11271(  1) - 03/30/07 11:20  - [  1]

                  HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11271

Version: 1    Check-in Time: 30-Mar-2007 15:20:26       STScI Edit Number: 0

Title
Establishing a Zero Motion Reference Frame for the FGS
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Type             Cycle     Parallel Pointing Tolerance
AR               16        <none>
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Investigators
                                                                                     Contact?
    PI: Dr. Bernard J. McNamara           New Mexico State University
   CoI: Dr. Barbara McArthur              University of Texas at Austin                 N
   CoI: Dr. Thomas Harrison               New Mexico State University                   N
   CoI: Mr. Doug Hoffman                  New Mexico State University                   N

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Abstract

We propose to measure the internal proper motions of the stars in M35 that are used
to calibrate the HST/FGS. The goal of this effort is to remove the influence these
stars have the FGS distortion map. Employing the approximately 108 orbits of
available archival FGS data, these motions can be determined to an accuracy of 0.05
mas/year. By iteratively measuring these motions using successively longer time
bases and then accounting for them in the distortion map, their influence on this
map can be essentially eliminated.
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