Data Set Overview
  =================
    This dataset contains Clear1 filter (broadband, 200-1100 nm), CN (387
    nm), OH (309 nm), C2 (514 nm), and dust continuum (Violet at 345 and
    Green at 526 nm) photometric measurements of comet 103/P Hartley 2
    derived from reversibly-calibrated, radiance (RADREV) images acquired
    by the Medium Resolution Visible CCD (MRI) from 01 October through
    26 November 2010, during the Hartley 2 encounter phase of the EPOXI
    mission.  The heliocentric distance of the comet ranged from 1.12 to
    1.06 AU.  These photometry data were used by Bodewits, et al., 2013,
    [BODEWITSETAL2013] to characterize the gas and dust coma of Hartley 2.
 
    The photometry measurements and their computed errors are provided as
    24, fixed-width, ASCII tables separated by filter and by photometry
    method.  Two different methods were used:  simple circular aperture
    photometry for radii of 1-30 pixels in 1-pixel increments and azimuthal
    averaged aperture photometry for 33 radii ranging from 1 to 248 pixels
    in graduated steps.  The simple aperture photometry is robust for radii
    of 5 to 20 pixels while the azimuthal average method, which rejected
    stars, is recommended for analysis at larger apertures (radii of 20
    or more pixels).
 
    The file naming convention for the data products is
       PhotMethod_DataType_FilterName.Ext
    where
       PhotMethod = APER for simple aperture photometry or
                    AZAV for azimuthal average photometry
       DataType   = PHOT for photometry measurements or
                    ERR for computed errors
       FilterName = CLEAR1, CN, C2, OH, GREEN_CONT, or VIOLET_CONT
       Ext        = TAB for a data table or
                    LBL for the corresponding PDS label
 
    The first record in each data table lists the radii, in pixels, used to
    measure photometry.  Subsequent records contain the measured photometry
    or computed errors; the columns in these records are:
 
      Col#  Description (units)
      ----  ------------------------------------------------------------------
        1   MRI RADREV FITS image filename
        2   Julian date for mid-obs
        3   Day of year for 2010
        4   Filter name
        5   X-coordinate of originally measured centroid, where CCD vertical
            center = 255.5 (pixel)
        6   Y-coordinate of originally measured centroid, where CCD horizontal
            center = 255.5 (pix)
        7   Image size, both dimensions (pixel)
        8   Horizontal distance of centroid to CCD vertical center line, where
            a negative value is left of that line (pixel)
        9   Vertical distance of centroid to CCD horizontal center line, where
            a negative value is below that line (pixel)
       10   Image quality flag, manually assigned
       11*  Target heliocentric distance* (AU)
       12*  Target-to-spacecraft distance* (km)
       13*  Phase angle, sun-target-spacecraft* (degree)
       14   30 or 33 columns of photometric measurements or errors,
            corresponding to the aperture radii specified in the first
            table record.  A value of -9.99E+03 indicates photometry could
            not be computed for the given aperture. (W/m^2/micron)
 
         * The geometry values in columns 11, 12, and 13 were extracted
           from the RADREV FITS image headers, which the EPOXI data pipeline
           computed at the epoch specified by the mid-obs time in column 2.
 
    Please read the accompanying report HARTLEY2_PHOTOMETRY_REPORT.PDF,
    which is located in the DOCUMENT directory.  It thoroughly describes
    the photometry methods, error analysis and limitations, and it provides
    more detail about the MRI observations and frequency of filter usage.

Confidence Level Overview
  =========================
    The data tables in this dataset were reviewed internally by the EPOXI
    project.
 
  Review
  ======
    This dataset was certified for scientific use on 05 March 2013, during
    a peer review conducted by the PDS Small Bodies Node.
 
  Data Coverage and Quality
  =========================
    See the Data Set Overview above and the accompanying report
    DOCUMENT/HARTLEY2_PHOTOMETRY_REPORT.PDF.
 
  Limitations
  ===========
    See the accompanying report DOCUMENT/HARTLEY2_PHOTOMETRY_REPORT.PDF.