Extinction Class Reference

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

#include <RefractionExtinction.hpp>

List of all members.

Public Member Functions
void	forward (const Vec3d *altAzPos, float *mag, const int num=1) const
	Compute extinction effect for arrays of size.
void	forward (const Vec3f *altAzPos, float *mag, const int num=1) const
void	forward (const double *sinAlt, float *mag, const int num) const
void	forward (const float *sinAlt, float *mag, const int num) const
void	forward (const double *sinAlt, float *mag) const
void	forward (const float *sinAlt, float *mag) const
void	backward (const Vec3d *altAzPos, float *mag, const int num=1) const
	Compute inverse extinction effect for arrays of size.
void	backward (const Vec3f *altAzPos, float *mag, const int num=1) const
void	backward (const double *sinAlt, float *mag, const int num=1) const
void	backward (const float *sinAlt, float *mag, const int num=1) const
void	setExtinctionCoefficient (float k)
	Set visual extinction coefficient (mag/airmass), influences extinction computation.
float	getExtinctionCoefficient () const

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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.

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Member Function Documentation

void Extinction::backward	(	const Vec3d *	altAzPos,
		float *	mag,
		const int	num = 1
	)			const

Compute inverse extinction effect for arrays of size.

Parameters:

	num	position vectors and magnitudes.
	altAzPos	are the NORMALIZED (!!) (apparent) 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 int	num = 1
	)			const

Compute extinction effect for arrays of size.

Parameters:

	num	position vectors and magnitudes.
	altAzPos	are the NORMALIZED (!!) (apparent) star position vectors, and their z components sin(apparent_altitude). This call must therefore be done after application of Refraction, and only 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.