Data Set Overview
  =================
    This data set contains reformatted records derived from data
    returned by the Voyager Ultraviolet Spectrometer Subsystem on
    board Voyager 2 during the Uranus encounter phase of the
    Voyager mission.  Original instrument data were merged with
    ancillary data from footprint SEDR files provided by the
    Voyager Project at the Jet Propulsion Laboratory.  The final
    product files are formatted as PDS binary tables.
 
    For a detailed description of the data set contents, see
    [BROADFOOTETAL1981; and BROADFOOTETAL1986].
 
 
  Parameters
  ==========
 
    Voyager 2 Neptune Encounter Times
    ---------------------------------
      Start Time  : 1986-010/09:00:03 (1986-01-10)
      Stop Time   : 1986-046/23:59:57 (1986-02-15)
 
 
  Processing
  ==========
    Creation of a UVS RDR record involves several steps.  First,
    the channel counts and some useful header information (FDS
    counts, time stamp, etc.) are extracted from an older format
    record, then a fixed pattern noise (flat fielding) correction
    is applied to the data in the 126 instrument channels.
    Following this, a correction is performed to remove the effects
    of internal instrumental scattering from the channel counts.
    The next step is to subtract background noise from the data, by
    interpolating in a table of background noise versus time.
    Finally, additional parameters derived from the footprint SEDR
    files are calculated and added to the record.
 
 
  Data
  ====
    The UVS RDR data are presented in a binary table form.  The
    product labels associated with each data file describe in
    detail each column of the table.  Each data file consists of
    the data from a single day, at whatever time resolution the UVS
    instrument counts were originally transmitted from the
    spacecraft.  For most of the encounter data, the instrument was
    read out every 3.84 seconds, but some spectra were accumulated
    as long as 48 seconds and as short as 0.32 seconds.
 
    The wavelength range covered by each channel of the Voyager 2
    UVS may be calculated by the following formula:
 
    w = 9.26x + 504.19
 
    where x represents the short-wavelength edge of a channel.  For
    example, the wavelength of the short-wavelength edge of channel
    76 is 1207.95 Angstroms (9.26*76.0 + 504.19).  To find the
    central wavelength of a channel, add 0.5 to the channel number.
    For example, the central wavelength of channel 21 is 703.28
    Angstroms (9.26*21.5 + 504.19).
 
 
  Ancillary Data
  ==============
    The scan platform (footprint) SEDR files were used to merge
    additional trajectory and pointing data with the instrument
    data and time stamps from the original EDR files, so that each
    spectral record includes (for example) vectors from the
    spacecraft to the central body and picture body and the
    positions of the center and ends of the field of view on the
    picture body.
 
 
  Coordinate System
  =================
    The vectors in the RDR record are presented in the Earth Mean
    Equatorial system, epoch of 1950.0 (EME50).
 
 
  Software
  ========
    A C language header file and an IDL include file describing the
    UVS RDR record structure have been included in the software/src
    directory.
 
 
  Media/Format
  ============
    The UVS RDR data will be delivered to the PDS on compact disk
    write once (CD-WO) media.  Formats will be based on standards
    for such products established by the Planetary Data System.

Confidence Level Overview
  =========================
    All original data records have been included, even those with
    channel noise due to spacecraft telemetry errors and those data
    acquired when the scan platform was in motion.  Data are also
    included when footprint SEDR information was unavailable so
    that additional ancillary parameters could not be calculated.
    Flags in each data record indicate when these conditions have
    ocurred.
 
  Review
  ======
    Data sets were reviewed internally and checked for consistency
    with earlier independent analyses.  These data products will be
    further reviewed by the PDS project.
 
 
  Data Coverage and Quality
  =========================
    Data coverage in time is more or less continuous, except for
    brief periods when spacecraft data were lost due to ground
    station problems related to equipment or weather.  The
    close-encounter period from 1986-024/14:00 to 1986-024/22:00
    was omitted due to high background noise.