Data Set Overview
      =================
      This data set contains all the infrared polarimetry data archived
      as part of the International Halley Watch (IHW) Infrared Studies
      Network (IRSN).  Data span the period 21 Sep 1985 to 1 June 1986.
 
      The data are presented as separate tables for each set of observations
      from an observer on a single night.
 
      Modification History
      ====================
      As part of the IHW restoration effort, the original data were
      reformatted, but not otherwise changed.  The reformatting
      process included:
 
        o  Converting FITS ASCII TABLE extensions into flat ASCII
           files (i.e., with carriage-control and without blank
           padding).
 
        o  Writing new PDS labels whic incorporate all information
           in the original FITS header, including comments and
           history notes.
 
        o  Deleting the original, detached FITS headers.
 
      In addition, known errata were corrected, including both the
      errata noted by Mikael Aronsson at JPL as he prapared the
      IHW Printed Archive and Printed Archive Index documents (and
      included on the HAL_0023 volume), and the errata collected
      after publication at the PDS Small Bodies Node.
 
      General Notes
      =============
      Times
      -----
      The observation times were reported as day fractions with
      anywhere from one to five decimal places of precision.
      These have been converted to the ISO standard format
      (YYYY-MM-DDThh:mm:ss) to a corrsponding level of accuracy.
 
      System Codes
      ------------
      The IHW directives for the SYSTEM keyword in the original
      FITS files mandated a format of 'dooottii', where
      d = discipline, ooo = IAU observatory code, tt = country
      code, and ii = (optional) telescope/instrument number
      assigned by the Infrared Studies Network.  For observatories
      that did not have an IAU code, ooo = 500 and in most of
      these cases ii = 00.  Thus, all U.S. observatories without
      and IAU code will have SYSTEM = '25001600' in their IRSN
      contributions.
 
      23 August 2006, A.C.Raugh

Confidence Level Overview
      =========================
      Error bars are included with the measurements in the files.
      Apart from that, no additional information was provided in
      the original archive.