Extinction Class Reference

This class performs extinction computations, following literature from atmospheric optics and astronomy. More...

#include <RefractionExtinction.hpp>

Public Types
enum	UndergroundExtinctionMode { UndergroundExtinctionZero = 0, UndergroundExtinctionMax = 1, UndergroundExtinctionMirror = 2 }
	Define the extinction strategy for rendering underground objects (useful when ground is not rendered) More...

Public Member Functions
void	forward (const Vec3d &altAzPos, float *mag) const
	Compute extinction effect for arrays of size num position vectors and magnitudes. More...
void	forward (const Vec3f &altAzPos, float *mag) const
void	backward (const Vec3d &altAzPos, float *mag) const
	Compute inverse extinction effect for arrays of size num position vectors and magnitudes. More...
void	backward (const Vec3f &altAzPos, float *mag) const
void	setExtinctionCoefficient (float k)
	Set visual extinction coefficient (mag/airmass), influences extinction computation. More...
float	getExtinctionCoefficient () const
void	setUndergroundExtinctionMode (UndergroundExtinctionMode mode)
UndergroundExtinctionMode	getUndergroundExtinctionMode () const

Detailed Description

This class performs extinction computations, following literature from atmospheric optics and astronomy.

Airmass computations are limited to meaningful altitudes. The solution provided here will [hopefully!] result in a visible "zone of avoidance" near the horizon down to altitude -2, and may show stars in their full brightness below -2 degrees. Typical horizons do not go down below -1, so all natural sites should be covered. Note that forward/backward are no absolute reverse operations! All the computations should be in effect (1) only if atmosphere effects are true (2) only for terrestrial locations, not on Moon/Mars/Saturn etc config.ini:astro/flag_extinction_below_horizon=true|false controls if extinction kills objects below -2 degrees altitude by setting airmass to 42.

Definition at line 45 of file RefractionExtinction.hpp.

Member Enumeration Documentation

enum Extinction::UndergroundExtinctionMode

Define the extinction strategy for rendering underground objects (useful when ground is not rendered)

Enumerator
UndergroundExtinctionZero	Zero extinction: stars visible in full brightness.
UndergroundExtinctionMax	Maximum extinction: coef 42, i.e practically invisible.
UndergroundExtinctionMirror	Mirror the extinction for the same altutide above the ground.

Definition at line 49 of file RefractionExtinction.hpp.

Member Function Documentation

void Extinction::backward ( const Vec3d &  altAzPos, float *  mag  ) const

inline

Compute inverse extinction effect for arrays of size num position vectors and magnitudes.

Parameters

altAzPos

are the NORMALIZED (!!) (geometrical) star position vectors, and their z components sin(geometric_altitude). Note that forward/backward are no absolute reverse operations!

Definition at line 76 of file RefractionExtinction.hpp.

void Extinction::forward ( const Vec3d &  altAzPos, float *  mag  ) const

inline

Compute extinction effect for arrays of size num position vectors and magnitudes.

Parameters

altAzPos

are the NORMALIZED (!!) (geometrical) star position vectors, and their z components sin(geometric_altitude). This call must therefore be done before application of Refraction if atmospheric effects are on. Note that forward/backward are no absolute reverse operations!

Definition at line 61 of file RefractionExtinction.hpp.

void Extinction::setExtinctionCoefficient ( float  k )

inline

Set visual extinction coefficient (mag/airmass), influences extinction computation.

Parameters

k=	0.1 for highest mountains, 0.2 for very good lowland locations, 0.35 for typical lowland, 0.5 in humid climates.

Definition at line 88 of file RefractionExtinction.hpp.

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The documentation for this class was generated from the following file:

• /home/aw/devel/stellarium/0.15/src/core/RefractionExtinction.hpp