NAME:
  drtimes
 PURPOSE:   (one line only)
  Compute disappearance and reappearance times for an occultation given a shape
 DESCRIPTION:
 CATEGORY:
  Occultations
 CALLING SEQUENCE:
  drtimes,jd0,rastar,decstar,shape,obscode,objcode,jd_d,jd_r
 INPUTS:
  jd0 - Julian date of the occultation.  Can be a geocentric time or topocentric,
           it is used as a starting point to find the minimum separation for the
           given site.
  rastar - Right ascension of the occultation star, J2000, at the epoch of jd0
  decstar - Declination of the occultation star, J2000, at the epoch of jd0
  shape  - [N,2] array of xi,eta coordinates for the shape of the object.
             [*,0] are the xi coordinates, [*,1] are the eta coordinates.
             xi,eta are to be given in km for the projected outline of the
             object and should be a closed figure.  It is assumed that a given
             line across this shape can intersect the figure in at most two
             points.
  obscode - observatory code (see ephem.pro)
  objcode - object code (see ephem.pro)
 OPTIONAL INPUT PARAMETERS:
  obspos  - Used for a manual observatory location if obscode='G**'
              (see ephem.pro for additional information)
 KEYWORD INPUT PARAMETERS:
 OUTPUTS:
  jd_d - Julian date of the time of disappearance (=0 if no occultation)
  jd_r - Julian date of the time of re-appearance (=0 if no occultation)
 KEYWORD OUTPUT PARAMETERS:
 CONFIGURATION:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  Written by Marc W. Buie, Southwest Research Institute, 2022/01/27
  2023/09/12, MWB, added missing default value on DEBUG