7994(  1) - 04/16/98 14:11  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      7994
                                                       Version: 1
                                                       Check-in Date: 16-Apr-1998
                                                                      14:08:28

1.Proposal Title:
Internal Dispersions of Proper Motions in Globular Clusters
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2. Proposal For  3. Cycle
AR               7
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4. Investigators
                                                                                     Contact?
    PI: Ivan King                         University of California
   CoI: Jay Anderson                      University of California                      N

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5. Abstract

We will measure internal dispersions of proper motion from archival WFPC2 and WFPC-1
images of 7 globular clusters, using newly developed techniques for rich fields that
push WFPC astrometry to unprecedented levels of accuracy. In 3 of the clusters our
measuring error per star will be smaller than the dispersion that we are trying to
measure. In the other clusters the two quantities will be comparable in size, but
the statistics of 1000 or more measured stars will lead to an accurate value of the
true dispersion. Comparison of dispersions of proper motion with those of radial
velocity will yield cluster distances that are more accurate than are available from
any other source. We will also study motions of Galactic bulge stars in Baade's
Window, extending ground- based studies of red giant stars to main-sequence stars
with HST.
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  Data Distribution

  Media:           ELECTRONIC
  Blocking Factor: 10
  Ship To:         PI_Address
  Ship Via:
  Email:
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                                                7994(  1) - 04/16/98 14:11  - [  2]

            Summary Form for Proposal  7994

  Item                         Used in this proposal
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  Proposal Category            AR
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