NAME: 
  obsplan
 PURPOSE:
  Generate a graphical summary of object location(s) for a given night.
 DESCRIPTION:
 CATEGORY:
  Astronomy
 CALLING SEQUENCE:
  obsplan,objcode,obs,date
 INPUTS:
  objcode - String array of standard object codes (see ephem.pro)
              -or-
            String containing file name of the list of objects but you
              must preceed the file name with @ to mark it as a file
              and not the name of an object.
            If supplied as a file, this file is a correspondence list
              of the type read by rdmatch.  Column 1 contains the standard
              object code and column 2 has a full or common name.  The
              columns are separated by a  character and the common name
              column MUST begin with a single quote (').  See RDMATCH
              for more details about this file format.
  obs     - Integer Marsden code of the observatory
               688 - Lowell Observatory
               500 - Geocentric
               If you provide an invalid code, 688 is assumed.
  date    - UT date and time vector near midnight,
                 [year,month,day,hour,minutes,seconds]
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
  ALLDAY  - Flag, if set generates a plot for a full 24 hour period.
  AMLIMIT - Cutoff airmass for plot, default = 2.6
  OBSFILE - Override on file name where observatory codes are to be found.
  STARCAT - Override on file name where star catalog is to be found (see
              coord for default).
 OUTPUTS:
  Generates a plot to the current graphics device.
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
 MODIFICATION HISTORY:
  94/10/07, Initial version written by Marc W. Buie, Lowell Observatory
  96/02/08, MWB, added parameter validation, airmass limit option,
                    and file option on objcode
  96/02/15, MWB, added support for star lookup and plotting.  Also, now
                    computes object position throughout night instead of
                    just at midnight.
  96/03/19, MWB, allow JD for input date.
  96/10/18, MWB, fixed bug that ignored h,m,s in input date.
  96/11/1,  MWB, Added ALLDAY keyword
  98/09/28, MWB, Fixed a coordinate interpolation bug.
  99/01/27, MWB, added support for stars.
  99/02/23, MWB, fixed some lingering problems.
  2001/03/16, David Tucker, changed rdobscod default file call.
  2002/12/04, MWB, added support for strings in obs input.