Data Set Overview
      =================
 
      The Asteroid Photometric Catalog (3rd update) is a compilation of all
      asteroid lightcurve photometry published up to and including the year
      1992.  This data set includes the Ida and Gaspra lightcurves in the
      APC 3rd update, plus some data published since the 3rd update and
      some unpublished lightcurves of Ida and Gaspra, with permission of
      the investigators.
 
      Parameters
      ==========
 
      The primary data file of this data set, named 'iglcapc.dat', has an
      entry for each photometric observation of an asteroid included in any
      asteroid lightcurve.  The parameters given for each observation
      include julian date of the observation, the observed magnitude, and
      the error value associated with the magnitude.  The index to this
      primary file, named 'iglcindx.tab', contains an entry for each
      asteroid lightcurve and refers to the individual photometric
      observations given in 'iglcapc.dat'.  Each entry identifies the
      asteroid, and specifies the filter used, the start and stop time of
      the lightcurve observation, the heliocentric distance, geocentric
      distance, phase angle, and geocentric ecliptic longitude and latitude
      of the asteroid at the time of the observation, the start byte and
      observation set size of the lightcurve in 'iglcapc.dat', a code for
      the original published reference reporting the observations, and a
      code for each comment line.  The file 'iglcrefs.tab' contains an
      entry for each published reference from which data is included in the
      data set, along with the reference code by which it is cited in
      'iglcindx.tab'.  The file 'iglcinfo.tab' contains an entry for each
      comment line with a code number by which it is referred to in
      'iglcindx.tab'.
 
      Processing
      ==========
 
      No processing has been applied to the photometric data.  Additional
      information for each observation, such as phase angle, has been
      determined.
 
      Data
      ====
 
      This data set includes the following data objects.
           iglcapc.dat   -  binary table of photometric measurements.
           iglcindx.tab -  ASCII table of lightcurves which serves as
                          an index to igapc.dat.
           iglcrefs.tab  -  ASCII table of published references.
           iglcinfo.tab  -  ASCII table of comment lines.
 
      Ancillary Data
      ==============
 
      Of the data objects listed above, iglcrefs.tab and iglcinfo.tab may
      be considered ancillary data.
 
      Media/Format
      ============
 
      This data set is released in the form of ASCII and binary files
      which may be stored on disk or other magnetic medium and which may
      be distributed by ftp, email, real-time access by remote login, or
      by whatever means is most convenient.

Confidence Level Overview
      =========================
 
      This is a compilation of all published asteroid lightcurve photometry
      on the asteroids 243 Ida and 951 Gaspra.  The data come from various
      sources. The original reference should be consulted for the
      confidence level of any given observation.
 
      Review
      ======
 
      This dataset underwent a formal external review in September 1995.
 
      Data Coverage and Quality
      =========================
 
      This data set is intended to include all published asteroid
      lightcurve information on 243 Ida and 951 Gaspra.  It is complete
      through the year 1994.