NAME:
  rdland
 PURPOSE: (one line)
  Read the Landolt Standards data file.
 DESCRIPTION:
  This program automates the process of reading the Landolt 1983 Standard
       file as provided on the CD-ROM from NSSDC.  Selected Astronomical
       Catalogs, Volume 1.  Also supported is the table for the 1992 catalog
       as supplied by Arlo Landolt at Louisiana State University.
 CATEGORY:
  File I/O
 CALLING SEQUENCE:
  rdland,catalog,id,ra,dec,mags,colors,errs,cerrs
 INPUTS:
     catalog - Integer key for the catalog to read in.  The only valid
                 inputs are:
                    83 - for the 1983 catalog.
                    92 - for the 1992 catalog.

 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
     EPOCH   - JD of epoch for of-date precession.
                 Default = catalog epoch (1985.0 for 83 catalog or
                 2000.0 for 92 catalog).
     FILE    - Name of star catalog file to read.  Defaults are:
                 For 83 = '/net/frakir/raid/buie/photometry/landolt/landolt.dat'
                 For 92 = '/net/frakir/raid/buie/photometry/landolt/landolt92.dat'

     Only one of the following is allowed to be set.  If none are set,
        the coordinates will be returned in the equinox of the catalog.
     B1950   - Coordinates should be referred to equinox of B1950.
     J2000   - Coordinates should be referred to equinox of J2000.
     OFDATE  - Coordinates should be referred to equinox of date.
                 If selected, EPOCH must be provided.

 OUTPUTS:
     id     - Name of the stars.
     ra     - Right Ascension in radians. Catalog epoch, unless one of the
                other choices, via keyword, is specified.
     dec    - Declination in radians. Catalog epoch, unless one of the
                other choices, via keyword, is specified.
     mags   - Stellar magnitudes, UBVRI
     colors - Stellar colors, U-B, B-V, V-R, R-I, V-I
     merrs  - Uncertainties on the magnitudes.
     cerrs  - Uncertainties on the colors.
     nobs   - Number of observations
     nnig   - Number of nights of observations
 COMMON BLOCKS:
     None.
 SIDE EFFECTS:
 RESTRICTIONS:
     This procedure is hard-coded for these particular files.  It is not
       intended to be a general file reading program.

     If file is not specified, the filename defaults are:
          /net/frakir/raid/buie/photometry/landolt/landolt.dat   (for 83 catalog)
          /net/frakir/raid/buie/photometry/landolt/landolt92.dat (for 92 catalog)
 PROCEDURE:
 MODIFICATION HISTORY:
  93/01/19, Written by Marc W. Buie, Lowell Observatory
  93/10/01, Modifications by Doug Loucks, Lowell Observatory.  The
            1992 Landolt Catalog (Epoch 2000) is now supported.  A new
            parameter allows selection of the the 1983 or the 1992 catalog.
  96/11/20, MWB, now returns number of nights and number of observations.
  2004/02/09, MWB, changed default path to catalog