NAME:
  tnoobs
 PURPOSE:
  Real-time planning and field selection tool for TNO survey observations.
 DESCRIPTION:
  This is a non-blocking widget tool.  It expects to read a file with
    a list of field coordinates.  Here's a few lines from a file with the
    correct format (not including lead semi-colon):

F09711   18 28 48.0    -22 04 27.1  2000.0  0.0  0.0
F09767   18 36  0.0    -17 46 52.9  2000.0  0.0  0.0
F09775   18 36  0.0    -22 34 52.9  2000.0  0.0  0.0
F09850   18 45 36.0    -17 01 31.7  2000.0  0.0  0.0

   The first field is the name of the field.  Next is ra, dec, and epoch.
     The parser expects white space between each field.  Colons or commas
     imbedded in the coordinates won't work.  This file format happens to be
     what is expected by the CTIO telescope system.  You can load this file
     using the "Open" option under the "File" menu.

   There is a second file that is written as you tag fields with their
     observation date and time.  This file is named 'fieldobs.dat' and is
     written to the directory where you where when you start this program.
     This file records the start times of the two visits to the field.
     You must provide the y/m/d as well as h:m:s in the time field.  Here
     are a few example lines from observed fields:

F09711 2000/07/28 23:48:45 2000/07/29 02:38:50
F09767 2000/07/28 23:41:58 2000/07/29 02:33:09
F09775 2000/07/28 23:33:50
F09850 2000/07/28 23:55:46 2000/07/29 02:45:07

   If a field is not present, it hasn't yet been observed.  If a field has
     only been observed once you'll only see one time (like F09775 above).

   Because the tool is non-blocking, you can continue to use IDL normally
     from the command line while this tool is running.  But, only one
     copy of this tool is permitted at any given time.

 CATEGORY:
  Astronomy

 CALLING SEQUENCE:
  tnoobs

 INPUTS:

 OPTIONAL INPUT PARAMETERS:

 KEYWORD INPUT PARAMETERS:

  AMCRIT  - Airmass limit, default=2.5

  DT      - Offset from true time in hours (default=0), this is used
               mostly for testing.

  OBSFILE - Name of the file containing the observatory code information.
               Default is obscode.dat.  !PATH is scanned to find this file.

  OBSCODE - Observatory id code, default is '688' (Lowell Observatory)

 OUTPUTS:

 KEYWORD OUTPUT PARAMETERS:

 COMMON BLOCKS:

 SIDE EFFECTS:

 RESTRICTIONS:
  Only one instance at a time is allowed.

 PROCEDURE:

 MODIFICATION HISTORY:
  Written by Marc W. Buie, Lowell Observatory, 2000/07/30
  2000/03/16, David Tucker, changed obsfile to support new rdobscod
  2001/04/18, MWB, changed systime call.
  2002/09/03, MWB, changed Str_sep call to strsplit
  2002/09/09, MWB, added support for string obscode values