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astGetRefPos - Return the reference position in a specified celestial coordinate system

Description:
This function returns the reference position (specified by attributes RefRA and RefDec) converted to the celestial coordinate system represented by a supplied SkyFrame. The celestial longitude and latitude values are returned in radians.

Synopsis:
void astGetRefPos( AstSpecFrame *this, AstSkyFrame *frm, double *lon, double *lat )

Parameters:
this
Pointer to the SpecFrame.
frm
Pointer to the SkyFrame which defines the required celestial coordinate system. If NULL is supplied, then the longitude and latitude values are returned as FK5 J2000 RA and Dec values.
lon
A pointer to a double in which to store the longitude of the reference point, in the coordinate system represented by the supplied SkyFrame (radians).
lat
A pointer to a double in which to store the latitude of the reference point, in the coordinate system represented by the supplied SkyFrame (radians).

Notes:
  • Values of AST__BAD will be returned if this function is invoked with the AST error status set, or if it should fail for any reason.



next up previous
Next: astGrfPop - Restore previously saved graphics functions used by a Plot
Up: AST Function Descriptions
Previous: astGetMapping - Obtain a Mapping that converts between two Frames in a FrameSet

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
30th April 2003
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2003 Central Laboratory of the Research Councils