Stellarium 0.13.0
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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 (usefull when ground is not rendered) More...
 

Public Member Functions

void forward (const Vec3d &altAzPos, float *mag) const
 Compute extinction effect for arrays of size. 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. 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.

Member Enumeration Documentation

Define the extinction strategy for rendering underground objects (usefull 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.

Member Function Documentation

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

Compute inverse extinction effect for arrays of size.

Parameters
numposition vectors and magnitudes.
altAzPosare the NORMALIZED (!!) (geometrical) star position vectors, and their z components sin(apparent_altitude). Note that forward/backward are no absolute reverse operations!
void Extinction::forward ( const Vec3d altAzPos,
float *  mag 
) const
inline

Compute extinction effect for arrays of size.

Parameters
numposition vectors and magnitudes.
altAzPosare the NORMALIZED (!!) (geometrical) star position vectors, and their z components sin(apparent_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!
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.