NAME:
  gaiafcat
 PURPOSE:   (one line only)
  Read a full Gaia DR2 catalog and convert to the fixed epoch format file
 DESCRIPTION:
 CATEGORY:
  Astrometry
 CALLING SEQUENCE:
  gaiafcat,fnin,epoch,fnout
 INPUTS:
  fnin  - Name of the file to read.  This is the raw Data DR2 catalog file
           as generated by the external program, "grefnet".
  epoch - Epoch, in years, for the output catalog file.
  fnout - Name of the output file to generate.  The output is written
            as a binary catalog file.
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
 OUTPUTS:
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  2018/05/07, Written by Marc W. Buie, Southwest Research Institute