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NOVAS31GeoPosVel Method
This function computes the geocentric position and velocity of an observer on the surface of the earth or on a near-earth spacecraft.

Namespace: ASCOM.Astrometry.NOVAS
Assembly: ASCOM.Astrometry (in ASCOM.Astrometry.dll) Version: 6.0.0.0 (6.3.0.2839)
Syntax
public short GeoPosVel(
	double JdTt,
	double DeltaT,
	Accuracy Accuracy,
	Observer Obs,
	ref double[] Pos,
	ref double[] Vel
)

Parameters

JdTt
Type: SystemDouble
TT Julian date.
DeltaT
Type: SystemDouble
Value of Delta T (= TT - UT1) at 'JdTt'.
Accuracy
Type: ASCOM.AstrometryAccuracy
Selection for accuracy
Obs
Type: ASCOM.AstrometryObserver
Data specifying the location of the observer
Pos
Type: SystemDouble
Position vector of observer, with respect to origin at geocenter, referred to GCRS axes, components in AU.
Vel
Type: SystemDouble
Velocity vector of observer, with respect to origin at geocenter, referred to GCRS axes, components in AU/day.

Return Value

Type: Int16
 0 ... everything OK
 1 ... invalid value of 'Accuracy'.
 
Remarks
The final vectors are expressed in the GCRS.
See Also