Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 3371c Report Date: 09-May-96:18:32 Version: ********** Check-in Date: ********** 1.Proposal Title: SATURN RING DYNAMICS - CYC2HIGH ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GTO/HSP 1081 Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Robert C. Bless WISCONSIN, UNIVERSITY OF USA 608-262-1715 ------------------------------------------------------------------------------------ 7. Abstract Understanding the dynamics of the rings is essential to our eventual understanding of their origin. Did they form recently or along with Saturn itself? We propose a series of stellar occultation observations in order to continue the dynamical investigation of Saturn's rings, at high spatial resolution, begun by the Voyager spacecraft. Revision History: Updated for cycle 2 submission, 4/24/92, asb.; cycle 2 updates, ASB 1/24/93; ------------------------------------------------------------------------------------ 8. Scientific Key Words: SATURN'S RINGS, OCCULTATIONS, RING DYNAMICS ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.01 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HSP ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 3371c PI: Robert C. Bless Proposal Title: SATURN RING DYNAMICS - CYC2HIGH ------------------------------------------------------------------------------------ 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 use the ST orbit parameters and catalogs of the objects of interest to identify those occultations of sufficient signal-to-noise ratio to achieve the goals outlined in Section 2. Each observation will require (i) external "darks", taken on the dark earth as a standard calibration source, (ii) a set of two sequential onboard acquisitions, (iii) a scan of about 30-40 arcseconds along the track that the object will follow relative to Saturn's rings; and (iv) 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. The default filter set is F750W/F320N. For now, we shall assume that the calibration and observation time will average about 3 hours per occultation observed. About ten occultations would be required to achieve ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. We can achieve a much better signal-to-noise ratio for Saturn ring occultations than would be possible from the ground because of (i) the absence of scintillation noise, which has strong components at frequencies corresponding to the occultation timescales, and (ii) our ability to reject background light from the rings themselves by employing small focal plane apertures. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. Acquisition of the star near Saturn may prove to be difficult. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. A prior scan over 30-40 arcseconds 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 the VAX 11-750 belonging to the planetary astronomy group. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. SV test HSP09A must be completed before these observations are made because the exact observation sequence may need to be modified depending on the results of the SV test. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Data reduction and analysis will be supported on computer facilities at MIT. Page 3 ------------------------------------------------------------------------------------ 13. Observations of a series of stellar occultations by Saturn's rings with the HSP (or perhaps FOS) can provide precise orbits of ringlets, other sharp features, waves, and other phenomena in the Saturn system at high spatial resolution. From these data further understanding of the present dynamical state of the ring system can be gained. This understanding should improve our knowledge of the past history and conditions of formation of the rings. ------------------------------------------------------------------------------------ 11. Address Information Name: ROBERT C. BLESS Category: PI Institution: UNIVERSITY OF WISCONSIN Address: DEPARTMENT OF ASTRONOMY City: MADISON State: WI Zip Code: 53706 Country: USA Telephone: 608-262-1715 Telex (or e-mail): ------------------------------------------------------------------------------------ Name: JAMES L. ELLIOT Category: CON Institution: MASSACHUSETTS INSTITUTE OF TECHNO Address: BLDG. 54-422 City: CAMBRIDGE State: MA Zip Code: 02139 Country: USA Telephone: 617-253-6308 Telex (or e-mail): 921473 MIT CAM ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 3371c [ 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| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 14 GSC5801- A,126 PLATE-ID = 00WO, J2000 BKG 1 B = 10.7 +/- 0.5 00416 RA = 21H 51M 32.049S +/- 0.06", DEC = -14D 30' 47.28" +/- 0.06", Comments: STAR TO BE OCCULTED BY SATURN. CLOSE APPROACH AT 7-DEC-93:19:13 SOLAR ELONG 69D ------------------------------------------------------------------------------------------------------------------------------------ 15 00416-OFFSET A,126 PLATE-ID = 00WO, J2000 1 B = 14.6 +/- 0.1 GSC5801- RA = 21H 51M 34.818S +/- 00480 0.03", DEC = -14D 30' 58.49" +/- 0.06", Comments: OFFSET TARGET FOR GSC5801-00416 ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 3371c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 18 | TARGET NAME: 00416-BACKGROUND ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET SATURN ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = SATURN | TYPE = POS_ANGLE, | RAD = 13.94, | ANG = 20.5, | 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 | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3371c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 4 DEFINE # HSP/ ACQ 1 1S 1 1 ONBRD- VIS ACQ ------------------------------------------------------------------------------------------------------------------------------------ 6 DEFINE # HSP/ SPLIT 1.0 F750W/ # 1 1S 1 1 SPATIAL SCAN BACK- PMT/ F320N SCAN VIS ------------------------------------------------------------------------------------------------------------------------------------ 7 DEFINE # HSP/ SPLIT 1.0 F750W/ # 1 1M 1 1 RING- PMT/ F320N OCC VIS ------------------------------------------------------------------------------------------------------------------------------------ 7.5 DEFINE ^ S/C DATA NONE FORMAT=FN 1 ^ 1 PAR WITH 7.0 RING- OCC Comments: CAPTURE FGS TLM DURING OCCULTATION. ------------------------------------------------------------------------------------------------------------------------------------ 12.01 USE 00416- SAMPLE- X467 SEQ 12.01 - 12.07 BACK- BACKGROUND TIME=0.01 GROUP 12.01 - SCAN DATA-FORMAT=ALL 12.09 WITHIN 9H PMT-ANALOG=1000 CYCLE 2/12.01 - VIS-ANALOG=100 12.32 ------------------------------------------------------------------------------------------------------------------------------------ 12.03 USE 00416- SAMPLE- X467 BACK- BACKGROUND TIME=0.01 SCAN DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 12.07 USE 00416- SAMPLE- X467 BACK- BACKGROUND TIME=0.01 SCAN DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 12.09 USE 00416- X60 ONBOARD ACQ FOR ONBRD- OFFSET 12.10 ACQ SEQ 12.09 - 12.10 NO GAP PCS MODE F / 12.09 - 12.10 Comments: USE FINE LOCK ONLY. IF BRIGHT ENOUGH GUIDE STARS CANNOT BE FOUND, CANCEL OBSERVATION. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 3371c [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 12.1 USE GSC5801- SAMPLE- X60 AT 7-DEC-93:20:16 RING- 00416 TIME=0.01 +/- 1M OCC DATA-FORMAT=ALL CRIT OBS PMT-ANALOG=1000 VIS-ANALOG=100 Comments: END EXPOSURE AT 7-DEC-93:21:15. OCCULTATION IS A NOMINAL MISS. TIMES WILL BE UPDATED (OR OBSERVATION WILL BE CANCELLED) 1.5 TO 4 MONTHS BEFORE OBSERVATION. CONTACT: AMANDA S. BOSH, MIT ------------------------------------------------------------------------------------------------------------------------------------ 12.26 USE 00416- SAMPLE- X467 SEQ 12.26 - 12.32 BACK- BACKGROUND TIME=0.01 GROUP 12.10 - SCAN DATA-FORMAT=ALL 12.32 WITHIN 9H PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 12.28 USE 00416- SAMPLE- X467 BACK- BACKGROUND TIME=0.01 SCAN DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ 12.32 USE 00416- SAMPLE- X467 BACK- BACKGROUND TIME=0.01 SCAN DATA-FORMAT=ALL PMT-ANALOG=1000 VIS-ANALOG=100 ------------------------------------------------------------------------------------------------------------------------------------ Scan Paramters Form Proposal ID: 3371c [ 8] ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 12.01, 12.07, 12.26, FGS Scan: CONTINUOUS Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 28.0000 Angle between sides (degrees) 90.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0750 PA of first scan line (degrees) 249.400 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 0. Width Offset (arc-sec): 0 ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 2 Exposure Logsheet lines: 12.03, 12.28 FGS Scan: CONTINUOUS Dwell Only: dwell points/line: 0 Seconds per dwell: 0.00 Scan width (arc-secs): 2.0000 Scan length (arc-secs): 28.0000 Angle between sides (degrees) 90.00 Number of lines: 5 Scan rate (arc-sec/sec): 0.0750 PA of first scan line (degrees) 249.400 Scan frame (CEL or S/C): CEL Length Offset (arc-sec): 0. Width Offset (arc-sec): 1.0000 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 3371c [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HSP/VIS HSP/PMT/VIS S/C ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ SPLIT DATA ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FORMAT=FN SAMPLE-TIME DATA-FORMAT PMT-ANALOG VIS-ANALOG ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/HSP ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.01 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SPATIAL SCAN; PAR WITH 7.0; SEQ 12.01 - 12.07; GROUP 12.01 - 12.09 WITHIN 9H; CYCLE 2/12.01 - 12.32; ONBOARD ACQ FOR 12.10; SEQ 12.09 - 12.10 NO GAP; PCS MODE F / 12.09 - 12.10; AT 7-DEC-93 20 16 +/- 1M; CRIT OBS; SEQ 12.26 - 12.32; GROUP 12.10 - 12.32 WITHIN 9H; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F750W/F320N ------------------------------------------------------------------------------------------------------------------------------------ Target Names GSC5801-00416 00416-OFFSET GSC5801-00480 00416-BACKGROUND ------------------------------------------------------------------------------------------------------------------------------------