Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1079c Report Date: 09-May-96:16:07 Version: ********** Check-in Date: ********** 1.Proposal Title: OPPORTUNITY OCCULTATIONS BY SMALL BODIES ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/HSP Target of Oppt. Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Robert C. Bless WISCONSIN, UNIVERSITY OF USA (608)262-1715 ------------------------------------------------------------------------------------ 7. Abstract Although an occultation by any specific comet, asteroid, satellite, or Pluto is unlikely to be observable from the ST, the scientific return from such an event would be great because of the superior signal-to-noise ratio achievable with the ST for occultation observations. We propose to observe occultations by these bodies with the ST, as the opportunites arise, to probe their atmospheres, determine their sizes and achieve other goals. With such diverse possibilities, one must examine each opportunity as it occurs and formulate an observing strategy to fit that particular case. Revision History: Received on RPS 9/1/89; Added to SCCS 9/5/89 Updated to V2 proposal instructions; - SALM 9/5/89 Updated to pass RPSS; asb@MIT 7May90; Small logic errors fixed--BJW 7/9/90; Changed SP. SCAN to SP. SCAN SING.-EXP --BJW 7/10/90; Changes in observations/ targets--amanda; Split proposal by cycle-- BJW 4/24/91; Updated target list-- BJW 8/1/91; Offset-target changes--amanda; Specification of cycles--BJW 10/25/91; ------------------------------------------------------------------------------------ 8. Scientific Key Words: COMET, ASTEROID, SATELLITE, PLUTO, OCCULTATION ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.75 par: 0 10. Num targs pri: 7 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1079c PI: Robert C. Bless Proposal Title: OPPORTUNITY OCCULTATIONS BY SMALL BODIES ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Edward L. Robinson TEXAS, UNIVERSITY OF USA Robert C. Bless WISCONSIN, UNIVERSITY OF USA G. W. Van Citters NATIONAL SCIENCE FOUNDATION USA Joseph F. Dolan NASA, GODDARD SPACE FLIGHT USA CENTER Richard L. White SPACE TELESCOPE SCIENCE USA INSTITUTE James L. Elliot MASSACHUSETTS INSTITUTE OF USA TECHNOLOGY ------------------------------------------------------------------------------------ 3. Description of proposed observations. We plan to identify those occultations of sufficient signal-to-noise ratio to achieve the goals outlined in Section 2. Each observation will require (i) a set of 2 onboard acquisitions; (ii) a scan of about ten arc-seconds along the track that the object will follow relative to the occulting body and (iii) a time series run on the object with whatever filter aperture combination that is chosen for the observation. For some occultations to be observed in the far UV, prior multi-filter photometry of the object will be necessary in order to determine the most appropriate filter to use for the occultation. For now, we shall assume that the calibration and observation time will average about 30 minutes per occultation observed. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. We can achieve a much better signal-to-noise ratio for the temperature profiles and other information than can be obtained for small body occultations than has been possible from the ground for the following reasons: (i) the greatly improved photometric stability of ST photometry, which will substantially reduce the errors in the numerical inversion of the data that is necessary to obtain the temperature profiles; (ii) our ability to reject background light from the occulting object (such as a comet ) by employing small focal plane apertures; and (iii) the absence of scintillation noise, which has strong components at frequencies comparable to the occultation timescale. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. For resolved bodies with possible atmospheres, tracking the occulted star will require a real time update, due to its complicated path caused by refraction in the occulting body's atmosphere and the uncertainties in predicting the ST orbit. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. For comets and the larger bodies (Titan, Triton, and Pluto) a prior scan over 10 arc-seconds is needed to map the scattered light field, which is needed for the data reduction. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Data will be reduced and analyzed at MIT with VAX 11-750 belonging to the planetary astronomy group. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). TBD Page 3 ------------------------------------------------------------------------------------ 13. An observation of an occultation by a comet, asteroid, satellite, or Pluto would yield a variety of information. For example, we could gain further information about the atmospheres of Pluto and Triton, including knowledge of the composition and structure of their atmospheres. Also, the presence of possible material in the neighborhood of an asteroid could be obtained. Opportunity stellar occultations by small bodies are proposed to be observed with the HSP or FOS. ------------------------------------------------------------------------------------ 11. Address Information Name: ROBERT C. BLESS Category: PI Institution: UNIVERSITY OF WISCONSIN Address: DEPARTMENT OF ASTRONOMY 475 NORTH CHARTER STREET City: MADISON State: WI Zip Code: 53706 Country: USA Telephone: 608-262-1715 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1079c [ 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 P14.C STAR TO BE OCCULTED BY RA = 15H 35M 41.257S +/- 2000 BKG 1 R = 15.3 +/- 0.1 PLUTO. 0.1", 2 V = 15.7 +/- 0.1 CLOSE APPROACH AT 17- DEC = -4D 12' 57.18" +/- JAN-92:02:20 0.1", Comments: POSREF = AMANDA. STAR POSITION FROM ASTROMETRIC CCD STRIP SCANS TAKEN AT WALLACE OBSERVATORY, MIT ------------------------------------------------------------------------------------------------------------------------------------ 11 P14.C-OFFSET OFFSET STAR TO BE RA = 15H 35M 40.723S +/- 2000 1 R = 15.8 +/- 0.2 STAR-153541- ACQUIRED 0.1", 041257 DEC = -4D 12' 29.46" +/- 0.1", Comments: POSREF = AMANDA. STAR POSITION FROM ASTROMETRIC CCD STRIP SCANS TAKEN AT WALLACE OBSERVATORY, MIT ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 1079c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 15 | TARGET NAME: PLUTO-BACKGROUND ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET PLUTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = PLUTO, ACQ = 0.1 | TYPE = POS_ANGLE, | RAD = 5.0, | ANG = 87.357, | REF = NORTH | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | | | FOR USE IN A SCAN OF BACKGROUND | | LEVELS ALONG THE PATH OF THE | | OCCULTED STAR | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 16 | TARGET NAME: PLUTO-CENTER ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET PLUTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = PLUTO, ACQ = 0.1 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V = 13.8 +/- 0.5 | ACQUISITION TARGET FOR PLUTO- | | BACKGROUND | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1079c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 DEFINE # HSP/ ACQ 1 5M 10 1 # EARLY ACQ FOR 2-3 HSP-OCC VIS SAME ORIENT FOR 2- 3 AS 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 ^ # HSP/ SPLIT 1.0 F750W/ SAMPLE- ^ ^ 5 # CRIT OBS / 2-3 PMT/ F320N TIME=0.01 1S SEQ 2-3 NO GAP VIS ------------------------------------------------------------------------------------------------------------------------------------ 3 ^ # ^ ^ ^ F750W/ ^ ^ # SPATIAL SCAN F320N SINGLE-EXP ------------------------------------------------------------------------------------------------------------------------------------ 4 DEFINE # FOS/RD ACQ/ 4.3 MIRROR ^ ^ 10 # EARLY ACQ FOR 5-6 FOS-OCC BINARY SAME ORIENT FOR 5- 6 AS 4 ------------------------------------------------------------------------------------------------------------------------------------ 5 ^ # ^ RAPID 0.5 G650L STEP-TIME=0.02 ^ ^ 5 # CRIT OBS / 5-6 1S SEQ 5-6 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 6 ^ # ^ ^ ^ ^ ^ ^ # SPATIAL SCAN SINGLE-EXP Comments: EITHER G160L OR G650L WILL BE USED AS THE SPECTRAL ELEMENT FOR THE FOS IN LINES 5-6 DEPENDING ON THE EXACT SPECTRAL TYPE AND MAGNITUDE OF THE OCCULTED STAR. ------------------------------------------------------------------------------------------------------------------------------------ 6.1 DEFINE # HSP/ SPLIT 1.0 F750W/ # 1 1M 1 1 CRIT OBS OCC PMT/ F320N GUID TOL 0.007" VIS Comments: USE FINE LOCK IF BRIGHT ENOUGH GUIDE STARS CAN BE FOUND. IF NOT, COARSE TRACK IS ACCEPTABLE. HSP09A (SV TEST) MUST BE COMPLETED BEFORE THESE OBSERVATIONS ------------------------------------------------------------------------------------------------------------------------------------ 6.2 DEFINE # HSP/ ACQ 1 180S 1 1 GUID TOL 0.007" ONBRD- VIS ACQ Comments: USE FINE LOCK FOR GUIDE STAR ACQ IF BRIGHT ENOUGH GUIDE STARS CAN BE FOUND. IF NOT, COARSE TRACK IS ACCEPTABLE. ------------------------------------------------------------------------------------------------------------------------------------ 6.3 DEFINE # HSP/ SPLIT 1.0 F750W/ # 1 1S 1 1 SPATIAL SCAN BACK- PMT/ F320N GUID TOL 0.007" SCAN VIS Comments: USE FINE LOCK IF BRIGHT ENOUGH GUIDE STARS CAN BE FOUND. IF NOT, COARSE TRACK IS ACCEPTABLE. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1079c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 USE PLUTO- ONBOARD ACQ FOR ONBRD- CENTER 10.01 ACQ SEQ 10.00 - 10.01 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 10.01 USE PLUTO- SAMPLE- X50 SEQ 10.01 - 10.03 BACK- BACKGROUND TIME=0.01 GROUP 10.01 - SCAN DATA-FORMAT=ALL 10.04 WITHIN 12H PRECISION=HIGH ANALOG-SCALE=10 Comments: EXECUTE 10.01 - 10.04 AS CLOSE TO TIME OF OCCULTATION AS IS SCHEDULABLE. ------------------------------------------------------------------------------------------------------------------------------------ 10.02 USE PLUTO- SAMPLE- X150 BACK- BACKGROUND TIME=0.01 SCAN DATA-FORMAT=ALL PRECISION=HIGH ANALOG-SCALE=10 ------------------------------------------------------------------------------------------------------------------------------------ 10.03 USE PLUTO- SAMPLE- X50 BACK- BACKGROUND TIME=0.01 SCAN DATA-FORMAT=ALL PRECISION=HIGH ANALOG-SCALE=10 ------------------------------------------------------------------------------------------------------------------------------------ 10.04 USE P14.C- ONBOARD ACQ FOR ONBRD- OFFSET 10.09 ACQ SEQ 10.04 - 10.09 NO GAP CYCLE 1 / 10.00 - 10.09 Comments: THIS PROPOSAL RESERVES GTO TIME COND IF FOR A TOTAL OF 7 EVENTS, THE OCCULTATION CHOICE OF HSP OR FOS DEPENDS ON GEOMETRY THE OCCULTING OBJECT AND THE FAVORABLE / 10.00 TYPE AND BRIGHTNESS OF THE - 10.09 OCCULTED STAR. ------------------------------------------------------------------------------------------------------------------------------------ 10.09 USE OCC P14.C SAMPLE- X20 AT 17-JAN-92:02:06 TIME=0.05 +/- 1M DATA-FORMAT=ALL PRECISION=HIGH ANALOG-SCALE=10 Comments: END EXPOSURE AT 17-JAN-92:02:24 TIME_PER_EXP WILL CHANGE DEPENDING ON FINAL PREDICTION AND HST ORBIT PARAMETERS. ------------------------------------------------------------------------------------------------------------------------------------ Scan Paramters Form Proposal ID: 1079c [ 8] ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 10.01, 10.03 FGS Scan: CONTINUOUS Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 10.0000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.2000 PA of first scan line (degrees) 267.357 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 0. Width Offset (arc-sec): 0. ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 2 Exposure Logsheet lines: 10.02 FGS Scan: CONTINUOUS Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 1.0000 Scan length (arc-secs): 10.0000 Angle between sides (degrees) 90.00 Number of lines: 3 Scan rate (arc-sec/sec): 0.2000 PA of first scan line (degrees) 267.357 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 0. Width Offset (arc-sec): 0.5000 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1079c [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HSP/VIS HSP/PMT/VIS ^ FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ SPLIT ^ ACQ/BINARY RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SAMPLE-TIME=0.01 STEP-TIME=0.02 SAMPLE-TIME DATA-FORMAT PRECISION ANALOG-SCALE ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/HSP ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.75 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements EARLY ACQ FOR 2-3; SAME ORIENT FOR 2-3 AS 1; CRIT OBS / 2-3; SEQ 2-3 NO GAP SPATIAL SCAN SINGLE-EXP; EARLY ACQ FOR 5-6; SAME ORIENT FOR 5-6 AS 4; CRIT OBS / 5-6; SEQ 5-6 NO GAP; CRIT OBS; GUID TOL 0.007"; SPATIAL SCAN; ONBOARD ACQ FOR 10.01; SEQ 10.00 - 10.01 NO GAP; SEQ 10.01 - 10.03; GROUP 10.01 - 10.04 WITHIN 12H; ONBOARD ACQ FOR 10.09; SEQ 10.04 - 10.09 NO GAP; CYCLE 1 / 10.00 - 10.09; COND IF OCCULTATION GEOMETRY FAVORABLE / 10.00 - 10.09; AT 17-JAN-92 02 06 +/- 1M; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F750W/F320N MIRROR G650L ^ ------------------------------------------------------------------------------------------------------------------------------------ Target Names P14.C P14.C-OFFSET STAR-153541-041257 PLUTO-BACKGROUND PLUTO-CENTER ------------------------------------------------------------------------------------------------------------------------------------