! File: 1079C.PROP ! Database: PEPDB ! Date: 16-FEB-1994:00:51:53 coverpage: title_1: OPPORTUNITY OCCULTATIONS BY SMALL BODIES sci_cat: SOLAR SYSTEM proposal_for: GTO/HSP targ_of_opp: Y pi_fname: ROBERT pi_mi: C. pi_lname: BLESS pi_inst: WISCONSIN, UNIVERSITY OF pi_country: USA pi_phone: (608)262-1715 keywords_1: COMET, ASTEROID, SATELLITE, PLUTO, OCCULTATION hours_pri: 1.75 num_pri: 7 realtime: X time_crit: Y ! end of coverpage abstract: line_1: Although an occultation by any specific comet, asteroid, satellite, or Pluto is line_2: unlikely to be observable from the ST, the scientific return from such an event line_3: would be great because of the superior signal-to-noise ratio achievable with line_4: the ST for occultation observations. We propose to observe occultations by line_5: these bodies with the ST, as the opportunites arise, to probe their line_6: atmospheres, determine their sizes and achieve other goals. With such diverse line_7: possibilities, one must examine each opportunity as it occurs and formulate an line_8: observing strategy to fit that particular case. line_9: Revision History: Received on RPS 9/1/89; Added to SCCS 9/5/89 line_10: Updated to V2 proposal instructions; - SALM 9/5/89 line_11: Updated to pass RPSS; asb@MIT 7May90; Small logic errors fixed--BJW 7/9/90; line_12: Changed SP. SCAN to SP. SCAN SING.-EXP--BJW 7/10/90; Changes in observations/ line_13: targets--amanda; Split proposal by cycle--BJW 4/24/91; Updated target list-- line_14: BJW 8/1/91; Offset-target changes--amanda; Specification of cycles--BJW line_15: 10/25/91; ! ! end of abstract general_form_proposers: lname: ROBINSON fname: EDWARD mi: L. inst: TEXAS, UNIVERSITY OF country: USA ! lname: BLESS fname: ROBERT mi: C. inst: WISCONSIN, UNIVERSITY OF country: USA ! lname: VAN CITTERS fname: G. mi: W. inst: NATIONAL SCIENCE FOUNDATION country: USA ! lname: DOLAN fname: JOSEPH mi: F. inst: NASA, GODDARD SPACE FLIGHT CENTER country: USA ! lname: WHITE fname: RICHARD mi: L. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: ELLIOT fname: JAMES mi: L. inst: MASSACHUSETTS INSTITUTE OF TECHNOLOGY country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: We plan to identify those occultations of sufficient signal-to-noise ratio to line_2: achieve the goals outlined in Section 2. Each observation will require (i) line_3: a set of 2 onboard acquisitions; (ii) a scan of about ten line_4: arc-seconds along the track that the object will follow relative to the line_5: occulting body and (iii) a time series run on the object with whatever filter line_6: aperture combination that is chosen for the observation. For some occultations line_7: to be observed in the far UV, prior multi-filter photometry of the object will line_8: be necessary in order to determine the most appropriate filter to use for the line_9: occultation. For now, we shall assume that the calibration and observation time line_10: will average about 30 minutes per occultation observed. ! question: 4 section: 1 line_1: We can achieve a much better signal-to-noise ratio for the temperature profiles line_2: and other information than can be obtained for small body occultations than has line_3: been possible from the ground for the following reasons: (i) the greatly line_4: improved photometric stability of ST photometry, which will substantially line_5: reduce the errors in the numerical inversion of the data that is necessary to line_6: obtain the temperature profiles; (ii) our ability to reject background light line_7: from the occulting object (such as a comet ) by employing small focal plane line_8: apertures; and (iii) the absence of scintillation noise, which has strong line_9: components at frequencies comparable to the occultation timescale. ! question: 5 section: 1 line_1: For resolved bodies with possible atmospheres, tracking the occulted star will line_2: require a real time update, due to its complicated path caused by refraction in line_3: the occulting body's atmosphere and the uncertainties in predicting the line_4: ST orbit. ! question: 6 section: 1 line_1: For comets and the larger bodies (Titan, Triton, and Pluto) a prior scan over 10 line_2: arc-seconds is needed to map the scattered light field, which is needed for the line_3: data reduction. ! question: 7 section: 1 line_1: Data will be reduced and analyzed at MIT with VAX 11-750 belonging to the line_2: planetary astronomy group. ! question: 10 section: 1 line_1: TBD ! question: 13 section: 1 line_1: An observation of an occultation by a comet, asteroid, satellite, or Pluto line_2: would yield a variety of information. For example, we could gain further line_3: information about the atmospheres of Pluto and Triton, including knowledge line_4: of the composition and structure of their atmospheres. line_5: Also, the presence of possible material in the neighborhood of an asteroid could line_6: be obtained. Opportunity stellar occultations by small bodies are proposed to line_7: be observed with the HSP or FOS. ! !end of general form text general_form_address: lname: BLESS fname: ROBERT mi: C. category: PI inst: UNIVERSITY OF WISCONSIN addr_1: DEPARTMENT OF ASTRONOMY addr_2: 475 NORTH CHARTER STREET city: MADISON state: WI zip: 53706 country: USA phone: 608-262-1715 ! ! end of general_form_address records fixed_targets: targnum: 10 name_1: P14.C descr_1: STAR TO BE OCCULTED BY PLUTO. descr_2: CLOSE APPROACH AT 17-JAN-92:02:20 pos_1: RA = 15H 35M 41.257S +/- 0.1", pos_2: DEC = -4D 12' 57.18" +/- 0.1", equinox: 2000 acqpr_1: BKG comment_1: POSREF = AMANDA. comment_2: STAR POSITION FROM ASTROMETRIC comment_3: CCD STRIP SCANS TAKEN AT comment_4: WALLACE OBSERVATORY, MIT fluxnum_1: 1 fluxval_1: R = 15.3 +/- 0.1 fluxnum_2: 2 fluxval_2: V = 15.7 +/- 0.1 ! targnum: 11 name_1: P14.C-OFFSET name_2: STAR-153541-041257 descr_1: OFFSET STAR TO BE ACQUIRED pos_1: RA = 15H 35M 40.723S +/- 0.1", pos_2: DEC = -4D 12' 29.46" +/- 0.1", equinox: 2000 comment_1: POSREF = AMANDA. comment_2: STAR POSITION FROM ASTROMETRIC comment_3: CCD STRIP SCANS TAKEN AT comment_4: WALLACE OBSERVATORY, MIT fluxnum_1: 1 fluxval_1: R = 15.8 +/- 0.2 ! ! end of fixed targets solar_system_targets: targnum: 15 name_1: PLUTO-BACKGROUND descr_1: OFFSET PLUTO lev1_1: STD = PLUTO, ACQ = 0.1 lev2_1: TYPE = POS_ANGLE, lev2_2: RAD = 5.0, lev2_3: ANG = 87.357, lev2_4: REF = NORTH comment_1: FOR USE IN A SCAN OF comment_2: BACKGROUND LEVELS ALONG comment_3: THE PATH OF THE OCCULTED STAR ! targnum: 16 name_1: PLUTO-CENTER descr_1: PLANET PLUTO lev1_1: STD = PLUTO, ACQ = 0.1 comment_1: ACQUISITION TARGET FOR comment_2: PLUTO-BACKGROUND fluxnum_1: 1 fluxval_1: V = 13.8 +/- 0.5 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: HSP-OCC targname: # config: HSP/VIS opmode: ACQ num_exp: 1 time_per_exp: 5M s_to_n: 10 fluxnum_1: 1 priority: # req_1: EARLY ACQ FOR 2-3; req_2: SAME ORIENT FOR 2-3 AS 1; ! linenum: 2.000 sequence_1: ^ targname: # config: HSP/PMT/VIS opmode: SPLIT aperture: 1.0 sp_element: F750W/F320N num_exp: ^ time_per_exp: ^ s_to_n: 5 s_to_n_time: 1S fluxnum_1: ^ priority: # param_1: SAMPLE-TIME=0.01, req_1: CRIT OBS / 2-3; SEQ 2-3 NO GAP ! linenum: 3.000 sequence_1: ^ targname: # config: ^ opmode: ^ aperture: ^ sp_element: F750W/F320N num_exp: ^ time_per_exp: ^ priority: # req_1: SPATIAL SCAN SINGLE-EXP; ! linenum: 4.000 sequence_1: DEFINE sequence_2: FOS-OCC targname: # config: FOS/RD opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: ^ time_per_exp: ^ s_to_n: 10 fluxnum_1: ^ priority: # req_1: EARLY ACQ FOR 5-6; req_2: SAME ORIENT FOR 5-6 AS 4; ! linenum: 5.000 sequence_1: ^ targname: # config: ^ opmode: RAPID aperture: 0.5 sp_element: G650L num_exp: ^ time_per_exp: ^ s_to_n: 5 s_to_n_time: 1S fluxnum_1: ^ priority: # param_1: STEP-TIME=0.02, req_1: CRIT OBS / 5-6; req_2: SEQ 5-6 NO GAP; ! linenum: 6.000 sequence_1: ^ targname: # config: ^ opmode: ^ aperture: ^ sp_element: ^ num_exp: ^ time_per_exp: ^ fluxnum_1: ^ priority: # req_1: SPATIAL SCAN SINGLE-EXP; comment_1: EITHER G160L OR G650L WILL BE USED AS comment_2: THE SPECTRAL ELEMENT FOR THE FOS IN comment_3: LINES 5-6 DEPENDING ON THE EXACT comment_4: SPECTRAL TYPE AND MAGNITUDE OF THE comment_5: OCCULTED STAR. ! linenum: 6.100 sequence_1: DEFINE sequence_2: OCC targname: # config: HSP/PMT/VIS opmode: SPLIT aperture: 1.0 sp_element: F750W/F320N num_exp: 1 time_per_exp: 1M fluxnum_1: 1 priority: 1 param_1: # req_1: CRIT OBS; req_2: GUID TOL 0.007"; comment_1: USE FINE LOCK IF BRIGHT ENOUGH comment_2: GUIDE STARS CAN BE FOUND. IF NOT, comment_3: COARSE TRACK IS ACCEPTABLE. comment_4: HSP09A (SV TEST) MUST BE COMPLETED comment_5: BEFORE THESE OBSERVATIONS ! linenum: 6.200 sequence_1: DEFINE sequence_2: ONBRD-ACQ targname: # config: HSP/VIS opmode: ACQ num_exp: 1 time_per_exp: 180S fluxnum_1: 1 priority: 1 req_1: GUID TOL 0.007"; comment_1: USE FINE LOCK FOR GUIDE STAR ACQ IF comment_2: BRIGHT ENOUGH GUIDE STARS CAN BE comment_3: FOUND. IF NOT, COARSE TRACK IS comment_4: ACCEPTABLE. ! linenum: 6.300 sequence_1: DEFINE sequence_2: BACK-SCAN targname: # config: HSP/PMT/VIS opmode: SPLIT aperture: 1.0 sp_element: F750W/F320N num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: # req_1: SPATIAL SCAN; req_2: GUID TOL 0.007"; comment_1: USE FINE LOCK IF BRIGHT ENOUGH comment_2: GUIDE STARS CAN BE FOUND. IF comment_3: NOT, COARSE TRACK IS ACCEPTABLE. ! linenum: 10.000 sequence_1: USE sequence_2: ONBRD-ACQ targname: PLUTO-CENTER req_1: ONBOARD ACQ FOR 10.01; req_2: SEQ 10.00 - 10.01 NO GAP; ! linenum: 10.010 sequence_1: USE sequence_2: BACK-SCAN targname: PLUTO-BACKGROUND time_per_exp: X50 param_1: SAMPLE-TIME = 0.01, param_2: DATA-FORMAT = ALL, param_3: PRECISION = HIGH, param_4: ANALOG-SCALE = 10, req_1: SEQ 10.01 - 10.03; req_2: GROUP 10.01 - 10.04 WITHIN 12H; comment_1: EXECUTE 10.01 - 10.04 AS CLOSE comment_2: TO TIME OF OCCULTATION AS IS comment_3: SCHEDULABLE. ! linenum: 10.020 sequence_1: USE sequence_2: BACK-SCAN targname: PLUTO-BACKGROUND time_per_exp: X150 param_1: SAMPLE-TIME = 0.01, param_2: DATA-FORMAT = ALL, param_3: PRECISION = HIGH, param_4: ANALOG-SCALE = 10, ! linenum: 10.030 sequence_1: USE sequence_2: BACK-SCAN targname: PLUTO-BACKGROUND time_per_exp: X50 param_1: SAMPLE-TIME = 0.01, param_2: DATA-FORMAT = ALL, param_3: PRECISION = HIGH, param_4: ANALOG-SCALE = 10, ! linenum: 10.040 sequence_1: USE sequence_2: ONBRD-ACQ targname: P14.C-OFFSET req_1: ONBOARD ACQ FOR 10.09; req_2: SEQ 10.04 - 10.09 NO GAP; req_3: CYCLE 1 / 10.00 - 10.09; req_4: COND IF OCCULTATION GEOMETRY req_5: FAVORABLE / 10.00 - 10.09; comment_1: THIS PROPOSAL RESERVES GTO TIME FOR A comment_2: TOTAL OF 7 EVENTS, THE CHOICE OF HSP comment_3: OR FOS DEPENDS ON THE OCCULTING comment_4: OBJECT AND THE TYPE AND BRIGHTNESS OF comment_5: THE OCCULTED STAR. ! linenum: 10.090 sequence_1: USE sequence_2: OCC targname: P14.C time_per_exp: X20 param_1: SAMPLE-TIME = 0.05, param_2: DATA-FORMAT = ALL, param_3: PRECISION = HIGH, param_4: ANALOG-SCALE = 10, req_1: AT 17-JAN-92:02:06 +/- 1M; comment_1: END EXPOSURE AT 17-JAN-92:02:24 comment_3: TIME_PER_EXP WILL CHANGE DEPENDING ON comment_4: FINAL PREDICTION AND HST ORBIT comment_5: PARAMETERS. ! ! end of exposure logsheet scan_data: line_list: 10.01, 10.03 fgs_scan: cont_dwell: C dwell_pnts: 0 dwell_secs: 0.00 scan_width: 0.0000 scan_length: 10.0000 sides_angle: 90.0000 number_lines: 1 scan_rate: 0.2000 first_line_pa: 267.3570 scan_frame: CEL len_offset: 0. wid_offset: 0. ! line_list: 10.02 fgs_scan: cont_dwell: C dwell_pnts: 0 dwell_secs: 0.00 scan_width: 1.0000 scan_length: 10.0000 sides_angle: 90.0000 number_lines: 3 scan_rate: 0.2000 first_line_pa: 267.3570 scan_frame: CEL len_offset: 0. wid_offset: 0.5 ! ! end of scan data