Data Set Overview
    =================
    NASA's International Halley Watch (IHW) has created a Comet
    Halley Archive. The collection of data spans the full
    wavelength range as submitted by scientists to the IHW. The
    observations belong to one of the following Disciplines:
    Amateur, Astrometry, Infrared Studies, Large-Scale
    Phenomena, Meteor Studies, Near-Nucleus Studies, Photometry
    and Polarimetry, Radio Studies, and Spectroscopy and
    Spectrophotometry. The data collected by these nine
    disciplines were augmented by Spacecraft measurements. The
    data were submitted to IHW, but the evaluation and selection
    for the Archive has been the primary responsibility of the
    Discipline Specialist Teams for each network in cooperation
    with the Lead Center. The Photometry and Polarimetry Network
    collected 884 polarimetric observations for the Polarimetry
    Subnetwork. The majority of these observations (752) are
    expressed as 'percent polarization'. These data span the
    dates from 1985 September 13 through 1986 May 17.
 
 
  Processing Level Id            : 3
  Software Flag                  : N
 
 
  Parameters
  ==========
  Data Set Parameter Name        : POLARIZATION
  Data Set Parameter Unit        : PERCENT
 
 
    Description
    -----------
      Polarization is a measure of the orientation of the electric
      (or magnetic) vectors in electromagnetic radiation. In
      general , an electromagnetic wave is elliptically polarized
      with the electric vector, as seen by a stationary observer,
      tracing out an ellipse. This can be decomposed into circular
      polarization and linear polarization which are the
      components normally measured. Linear polarization is
      specified as the orientation of the electric vector (+/- 180
      degrees). In the IHW data sets, the orientation of linear
      polarization is specified relative to the plane of
      scattering (the plane containing Sun, Comet, and Earth), 0
      for electric vectors parallel to the plane of scattering and
      90 for electric vectors perpendicular to the plane of
      scattering. Other conventions are used in other branches of
      astronomy. Circular polarization is specified as left hand
      if the electric vector of an approaching wave rotates
      clockwise as seen by a stationary observer and as right hand
      if it rotates counter-clockwise. This is the opposite of the
      convention used by physicists but corresponds to that used
      by radio engineers. Unpolarized light is a superposition of
      orthogonally polarized waves (left and right circular or
      orthogonal linear components). The degree of polarization,
      usually expressed as a percentage, is the fraction of the
      total radiation which is completely polarized.
 
 
    Source Instrument Parameters
    ============================
    Instrument Host ID              : PPN
    Data Set Parameter Name         : POLARIZATION
    Instrument Parameter Name       : N/A
    Important Instrument Parameters : 0
 
 
  Measurement Information
  =======================
 
    Atmospheric Conditions
    ----------------------
      N/A
 
 
    Source
    ------
      N/A
 
 
    Calibration Standard
    --------------------
      N/A
 
 
    Wavelength Calibration
    ----------------------
      N/A
 
 
    Processing
    ==========
    N/A

Overview
    ========
    N/A