ArchaeoLines Plug-in

Classes
class	ArchaeoLinesDialog
	Main window of the ArchaeoLines plug-in. More...
class	SkyLine
	GridLinesMgr.cpp at V0.13.2, but with small-circle drawing. More...

Detailed Description

A tool for archaeo-/ethnoastronomical alignment studies.

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.

1. Declinations of equinoxes (i.e. equator) and the solstices
2. Declinations of the crossquarter days (days right between solstices and equinoxes)
3. Declinations of the Major Lunar Standstills
4. Declinations of the Minor Lunar Standstills
5. Declination of the Zenith passage
6. Declination of the Nadir passage
7. Declination of the currently selected object
8. Current declination of the sun
9. Current declination of the moon
10. Current declination of a naked-eye planet

Some religions, most notably Islam, adhere to a practice of observing a prayer direction towards a particular location. Azimuth lines (vertical semicircles from zenith to nadir) for two locations can be shown. Default locations are Mecca (Kaaba) and Jerusalem. The directions are computed based on spherical trigonometry on a spherical Earth. In addition, up to 2 custom azimuth lines, and up to 2 custom declination lines can be drawn, also with customized labels.

The lunar lines include horizon parallax effects. There are two lines each drawn, for maximum and minimum distance of the moon. Note that declination of the moon at the major standstill can exceed the indicated limits if it is high in the sky due to parallax effects.

It may be very instructive to let the time run quite fast and observe the line of "current moon" swinging between its north and south limits each month. These limits grow and shrink between the Major and Minor Standstills.

The sun likewise swings between the solstices. Over centuries, the solstice declinations very slightly move as well.