NSSDCA ID: 1990-037B-09
Mission Name: HSTThis investigation uses the facilities of the optical telescope assembly, instead of requiring a separate instrument. The HST guidance system consists of three identical fine guidance sensors (FGS) distributed in an annulus centered on the optical axis of the HST. Each sensor has its own field of view (FOV). In normal operations, two of the sensors are used for fine pointing the HST. The sensor that is not used for telescope pointing is the primary astrometric instrument at that particular time. An FGS consists of a set of gimbaled mirrors constructed so that any star within its FOV can be placed on an image dissector/interferometer combination. The encoder readings of the gimbaled mirror axes supply the object position in the FOV; the output of each of the pairs of interferometers supplies a fine error signal. Each sensor contains a set of movable filters, plus temperature, voltage, and other monitors. The astrometry experimenter observes stars in an approximate magnitude range of 4 to 17. Relative positions of stars can be measured with a precision of 0.002 arc-s.
Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Laurence W. Fredrick | Co-Investigator | University of Virginia | lwf@virginia.edu |
Dr. William F. Van Altena | Co-Investigator | Yale University | vanalten@astro.yale.edu |
Dr. George Fritz Benedict | Co-Investigator | University of Texas, Austin | fritz@dorrit.as.utexas.edu |
Dr. Peter J. Shelus | Co-Investigator | University of Texas, Austin | pjs@astro.as.utexas.edu |
Dr. Raynor L. Duncombe | Co-Investigator | University of Texas, Austin | aoug065@emx.utexas.edu |
Dr. Paul D. Heminway | Co-Investigator | University of Texas, Austin | |
Dr. Otto G. Franz | Co-Investigator | Lowell Observatory | ogf@lowell.edu |
Dr. William H. Jefferys | Principal Investigator | University of Texas, Austin | bill@astro.as.utexas.edu |