To convert right ascension and declination to ecliptic longitude and latitude.

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

Syntax

C#
public short Equ2Ecl(
	double JdTt,
	CoordSys CoordSys,
	Accuracy Accuracy,
	double Ra,
	double Dec,
	ref double ELon,
	ref double ELat
)
Visual Basic
Public Function Equ2Ecl ( _
	JdTt As Double, _
	CoordSys As CoordSys, _
	Accuracy As Accuracy, _
	Ra As Double, _
	Dec As Double, _
	ByRef ELon As Double, _
	ByRef ELat As Double _
) As Short
Visual C++
public:
virtual short Equ2Ecl(
	double JdTt, 
	CoordSys CoordSys, 
	Accuracy Accuracy, 
	double Ra, 
	double Dec, 
	double% ELon, 
	double% ELat
) sealed

Parameters

JdTt
Type: System..::..Double
TT Julian date of equator, equinox, and ecliptic used for coordinates.
CoordSys
Type: ASCOM.Astrometry..::..CoordSys
Coordinate system: 0 ... mean equator and equinox of date 'JdTt'; 1 ... true equator and equinox of date 'JdTt'; 2 ... ICRS
Accuracy
Type: ASCOM.Astrometry..::..Accuracy
Selection for accuracy
Ra
Type: System..::..Double
Right ascension in hours, referred to specified equator and equinox of date.
Dec
Type: System..::..Double
Declination in degrees, referred to specified equator and equinox of date.
ELon
Type: System..::..Double%
Ecliptic longitude in degrees, referred to specified ecliptic and equinox of date.
ELat
Type: System..::..Double%
Ecliptic latitude in degrees, referred to specified ecliptic and equinox of date.

Return Value

 0 ... everything OK
 1 ... invalid value of 'CoordSys'
 

Remarks

To convert ICRS RA and dec to ecliptic coordinates (mean ecliptic and equinox of J2000.0), set 'CoordSys' = 2; the value of 'JdTt' can be set to anything, since J2000.0 is assumed. Except for the input to this case, all input coordinates are dynamical.

See Also