Converts GCRS right ascension and declination to coordinates with respect to the equator of date (mean or true).

Namespace: ASCOM.Astrometry.NOVAS
Assembly: ASCOM.Astrometry (in ASCOM.Astrometry.dll) Version: 6.0.0.0 (6.1.1.2619)

Syntax

C#
public short Gcrs2Equ(
	double JdTt,
	CoordSys CoordSys,
	Accuracy Accuracy,
	double RaG,
	double DecG,
	ref double Ra,
	ref double Dec
)
Visual Basic
Public Function Gcrs2Equ ( _
	JdTt As Double, _
	CoordSys As CoordSys, _
	Accuracy As Accuracy, _
	RaG As Double, _
	DecG As Double, _
	ByRef Ra As Double, _
	ByRef Dec As Double _
) As Short
Visual C++
public:
virtual short Gcrs2Equ(
	double JdTt, 
	CoordSys CoordSys, 
	Accuracy Accuracy, 
	double RaG, 
	double DecG, 
	double% Ra, 
	double% Dec
) sealed

Parameters

JdTt
Type: System..::..Double
TT Julian date of equator to be used for output coordinates.
CoordSys
Type: ASCOM.Astrometry..::..CoordSys
Coordinate system selection for output coordinates.; 0 ... mean equator and equinox of date; 1 ... true equator and equinox of date; 2 ... true equator and CIO of date
Accuracy
Type: ASCOM.Astrometry..::..Accuracy
Selection for accuracy
RaG
Type: System..::..Double
GCRS right ascension in hours.
DecG
Type: System..::..Double
GCRS declination in degrees.
Ra
Type: System..::..Double%
Right ascension in hours, referred to specified equator and right ascension origin of date.
Dec
Type: System..::..Double%
Declination in degrees, referred to specified equator of date.

Return Value

    0 ... everything OK
 >  0 ... error from function 'Vector2RaDec'' 
 > 10 ... 10 + error from function 'CioLocation'
 > 20 ... 20 + error from function 'CioBasis'
 
>

Remarks

For coordinates with respect to the true equator of date, the origin of right ascension can be either the true equinox or the celestial intermediate origin (CIO).

This function only supports the CIO-based method.

See Also