NAME:
  rdxtrack
 PURPOSE:   (one line only)
  Read an occultation definition file
 DESCRIPTION:
 CATEGORY:
  File I/O
 CALLING SEQUENCE:
  rdxtrack,event,objectid,ra,dec,jdgeo,tsig,xsig
 INPUTS:
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
  FILE - File to read, default='xtrack.in'
 OUTPUTS:
  event    - Name of the event
  objectid - Object code (see ephem.pro)
  ra       - RA of star [radians]
  dec      - Dec of star [radians]
  jdgeo    - JD (UTC) of time of geocentric appulse [days]
  tsig     - 1-sigma uncertainty of event, downtrack [sec]
  xsig     - 1-sigma cross-track uncertainty of centerline [km]
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  Written by Marc W. Buie, Southwest Research Institute, 2020/03/29