -20° 01’ 30.9” 65.79s

2021-Jun-02 00:00

22h 15m 57.19s -11° 42’ 07.4” 22h 15m 57.19s -11° 42’ 07.5” 66.11s

2021-Nov-01 00:00

21h 41m 47.81s -14° 59’ 25.0” 21h 41m 47.82s -14° 59’ 25.0” 66.43s

2022-Apr-02 00:00

23h 30m 31.22s -04° 17’ 01.0” 23h 30m 31.23s -04° 17’ 01.0” 66.76s

CALLISTO(JIV)

1601-Jan-01 00:00

11h 33m 15.59s +04° 19’ 21.5” 11h 33m 15.73s +04° 19’ 20.6” 140.18s

1601-Jun-02 00:00

10h 59m 22.98s +07° 55’ 21.8” 10h 59m 23.12s +07° 55’ 20.9” 139.71s

1601-Nov-01 00:00

12h 39m 17.32s -02° 59’ 27.6” 12h 39m 17.47s -02° 59’ 28.8” 139.25s

1602-Apr-02 00:00

13h 08m 09.98s -05° 32’ 01.2” 13h 08m 10.10s -05° 32’ 02.1” 138.78s

2021-Jan-01 00:00

20h 20m 42.72s -20° 00’ 56.3” 20h 20m 42.73s -20° 00’ 56.3” 65.79s

2021-Jun-02 00:00

22h 15m 55.40s -11° 42’ 15.1” 22h 15m 55.41s -11° 42’ 15.1” 66.11s

2021-Nov-01 00:00

21h 41m 58.24s -14° 58’ 23.9” 21h 41m 58.25s -14° 58’ 23.9” 66.43s

2022-Apr-02 00:00

23h 30m 53.15s -04° 14’ 15.0” 23h 30m 53.15s -04° 14’ 15.0” 66.76s

Table F.3: An ephemeris comparison between Stellarium and JPL Horizons, based on JPL

DE440/441. Both are showing geocentric apparent coordinates (with slightly different

models for precession, nutation and aberration; JPL results are also corrected for light

deﬂection). This table shows ephemeris comparison in Dynamical time (TT), to avoid

showing divergences which are only caused by differences in

∆T

handling. (JPL’s values

for ∆T are listed for reference, but not used.)

JPL Horizons Stellarium 0.21.2β

TT Date Time RA J2000.0 DE J2000.0 ∆T α

J2000.0

SUN

b2500-Jan-01 00:00

17h21m25.18s -23°40’30.1” 58893.015756s 17h21m26.91s -23°40’34.2”

b2500-Jun-02 00:00

03h03m40.51s +17°43’04.0” 58881.693980s 03h03m42.09s +17°43’12.5”

b2500-Nov-01 00:00

13h09m12.65s -07°32’06.5” 58870.373294s 13h09m14.12s -07°32’16.5”

b2499-Apr-02 00:00

23h24m04.53s -03°58’17.6” 58859.053698s 23h24m06.02s -03°58’08.4”

b0500-Jan-01 00:00

18h24m36.63s -23°37’53.7” 16988.259557s 18h24m37.49s -23°37’54.4”

b0500-Jun-02 00:00

04h08m26.19s +21°15’14.4” 16982.002779s 04h08m26.99s +21°15’17.6”

b0500-Nov-01 00:00

14h03m40.03s -12°44’27.5” 16975.747099s 14h03m40.76s -12°44’32.1”

b0499-Apr-02 00:00

00h20m28.76s +02°14’57.0” 16969.492518s 00h20m29.48s +02°15’01.7”

0500-Jan-01 00:00

18h52m48.93s -23°04’32.9” 5608.981515s 18h52m49.49s -23°04’32.9”

0500-Jun-01 00:00

04h39m00.52s +22°19’15.9” 5605.028887s 04h39m01.07s +22°19’17.7”

0500-Oct-31 00:00

14h29m11.35s -14°51’03.8” 5601.076499s 14h29m11.84s -14°51’06.7”

0501-Apr-01 00:00

00h46m09.14s +05°00’08.5” 5597.124355s 00h46m09.61s +05°00’11.6”

0501-Aug-31 00:00

10h41m02.87s +08°24’23.2” 5593.172456s 10h41m03.36s +08°24’20.5”

1600-Jan-01 00:00

18h43m27.73s -23°06’56.9” 110.462079s 18h43m27.90s -23°06’57.0”

1600-Jun-01 00:00

04h35m36.87s +22°04’24.3” 109.804702s 04h35m37.03s +22°04’24.8”

1600-Oct-31 00:00

14h21m56.15s -14°09’37.4” 109.148794s 14h21m56.30s -14°09’38.2”

1601-Apr-01 00:00

00h41m18.21s +04°27’17.7” 108.494367s 00h41m18.35s +04°27’18.6”

382 Appendix F. Accuracy

JPL Horizons Stellarium 0.21.2β

TT Date Time RA J2000.0 DE J2000.0 ∆T α

J2000.0

1601-Aug-31 00:00 10h36m30.02s +08°48’12.4” 107.841429s 10h36m30.16s +08°48’11.7”

MERCURY

b2500-Jan-01 00:00

17h02m08.10s -25°14’54.4” 58893.015756s 17h02m09.83s -25°14’59.3”

b2500-Jun-02 00:00

04h55m00.41s +23°03’30.5” 58881.693980s 04h55m02.12s +23°03’35.5”

b2500-Nov-01 00:00

11h54m04.49s +03°27’59.5” 58870.373294s 11h54m05.97s +03°27’49.8”

b2499-Apr-02 00:00

22h57m59.14s -07°54’02.4” 58859.053698s 22h58m00.66s -07°53’53.6”

b0500-Jan-01 00:00

18h38m56.17s -25°28’13.0” 16988.259557s 18h38m57.04s -25°28’13.3”

b0500-Jun-02 00:00

05h38m38.91s +22°22’48.0” 16982.002779s 05h38m39.75s +22°22’49.6”

b0500-Nov-01 00:00

12h55m48.65s -03°50’09.1” 16975.747099s 12h55m49.37s -03°50’13.9”

b0499-Apr-02 00:00

00h19m39.97s +01°41’26.3” 16969.492518s 00h19m40.68s +01°41’31.2”

0500-Jan-01 00:00

18h23m11.76s -25°14’05.2” 5608.981515s 18h23m12.34s -25°14’05.6”

0500-Jun-01 00:00

06h29m15.56s +24°33’46.9” 5605.028887s 06h29m16.13s +24°33’47.2”

0500-Oct-31 00:00

13h28m09.82s -06°51’31.3” 5601.076499s 13h28m10.29s -06°51’34.4”

0501-Apr-01 00:00

23h54m49.90s -02°49’01.2” 5597.124355s 23h54m50.38s -02°48’58.1”

0501-Aug-31 00:00

12h03m21.92s -01°46’20.3” 5593.172456s 12h03m22.39s -01°46’23.4”

1600-Jan-01 00:00

19h16m54.82s -24°27’05.8” 110.462079s 19h16m54.99s -24°27’05.7”

1600-Jun-01 00:00

05h27m00.83s +22°06’51.2” 109.804702s 05h27m01.00s +22°06’51.5”

1600-Oct-31 00:00

13h24m30.45s -06°45’14.3” 109.148794s 13h24m30.59s -06°45’15.2”

1601-Apr-01 00:00

00h45m29.79s +03°58’00.7” 108.494367s 00h45m29.92s +03°58’01.7”

1601-Aug-31 00:00

12h08m26.49s -04°19’13.1” 107.841429s 12h08m26.63s -04°19’14.0”

VENUS

b2500-Jan-01 00:00

14h37m07.30s -10°25’08.5” 58893.015756s 14h37m08.81s -10°25’17.6”

b2500-Jun-02 00:00

01h28m34.06s +08°11’02.7” 58881.693980s 01h28m35.54s +08°11’12.6”

b2500-Nov-01 00:00

14h01m18.60s -13°03’41.8” 58870.373294s 14h01m20.11s -13°03’51.3”

b2499-Apr-02 00:00

02h04m39.28s +15°58’24.8” 58859.053698s 02h04m40.81s +15°58’34.2”

b0500-Jan-01 00:00

15h15m08.22s -13°55’20.5” 16988.259557s 15h15m08.98s -13°55’24.4”

b0500-Jun-02 00:00

02h40m55.02s +14°44’15.5” 16982.002779s 02h40m55.77s +14°44’19.8”

b0500-Nov-01 00:00

15h13m42.04s -18°47’53.8” 16975.747099s 15h13m42.82s -18°47’57.7”

b0499-Apr-02 00:00

03h09m40.90s +21°23’39.0” 16969.492518s 03h09m41.68s +21°23’43.0”

0500-Jan-01 00:00

20h18m48.52s -15°30’50.9” 5608.981515s 20h18m49.05s -15°30’49.8”

0500-Jun-01 00:00

02h10m53.15s +11°08’35.0” 5605.028887s 02h10m53.64s +11°08’38.0”

0500-Oct-31 00:00

14h33m13.65s -14°37’22.9” 5601.076499s 14h33m14.14s -14°37’25.8”

0501-Apr-01 00:00

03h02m54.73s +18°45’37.5” 5597.124355s 03h02m55.25s +18°45’40.1”

0501-Aug-31 00:00

09h10m56.37s +08°17’52.4” 5593.172456s 09h10m56.87s +08°17’50.6”

1600-Jan-01 00:00

17h09m26.64s -18°08’55.7” 110.462079s 17h09m26.80s -18°08’56.1”

1600-Jun-01 00:00

02h28m52.77s +12°50’46.3” 109.804702s 02h28m52.92s +12°50’47.1”

1600-Oct-31 00:00

14h54m13.16s -16°15’01.5” 109.148794s 14h54m13.31s -16°15’02.3”

1601-Apr-01 00:00

03h18m37.29s +20°05’59.9” 108.494367s 03h18m37.45s +20°06’00.6”

1601-Aug-31 00:00

07h48m52.75s +16°06’13.4” 107.841429s 07h48m52.90s +16°06’13.2”

MOON

b2500-Jan-01 00:00

23h43m54.13s -04°46’15.6” 58893.015756s 23h43m55.61s -04°46’06.1”

b2500-Jun-02 00:00

12h15m08.68s -00°12’02.6” 58881.693980s 12h15m10.14s -00°12’12.5”

b2500-Nov-01 00:00

02h16m07.77s +16°35’31.3” 58870.373294s 02h16m09.31s +16°35’40.6”

b2499-Apr-02 00:00

15h07m11.31s -22°11’27.1” 58859.053698s 15h07m12.93s -22°11’35.4”

b0500-Jan-01 00:00

02h04m52.71s +13°33’43.2” 16988.259557s 02h04m53.45s +13°33’47.8”

b0500-Jun-02 00:00

14h51m07.34s -15°30’50.9” 16982.002779s 14h51m08.09s -15°30’55.1”

b0500-Nov-01 00:00

05h08m19.28s +18°56’30.3” 16975.747099s 05h08m20.10s +18°56’32.5”

b0499-Apr-02 00:00

17h59m21.65s -18°38’44.9” 16969.492518s 17h59m22.47s -18°38’46.1”

0500-Jan-01 00:00

05h29m38.64s +28°17’23.7” 5608.981515s 05h29m39.22s +28°17’24.9”

0500-Jun-01 00:00

19h35m39.76s -24°49’55.2” 5605.028887s 19h35m40.33s -24°49’54.6”

0500-Oct-31 00:00

08h38m03.41s +19°57’58.9” 5601.076499s 08h38m03.95s +19°57’57.5”

0501-Apr-01 00:00

22h23m01.61s -08°15’47.6” 5597.124355s 22h23m02.11s -08°15’45.1”

0501-Aug-31 00:00

11h25m37.06s -00°20’06.1” 5593.172456s 11h25m37.53s -00°20’09.0”

1600-Jan-01 00:00

07h04m50.63s +24°04’49.5” 110.462079s 07h04m50.78s +24°04’49.4”

1600-Jun-01 00:00

19h54m11.52s -20°26’52.9” 109.804702s 19h54m11.67s -20°26’52.7”

1600-Oct-31 00:00

10h11m21.07s +07°13’32.6” 109.148794s 10h11m21.20s +07°13’32.0”

1601-Apr-01 00:00

22h46m17.79s -02°54’56.8” 108.494367s 22h46m17.91s -02°54’56.1”

1601-Aug-31 00:00

12h52m06.59s -10°52’15.0” 107.841429s 12h52m06.72s -10°52’15.8”

MARS

1601-Jan-01 00:00

19h26m55.96s -23°01’43.2” 108.881677s 19h26m56.12s -23°01’43.1”

1601-Jun-02 00:00

02h59m06.71s +16°41’20.6” 108.227856s 02h59m06.87s +16°41’21.3”

1601-Nov-01 00:00

09h48m48.40s +15°01’38.7” 107.575530s 09h48m48.55s +15°01’38.1”

1602-Apr-02 00:00

10h25m38.61s +13°17’29.7” 106.924708s 10h25m38.76s +13°17’28.9”

JUPITER

1601-Jan-01 00:00

11h33m23.43s +04°18’09.3” 108.881677s 11h33m23.57s +04°18’08.4”

1601-Jun-02 00:00

10h59m49.50s +07°52’18.1” 108.227856s 10h59m49.64s +07°52’17.3”

1601-Nov-01 00:00

12h39m41.26s -03°02’14.0” 107.575530s 12h39m41.40s -03°02’14.9”

1602-Apr-02 00:00

13h08m44.21s -05°35’33.8” 106.924708s 13h08m44.34s -05°35’34.7”

SATURN

1750-Jan-01 00:00 15h46m12.26s -17°54’37.7” 17.322273s 15h46m12.36s -17°54’38.1”

F.9 Comparison to Reference Data 383

JPL Horizons Stellarium 0.21.2β

TT Date Time RA J2000.0 DE J2000.0 ∆T α

J2000.0

1750-Jun-02 00:00 15h44m23.78s -17°34’00.9” 17.413029s 15h44m23.88s -17°34’01.3”

1750-Nov-01 00:00

15h59m18.99s -18°50’41.0” 17.503706s 15h59m19.09s -18°50’41.4”

1751-Apr-02 00:00

16h49m11.73s -20°39’30.2” 17.594270s 16h49m11.82s -20°39’30.5”

URANUS

1600-Jan-01 00:00

01h41m51.35s +10°01’26.1” 110.462079s 01h41m51.49s +10°01’26.9”

1600-Jun-01 00:00

02h05m21.56s +12°13’45.5” 109.804702s 02h05m21.71s +12°13’46.3”

1600-Oct-31 00:00

02h04m09.96s +12°05’40.0” 109.148794s 02h04m10.11s +12°05’40.8”

1601-Apr-01 00:00

02h07m08.61s +12°25’31.4” 108.494367s 02h07m08.76s +12°25’32.3”

1601-Aug-31 00:00

02h28m09.10s +14°11’23.3” 107.841429s 02h28m09.25s +14°11’24.1”

NEPTUNE

1801-Jan-01 00:00

15h07m04.41s -15°44’47.2” 18.261920s 15h07m04.49s -15°44’47.6”

1801-Jun-02 00:00

15h01m57.08s -15°18’05.9” 18.107889s 15h01m57.15s -15°18’06.3”

1801-Nov-01 00:00

15h07m02.35s -15°46’26.5” 17.952783s 15h07m02.43s -15°46’26.9”

1802-Apr-02 00:00

15h17m01.46s -16°20’15.8” 17.797431s 15h17m01.54s -16°20’16.2”

IO(JI)

1601-Jan-01 00:00

11h33m30.35s +04°17’19.8” 108.881677s 11h33m30.50s +04°17’18.9”

1601-Jun-02 00:00

10h59m55.42s +07°51’35.9” 108.227856s 10h59m55.57s +07°51’35.0”

1601-Nov-01 00:00

12h39m41.55s -03°02’20.3” 107.575530s 12h39m41.71s -03°02’21.4”

1602-Apr-02 00:00

13h08m39.95s -05°35’12.3” 106.924708s 13h08m40.11s -05°35’13.4”

EUROPA(JII)

1601-Jan-01 00:00

11h33m16.18s +04°19’07.0” 108.881677s 11h33m16.31s +04°19’06.2”

1601-Jun-02 00:00

10h59m53.24s +07°51’59.3” 108.227856s 10h59m53.38s +07°51’58.6”

1601-Nov-01 00:00

12h39m49.02s -03°03’11.0” 107.575530s 12h39m49.17s -03°03’11.8”

1602-Apr-02 00:00

13h08m40.14s -05°35’20.5” 106.924708s 13h08m40.29s -05°35’21.4”

GANYMEDE(JIII)

1601-Jan-01 00:00

11h33m29.32s +04°17’17.3” 108.881677s 11h33m29.46s +04°17’16.4”

1601-Jun-02 00:00

11h00m04.62s +07°50’38.1” 108.227856s 11h00m04.77s +07°50’37.3”

1601-Nov-01 00:00

12h39m41.87s -03°02’07.5” 107.575530s 12h39m42.01s -03°02’08.4”

1602-Apr-02 00:00

13h08m24.32s -05°33’17.9” 106.924708s 13h08m24.46s -05°33’18.9”

CALLISTO(JIV)

1601-Jan-01 00:00

11h33m15.60s +04°19’21.4” 108.881677s 11h33m15.74s +04°19’20.5”

1601-Jun-02 00:00

10h59m22.96s +07°55’21.9” 108.227856s 10h59m23.10s +07°55’21.0”

1601-Nov-01 00:00

12h39m17.27s -02°59’27.3” 107.575530s 12h39m17.41s -02°59’28.3”

1602-Apr-02 00:00

13h08m10.01s -05°32’01.4” 106.924708s 13h08m10.14s -05°32’02.4”

G. GNU Free Documentation License

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G.4 COPYING IN QUANTITY 387

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G.7 COLLECTIONS OF DOCUMENTS 389

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390 Appendix G. GNU Free Documentation License

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G.12 RELICENSING

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H. Acknowledgements

H.1 Contributors to this User Guide

When not listed as chapter authors, the following were the main contributors to the User Guide, mostly for

versions before V0.15:

Matthew Gates

Primary author of the ﬁrst User Guide (versions 0.9 to 0.12)

Paul Robinson Sky guide; exercise ideas

Andras Mohari

Celestial sphere diagrams; numerous corrections

Rudy Gobits, Dirk Schwarzhans

Mac platform speciﬁcs

Barry Gerdes (†2014)

Windows platform speciﬁcs

Customisation of .fab ﬁles

Documentation Maintainer up to V0.12

Sigma

Japanese translation; many corrections

Richard Powell

Figure 19.3 (colour/magnitude diagram) is a modiﬁcation

of his diagram; he kindly granted permission for it to be

distributed under the FDL

John Twin

Many spelling corrections

Georg Zotti Lead author of the 0.15+ editions

Alexander Wolf

New layout, many contributions for the 0.15+ editions

The rest of the Stellarium developer team

You know who you are. . . :-)

Additional material has been incorporated into the guide from sources that are published under the GNU

FDL, including material from Wikipedia and the Astronomy book at Wikibooks.

H.2 Developers

Stellarium is not a company. It is a project created by a community of amateur and professional astronomers,

software engineers, 3D graphics experts, cultural astronomers and experts in other related ﬁelds. Together

we created something unique.

H.2.1 Developers

Project coordinator & lead developer Fabien Chéreau

Graphic/other designer Martín Bernardi

Developer Guillaume Chéreau

Developer Georg Zotti

Developer Alexander V. Wolf

Developer Ruslan Kabatsayev

Developer Worachate Boonplod

Developer Henry Leung

392 Appendix H. Acknowledgements

Sky cultures researcher Susanne M. Hoffmann

Tester Khalid AlAjaji

H.2.2 Former Developers

Several people have made signiﬁcant contributions, but are no longer active. Their work has made a big

difference to the project:

Graphic/other designer Johan Meuris

Doc author/developer Matthew Gates

Developer Johannes Gajdosik

Developer Rob Spearman

Developer Bogdan Marinov

Developer Timothy Reaves

Developer Florian Schaukowitsch

Developer András Mohari

Developer Mike Storm

Developer Ferdinand Majerech

Developer Jörg Müller

Developer Marcos Cardinot

OSX Developer Nigel Kerr

OSX Developer Diego Marcos

Continuous Integration Hans Lambermont

H.2.3 Contributors

Many individuals have made contributions to the project and their work has made Stellarium better. Alpha-

betically sorted list of all contributors:

Adam Majer, Adriano Stefﬂer, Alec Clews, Alessandro Siniscalchi, Alex Gamper, Alexander Belopolsky,

Alexander Duytschaever, Alexander Miller, Alexander V. Wolf, Alexandros Kosiaris, Alexey Dokuchaev,

Alexey Sokolov, Allan Johnson, Andras Mohari, Andrei Borza, Andrew Jeddeloh, Andy Kirkham, Angelo

Fraietta, Annette S. Lee, Antoine Jacoutot, Anton Samoylov, Arjen de Korte, Aspere, Atque, Barry Gerdes,

Bernd K, Björn Höﬂing, Bogdan Marinov, Brian Kloppenborg, Cassy, Chi Huynh, ChrUnger, Chris Xiao,

Clement Sommelet, Clepalitto, Colin Gaudion, Cosimo Cecchi, Dan Joplin, Dan Smale, Daniel, Daniel

Adastra, Daniel De Mickey, Daniel Michalik, Danny Milosavljevic, Dark Dragon, David Baucum, Dempsey-

p, Dhia, Diego Marcos, Dominik Maximilián Ramík, Edgar Scholz, Elaina, Eleni Maria Stea, Emmanuel,

EuklidAlexandria, Fabien Chereau, Felix Z, Ferdinand Majerech, Florian Schaukowitsch, François Scholder,

Freeman Li, FreewareTips, Froenchenko Leonid, Fòram na Gàidhlig, Georg Zotti, Gion Kunz, GitHaarek,

Giuseppe Putzolu, Greg Alexander, Guillaume Chereau, Guillaume Communie, Gábor Péterffy, Hans

Lambermont, Hector Quemada, Henry Leung, Hernan Martinez, Hleb Valoshka, Holger, Holger Nießner,

Iceﬂower, Ivan Marti-Vidal, J.L.Canales, JAY RESPLER, JMejuto, Jack Schmidt, Jean-Philippe Lambert,

Jocelyn GIROD, Johan Meuris, Johannes Gajdosik, Jonas Persson, Jörg Müller, Katrin Leinweber, Kenan

Derviševi

c, Khalid AlAjaji, Kirill Snezhko, Konrad Rybka, Kutaibaa Akraa, Louis Strous, M.S. Adityan,

Maciej Serylak, Marc Espie, Marcos Cardinot, Martin Bernardi, Martin Bernardi (Laptop), Matt Hughes,

Matthew Gates, Matthias Drochner, Matwey V. Kornilov, Max Digruber, Michael Dickens, Michael Storm,

Michael Taylor, Michal Sojka, Mike Boyle, Mike Garrahan, Minmin Gong, Mircea Lite, Miroslav Broz,

Mykyta Sytyi, Nick Fedoseev, Nick Kanel, Nicolas Martignoni, Nidroide, Nir Lichtman, Norman Rasmussen,

Oleg Ginzburg, Oscar Roig Felius, Paolo Cancedda (Pac), Paolo Stivanin, ParkSangJun, Patrick, Paul Krizak,

Pavel Klimenko, Pawel Stolowski, Peter, Peter Hickey, Peter Mousley, Peter Neubauer, Peter Vasey, Peter

Walser, Petr Kubánek, Pino Toscano, Pluton Helleformer, Qam1, RVS, Ralph Schäfermeier, Ray, Rob

Spearman, Robert S. Fuller, Roland Bosa, Ross Mitchell, Rumen Bogdanovski, Ruslan Kabatsayev, Sam

Lanning, Sebastian Jennen, Sergej Krivonos, Sergey, Shantanu Agarwal, Sibi Antony, SilverAstro, Simon

Parzer, Song Li, Sripath Roy Koganti, Steven Bellavia, Sun Shuwei, Susanne M Hoffmann, Sveinn í Felli,

Tanmoy Saha, Teemu Nätkinniemi, Teresa Huertas, Thilo, Thomas1664, Tig la Pomme, Timothy Reaves,

Tomasz Buchert, Tony Furr, TotalCaesar659, Tuomas Teipainen, T

evita O. Ka

‘

ili, Vancho Stojkoski, Vicente

Reyes, Victor Reijs, Vishvas Vasuki, Vladislav Bataron, Volker Hören, Wang Siliang, William Formyduval,

Wolfgang Laun, Wonkyo Choe, Worachate Boonplod, Yaakov Selkowitz, Youssif Ghantous Filho, Yuri

Chornoivan, Yury Solomonov, adalava, afontenot, bkuhls, bv6679, chithihuynh, colossatr0n, henrysky,

leonardcj, luz paz, luzpaz, misibacsi, pkrawczun, rikardfalkeborn, riodoro1, sebagr, toﬁlwiktor, uwes-ufo,

ysjbserver, zhu1995zpb, Łukasz ’sil2100’ Zemczak.

H.3 How you can help 393

H.3 How you can help

We especially welcome contributions in shape of working program code for interesting features, but also bug

reports, feature requests and other feedback through the usual channels (trackers, forums and so on):

Stellarium on Github https://github.com/Stellarium/

Questions for Stellarium (FAQ) https://github.com/Stellarium/stellarium/wiki/FAQ

Current issues (FAQ) https://github.com/Stellarium/stellarium/wi ki /Common-Pro bl em

s-for-the-current-version

Google Group https://groups.google.com/group/stellarium

Another form of support, donations, can be given via

https://opencollective.com/stellarium/

donate.

H.4 Technical Articles

Stellarium would not look the same and work without these works from computer graphics and astronomy.

The tone reproductor class

The class mainly performs a fast implementation of the algorithm from Tum-

blin and Rushmeier (1993), with more accurate values from Devlin et al. (2002). The blue shift

formula is taken from Jensen et al. (2000) and combined with the Scotopic vision formula from

Larson, Rushmeier, and Piatko (1997).

The skylight class

The class governs sky colors and is a fast implementation of the algorithm by Preetham,

Shirley, and Smits (1999).

The skybright class

The class governs physical sky brightness values based on Bradley Schaefer’s VIS-

LIMIT.BAS basic source code (B. Schaefer, 1998). The basic sources are available on the Sky and

Telescope web site (code “offered as-is and without support”).

The ∆T calculations For implementation of calculation routines for ∆T we used the following sources:

1. ∆T

webpage by Rob van Gent:

https://webspace.science.uu.nl/~gent0113/deltat

/deltat.htm

Five Millennium Canon of Solar Eclipses: -1900 to +3000 (Espenak and Meeus, 2006) (

https:

//eclipse.gsfc.nasa.gov/SEhelp/deltatpoly2004.html)

Thousand Year Canon of Solar Eclipses 1501 to 2500 (Espenak, 2014) (

https://eclipsew

ise.com/help/deltatpoly2014.html)

4. “On the system of astronomical constants” (Clemence, 1948)

“The rotation of the earth, and the secular accelerations of the sun, moon and planets” (Spencer

Jones, 1939)

“Polynomial approximations for the correction delta T E.T.-U.T. in the period 1800-1975”

(Schmadel and Zech, 1979)

7. “ELP 2000-85 and the dynamic time-universal time relation” (Borkowski, 1988)

“Empirical Transformations from U.T. to E.T. for the Period 1800-1988” (Schmadel and Zech,

1988)

“Historical values of the Earth’s clock error

∆

T and the calculation of eclipses” (Morrison and

F. R. Stephenson, 2004) with Addendum (Morrison and F. R. Stephenson, 2005)

10. “Polynomial approximations to Delta T, 1620-2000 AD” (Meeus and Simons, 2000)

11. Canon of Solar Eclipses -2003 to +2526 (Mucke and Meeus, 1983)

12.

“The accelerations of the earth and moon from early astronomical observations” (Muller and

F. R. Stephenson, 1975)

13. “Pre-Telescopic Astronomical Observations” (F. R. Stephenson, 1978)

14.

“Long-term changes in the rotation of the earth - 700 B.C. to A.D. 1980” (F. R. Stephenson and

Morrison, 1984)

15.

“Long-Term Fluctuations in the Earth’s Rotation: 700 BC to AD 1990” (F. R. Stephenson and

Morrison, 1995)

16. Historical Eclipses and Earth’s Rotation (F. Richard Stephenson, 1997)

17. Astronomical Algorithms (Meeus, 1998)

18. Astronomy on the Personal Computer (Montenbruck and Pﬂeger, 2000)

19. Calendrical Calculations (The Millennium Edition) (Reingold and Dershowitz, 2001)

20. ∆T webpage by V. Reijs: http://www.iol.ie/~geniet/eng/DeltaTeval.htm

Precession:

“New precession expressions, valid for long time intervals” (Vondrák, Capitaine, and Wallace,

2011) with correction (Vondrák, Capitaine, and Wallace, 2012)

394 Appendix H. Acknowledgements

Nutation:

“An abridged model of the precession-nutation of the celestial pole” (McCarthy and Luzum,

2003) This model provides accuracy better than 1 milli-arcsecond in the time 1995-2050. It is applied

for years -4000..+8000 only.

Martian polar caps: Based on data from Smith et al. (2009) and Piqueux et al. (2015).

Solar limb darkening: Livingston (2002).v 23.1

Color of Neptune: Irwin et al. (2024).v 25.1

H.5 Included Source Code

•

Some computation of the sidereal time (

sidereal_time.h/c

) and Pluto orbit contains code from

the libnova library (LGPL) by Liam Girdwood.

•

The

orbit.cpp/h

and

solve.h

ﬁles were directly borrowed from Celestia (Chris Laurel; GPL

license). They have now evolved a bit.

•

Several implementations of IMCCE theories for planet and satellite movement by Johannes Gajdosik

(MIT-style license, see the corresponding ﬁles for the license text)

•

The tesselation algorithms were originally extracted from the glues library version 1.4 by Mike

Gorchak <mike@malva.ua> (SGI FREE SOFTWARE LICENSE B).

•

Parts of the code to work with DE430/DE431 and DE440/DE441 data ﬁles have been taken from

Project Pluto (GPL license).

•

The

SpoutLibrary.dll

and header from the SpoutSDK version 2.005 available at

http://spout.

zeal.co (BSD license).

H.6 Data

The Hipparcos star catalog From ESA (European Space Agency) and the Hipparcos mission. ref.

ESA, 1997, The Hipparcos and Tycho Catalogues, ESA SP-1200

http://cdsweb.u-strasbg.fr/

ftp/cats/I/239

2. The solar system data mainly comes from IMCCE and partly from Celestia.

3. Polynesian constellations are based on diagrams from the Polynesian Voyaging Society

4. Chinese constellations are based on diagrams from the Hong Kong Space Museum

Egyptian constellations are based on the work of Juan Antonio Belmonte, Instituto de Astroﬁsica de

Canarias

The Tycho-2 Catalogue of the 2.5 Million Brightest Stars Hog E., Fabricius C., Makarov V.V., Urban

S., Corbin T., Wycoff G., Bastian U., Schwekendiek P., Wicenec A. Astron. Astrophys. 355, L27

(2000) http://cdsweb.u-strasbg.fr/ftp/cats/I/259

Naval Observatory Merged Astrometric Dataset (NOMAD) version 1 (

http://www.nofs.navy.mi

l/nomad) Norbert Zacharias writes:

“There are no fees, both UCAC and NOMAD are freely available with the only

requirement that the source of the data (U.S. Naval Observatory) and original product

name need to be provided with any distribution, as well as a description about any changes

made to the data, if at all.”

The changes made to the data are:

•

try to compute visual magnitude and color from the b,v,r values

•

compute nr_of_measurements = the number of valid b, v, r values

•

throw away or keep stars (depending on magnitude, nr_of_measurements, combination of ﬂags,

tycho2 number)

•

add all stars from Hipparcos (incl. component solutions), and tycho2+1st supplement

•

reorganize the stars in several brightness levels and triangular zones according to position and

magnitude

The programs that are used to generate the star ﬁles are called MakeCombinedCatalogue, ParseHip,

ParseNomad, and can be found in the util subdirectory in source code. The position, magnitudes,

and proper motions of the stars coming from NOMAD are unchanged, except for a possible loss

of precision, especially in magnitude. When there is no V magnitude, it is estimated from R or B

magnitude. When there is no B or V magnitude, the color B-V is estimated from the other magnitudes.

Also proper motions of faint stars are neglected at all.

H.7 Graphics 395

Stellarium’s Catalog of Variable Stars based on General Catalog of Variable Stars (GCVS) version

2013Apr.

http://www.sai.msu.su/gcvs/gcvs/

Samus N.N., Durlevich O.V., Kazarovets E V.,

Kireeva N.N., Pastukhova E.N., Zharova A.V., et al., General Catalogue of Variable Stars (Samus+

2007-2012) http://cdsarc.u-strasbg.fr/viz-bin/Cat?cat=B%2Fgcvs&

9. Consolidated DSO catalog was created from various data:

a. NGC/IC data taken from SIMBAD Astronomical Database http://simbad.u-strasbg.fr

Distance to NGC/IC data taken from NED (NASA/IPAC EXTRAGALACTIC DATABASE)

http://ned.ipac.caltech.edu

Catalogue of HII Regions (Sharpless, 1959) (

http://vizier.u-strasbg.fr/viz-bin/V

izieR?-source=VII/20)

H-

emission regions in the Southern Milky Way (Rodgers+, 1960) (

http://vizier.u-str

asbg.fr/viz-bin/VizieR?-source=VII/216)

Catalogue of Reﬂection Nebulae (Van den Bergh, 1966) (

http://vizier.u-strasbg.fr/

viz-bin/VizieR?-source=VII/21)

Lynds’ Catalogue of Dark Nebulae (LDN) (Lynds, 1962) (

http://vizier.u-strasbg.fr/

viz-bin/VizieR?-source=VII/7A)

Lynds’ Catalogue of Bright Nebulae (Lynds, 1965) (

http://vizier.u-strasbg.fr/viz-b

in/VizieR?-source=VII/9)

Catalog of bright diffuse Galactic nebulae (Cederblad, 1946) (

http://vizier.u-strasbg.f

r/viz-bin/VizieR?-source=VII/231)

Barnard’s Catalogue of 349 Dark Objects in the Sky (Barnard, 1927) (

http://vizier.u-str

asbg.fr/viz-bin/VizieR?-source=VII/220A)

A Catalogue of Star Clusters shown on Franklin-Adams Chart Plates (Melotte, 1915) from

NASA ADS (http://adsabs.harvard.edu/abs/1915MmRAS..60..175M)

On Structural Properties of Open Galactic Clusters and their Spatial Distribution. Catalog of

Open Galactic Clusters (Collinder, 1931) from NASA ADS (

http://adsabs.harvard.edu

/abs/1931AnLun...2....1C)

The Collinder Catalog of Open Star Clusters. An Observer’s Checklist. Edited by Thomas

Watson from CloudyNights (

http://www.cloudynights.com/page/articles/cat/art

icles/the-collinder-catalog-updated-r2467)

10. Cross-identiﬁcation of objects in consolidated DSO catalog was made with:

a. SIMBAD Astronomical Database http://simbad.u-strasbg.fr

Merged catalogue of reﬂection nebulae (Magakian, 2003)

http://vizier.u-strasbg.fr/

viz-bin/VizieR-3?-source=J/A+A/399/141

Messier Catalogue from Wikipedia (includes morphological classiﬁcation and distances)

https:

//en.wikipedia.org/wiki/List_of_Messier_objects

Caldwell Catalogue from Wikipedia (includes morphological classiﬁcation and distances)

https://en.wikipedia.org/wiki/Caldwell_catalogue

11.

Morphological classiﬁcation and magnitudes (partially) for Melotte catalogue from DeepSkyPedia

http://deepskypedia.com/wiki/List:Melotte

H.7 Graphics

All graphics are copyrighted by the Stellarium’s Team (GNU GPLv2 or later) except the ones mentioned

below:

•

The “earthmap” texture was created by NASA (Reto Stockli, NASA Earth Observatory) using data

from the MODIS instrument aboard the Terra satellite (Public Domain). See section H.7.1 for full

credits.

•

Moon texture map was combined from maps by USGS Astrogeology Research Program,

http:

//a strogeol ogy.usgs.gov

(Public Domain, DFSG-free) and by Lunar surface textures from

Celestia, based on Clementine data (Public Domain).

•

Jupiter map created by James Hastings-Trew from Cassini data. “The maps are free to download and

use as source material or resource in artwork or rendering (CGI or real time).”

•

The Sun and Iapetus maps, and rings of Uranus are from Celestia (

http://shatters.net/celes

tia/) under the GNU General Purpose License, version 2 or any later version:

– Iapetus map is from dr. Fridger Schrempp (t00fri).

•

The Amalthea, Europa, Ganymede, Gaspra,Mercury, Uranus, Neptune, Mimas, Bianca, Epimetheus,

396 Appendix H. Acknowledgements

Ida, Vesta, Hyperion, Io, Janus, Phoebe, Saturn, Tethys, Venus, Ceres, Uranus, Epimetheus, Deimos,

Proteus and comet maps are processed by Oleg Pluton a.k.a Helleformer License: Creative Commons

Attribution 4.0 International

•

The Titania, Umbriel, Pluto, Charon, Sedna and 2007 OR10 maps are created by Kexitt and postpro-

cessed by Oleg Pluton a.k.a Helleformer License: Creative Commons Attribution 4.0 International

•

The Ariel, Haumea, Miranda, Oberon and Nereid maps are created by Snowfall and postprocessed by

Oleg Pluton a.k.a Helleformer License: Creative Commons Attribution 4.0 International

•

The Eris and Dysnomia maps are created by MrSpace43 and postprocessed by Oleg Pluton a.k.a

Helleformer License: Creative Commons Attribution 4.0 International

•

The Rhea map are created by FarGetaNik and postprocessed by Oleg Pluton a.k.a Helleformer License:

Creative Commons Attribution 4.0 International

•

The Titan (Clouds) map are created by Magenta Meteorite and postprocessed by Oleg Pluton a.k.a

Helleformer License: Creative Commons Attribution 4.0 International

•

Callisto map is created by John van Vliet from PDS data and modiﬁed by RVS. License: cc-by-sa.

•

Dione and Enceladus maps are created by NASA (CICLOPS team) from Cassini data, colored by

RVS. Public domain.

•

All other planet maps from David Seal’s site:

http://maps.jpl.nasa.gov/

see license in section

H.7.2

•

Bennu map is created by NASA from OSIRIS-REx spacecraft data. Public domain. Full size mosaic:

https://www.asteroidmission.org/bennu_global_mosaic/

•

The fullsky milky way panorama is created by Axel Mellinger, University of Potsdam, Germany.

Further information and more pictures available from

http://home.arcor-online.de/axel.me

llinger/

License: permission given to “Modify and redistribute this image if proper credit to the

original image is given.”

•

All messiers nebula pictures except those mentioned below from the Grasslands Observatory : “Images

courtesy of Tim Hunter and James McGaha, Grasslands Observatory at

http://www.3towers.com

.”

License: permission given to “use the image freely” (including right to modify and redistribute) “as

long as it is credited.”

•

M31 pictures come from LEE ang HG731GZ License: Creative Commons Attribution 3.0 Unported

•

Images of NGC4526, NGC6544, NGC6553 from Yang Kai License: public domain

•

Images of M1, M27, M57, M97, NGC6946 from Stephane Dumont

•

Images of NGC856, NGC884 from Maxime Spano

•

Constellation art, GUI buttons, logo created by Johan Meuris (jomejome at users.sourceforge.net)

http://www.joh anmeuris.eu/

License: released under the Free Art License (

http://artlib

re.org/ licence.php/lalgb.html

) Icon created by Johan Meuris License: Creative Commons

Attribution-ShareAlike 3.0 Unported

•

The “earth-clouds” texture includes imagery owned by NASA. See NASA’s Visible Earth project at

http://visibleearth.nasa.gov/ License:

1. The imagery is free of licensing fees

2. NASA requires that they be provided a credit as the owners of the imagery

The cloud texturing was taken from Celestia (GPL), http://www.shatters.net/celestia/

•

The folder icon derived from the Tango Desktop Project, used under the terms of the Creative

Commons Attribution Share-Alike license.

•

Images of NGC7317, NGC7319, NGC7320 from Andrey Kuznetsov, Kepler Observatory

http:

//kepler-observatorium.ru License: Creative Commons Attribution 3.0 Unported

•

Images of NGC2903, NGC3185, NGC3187, NGC3189, NGC3190, NGC3193, NGC3718, NGC3729,

NGC5981, NGC5982, NGC5985 from Oleg Bryzgalov

http://olegbr. astroclub.kiev.ua/

License: Creative Commons Attribution 3.0 Unported

•

Image of eta Carinae from Harel Boren

http://www.pbase.com/

License: Creative Commons

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•

Images of NGC3726 from KPNO/NOIRLab/NSF/AURA/George Hickey/Adam Block, post-processing:

Sun Shuwei

https://noirlab.edu/public/

License: Creative Commons Attribution 4.0 Interna-

tional

•

Images of M21, M47, NGC3324, NGC7590, RCW158 from Trevor Gerdes

http://www.sarcasmo

gerdes.com/

•

Images of NGC1532 from users of Ice In Space http://www.iceinspace.com.au/

•

Images of NGC3293 from ESO/G. Beccari

http://eso.org/public/

License: Creative Commons

H.7 Graphics 397

Attribution 4.0 International

•

Images of SMC (Magellanic Clouds) from Albert Van Donkelaar

•

Images of NGC1261, NGC3201, NGC4833, NGC5286, NGC5823, NGC6025, NGC6087, NGC6101,

NGC6124, NGC6352, NGC6397, NGC6541, NGC6752 from Tian Mai, Image processing: Sun

Shuwei License: Creative Commons Attribution 4.0 International

•

The Vesta and Ceres map was taken from USGS website

https://astrogeology.usgs.gov/

and

colored by RVS. License: public domain.

•

Images of M15, M24, M51, M58, M63, M76, M82, M96, M101, M105, M106, IC1727, NGC246,

NGC457, NGC467, NGC470, NGC474, NGC488, NGC672, NGC691, NGC1514, NGC1961,

NGC2174, NGC2371, NGC2392, NGC2403, NGC2506, NGC2655, NGC2685, NGC2805, NGC2814,

NGC2820, NGC2841, NGC3079, NGC3166, NGC3310, NGC3344, NGC3359, NGC3504, NGC3512,

NGC3521, NGC3938, NGC4151, NGC4274, NGC4535, NGC4559, NGC4631, NGC4656, NGC4657,

NGC5033, NGC5363, NGC7008, NGC7331, NGC7479, NGC7640, NGC7789, PGC1803573,

Barnard 142, Barnard 173, Sh2-101, Sh2-188, LDN1235, Sadr region (Gamma Cygni), Medusa,

Jones-Emberson 1, NGC2146 from Peter Vasey, Plover Hill Observatory

http://www.madpc.co.u

k/~peterv/

•

Image of IC3568 from Howard Bond (Space Telescope Science Institute), Robin Ciardullo (Pennsyl-

vania State University) and NASA License: public domain

•

Image of solar corona from eclipse 2008-08-01 by Georg Zotti

•

Images of NGC2359 from Carole Pope

https://sites.google.com/site/caroleastroimagi

ng/

•

Images of NGC2261, NGC2818, NGC2936, NGC3314, NGC3690, NGC3918, NGC4038-4039,

NGC5257, NGC5307, NGC6027, NGC6050, NGC6369, NGC6826, NGC7742, IC883, IC4406,

PGC2248, UGC1810, UGC8335, UGC9618, Red Rectangle and Calabash Nebula from NASA,

ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration License: public domain;

http://hubblesite.org/copyright/

•

Image of NGC40 from Steven Bellavia

•

Images of NGC2467, NGC6590, Barnard Loop, IC342 from Sun Shuwei License: public domain

•

Images of M77, NGC3180, NGC5474, NGC6231, Sh2-264, Sh2-308, LDN1622 from Wang Lingyi

License: public domain

•

Images of PGC6830, PGC29653 from Lowell Observatory

http://www2.lowe ll.edu/

License:

public domain

•

Images of M89, IC2220, IC2631, NGC1433, NGC2434, NGC3572, PGC10074, RCW32, RCW38,

RCW49, Fornax Cluster, Virgo Cluster from ESO/Digitized Sky Survey 2

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ic/ License: Creative Commons Attribution 4.0 International

•

Images of NGC3603 from ESO/La Silla Observatory

http://eso.org/public/

License: Creative

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•

Images of NGC4228, NGC4244 from Ole Nielsen License: Creative Commons Attribution-Share

Alike 2.5 Generic

•

Images of NGC2808, NGC7023, Hercules Cluster from NASA License: public domain

•

Images of M44, IC1396 from Giuseppe Donatiello License: Creative Commons CC0 1.0 Universal

Public Domain Dedication

•

Images of M12, M14, M20, M22, M55, M56, M62, M88, M92, M108, IC5146, NGC225, NGC281,

NGC663, NGC891, NGC1931, NGC6823, NGC7814 from Hewholooks

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•

Images of NGC4565 from Ken Crawford

http://www.imagingdeepsky.com/

License: This work

is free and may be used by anyone for any purpose. If you wish to use this content, you do not need to

request permission as long as you follow any licensing requirements mentioned on this page.

•

Images of M61, M64, M65, M66, M91, M99, M100, NGC613, NGC772, NGC918, NGC1042,

NGC1360, NGC1398, NGC1501, NGC1535, NGC1555, NGC2158, NGC2282, NGC2346, NGC2362,

NGC2440, NGC2683, NGC2775, NGC3132, NGC3242, NGC3486, NGC3750, NGC4170, NGC4216,

NGC4361, NGC4395, NGC4414„NGC4450, NGC4676, NGC4725, NGC5216, NGC5248, NGC5426,

NGC5466, NGC6302, NGC6522, NGC6543, NGC6563, NGC6781, NGC6894, NGC7000, NGC7354,

NGC7822, SH2-136, UGC3697, Abell31, Abell33, Abell39, Cassiopeia A, LBN438, Wild’s Triplet

from Adam Block/Mount Lemmon SkyCenter/University of Arizona

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atory.com/ License: Creative Commons Attribution-Share Alike 3.0 Unported

•

Images of IC1295, NGC134, NGC92, NGC55, NGC908, NGC936, NGC1232, NGC1313, NGC1792,

398 Appendix H. Acknowledgements

NGC1978, NGC2207, NGC2736, NGC3199, NGC3699, NGC3766, NGC3532, NGC4945, NGC5128,

NGC5189, NGC6537, NGC6769, NGC6822, NGC7793 from ESO

http://eso.org/public/

License: Creative Commons Attribution 4.0 International

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Images of M33, M42, NGC253, NGC5566, LBN782, the Pleiades from HG731GZ License: Creative

Commons Attribution 3.0 Unported

•

Images of M8, M17, M94, IC2944, IC4628, NGC5367, NGC6357, NGC6334, NGC7293, LDN43,

SMC (Hydrogen Alpha) from Dylan O’Donnell

http://deography.com/

License: public domain

•

Images of NGC247 No machine-readable source provided. Own work assumed (based on copyright

claims). No machine-readable author provided. Fany Toporenko assumed (based on copyright claims).

License: Permission is granted to copy, distribute and/or modify this document under the terms of the

GNU Free Documentation License, Version 1.2 or any later version published by the Free Software

Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of

the license is included in the section entitled GNU Free Documentation License.

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Images of Sh2-73, Sh2-129 from Maurizio Cabibbo, post-processing: Sun Shuwei

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s.wikimedia.org/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

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Images of M16, IC4592, IC4601, NGC4236, NGC6914, Perseus Cluster from Sun Gang License:

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Images of NGC4651, NGC5906 from R. Jay GaBany

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es/ License: Creative Commons Attribution-Share Alike 3.0 Unported

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NGC6144, PGC143, UGC12613 from Starhopper

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Images of NGC6818 from Robert Rubin (NASA/ESA Ames Research Center), Reginald Dufour

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Images of IC2118, NGC1499 from Zhao Jingna License: Creative Commons Attribution 3.0 Unported

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Images of UGC10822 from Science NASA, ESA, Eduardo Vitral (STScI), Roeland van der Marel

(STScI), Sangmo Tony Sohn (STScI), DSS Image Processing: Joseph DePasquale (STScI)

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NGC1931, NGC2264, LBN437, Sh2-191, Sh2-247 from Giuseppe Donatiello, post-processing: Sun

Shuwei

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Universal Public Domain Dedication

H.7 Graphics 399

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Images of NGC1055 from Jeffjnet

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Images of NGC2867, NGC6884 from Howard Bond (ST ScI) and NASA/ESA

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Images of NGC5897 from San Esteban

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License: Creative Commons

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Images of NGC6388 from ESO, F. Ferraro (University of Bologna)

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Images of NGC7380, SH2-80, SH2-106 from Cristina Cellini

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Images of NGC1333 from AAE-Agrupacio Astronomica d’Eivissa

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Images of NGC5139 from Jose Mtanous

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License:

Creative Commons Attribution-Share Alike 3.0 Unported

400 Appendix H. Acknowledgements

•

Images of NGC6960 from Jose Mtanous

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License:

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Images of NGC6445 from The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive

have been made possible through contributions by the Institute for Astronomy, the University of

Hawaii, the Pan-STARRS Project Ofﬁce, the Max-Planck Society and its participating institutes, the

Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial

Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh,

the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres

Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the

Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant

No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission

Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland,

Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty

Moore Foundation.

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License: public

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Images of LMC (Magellanic Clouds) from ESO/R. Gendler and Sun Shuwei

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blic/

License: Creative Commons Attribution 4.0 International. This work is a derivative of “Map

of the Large Magellanic Cloud” and “The entire Large Magellanic Cloud with annotations” by ESO/R.

Gendler, used under Creative Commons Attribution 4.0 International. This work is licensed under

Creative Commons Attribution 4.0 International by Sun Shuwei.

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Images of rho Oph from ESO/S. Guisard

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Images of IC59, IC63 from Zhang Ruiping License: Creative Commons Attribution 4.0 International

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Images of NGC6366 from Robert Eder, post-processing: Sun Shuwei

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Images of IC418, IC4593, NGC5315, NGC6751 from NASA/ESA and The Hubble Heritage Team

(STScI/AURA)

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Images of NGC7009 from ESO/J. Walsh

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Images of NGC7027 from Judy Schmidt

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Images of NGC6309, NGC6891 from Fabian RRRR

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Images of NGC2022 from ESA/Hubble & NASA, R. Wade

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Images of NGC654 from Antonio F. Sanchez

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Images of NGC6496 from Mohamad Abbas

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License:

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Images of PGC3589 from ESA/Hubble, Digitized Sky Survey 2

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rg/ License: Creative Commons Attribution 4.0 International

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Images of NGC1672 from Davide De Martin (ESA/Hubble), the ESA/ESO/NASA Photoshop FITS

Liberator & Digitized Sky Survey 2

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License: Creative

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Images of NGC4298 from NASA, ESA, Digitized Sky Survey 2; Acknowledgement: Davide De

Martin

https://www.space telescope.org/

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Images of NGC1502 from Kamil Pecinovsky

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Images of NGC752 from Tayson82

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Images of Sh2-170 from Wang Wei License: Creative Commons Attribution-Share Alike 3.0 Unported

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The

miscWorldMap.jpg

image was created from NASA Blue Marble Next Generation dataset for

July 2004. Public domain.

https://visibleearth.nasa.gov/images/74092/july-blue-m

H.7 Graphics 401

arble-next-generation

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Images of M80, M90, RCW101 from NOIRLab/NSF/AURA, post-processing: Sun Shuwei

https:

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Images of Dark Doodad Nebula, IC1613, NGC1216, NGC4372 from Hansjorg Walchli, post-

processing: Sun Shuwei

https://www.deepskycorner.ch/index.de.php

License: Creative

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Images of NGC1566, NGC1808 from Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NS-

F/AURA, Image processing: T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), J. Miller

(Gemini Observatory/NSF NOIRLab), M. Zamani & D. de Martin (NSF NOIRLab), post-processing:

Sun Shuwei

https://www.deepskycorner.ch/index.de.php

License: Creative Commons

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Images of IC289, NGC185 from Thedarksideobservatory, post-processing: Sun Shuwei

https:

//comm ons.wikimedia.org/wiki/

License: Creative Commons Attribution-Share Alike 4.0

International

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Images of NGC5005 from KPNO/NOIRLab/NSF/AURA/Ray and Emily Magnani/Adam Block

http

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Images of NGC80, NGC147, NGC1491, NGC1624, NGC7026 from Radek Chromik, post-processing:

Sun Shuwei

https://www.deepskycorner.ch/index.de.php

License: Creative Commons

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Images of IC4954 from KPNO/NOIRLab/NSF/AURA/Adam Block, post-processing: Sun Shuwei

https://noirlab.edu/public/ License: Creative Commons Attribution 4.0 International

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Images of IC2574, Sh2-313 from Jerry Macon, post-processing: Sun Shuwei

https://commons.wi

kimedia.org/wiki/ License: Creative Commons Attribution 4.0 International

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Images of NGC5395 from KPNO/NOIRLab/NSF/AURA/Doug Matthews and E. J. Jones/Adam

Block, post-processing: Sun Shuwei

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License: Creative

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Images of RCW77 from KPNO/NOIRLab/NSF/AURA/Doug Matthews and E. J. Jones/Adam Block,

post-processing: Sun Shuwei https://esahubble.org/ License: public domain

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Images of Sh2-216 from Ram samudrala, post-processing: Sun Shuwei

https://commons.wikime

dia.org/wiki/ License: Creative Commons Attribution 4.0 International

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Images of Sh2-174, Sh2-239 from T.A. Rector (University of Alaska Anchorage) and H. Schweiker

(WIYN and NOIRLab/NSF/AURA), post-processing: Sun Shuwei

https://noirlab.edu/publ

ic/ License: Creative Commons Attribution 4.0 International

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Images of Sh2-82, Sh2-91, Sh2-119, Sh2-135, Sh2-235, Sh2-261, VDB158 from Sebastian Goralik,

post-processing: Sun Shuwei

https://flickr.com /photos/sebastiangoralik/

License:

Creative Commons CC0 1.0 Universal Public Domain Dedication

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Images of NGC4976 from ESO/Dss2, Giuseppe Donatiello, post-processing: Sun Shuwei

https:

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Domain Dedication

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Images of NGC3109 from DESI LIS, Giuseppe Donatiello, post-processing: Sun Shuwei

https:

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Domain Dedication

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Images of Sh2-157 from Sebastian Goralikpost-processing: Sun Shuwei

https://flickr.com

/photos/sebastiang oralik/

License: Creative Commons CC0 1.0 Universal Public Domain

Dedication

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Images of Sh2-1 from Nicolarge, post-processing: Sun Shuwei

https://commons.wikimedia.or

g/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

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Images of RCW86 from CTIO/NOIRLab/NSF/AURA/T.A. Rector (University of Alaska Anchor-

age/NSF NOIRLab) Image processing: T.A. Rector (University of Alaska Anchorage/NSF NOIR-

Lab), M. Zamani (NSF NOIRLab) & D. de Martin (NSF NOIRLab), post-processing: Sun Shuwei

https://noirlab.edu/public/ License: Creative Commons Attribution 4.0 International

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Images of NGC7318 from Juan lacruz, post-processing: Sun Shuwei

https://commons.wikimedi

a.org/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

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Images of IC1505, NGC70, NGC529, NGC1530, NGC2366, NGC2768, NGC3227, NGC3561,

NGC6621, NGC6951, NGC7139, NGC7741, UGC4305, Jones1 from Juan lacruz, post-processing:

Sun Shuwei

https://commons.wikimedia.org/wiki/

License: Creative Commons Attribution

4.0 International

402 Appendix H. Acknowledgements

•

Images of M78, IC348, IC423, IC434, NGC6726, LBN550, LDN1251, Sh2-124, RCW29, RCW58,

RCW89, VDB123, Vela supernova remnant from Manuel Peitsch, post-processing: Sun Shuwei

https://manuel-astro.ch/ License: Creative Commons Attribution 4.0 International

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Images of M7, NGC1316, NGC2442, NGC2899, RCW100, Sh2-54, Westerlund1 from ESO, post-

processing: Sun Shuwei

http://eso.org/public/

License: Creative Commons Attribution 4.0

International

•

Images of NGC2210, NGC2579 from Legacy Surveys / D.Lang (Perimeter Institute) & Meli thev,

post-processing: Sun Shuwei

https://www.legacy survey.org/acknowledgment

License:

Creative Commons Attribution-Share Alike 4.0 International

•

Images of NGC3628, Sh2-113 from Chuck Ayoub, post-processing: Sun Shuwei

https://commons.

wikimedia.org/wiki/

License: Creative Commons CC0 1.0 Universal Public Domain Dedication

•

Images of M49, M59, M60, NGC547, NGC2681, NGC3893, NGC4096, NGC4147, NGC4494,

NGC4517, NGC4527, NGC4664, NGC4697, NGC4753, NGC762, NGC6535, NGC6934, NGC7619,

UGC9792 from Sloan Digital Sky Survey

https://live-sdss4org-dr14.pantheonsite.io/

License: Creative Commons Attribution 4.0 International

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Images of NGC3211, NGC7492 from Legacy Surveys / D.Lang (Perimeter Institute) & Meli thev,

post-processing: Sun Shuwei

https://commons.wikimedia.org/wiki/

License: Creative

Commons Attribution-Share Alike 4.0 International

•

Images of Frosty Leo Nebula from ESA/Hubble & NASA, post-processing: Sun Shuwei

http:

//www.spacetelescope.org/ License: public domain

•

Images of NGC4666 from ESO/J. Dietrich, post-processing: Sun Shuwei

http://www.eso.org/pu

blic/ License: Creative Commons Attribution 4.0 International

•

Images of M104 from Adam Block/Mount Lemmon SkyCenter/University of Arizona & Ngc1535,

post-processing, post-processing: Sun Shuwei

https://commons.wikimedia.org/wiki/

License:

Creative Commons Attribution-Share Alike 4.0 International

•

Images of M72 from Starhopper, post-processing: Sun Shuwei

https://commons.wikimedia.or

g/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

•

Images of NGC4699 from KPNO/NOIRLab/NSF/AURA/Michael Vogel and Robert Mitsch/Adam

Block, Image processing: Sun Shuwei

https://noirlab.edu/ public/

License: Creative

Commons Attribution 4.0 International

•

Images of NGC6872 from Abdallah jawhari, post-processing: Sun Shuwei

https://commons.wi

kimedia.org/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

•

Images of UGC5373 from KPNO/NOIRLab/NSF/AURA Data obtained and processed by: P. Massey

(Lowell Obs.), G. Jacoby, K. Olsen, & C. Smith (AURA/NSF) Image processing: T.A. Rector

(University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab) and D. de Martin

(NSF NOIRLab), post-processing: Sun Shuwei

https://noirlab.edu/public/

License: Creative

Commons Attribution 4.0 International

•

Images of M54, M70 from REU Program/NOIRLab/NSF/AURA, post-processing: Sun Shuwei

https://noirlab.edu/public/ License: Creative Commons Attribution 4.0 International

•

Images of sh2-71 from Cristina Cellini, post-processing: Sun Shuwei

https://commons.wikime

dia.org/wiki/ License: Creative Commons Attribution 4.0 International

•

Images of DWB20, sh2-173 from Astrophoto Andy, post-processing: Sun Shuwei

https://www.fl

ickr.com/photos/andyweeks/53246079280/in/dateposted/ License: public domain

•

Images of MHC6325, NGC6355, NGC6440, NGC6638, NGC6642, NGC6717, NGC6749 from

The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible

through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS

Project Ofﬁce, the Max-Planck Society and its participating institutes, the Max Planck Institute for

Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns

Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast,

the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope

Network Incorporated, the National Central University of Taiwan, the Space Telescope Science

Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued

through the Planetary Science Division of the NASA Science Mission Directorate, the National

Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University

(ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation, Image

processing: Sun Shuwei

https://ps1images.stsci.edu/cgi-bin

License: Creative Commons

Attribution-Share Alike 4.0 International

H.7 Graphics 403

•

Images of NGC5946,NGC6517 from Donald Pelletier, post-processing: Sun Shuwei

https://comm

ons.wikimedia.org/wiki/

License: Creative Commons Attribution-ShareAlike 4.0 International

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Images of WR134 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei from

the original ﬁle. The original image ﬁle was published by Luc Viatour / https://Lucnix.be at

https:

//commons.wiki media.org/wiki/File:WR134-Hamois-06-08-2024-Luc-Viatour.jpg

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License: Creative Commons Attribution-Share Alike

4.0 International

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Images of NGC3503 from Donald Cappellettiariel, post-processing: Sun Shuwei

https://commons.

wikimedia.org/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

•

Images of IC239, NGC5850 from Adam Block/Mount Lemmon SkyCenter/University of Arizona,

Image processing: Sun Shuwei

https://commons.wiki media.org/wiki/

License: Creative

Commons Attribution-Share Alike 4.0 International

•

Images of NGC1569 from Adam Block/ Josep Drudis/Mount Lemmon SkyCenter/University of

Arizona, Ngc1535, post-processing: Sun Shuwei

https://commons.wikimedia.org/wiki/

License: Creative Commons Attribution-Share Alike 4.0 International

•

Images of NGC45, NGC6337 from Meli thev, post-processing: Sun Shuwei

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kimedia.org/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

•

Images of UGC11668 from KPNO/NOIRLab/NSF/AURA/Chas Sourek and Diana Hartrampf/Adam

Block, post-processing: Sun Shuwei

https://noirlab.edu/public/

License: Creative Commons

Attribution 4.0 International

•

Images of PGC3074547 from NASA, ESA and The Hubble Heritage Team STScI/AURA, post-

processing: Sun Shuwei

https://esahubble.org/

License: Creative Commons Attribution 4.0

International

•

Images of NGC289 from Adam Block/ChileScope, Ngc1535, post-processing: Sun Shuwei

https:

//comm ons.wikimedia.org/wiki/

License: Creative Commons Attribution-Share Alike 4.0

International

•

Images of NGC1365 from ESO/IDA/Danish 1.5 m/ R. Gendler, J-E. Ovaldsen, C. Th?ne, and C.

Feron., post-processing: Sun Shuwei

http://www.eso.org/public/

License: Creative Commons

Attribution 4.0 International

•

Images of NGC6565 from ESA/Hubble & NASA, Acknowledgement: M. Novak, post-processing:

Sun Shuwei https://esahubble.org/ License: Creative Commons Attribution 4.0 International

•

Images of NGC300 from ESO/DSS2 / Giuseppe Donatiello, post-processing: Sun Shuwei

https:

//flickr.com/photos/133259498@N05/37401736025/ License: public domain

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Images of M109 from KPNO/NOIRLab/NSF/AURA/George Hatﬁeld and Flynn Haase, post-processing:

Sun Shuwei

https://noirlab.edu/public/

License: Creative Commons Attribution 4.0 Interna-

tional

•

Images of IC5076, NGC2419, NGC4157, Ced211 from Adam Block/Mount Lemmon SkyCenter/Uni-

versity of Arizona, post-processing: Sun Shuwei

http://www.caelumobservatory.com/

License:

Creative Commons Attribution-Share Alike 3.0 United States

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Images of Necklace Nebula from NASA, ESA and the Hubble Heritage Team (STScI/AURA), post-

processing: Sun Shuwei

https://esahubble.org/

License: Creative Commons Attribution 4.0

International

•

Images of NGC2300 from NASA, ESA, STScI, Adam Block (Steward Observatory), post-processing:

Sun Shuwei

https://commons.wi kimedia.org/wiki/File:NGC_2276_Wide-Field_(2021

-029).png License: public domain

•

Images of M19 from Doug Williams, REU Program/NOIRLab/NSF/AURA, post-processing: Sun

Shuwei

https://noirlab.edu/public/

License: Creative Commons Attribution 4.0 International

•

Images of IC1276 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei from

the original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flickr

.com/photos/143529236@N06/51139472108/in/dateposted/

https://www.flickr .com/

License: Creative Commons Attribution-ShareAlike 4.0 International

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Images of NGC5371 from KPNO/NOIRLab/NSF/AURA/Joe Jordan/Adam Block, post-processing:

Sun Shuwei

https://noirlab.edu/public /

License: Creative Commons Attribution 4.0

International

•

Images of NGC3953 from KPNO/NOIRLab/NSF/AURA/Tom and Gail Haynes/Adam Block, post-

processing: Sun Shuwei

https://noirlab.edu/public/

License: Creative Commons Attribution

4.0 International

404 Appendix H. Acknowledgements

•

Images of IC1287 from Roberto Mura, post-processing: Sun Shuwei

https://commons.wikimedi

a.org/wiki/ License: Creative Commons Attribution-Share Alike 4.0 International

•

Images of M81, NGC1579 from Kees Scherer, post-processing: Sun Shuwei

https://www.flickr

.com/photos/kees-scherer/ License: public domain

•

Images of NGC7635, Sh2-136, VDB 14, VDB 15 from K Bahr, post-processing: Sun Shuwei

https://www.flickr.com/photos/158350039@N03/ License: public domain

•

Images of NGC3786 from Rudy Kokich, post-processing: Sun Shuwei

https://www.flickr.com

/photos/140097441@N02/ License: public domain

•

Images of NGC1851 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei

from the original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flic

kr.com/photos/143529236@N06/46234214731/

. License: Creative Commons Attribution-Share

Alike 4.0 International

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Images of NGC2808 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei

from the original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flic

kr.com/photos/143529236@N06/31856303507/

. License: Creative Commons Attribution-Share

Alike 4.0 International

•

Images of NGC6356 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei

from the original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flic

kr.com/photos/143529236@N06/48912086568/

. License: Creative Commons Attribution-Share

Alike 4.0 International

•

Images of NGC6362 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei

from the original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flic

kr.com/photos/143529236@N06/43257251884/

. License: Creative Commons Attribution-Share

Alike 4.0 International

•

Images of NGC6760 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei

from the original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flic

kr.com/photos/143529236@N06/51137814465/

. License: Creative Commons Attribution-Share

Alike 4.0 International

•

Images of Sh2-112 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei from

the original ﬁle. The original image ﬁle was published by Carsten Frenzl at

https://flickr.com

/photos/castro-pic/50667636156/. License: Creative Commons Attribution 4.0 International

•

Images of Sh2-112 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei from

the original ﬁle. The original image ﬁle was published by Carsten Frenzl at

https://flickr.com

/photos/castro-pic/50666893358/. License: Creative Commons Attribution 4.0 International

•

Images of NGC2985 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei

from the original ﬁle. The original image ﬁle was published by Carsten Frenzl at

https://flic

kr.com/phot os/191225735@N03/51941 601154

. License: Creative Commons Attribution 4.0

International

•

Images of M9 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei from the

original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flickr.com

/photos/143529236@N06/48912773222/

. License: Creative Commons Attribution-Share Alike

4.0 International

•

Images of M68 This image ﬁle was remixed, transformed, and post-processed by Sun Shuwei from

the original ﬁle. The original image ﬁle was published by Yu-Hang Kuo at

https://www.flickr

.com /photos/1435292 36@N06/47278554542/

. License: Creative Commons Attribution-Share

Alike 4.0 International

•

Images of Sh2-280 from Wang Jianjun, post-processing: Sun Shuwei License: Creative Commons

Attribution 4.0 International

•

Images of Sh2-282, Sh2-284 from ESO/Digitized Sky Survey 2. Acknowledgement: Davide De

Martin, post-processing: Sun Shuwei

http://eso.org/public/

License: Creative Commons

Attribution 4.0 International

•

Images of NGC7048 from KPNO/NOIRLab/NSF/AURA/Richard Robinson and Beverly Erdman/Adam

Block, post-processing: Sun Shuwei

https://noirlab.edu/public/

License: Creative Commons

Attribution 4.0 International

•

Images of NGC4449 from KPNO/NOIRLab/NSF/AURA/John and Christie Connors/Adam Block,

post-processing: Sun Shuwei

https://noirlab.edu/public/

License: Creative Commons

Attribution 4.0 International

H.7 Graphics 405

•

Images of NGC3640 from ESO/INAF/M. Mirabile et al./R. Ragusa et al, post-processing: Sun Shuwei

http://www.eso.org/public/ License: Creative Commons Attribution 4.0 International

H.7.1 Full credits for “earthmap” texture

Author: Reto Stockli, NASA Earth Observatory, rstockli(at)climate.gsfc.nasa.gov

Address of correspondence: Reto Stockli

ETH/IAC (NFS Klima) & NASA/GSFC Code 913 (SSAI)

University Irchel

Building 25 Room J53

Winterthurerstrasse 190

8057 Zurich, Switzerland

Phone: +41 (0)1 635 5209

Fax: +41 (0)1 362 5197

Email: rstockli(at)climate.gsfc.nasa.gov

URL: http://earthobservatory.nasa.gov, http://www.iac.ethz.ch/staff/stockli

Supervisors: Fritz Hasler and David Herring, NASA/Goddard Space Flight Center

Funding: This project was realized under the SSAI subcontract 2101-01-027 (NAS5-01070)

License:

“Any and all materials published on the Earth Observatory are freely available for re-publication

or re-use, except where copyright is indicated.”

H.7.2 License for the JPL planets images

From http://www.jpl.nasa.gov/images/policy/index.cfm:

Unless otherwise noted, images and video on JPL public web sites (public sites ending with a

jpl.nasa.gov

address) may be used for any purpose without prior permission, subject to the

special cases noted below. Publishers who wish to have authorization may print this page and

retain it for their records; JPL does not issue image permissions on an image by image basis.

By electing to download the material from this web site the user agrees:

that Caltech makes no representations or warranties with respect to ownership of copy-

rights in the images, and does not represent others who may claim to be authors or

owners of copyright of any of the images, and makes no warranties as to the quality of

the images. Caltech shall not be responsible for any loss or expenses resulting from the

use of the images, and you release and hold Caltech harmless from all liability arising

from such use.

to use a credit line in connection with images. Unless otherwise noted in the caption

information for an image, the credit line should be “Courtesy NASA/JPL-Caltech.”

that the endorsement of any product or service by Caltech, JPL or NASA must not be

claimed or implied.

Special Cases:

•

Prior written approval must be obtained to use the NASA insignia logo (the blue “meat-

ball” insignia), the NASA logotype (the red “worm” logo) and the NASA seal. These

images may not be used by persons who are not NASA employees or on products (in-

cluding Web pages) that are not NASA sponsored. In addition, no image may be used to

explicitly or implicitly suggest endorsement by NASA, JPL or Caltech of commercial

goods or services. Requests to use NASA logos may be directed to Bert Ulrich, Public

Services Division, NASA Headquarters, Code POS, Washington, DC 20546, telephone

(202) 358-1713, fax (202) 358-4331, email bert.ulrich(at)hq.nasa.gov.

•

Prior written approval must be obtained to use the JPL logo (stylized JPL letters in red

or other colors). Requests to use the JPL logo may be directed to the Television/Imaging

Team Leader, Media Relations Ofﬁce, Mail Stop 186-120, Jet Propulsion Laboratory,

Pasadena CA 91109, telephone (818) 354-5011, fax (818) 354-4537.

•

If an image includes an identiﬁable person, using the image for commercial purposes may

infringe that person’s right of privacy or publicity, and permission should be obtained

from the person. NASA and JPL generally do not permit likenesses of current employees

to appear on commercial products. For more information, consult the NASA and JPL

points of contact listed above.

•

JPL/Caltech contractors and vendors who wish to use JPL images in advertising or public

relation materials should direct requests to the Television/Imaging Team Leader, Media

406 Appendix H. Acknowledgements

Relations Ofﬁce, Mail Stop 186-120, Jet Propulsion Laboratory, Pasadena CA 91109,

telephone (818) 354-5011, fax (818) 354-4537.

•

Some image and video materials on JPL public web sites are owned by organizations

other than JPL or NASA. These owners have agreed to make their images and video

available for journalistic, educational and personal uses, but restrictions are placed on

commercial uses. To obtain permission for commercial use, contact the copyright owner

listed in each image caption. Ownership of images and video by parties other than JPL

and NASA is noted in the caption material with each image.

H.7.3 DSS

From http://archive.stsci.edu/dss/acknowledging.html:

The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S.

Government grant NAG W-2166. The images of these surveys are based on photographic

data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt

Telescope. The plates were processed into the present compressed digital form with the

permission of these institutions.

The National Geographic Society - Palomar Observatory Sky Atlas (POSS-I) was made by

the California Institute of Technology with grants from the National Geographic Society.

The Second Palomar Observatory Sky Survey (POSS-II) was made by the California

Institute of Technology with funds from the National Science Foundation, the National Geo-

graphic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak

Corporation.

The Oschin Schmidt Telescope is operated by the California Institute of Technology and

Palomar Observatory.

The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with

funding from the UK Science and Engineering Research Council (later the UK Particle Physics

and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian

Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together

known as the SERC-J), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey

(SES) were all taken with the UK Schmidt.

All data are subject to the copyright given in the copyright summary

. Copyright informa-

tion speciﬁc to individual plates is provided in the downloaded FITS headers.

Supplemental funding for sky-survey work at the ST ScI is provided by the European

Southern Observatory.

http://archive.stsci.edu/dss/copyright.html

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Index

aberration of light . . . . . . . . . . . . . . . . . . 25, 258

absolute magnitude . . . . . . . . . . . . . . . . . . . . 254

Adams, Douglas . . . . . . . . . . . . . . . . . . . . . . . 248

air mass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .272

Almagest. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

American Association of Variable Star Observers

148

Andromeda Galaxy. . . . . . . . . . . . . . . . . . . . .287

annual parallax . . . . . . . . . . . . . . . . . . . . . . . . 257

antisolar point . . . . . . . . . . . . . . . . . . . . . . . . . 247

apogee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186

apparent magnitude . . . . . . . . . . . . . . . . . . . . 254

apparent radiant . . . . . . . . . . . . . . . . . . . . . . . 179

ASCOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

ashen glow . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

asterisms . . . . . . . . . . . . . . . . . . . . . . . . . 105, 116

Atmospheric Extinction . . . . . . . . . . . . . . . . 272

Atmospheric Refraction . . . . . . . . . . . . . . . . 272

Augustus . . . . . . . . . . . . . . . . . . . . . . . . . 154, 377

azimuth . . . . . . . . . . . . . . . . . . . . . . . . . . 244, 246

Barnard’s Star. . . . . . . . . . . . . . . . . . . . .258, 289

Bayer, Johann . . . . . . . . . . . . . . . . . . . . . . . . . 262

binoculars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

Blazhko effect . . . . . . . . . . . . . . . . . . . . . . . . . 314

Bortle, John E. . . . . . . . . . . . . . . . . . . . . . . . . 301

Bradley, James . . . . . . . . . . . . . . . . . . . . . . . . 258

Brahe, Tycho . . . . . . . . . . . . . . . . . . . . . . . . . . 247

brown dwarfs. . . . . . . . . . . . . . . . . . . . . . . . . . 264

Caesar, Julius . . . . . . . . . . . . . . . . . . . . . 154, 377

cardinal points . . . . . . . . . . . . . . . . . . . . . . . . . 244

Celestial Equator . . . . . . . . . . . . . . . . . . . . . . 244

Celestial Poles . . . . . . . . . . . . . . . . . . . . . . . . . 243

Celestial Sphere . . . . . . . . . . . . . . . . . . . . . . . 243

central meridian . . . . . . . . . . . . . . . . . . . . . . . 366

Chauvenet, William . . . . . . . . . . . . . . . . . . . . 271

circumpolar. . . . . . . . . . . . . . . . . . . . . . .191, 245

Colure

Equinoctial. . . . . . . . . . . . . . . . . . . . . . . .246

Solstitial . . . . . . . . . . . . . . . . . . . . . . . . . . 246

conﬁguration ﬁle . . . . . . . . . . . . . . . . . . . . . . . .59

conjunction. . . . . . . . . . . . . . . . . . . . . . . . . . . .247

conjunction, inferior. . . . . . . . . . . . . . . . . . . .247

conjunction, superior . . . . . . . . . . . . . . . . . . . 247

constellation. . . . . . . . . . . . . . . . . . . . . . . . . . .114

area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

convex hull. . . . . . . . . . . . . . . . . . . . . . . .115

dark . . . . . . . . . . . . . . . . . . . . . . . . . 114, 115

single-star. . . . . . . . . . . . . . . . . . . . . . . . .114

contact times . . . . . . . . . . . . . . . . . . . . . . . . . . 272

Coordinate System

Ecliptical . . . . . . . . . . . . . . . . . . . . . . . . . 247

Equatorial. . . . . . . . . . . . . . . . . . . . . . . . .244

Fixed Equatorial . . . . . . . . . . . . . . . . . . . 247

Galactic . . . . . . . . . . . . . . . . . . . . . . . . . . 248

Horizontal . . . . . . . . . . . . . . . . . . . . . . . . 244

coordinates,planetocentric . . . . . . . . . . . . . . 367

coordinates,planetographic . . . . . . . . . . . . . . 367

Cortés, Hernán. . . . . . . . . . . . . . . . . . . . . . . . .157

418 Index

COSPAR ID (satellite ID) . . . . . . . . . . . . . . 185

crossbow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

culmination, lower . . . . . . . . . . . . . . . . . . . . . 245

culmination, upper . . . . . . . . . . . . . . . . . . . . . 245

Danjon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Danjon scale. . . . . . . . . . . . . . . . . . . . . . . . . . .271

Danjon, André . . . . . . . . . . . . . . . . . . . . . . . . . 271

DE430 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

DE431 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

DE440 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

DE441 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

declination . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

Deep-sky objects. . . . . . . . . . . . . . . . . . . . . . . .32

deﬁning stars . . . . . . . . . . . . . . . . . . . . . . . . . . 119

digression, greatest. . . . . . . . . . . . . . . . . . . . .246

double stars . . . . . . . . . . . . . . . . . . . . . . . . . . . 320

Doyle, Brian. . . . . . . . . . . . . . . . . . . . . . . . . . . .74

dwarf stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

earthshine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

ecliptic . . . . . . . . . . . . . . . . . . . . . . . . . . . 245, 247

ecliptical latitude. . . . . . . . . . . . . . . . . . . . . . .247

ecliptical longitude . . . . . . . . . . . . . . . . . . . . . 247

ECMAScript . . . . . . . . . . . . . . . . . . . . . . . . . . 233

elongation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

elongation, eastern . . . . . . . . . . . . . . . . . . . . . 247

elongation, western . . . . . . . . . . . . . . . . . . . . 247

epoch . . . . . . . . . . . . . . . . . . . . . . . . 149, 268, 357

equator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

equinox . . . . . . . . . . . . . . . . . . . . . . . . . . 245, 357

Evening Star . . . . . . . . . . . . . . . . . . . . . . . . . . 120

exoplanets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

FAQ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10, 393

First Point of Aries. . . . . . . . . . . . . . . . . . . . . 245

First Point of Cancer . . . . . . . . . . . . . . . . . . . 246

First Point of Capricorn. . . . . . . . . . . . . . . . .246

FITS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99

Flamsteed, John . . . . . . . . . . . . . . . . . . . . . . . 262

galactic latitude . . . . . . . . . . . . . . . . . . . . . . . .248

galactic longitude . . . . . . . . . . . . . . . . . . . . . . 248

General Catalogue of Variable Stars . . . . . 148

giants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

GPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Great Red Spot . . . . . . . . . . . . . . . . . . . . . . . . 248

Halley, Edmund . . . . . . . . . . . . . . . . . . . 268, 359

Hammer, Ernst von. . . . . . . . . . . . . . . . . . . . . .30

Handy Angles . . . . . . . . . . . . . . . . . . . . . 253, 287

help rays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Herschel, John. . . . . . . . . . . . . . . . . . . . . . . . .250

Hertzsprung, Ejnar . . . . . . . . . . . . . . . . . . . . . 264

Hierarchical Progressive Surveys . . . . . . . . 125

Hipparchus. . . . . . . . . . . . . . . . . . .247, 254, 262

Hour Angle . . . . . . . . . . . . . . . . . . . . . . . 247, 250

IAU . . 138, 165, 251, 260, 262, 266, 340, 355,

365–367, 369, 377

ICRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

INDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

inferior planets. . . . . . . . . . . . . . . . . . . . . . . . .271

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

installation directory. . . . . . . . . . . . . . . . . . . . .57

International Variable Star Index . . . . . . . . 148

International Virtual Observatory Alliance125

JavaScript . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

JPL Horizons . . . . . . . . . . . . . . . . . . . . . . . . . . 361

Julian Day . . . . . . . . . . . . . . . . . . . . . . . . . 19, 250

Modiﬁed . . . . . . . . . . . . . . . . . . . . . . 19, 250

Kepler orbits . . . . . . . . . . . . . . . . . . . . . . 149, 268

Kepler, exoplanets . . . . . . . . . . . . . . . . . . . . . 164

Kepler, Johannes . . . . . . . . . . . . . . . . . . 149, 268

Libration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .248

logﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

luminosity class . . . . . . . . . . . . . . . . . . . . . . . 264

lunar mansions . . . . . . . . . . . . . . . . . . . . . . . . 119

lunar stations . . . . . . . . . . . . . . . . . . . . . . . . . . 118

INDEX 419

M31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270, 287

Magellanic Cloud

Large . . . . . . . . . . . . . . . . . . . . . . . . 269, 282

Small . . . . . . . . . . . . . . . . . . . . . . . . 269, 283

magnitudes, instrumental . . . . . . . . . . . . . . . 267

magnitudes, visual . . . . . . . . . . . . . . . . . . . . . 267

main sequence . . . . . . . . . . . . . . . . . . . . . . . . . 263

mathematical horizon . . . . . . . . . . . . . . . . . . 244

Mayer, Johann Tobias . . . . . . . . . . . . . . . . . . 280

Mercator, Gerardus. . . . . . . . . . . . . . . . . . . . . .30

meridian convergence . . . . . . . . . . . . . . . . . . 200

Messier, Charles . . . . . . . . . . . . . . . . . . . . . . . 269

meteor shower . . . . . . . . . . . . . . . . . . . . . . . . . 179

meteoroids . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Milankovi

c, Milutin . . . . . . . . . . . . . . . . . . . . 154

Milky Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

Miller, Osborn Maitland . . . . . . . . . . . . . . . . . 30

Moore, Patrick. . . . . . . . . . . . . . . . . . . . . . . . .270

Morning Star . . . . . . . . . . . . . . . . . . . . . . . . . . 120

nadir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

nakshatras. . . . . . . . . . . . . . . . . . . . . . . . . . . . .118

NMEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Northern Ecliptical Pole . . . . . . . . . . . . . . . . 247

obliquity, ecliptic . . . . . . . . . . . . . 191, 247, 255

opposition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

opposition surge . . . . . . . . . . . . . . . . . . . . . . . 266

Opposition/Conjunction Line. . . . . . . . . . . .247

orbital elements, osculating. . . . . . . . .149, 268

parallax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

penumbra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

perigee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

planetary nebulae . . . . . . . . . . . . . . . . . . . . . . 248

plate solving. . . . . . . . . . . . . . . . . . . . . . . . . . . .99

Pogson, Norman . . . . . . . . . . . . . . . . . . . . . . . 254

pole, celestial . . . . . . . . . . . . . . . . . . . . . 245, 246

population index . . . . . . . . . . . . . . . . . . . . . . . 179

Pound, James . . . . . . . . . . . . . . . . . . . . . . . . . . 280

precession . . . . . . . . . . . . . . . . . . . 245, 248, 255

precession circles . . . . . . . . . . . . . . . . . . . . . . 247

proper motion . . . . . . . . . . . . . . . . . . . . . . . . . 258

Ptolemy . . . . . . . . . . . . . . . . . . . . . 155, 247, 262

pulsars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .248

quadrature. . . . . . . . . . . . . . . . . . . . . . . . . . . . .247

radiant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

RCS, Radar Cross Section. . . . . . . . . .185, 188

Right ascension . . . . . . . . . . . . . . . . . . . . . . . .244

Right Ascension/Declination . . . . . . . . . . . . 244

rotation,prograde . . . . . . . . . . . . . . . . . . . . . . 366

rotation,retrograde . . . . . . . . . . . . . . . . . . . . . 366

RTS2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

Russell, Henry Norris . . . . . . . . . . . . . . . . . . 264

scintillation . . . . . . . . . . . . . . . . . . . . . . . . 29, 276

screenshot save directory. . . . . . . . . . . . . . . . .57

script save directory . . . . . . . . . . . . . . . . . . . . . 57

sidereal time . . . . . . . . . . . . . . . . . . . . . . . . . . 250

sky culture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

sky survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

solar longitude. . . . . . . . . . . . . . . . . . . . . . . . .180

solstice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .191

Sosigenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

spectral types . . . . . . . . . . . . . . . . . . . . . . . . . .263

spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

standard epoch . . . . . . . . . . . . . . . . . . . . . . . . 245

standard magnitude (satellites) . . . . . . . . . . 185

stellar parallax . . . . . . . . . . . . . . . . . . . . . . . . . 257

subsolar point . . . . . . . . . . . . . . . . . . . . . . . . . 366

super-giants . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

terminator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

time dragging. . . . . . . . . . . . . . . . . . . . . . . . . . .13

TLE, two-line element. . . . . . . . . . . . . . . . . .185

Tsenpo, Nyatri. . . . . . . . . . . . . . . . . . . . . . . . .156

twilight

astronomical . . . . . . . . . . . . . . . . . . . . . . 259

civil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

nautical . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

umbra. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .271

420 Index

undersampling . . . . . . . . . . . . . . . . . . . . . . . . . . 45

user data directory. . . . . . . . . . . . . . . . . . . . . . .57

user directory . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Venus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

vernal equinox. . . . . . . . . . . . . . . . . . . . . . . . .245

VSOP87 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

WGCCRE. . . . . . . . . . . . . . . . . . . . . . . . . . . . .377

white dwarfs . . . . . . . . . . . . . . . . . . . . . . . . . . 264

zenith. . . . . . . . . . . . . . . . . . . . . . . .243, 244, 246

Zenithal Hourly Rate . . . . . . . . . . . . . . . . . . . 179

zodiac

sidereal . . . . . . . . . . . . . . . . . . . . . . 117, 156

tropical . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

zodiacal signs . . . . . . . . . . . . . . . . . . . . . . . . . 117