Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2199c Report Date: 09-May-96:16:57 Version: ********** Check-in Date: ********** 1.Proposal Title: GST5 COMPARE MINOR PLANET POSITIONS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GST/AST Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone William H. Jefferys UNIVERSITY OF TEXAS USA 512-471-4461 X PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract The goal of this test is to determine any systematic differences between the position determined from the 4Kbit/sec astrometry telemetry stream, using the age- word in the FGE, and the position determined from the 32Kbit/sec astrometry telemetry data stream, using the timing derived from the full data set itself. THIS TEST IS SUBMITTED FOR GST5 TEST PURPOSES ONLY ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0.30 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2199c PI: William H. Jefferys Proposal Title: GST5 COMPARE MINOR PLANET POSITIONS ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ ASTROMETRY SCIENCE TEAM ------------------------------------------------------------------------------------ 2. Scientific Justification. The Fine Guidance Electronics allows the time of the acquisition of each data sample by use of some timing data included in the "age word." The time is supposed to be good to 0.010 seconds related to UTC. The "age word" applies to data transmitted in the 4kbit/sec telemetry mode. By analyzing the data in the 32kbit/sec telemetry mode, and by looking at the clocking strobe rates of the format, the time of the FGS samples may be determined independently of the age word. Because the time relatability to 10 ms is critical to the accuracy of moving target observations, the consistancy of the positions derived from the 4kbit/sec and 32 kbit/sec data must be tested for each FGS. The result is the definitive demonstration of whether the 4 kbit/sec telemetrymode is acceptable for moving target astrometry. The test requires relating the central position determined at the 4 kbit format to the position interpolated between two 32 kbit format positions. To minimize nonlinearities in the observed motion between the two 32 kbit positions, the observations with one FGS should be made contiguously. Comparisons of positions derived for the reference stars will allow a comparison of the position algorithms for data from the 4 and 32 kbit modes. ------------------------------------------------------------------------------------ 3. Description of proposed observations. Description of proposed observations: 1) Position ST so that the moving target is in FGS 2. Acquire guide stars in FGS 1 and 3. Position FGS 2 at the expected position of the Moving Targetat a specific expected time. Acquire the moving target in POS mode. Take data for 3 minutes in the 32 kbit/sec telemetry mode, allowing the FGS to track the moving target. 2) Acquire the first reference star. Take astrometric data on the first reference star for 1 minute. 3) Repeat step 2 for the other reference stars (if any). 4) Switch to the 4kbit/sec telemetry mode. 5) Position FGS 2 at the expected position of the Moving Target at a specific expected time. Acquire the moving target in POS mode. Take data for 3 minutes in the 4kbit/sec telemetry mode, allowing the FGS to track the moving target. Repeat steps 2-3. 6) Switch to the 32kbit/sec telemetry mode. 7) Repeat steps 1-3. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. See (2) above. Precursor and post-ST ground based observations may be necessary to provide adequate ephemeris data after the fact. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. These observations will be time critical. The time of observations will be when a minor planet moves through a pre-measured star field. SV Minimum Plan observations: Exposure Log lines 1-16 SV Delta Plan observations: Exposure Log lines 20-26 OV Prerequisites: OV Proposals 1556 (Verify Astrometry Telemetry) and 2186 (Verify Moving Target Astrometry) should be completed prior to performing this test. The ability of the FGS's to accurately measure the position of a moving target will depend on the ability to determine the time of observation accurately. If the 4 kbit mode is to be used in general, (making a significant impact on the use of TDRSS), then this test applies to all other moving target astrometry with the FGS's. Page 3 ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. ADRS within SDAS will be used to determine the positions of the moving target at the times of observation. These positions will be compared with the ephemeris motion over the interval, and the 4kbit point willbe compared with the 32Kbit points for positional consistancy. The positional change between the 3 points should be in direct proportion to the ratio of the times and given by a table of the ephemeris motion, to within the errors of observation. Should a discrepancy arise, the size of the time discrepancywill indicate how much of a positional problem exists, and further tests must be performed to determine the cause of the problem. In the meantime, use of the 4kbit/sec mode for moving targets with a particular FGS unit must be restricted or curtailed. Positions of the reference stars will be compared to verify that the positions derived from the 4 and 32 kbit/sec astrometry formats are consistant with each other. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. All FGS numbers refer to bay numbers. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). ADRS will be available at Austin. A representative of the Astrometry Team will be available at STScI or GSFC to carry out the reduction. ------------------------------------------------------------------------------------ 11. Address Information Name: WILLIAM H. JEFFERYS Category: PI Institution: UNIVERSITY OF TEXAS Address: PHONE 512-471-4461 X 455 City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2199c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 POINT291 POINTING FOR MP291 RA = 144.288534D +/- 2000.0 0.0004D, DEC = 13.935215D +/- 0.0004D ------------------------------------------------------------------------------------------------------------------------------------ 10 2-6-REF REFERENCE STAR FOR RA = 144.461465D +/- 2000.0 1 B=15.4 MP291 FOR FGS-2 0.0004D, DEC = 13.851444D +/- 0.0004D ------------------------------------------------------------------------------------------------------------------------------------ 11 2-7-REF REFERENCE STAR FOR RA = 144.494785D +/- 2000.0 1 B=15.2 MP291 FOR FGS-2 0.0004D, DEC = 13.851444D +/- 0.0004D ------------------------------------------------------------------------------------------------------------------------------------ 12 2-8-REF REFERENCE STAR FOR RA = 144.494785D +/- 2000.0 1 B=15.0 MP291 FOR FGS-2 0.0004D, DEC = 13.868104D +/- 0.0004D ------------------------------------------------------------------------------------------------------------------------------------ 13 MP291 MINOR PLANET RA = 144.478125D +/- 2000.0 1 B = 14.6 0.0004D, DEC = 13.851444D +/- 0.0004D ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2199c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 POINT291 S/C POINTIN V1 1 0M 1 AT JD 2447600.5 +/ G - 1H ------------------------------------------------------------------------------------------------------------------------------------ 2 MP291 FGS POS 2 F550W DATA-RATE=32 1 3M 1 1 SAME POS FOR 2-7 AS 1 SEQ 1-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 3 2-6-REF ^ ^ ^ ^ ^ ^ 1M 1 ^ DO FOR TARG 10-12 ------------------------------------------------------------------------------------------------------------------------------------ 4 MP291 ^ ^ ^ ^ DATA-RATE=4 ^ 3M ^ ------------------------------------------------------------------------------------------------------------------------------------ 5 2-6-REF ^ ^ ^ ^ ^ ^ 1M ^ DO FOR TARG 10-12 ------------------------------------------------------------------------------------------------------------------------------------ 6 MP291 ^ ^ ^ ^ DATA-RATE=32 ^ 3M ^ ------------------------------------------------------------------------------------------------------------------------------------ 7 2-6-REF ^ ^ ^ ^ ^ ^ 1M ^ DO FOR TARG 10-12 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2199c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations S/C FGS ^ ------------------------------------------------------------------------------------------------------------------------------------ Opmodes POINTING POS ^ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters DATA-RATE=32 DATA-RATE=4 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GST/AST ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 0.30 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AT JD 2447600.5 +/- 1H; SAME POS FOR 2-7 AS 1; SEQ 1-7 NON-INT; DO FOR TARG 10-12; DO FOR TARG 10-12 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F550W ^ ------------------------------------------------------------------------------------------------------------------------------------ Target Names POINT291 2-6-REF 2-7-REF 2-8-REF MP291 ------------------------------------------------------------------------------------------------------------------------------------