! File: 2199C.PROP ! Database: PEPDB ! Date: 17-FEB-1994:03:17:34 coverpage: title_1: GST5 COMPARE MINOR PLANET POSITIONS proposal_for: GST/AST pi_fname: WILLIAM pi_mi: H. pi_lname: JEFFERYS pi_inst: UNIVERSITY OF TEXAS pi_country: USA pi_phone: 512-471-4461 X455 hours_pri: 0.30 num_pri: 1 time_crit: X pi_position: PROFESSOR ! end of coverpage abstract: line_1: The goal of this test is to determine any systematic differences between the line_2: position determined from the 4Kbit/sec astrometry telemetry stream, using the line_3: age-word in the FGE, and the position determined from the 32Kbit/sec astrometry line_4: telemetry data stream, using the timing derived from the full data set itself. line_6: THIS TEST IS SUBMITTED FOR GST5 TEST PURPOSES ONLY ! ! end of abstract general_form_proposers: lname: inst: ASTROMETRY SCIENCE TEAM ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: The Fine Guidance Electronics allows the time of the acquisition of each data line_2: sample by use of some timing data included in the "age word." The time is line_3: supposed to be good to 0.010 seconds related to UTC. The "age word" applies to line_4: data transmitted in the 4kbit/sec telemetry mode. line_6: By analyzing the data in the 32kbit/sec telemetry mode, and by looking at the line_7: clocking strobe rates of the format, the time of the FGS samples may be line_8: determined independently of the age word. line_10: Because the time relatability to 10 ms is critical to the accuracy of moving line_11: target observations, the consistancy of the positions derived from the line_12: 4kbit/sec and 32 kbit/sec data must be tested for each FGS. The result is the line_13: definitive demonstration of whether the 4 kbit/sec telemetrymode is acceptable line_14: for moving target astrometry. line_16: The test requires relating the central position determined at the 4 kbit format line_17: to the position interpolated between two 32 kbit format positions. To minimize line_18: nonlinearities in the observed motion between the two 32 kbit positions, the line_19: observations with one FGS should be made contiguously. Comparisons of line_20: positions derived for the reference stars will allow a comparison of the line_21: position algorithms for data from the 4 and 32 kbit modes. ! question: 3 section: 1 line_1: Description of proposed observations: line_2: 1) Position ST so that the moving target is in FGS 2. line_3: Acquire guide stars in FGS 1 and 3. line_4: Position FGS 2 at the expected position of the Moving Targetat a specific line_5: expected time. line_6: Acquire the moving target in POS mode. line_7: Take data for 3 minutes in the 32 kbit/sec telemetry mode, allowing the FGS line_8: to track the moving target. line_9: 2) Acquire the first reference star. line_10: Take astrometric data on the first reference star for 1 minute. line_11: 3) Repeat step 2 for the other reference stars (if any). line_12: 4) Switch to the 4kbit/sec telemetry mode. line_13: 5) Position FGS 2 at the expected position of the Moving Target at a specific line_14: expected time. Acquire the moving target in POS mode. line_15: Take data for 3 minutes in the 4kbit/sec telemetry mode, allowing the FGS line_16: to track the moving target. line_17: Repeat steps 2-3. line_18: 6) Switch to the 32kbit/sec telemetry mode. line_19: 7) Repeat steps 1-3. ! question: 4 section: 1 line_1: See (2) above. Precursor and post-ST ground based observations may be necessary line_2: to provide adequate ephemeris data after the fact. ! question: 5 section: 1 line_1: These observations will be time critical. The time of observations will be line_2: when a minor planet moves through a pre-measured star field. line_4: SV Minimum Plan observations: Exposure Log lines 1-16 line_5: SV Delta Plan observations: Exposure Log lines 20-26 line_7: OV Prerequisites: line_8: OV Proposals 1556 (Verify Astrometry Telemetry) and 2186 (Verify line_9: Moving Target Astrometry) should be completed prior to performing line_10: this test. line_12: The ability of the FGS's to accurately measure the position of a moving line_13: target will depend on the ability to determine the time of observation line_14: accurately. If the 4 kbit mode is to be used in general, (making a line_15: significant impact on the use of TDRSS), then this test applies to all line_16: other moving target astrometry with the FGS's. ! question: 7 section: 1 line_1: ADRS within SDAS will be used to determine the positions of the moving target line_2: at the times of observation. These positions will be compared with the line_3: ephemeris motion over the interval, and the 4kbit point willbe compared with line_4: the 32Kbit points for positional consistancy. The positional change between line_5: the 3 points should be in direct proportion to the ratio of the times and given line_6: by a table of the ephemeris motion, to within the errors of observation. line_7: Should a discrepancy arise, the size of the time discrepancywill indicate how line_8: much of a positional problem exists, and further tests must be performed to line_9: determine the cause of the problem. In the meantime, use of the 4kbit/sec mode line_10: for moving targets with a particular FGS unit must be restricted or curtailed. line_11: Positions of the reference stars will be compared to verify that the positions line_12: derived from the 4 and 32 kbit/sec astrometry formats are consistant with each line_13: other. ! question: 8 section: 1 line_1: All FGS numbers refer to bay numbers. ! question: 10 section: 1 line_1: ADRS will be available at Austin. A representative of the Astrometry Team will line_2: be available at STScI or GSFC to carry out the reduction. ! !end of general form text general_form_address: lname: JEFFERYS fname: WILLIAM mi: H. title: PRO., category: PI inst: UNIVERSITY OF TEXAS addr_2: PHONE 512-471-4461 X 455 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: POINT291 descr_1: POINTING FOR MP291 pos_1: RA = 144.288534D +/- 0.0004D, pos_2: DEC = 13.935215D +/- 0.0004D equinox: 2000.0 ! targnum: 10 name_1: 2-6-REF descr_1: REFERENCE STAR FOR descr_2: MP291 FOR FGS-2 pos_1: RA = 144.461465D +/- 0.0004D, pos_2: DEC = 13.851444D +/- 0.0004D equinox: 2000.0 fluxnum_1: 1 fluxval_1: B=15.4 ! targnum: 11 name_1: 2-7-REF descr_1: REFERENCE STAR FOR descr_2: MP291 FOR FGS-2 pos_1: RA = 144.494785D +/- 0.0004D, pos_2: DEC = 13.851444D +/- 0.0004D equinox: 2000.0 fluxnum_1: 1 fluxval_1: B=15.2 ! targnum: 12 name_1: 2-8-REF descr_1: REFERENCE STAR FOR descr_2: MP291 FOR FGS-2 pos_1: RA = 144.494785D +/- 0.0004D, pos_2: DEC = 13.868104D +/- 0.0004D equinox: 2000.0 fluxnum_1: 1 fluxval_1: B=15.0 ! targnum: 13 name_1: MP291 descr_1: MINOR PLANET pos_1: RA = 144.478125D +/- 0.0004D, pos_2: DEC = 13.851444D +/- 0.0004D equinox: 2000.0 fluxnum_1: 1 fluxval_1: B = 14.6 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: POINT291 config: S/C opmode: POINTING aperture: V1 num_exp: 1 time_per_exp: 0M priority: 1 req_1: AT JD 2447600.5 +/- 1H; ! linenum: 2.000 targname: MP291 config: FGS opmode: POS aperture: 2 sp_element: F550W num_exp: 1 time_per_exp: 3M fluxnum_1: 1 priority: 1 param_1: DATA-RATE=32 req_1: SAME POS FOR 2-7 AS 1; req_3: SEQ 1-7 NON-INT; ! linenum: 3.000 targname: 2-6-REF config: ^ opmode: ^ aperture: ^ sp_element: ^ num_exp: ^ time_per_exp: 1M fluxnum_1: 1 priority: ^ param_1: ^ req_1: DO FOR TARG 10-12; ! linenum: 4.000 targname: MP291 config: ^ opmode: ^ aperture: ^ sp_element: ^ num_exp: ^ time_per_exp: 3M fluxnum_1: ^ priority: ^ param_1: DATA-RATE=4 ! linenum: 5.000 targname: 2-6-REF config: ^ opmode: ^ aperture: ^ sp_element: ^ num_exp: ^ time_per_exp: 1M fluxnum_1: ^ priority: ^ param_1: ^ req_1: DO FOR TARG 10-12; ! linenum: 6.000 targname: MP291 config: ^ opmode: ^ aperture: ^ sp_element: ^ num_exp: ^ time_per_exp: 3M fluxnum_1: ^ priority: ^ param_1: DATA-RATE=32 ! linenum: 7.000 targname: 2-6-REF config: ^ opmode: ^ aperture: ^ sp_element: ^ num_exp: ^ time_per_exp: 1M fluxnum_1: ^ priority: ^ param_1: ^ req_1: DO FOR TARG 10-12 ! ! end of exposure logsheet ! No scan data records found