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NOVAS31Ter2Cel Method
This function rotates a vector from the terrestrial to the celestial system.

Namespace: ASCOM.Astrometry.NOVAS
Assembly: ASCOM.Astrometry (in ASCOM.Astrometry.dll) Version: 6.0.0.0 (6.3.0.2839)
Syntax
public short Ter2Cel(
	double JdHigh,
	double JdLow,
	double DeltaT,
	Method Method,
	Accuracy Accuracy,
	OutputVectorOption OutputOption,
	double xp,
	double yp,
	double[] VecT,
	ref double[] VecC
)

Parameters

JdHigh
Type: SystemDouble
High-order part of UT1 Julian date.
JdLow
Type: SystemDouble
Low-order part of UT1 Julian date.
DeltaT
Type: SystemDouble
Value of Delta T (= TT - UT1) at the input UT1 Julian date.
Method
Type: ASCOM.AstrometryMethod
Selection for method: 0 ... CIO-based method; 1 ... equinox-based method
Accuracy
Type: ASCOM.AstrometryAccuracy
Selection for accuracy
OutputOption
Type: ASCOM.AstrometryOutputVectorOption
0 ... The output vector is referred to GCRS axes; 1 ... The output vector is produced with respect to the equator and equinox of date.
xp
Type: SystemDouble
Conventionally-defined X coordinate of celestial intermediate pole with respect to ITRF pole, in arcseconds.
yp
Type: SystemDouble
Conventionally-defined Y coordinate of celestial intermediate pole with respect to ITRF pole, in arcseconds.
VecT
Type: SystemDouble
Position vector, geocentric equatorial rectangular coordinates, referred to ITRF axes (terrestrial system) in the normal case where 'option' = 0.
VecC
Type: SystemDouble
Position vector, geocentric equatorial rectangular coordinates, referred to GCRS axes (celestial system) or with respect to the equator and equinox of date, depending on 'Option'.

Return Value

Type: Int16
    0 ... everything is ok
    1 ... invalid value of 'Accuracy'
    2 ... invalid value of 'Method'
 > 10 ... 10 + error from function 'CioLocation'
 > 20 ... 20 + error from function 'CioBasis'
 
Remarks
'x' = 'y' = 0 means no polar motion transformation.

The 'option' flag only works for the equinox-based method.

See Also