Data Set Overview
  =================
    This data set contains a clear-filtered High Resolution Visible CCD
    (HRIV) point spread function (PSF) for exoplanet transit targets
    GJ 436, HAT-P-4, HAT-P-7, TrES-2, TrES-3, XO-2, and XO-3 as well as
    PSFs for the HRIV PSF for stellar calibrator targets for the EPOXI
    mission.  The PSFs were produced by applying the drizzle method
    described by Fruchter and Hook, 2002, [FRUCHTER&HOOK2002] to sets of
    HRIV images of the targets acquired during 2008.  A PSF for transit
    target WASP-3 was not produced due to a crowded star field.
 
    The EPOXI mission observes the transits of exoplanets, Earth and Mars,
    and a comet nucleus using the HRIV CCD on board the Deep Impact flyby
    spacecraft (DIF).  However the 0.3-m f/35 High Resolution telescope is
    permanently defocused by 0.6 cm.  Consequently the point spread function
    for the HRIV instrument covers approximately nine pixels at full-width
    half-max and is characterized by a patch with three-fold symmetry (six
    points) due to the three-point support structures of the primary and
    secondary mirrors.  The resulting PSF is also strongly dependent on
    color, varying in shape and size with respect the HRIV filter being
    used and the color of the target.  Therefore all resolved HRIV images
    analyzed for the mission should be deconvolved with one of the
    instrument PSFs provided in the data sets.  The HRIV PSFs in this data
    set were also used to optimize exoplanet transit analysis for the EPOXI
    mission.
 
    The PSFs are provided as 2-dimensional FITS images by target and filter
    when applicable.  The 'Development and Utilization of the HRIV Point
    Spread Function for the EPOXI Mission' report included in this data set
    describes how the PSFs for the stellar calibrators and exoplanet transit
    targets were constructed for and utilized by the EPOXI team.  (Or see
    Barry, et al., 2010 [BARRYETAL2010].)
 
    The following PDS data sets, available online at http://pds.nasa.gov,
    are related to this one and may be useful for research:
 
      DIF-X-HRIV-3-EPOXI-EXOPLANETS-V1.0
        - Radiance calibrated HRIV extrasolar planet transit observations
          GJ 436, HAT-P-4, HAT-P-7, TRES-2, TRES-3, WASP-3, XO-2, and
          XO-2 acquired during 2008; The EPOCh team used subsets of the
          reversibly calibrated images (known as 'RADREV') in this data set
          to construct PSFs.
 
      DIF-CAL-HRIV-2-EPOXI-CALIBRATIONS-V1.0
        - Raw in-flight HRIV calibrations including the stellar
          calibrators 16 Cyg A, Achernar, Beta Hyi, Canopus, HD 60753,
          HD 79447, and Vega; The EPOCh team used reversibly calibrated
          subsets of these raw data to construct PSFs.
 
      DIF-X-HRIV-5-EPOXI-EXOPLANETS-PHOT-V1.0
        - HRIV photometry (light curves) of the transiting planet
          systems observed by EPOXI.
 
      DI-C-HRII/HRIV/MRI/ITS-6-DOC-SET-V3.0
        - Deep Impact and EPOXI documentation set provides overviews
          of the EPOXI mission.

Confidence Level Overview
  =========================
    The EPOXI/EPOCh team applied the PSF data files in this data set
    to their analysis of exoplanet transit targets and resulting
    photometry.
 
  Review
  ======
    This data set was peer reviewed at the PDS Small Bodies Node (SBN)
    and certified for archiving on 29 September 2010 pending the
    resolution of liens.  Liens were resolved in December 2010.  This
    data set is archived at SBN and and the Multi-Mission Archive at
    STScI (MAST).
 
  Data Coverage and Quality
  =========================
    The EPOXI/EPOCh team did not construct a PSF for transit target WASP-3
    due to a crowded star field.  The EPOXI team recommends using one of
    the PSFs for a calibrator star when working with WASP-3 images.
 
  Limitations
  ===========
 
    HRI Telescope Focus
    -------------------
      Images of stars acquired early during the Deep Impact mission in
      2005 indicated the HRI telescope was out of focus.  In-flight
      bakeouts during late February and early March 2005 reduced the
      defocus from about 1.0 cm to about 0.6 cm, resulting in a decrease
      in the width of stars from about 12 pixels to 9 pixels.  For more
      details, please see the Deep Impact instrument calibration paper by
      Klaasen, et al. (2008) [KLAASENETAL2006] and the Deep Impact image
      restoration paper by Lindler, et al. (2007) [LINDLERETAL2007].