PDS_VERSION_ID                    = PDS3
RECORD_TYPE                       = STREAM
LABEL_REVISION_NOTE               = "NULL"

OBJECT                            = INSTRUMENT
  INSTRUMENT_HOST_ID              = "AMON"
  INSTRUMENT_ID                   = "AMVIS"

  OBJECT                          = INSTRUMENT_INFORMATION
    INSTRUMENT_NAME               = "AMATEUR VISUAL OBSERVATIONS"
    INSTRUMENT_TYPE               = "EYE"
    INSTRUMENT_DESC               = "

    Instrument Overview
    ===================
    To better standardize the magnitude estimates, comparison
    star charts were mailed to observers in the Amateur
    Observation network. In spite of this effort, the data
    (documented in the FITS header) lists dozens of reference
    sources used by the observer. It is incumbent on any archive
    user to decide which sets of comparison charts are
    acceptable for research.
 
       The archive actually includes all those data that, based
    on each observer's report itself, appear to have been made
    in the Manual-prescribed manner. Even this approach to data
    inclusion still resulted in the discard of roughly
    one-quarter of the submitted observations.
 
       Workers interested in using experience as a selection
    criteria are referred to 'The Comet Halley Archive Summary
    Volume' (Sekanina, Z., 1991) article about the Amateur
    Observation network. The table below (from Appendix A) is
    based on those whose data appear in the International Comet
    Quarterly files and includes both the most active ICQ
    observers of P/Halley and the most active observers of all
    comets in the ICQ archives.
 
      Active ICQ Observers of All Comets discussed by Morris
    and Green (1987)
 
 
 
    Observer       Number of               Number of
                Positive Observations   Negative Observations
 
    John E. Bortle    1,952                     74
    Charles Morris    1,799                     36
    Reinder Bouma       914                      8
    Daniel W.E. Green   863                      3
    David Seargent      618                      1
    Richard Keen        607                      0
 
 
 
    Scientific Objectives
    =====================
         Amateur observations of periodic Comet Halley commenced
    with the visual recovery of the comet by S. J. O'Meara on
    1985 January 23. They ended with D. H. Levy's observation on
    1988 February 23. Within that period 11641 magnitudes and
    other related visual estimates were made. 2170 photographs
    span 1985 August 12 to 1988 February 16. Observations from
    637 amateur astronomers were used in the archive.
 
        The observations, compiled by the Discipline Specialist
    Team, can be grouped into two distinct categories:
 
        (1) Visual-appearance descriptions.
        (2) Photographs.
 
        Because of the subjective nature of visual-appearance
    observation methods there is diversity in the type and
    quality of information recorded in the archive. When a range
    of values was given by the observer the more conservative
    value was adopted, i.e. a shorter tail, more diffuse
    condensation, smaller coma, and fainter magnitude.
 
        All the photographic images listed are on file and were
    examined for quality before inclusion in the archive
    listings."

  END_OBJECT                      = INSTRUMENT_INFORMATION

  OBJECT                          = INSTRUMENT_REFERENCE_INFO
    REFERENCE_KEY_ID              = "JPL D-400-450"
  END_OBJECT                      = INSTRUMENT_REFERENCE_INFO

  OBJECT                          = INSTRUMENT_REFERENCE_INFO
    REFERENCE_KEY_ID              = "MORRIS&GREEN1987"
  END_OBJECT                      = INSTRUMENT_REFERENCE_INFO
END_OBJECT                        = INSTRUMENT
END