GSSSADXY

       Converts RA and DEC (J2000) to (X,Y) for an STScI GuideStar image.

       The sky coordinates may be printed and/or returned in variables.

       GSSSADXY, GSA, Ra,Dec, [ X, Y, /Print ]

       GSA - the GSSS Astrometry structure created by GSSSEXTAST
       RA  - the RA coordinate(s) in *degrees*, scalar or vector
       DEC - the DEC coordinate(s) in *degrees*, scalar or vector

       /PRINT - If this keyword is set and non-zero, then coordinates will be
               displayed at the terminal

       X - the corresponding X pixel coordinate(s), double precision
       Y - the corresponding Y pixel coordinate(s), double precision
       X and Y will be in IDL convention (first pixel 0,0)

       Given a FITS header, hdr, from the STScI Guidestar Survey, determine
       the X,Y coordinates of 3C 273 (RA = 12 29 6.7  +02 03 08)
       IDL> GSSSEXTAST, hdr, gsa          ;Extract astrometry structure
       IDL> GSSSADXY, gsa, ten(12,29,6.7)*15,ten(2,3,8),/print

       For most purpose users can simply use ADXY, which will call GSSSADXY
       if it is passed a GSSS header.

       ASTDISP - Print RA, Dec in standard format

       10-JUL-90 Version 1 written by Eric W. Deutsch
               Derived from procedures written by Brian McLean
       Vectorized code   W. Landsman        March, 1991
       14-AUG-91 Fixed error which caused returned X and Y to be .5 pixels too
               large.  Now X,Y follows same protocol as ADXY.
       June 1994 - Dropped PRFLAG parameter, added /PRINT  W. Landsman (HSTX)
       Converted to IDL V5.0   W. Landsman   September 1997
       29-JUN-99 Added support for AMD[X,Y]1[2-3] for DSS images by E. Deutsch
       Reduce memory requirements for large arrays D. Finkbeiner April 2004

[Home Page] [Software, Documentation] [IDL Documentation] [Quick Reference] [Feedback]