SCOSPOS_XYTOAD - convert (X,Y) to (RA,Dec)

      SUBROUTINE SCOSPOS_XYTOAD ( X, Y, DTSYS__TRAN, PTSYS__TRAN,
     :  DEQIN__TRAN, PEPCH__TRAN, BAKCF__TC, DISTR__TC, RACEN__TC,
     :  DECEN__TC, PRMS__MO, ALPHA, DELTA, STATUS )

   X  =  DOUBLE PRECISION (Given)
      Plate X position measured by SuperCOSMOS (0.01 micron).
   Y  =  DOUBLE PRECISION (Given)
      Plate Y position measured by SuperCOSMOS (0.01 micron).
   DTSYS__TRAN = CHARACTER*12 (Given)
      Desired time system.
   PTSYS__TRAN = CHARACTER*12 (Given)
      Plate time system.
   DEQIN__TRAN = DOUBLE PRECISION (Given)
      Desired equinox.
   PEPCH__TRAN = DOUBLE PRECISION (Given)
      Plate epoch.
   BAKCF__TC(6) = DOUBLE PRECISION (Given)
      Transform coefficients: x,y to RA,dec.
   DISTR__TC = DOUBLE PRECISION (Given)
      Distortion coefficient.
   RACEN__TC = DOUBLE PRECISION (Given)
      Right Ascension of the plate centre (radians).
   DECEN__TC = DOUBLE PRECISION (Given)
      Declination of the plate centre (radians).
   PRMS__MO(35) = DOUBLE PRECISION (Given)
      array for converting mean to observed coordinates
   ALPHA  =  DOUBLE PRECISION (Returned)
      Right Ascension in the mean, desired system specified in the
      housekeeping file (radians).
   DELTA  =  DOUBLE PRECISION (Returned)
      Declination in the mean, desired system specified in the
      housekeeping file (radians).
   STATUS = INTEGER (Given and Returned)
      The global status.