Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5641 Report Date: 18-Jul-95:17:47 Version: ********** Check-in Date: ********** 1.Proposal Title: OBSERVATIONS OF MINOR PLANETS AT CROSSING POINTS PART 1, CYCLE 4, HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/AST Sub Category MINOR PLANETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone William H. Jefferys UNIVERSITY OF TEXAS AT AUSTI USA ------------------------------------------------------------------------------------ 7. Abstract Observations of moving solar system objects in POS mode with the FGSs have the potential of improving the angular accuracy of such measurements by an order of magnitude over ground- based measurements. Such measurements would provide the most accurate plate scale determination for HST, as well as improve the determination of the motions of such objects for both orbital and solar system gravity field determinations. We will measure the FGS Astrometer Plate Scale by observing a target minor planet as it traverses the FGS Astrometer Field of View. The measuring precision is expected to be better than a milliarcsecond. The derived plate scale is expected to be accurate to a few milliarcseconds over the length of the pickle, limited by knowledge of the ephemeris motion. Continuing ground-based observations are being made to provide the necessary updated ephemeris. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 0.67 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FGS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5641 PI: William H. Jefferys Proposal Title: OBSERVATIONS OF MINOR PLANETS AT CROSSING POINTS PART 1, CYCLE 4, HIGH ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Dr. William H. Jefferys UNIVERSITY OF TEXAS AT AUSTIN USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. a) Observations will be made with the FGSs in POS mode. 1 obs-set will consist of one observation of the minor planet followed by 4 ref stars, a repeat of the mp, a repeat of the 4 ref stars in reverse order, and a final repeat of the mp. (3min/mpobs,1min/ref-star) Two of the reference stars are located at each end of the pickle, to insure against losing the calibration if one of the ref stars is double and cannot be locked in fine lock. The repeated observations are required to solve for he apparent rotation of the astrometer FGS during the obs set. We hve been successful solving for this apparent rotation using the symmetric ref star procedure with previous FGS measurements of Hipparcos star/QSO fields. The amplitude of the motion can be as high as 10 milliarcseconds during an observation set, while the solution yields submilliarcsecond consistancy in many cases. The observation set will be repeated for a total of 5 times as the minor planet moves across the FGSFOV (pickle). Ideally, one observation set at each end of the pickle would suffice. However, because of scheduling constraints and in order to provide redundancy and possibly higher accuracy, five sets across the pickle is the minimum acceptable. If one observation set at the end of the pickle is lost for whatever reason, we would still have enough information to recover an acceptable scale determination. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. This measurement is necessary for the accurate calibration of the FGS Astrometer Plate Scale at the milliarcsecond level of accuracy over the length of the FGSFOV (18.6 arcminutes). The next-best calibration is using FGS observations of Hipparcos stars, and should be a factor of 4 - 5 worse than this method. This calibration is necessary for HST Solar System Astrometry with the FGS Astrometer, and for the calibration of FGS measurements with respect to Extragalactic Objects already made and continuing. The most accurate value of the plate scale would come from measuring the position of the minor planet continuously as as it traverses the FGSFOV (Pickle). Repeated measurements of several reference stars are necessary to track the apparent motion of the Pickle during the observation set. The minimum measurement would consist of two observation sets, one at each end of the Pickle. However, to be safe and allow for observational and scheduling contingencies which would cancel one or more observation sets as has happened in previous apparitions of this proposal, we request five observation sets spread across the Pickle which will yield an acceptable calibration, even if one of the end obs sets does not get (continued under question 5).... Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. This observation is time critical, based on asteroid size, magnitude, speed and direction of motion through the pickle, reference and guidestar availability, and many other factors. QUESTION 4 continued: get executed for some reason. Each observation set will take about 30 minutes i.e., one orbit. The target will be near opposition so that the observation will be made on the on the dark side of the orbit. Cycling through the minor planet and the reference stars in the given order is necessary to "track" the apparent motion of the Astrometer reference frame on the sky. Repeated observations of the minor planet are necessary in case one is missed, and to give higher accuracy and repeatability (error estimates) when more than one setting is obtained in an observation set. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. for further information contact Paul Hemenway, University of Texas, Astronomy Department paul@astro.as.utexas.edu currently at University of St. Andrews, Scotland. e-mail to the above address will be automatically forwarded. ------------------------------------------------------------------------------------ 11. Address Information Name: PAUL D HEMENWAY Category: CON Institution: UNIVERSITY OF TEXAS AT AUSTIN Address: DEPARTMENT OF ASTRONOMY UNIVERSITY OF TEXAS AT AUSTIN City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: (512)471-3431 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: WILLIAM H. JEFFERYS Category: PI Institution: UNIVERSITY OF TEXAS AT AUSTIN Address: DEPARTMENT OF ASTRONOMY UNIVERSITY OF TEXAS AT AUSTIN City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: (512)471-1455 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5641 [ 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| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 10 MP-POINTING J, 701 RA = 18H 45M 44.177S +/- J2000 .008S, DEC = -20D 13' 35.030" +/- .008" ------------------------------------------------------------------------------------------------------------------------------------ 12 PAUL1 J, 701 RA = 281.50496D +/- J2000 1 V = 13.08 0.00001D, DEC = -20.43744D +/- 0.00001D ------------------------------------------------------------------------------------------------------------------------------------ 14 PAUL2 J, 701 RA 281.46472D +/- 0.00001D, J2000 1 V = 13.08 DEC = -20.42449D +/- 0.00001D ------------------------------------------------------------------------------------------------------------------------------------ 16 PAUL3 J, 701 RA = 281.29662D +/- J2000 1 V = 13.08 0.00001D, DEC = -20.37026D +/- 0.00001D ------------------------------------------------------------------------------------------------------------------------------------ 18 PAUL4 J, 701 RA = 281.27234D +/- J2000 1 V = 13.08 0.00001D, DEC = -20.36241D +/- 0.00001D ------------------------------------------------------------------------------------------------------------------------------------ 19 PAUL5 J, 701 RA = 281.23121D +/- J2000 1 V = 13.08 0.00001D, DEC = -20.34910D +/- 0.00001D ------------------------------------------------------------------------------------------------------------------------------------ 20 MPREF1-REF J, 701 RA = 18H 46M 01.169S +/- J2000 1 V = 13.08 .008S, DEC = -20D 25' 37.740" +/- .008" ------------------------------------------------------------------------------------------------------------------------------------ 30 MPREF2-REF J, 701 RA = 18H 45M 54.384S +/- J2000 1 V = 13.28 .008S, DEC = -20D 26' 22.200" +/- .008" ------------------------------------------------------------------------------------------------------------------------------------ 40 MPREF3-REF J, 701 RA = 18H 45M 07.692S +/- J2000 1 V = 13.10 .008S, DEC = -20D 23' 46.788" +/- .008" ------------------------------------------------------------------------------------------------------------------------------------ 50 MPREF4-REF J, 701 RA = 18H 45M 02.796S +/- J2000 1 V = 13.49 .008S, DEC = -20D 21' 50.400" +/- .008" ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5641 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 60 | TARGET NAME: MP1626 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: ASTEROID 1626 ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=ASTEROID, | A=2.3631911, E=0.2750806, | I=25.31048, O=279.05397, | W=148.78383, M=286.60422, | EPOCH=24-MAY-91:00:00:00, | EQUINOX=B1950 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5641 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 100 DEFINE MP-POINTING S/C POINTIN V1 0 0.0S SEQ 100-111 NO GAP MP-OBS1 G SAME POS FOR 101- 111 AS 100 ------------------------------------------------------------------------------------------------------------------------------------ 101 DEFINE # FGS POS 3 F583W FES-TIME=0.025 1 3M MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 102 DEFINE MPREF1-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 103 DEFINE MPREF2-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 104 DEFINE MPREF3-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 105 DEFINE MPREF4-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 106 DEFINE # FGS POS 3 F583W FES-TIME=0.025 1 3M MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 107 DEFINE MPREF4-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5641 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 108 DEFINE MPREF3-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 109 DEFINE MPREF2-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 110 DEFINE MPREF1-REF FGS POS 3 F583W FES-TIME=DEF 1 51.2S MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 111 DEFINE # FGS POS 3 F583W FES-TIME=0.025 1 3M MP-OBS1 NULL=YES LOCK=FINE DATA-RATE=32 ACQ-MODE=SEARCH ACQ-DIST=15 ------------------------------------------------------------------------------------------------------------------------------------ 200 USE MP- PAUL1 AT 9-JUL-94:21:40 OBS1 +/- 2.67H ORIENT 109.5D +/- 0.01D CYCLE 4 Comments: IT IS ABSOLUTELY IMPERATIVE TO KEEP THE SAME POINTING AND ORIENT FOR ALL OBSERVATIONS ------------------------------------------------------------------------------------------------------------------------------------ 300 USE MP- PAUL2 AT JD2449543.526 + OBS1 /- .111D ORIENT 109.5D +/- 0.01D CYCLE 4 / 300-600 Comments: IT IS ABSOLUTELY IMPERATIVE TO KEEP THE SAME POINTING AND ORIENT FOR ALL OBSERVATIONS ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5641 [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 400 USE MP- PAUL3 AT JD2449543.85 +/ OBS1 - .111D ORIENT 109.5D +/- 0.01D Comments: IT IS ABSOLUTELY IMPERATIVE THAT WE KEEP THE SAME POINTING AND ORIENT FOR ALL OBSERVATIONS ------------------------------------------------------------------------------------------------------------------------------------ 500 USE MP- PAUL4 AT JD2449543.972 + OBS1 /- .111D ORIENT 109.5D +/- 0.01D Comments: IT IS ABSOLUTELY IMPERATIVE TO KEEP THE SAME POINTING AND ORIENT FOR ALL OBSERVATIONS ------------------------------------------------------------------------------------------------------------------------------------ 600 USE MP- PAUL5 AT JD2449544.154 + OBS1 /- .060D ORIENT 109.5D +/- 0.01D Comments: IT IS ABSOLUTELY IMPERATIVE TO KEEP THE SAME POINTING AND ORIENT FOR ALL OBSERVATIONS ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5641 [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations S/C FGS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes POINTING POS ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FES-TIME=0.025 NULL LOCK DATA-RATE=32 ACQ-MODE ACQ-DIST FES-TIME=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/AST ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 0.67 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category MINOR PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SEQ 100-111 NO GAP; SAME POS FOR 101-111 AS 100 AT 9-JUL-94 21 40 +/- 2.67H; ORIENT 109.5D +/- 0.01D; CYCLE 4 AT JD2449543.526 +/- .111D; CYCLE 4 / 300-600 AT JD2449543.85 +/- .111D; AT JD2449543.972 +/- .111D; AT JD2449544.154 +/- .060D; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F583W ------------------------------------------------------------------------------------------------------------------------------------ Target Names MP-POINTING PAUL1 PAUL2 PAUL3 PAUL4 PAUL5 MPREF1-REF MPREF2-REF MPREF3-REF MPREF4-REF MP1626 ------------------------------------------------------------------------------------------------------------------------------------