Data Set Overview
  =================
 The Stardust mission required both astrometric and photometric
 observations from ground-based telescopes to fine-tune the circumstances
 for the 2004 January 2 UT spacecraft encounter with comet 81P/Wild 2.  The
 astrometric data provided critical third-dimension information that
 improved the encounter time, while the photometric data provided
 information on the level of activity for the comet, which was used to
 decide on a flyby distance.  The Stardust project arranged for some of
 these observations to be made with the Keck II telescope on Mauna Kea
 using the ESI instrument in imaging mode, which illuminates a subset of
 the detector with a 2 by 8 arcmin field.  The R filter provided by Richard
 Ellis (the 'Ellis R filter') was used for all observations because it is
 the only one in the ESI instrument that accommodates the full 2 by 8
 arcmin field of view.  Altogether, 57 images of the comet were obtained on
 the nights of 2003 December 19-21 UT, as well as bias frames, flat field
 frames, and images of Landolt standard stars.  The processed images in
 this data set have had the average value of the overscan region
 subtracted, a two-dimensional bias pattern subtracted based on an average
 of several overscan-subtracted bias images, and were divided by a flat
 field image based on the median of all the overscan-subtracted and bias
 subtracted twilight sky flat field images.  All three nights were
 photometric.  To compute the photometric zero point of the images, a
 synthetic aperture of radius 40 pixels was utilized on all astrometric
 reference stars.  The pixel size is 0.155 arcseconds.

NONE PROVIDED