! $Id: 5508,v 6.1 1994/08/29 16:43:49 pepsa Exp $ coverpage: title_1: TRACKING FEATURES IN TITAN'S LOWER ATMOSPHERE AND ON ITS SURFACE: title_2: CYCLE4 HIGH sci_cat: SOLAR SYSTEM sci_subcat: SATELLITES proposal_for: GO pi_fname: PETER pi_mi: H pi_lname: SMITH pi_inst: LUNAR AND PLANETARY LABORATORY pi_country: USA pi_phone: (602) 621-2725 hours_pri: 7.00 num_pri: 1 wf_pc: Y off_fname: MICHAEL off_lname: CUSANOVICH off_title: DR. off_addr_1: VICE PRESIDENT FOR RESEARCH off_addr_2: UNIVERSITY OF ARIZONA off_city: TUCSON off_state: AZ off_zip: 85721 off_country: USA off_phone: (602) 621-3511 ! end of coverpage abstract: line_1: We propose here to take a major step forward in the study of Titan's atmosphere line_2: and surface by doing a partial survey of the detectable features at red and NIR line_3: wavelengths, probing from 100km to the surface. In cycle 2 of the HST, 8 images line_4: of Titan were obtained with the Planetary Camera; in the F850LP, several small- line_5: scale features, that could be either on the surface or in the lower atmosphere, line_6: or both, were clearly seen (Smith et al., 1992). The 1992 images proved the ex- line_7: istence of trackable features; however, the photometry is inaccurate because of line_8: the image reconstruction difficulties with WFPC1. A partial orbital revolution line_9: of Titan will now be observed, with several filter sets, at several intervals. line_10: We will identify, track, and characterize all surface and near-surface features line_11: using five filters chosen to sound the altitude range. Methane band filters are line_12: particularly useful in providing high contrast and accurate altimetry. Features line_13: tidally locked with Saturn are likely to be on the surface. Features not synch- line_14: ronous with Saturn are probably atmospheric. Wind vectors can be derived from line_15: them. A three-dimensional map of observed features, and their velocity vectors, line_16: will be produced, using time history and limb-darkening information. The final line_17: product will include a new global circulation model for Titan, a revised atmos- line_18: pheric scattering model and a surface map. ! ! end of abstract general_form_proposers: lname: SMITH fname: PETER mi: H inst: LUNAR AND PLANETARY LABORATORY country: USA ! lname: CALDWELL fname: JOHN mi: J inst: INSTITUTE FOR SPACE AND TERRESTRIAL SCIENCE country: CANADA ! lname: ALLISON fname: MICHAEL mi: D inst: NASA GODDARD INSTITUTE FOR SPACE SCIENCE country: USA ! lname: SROMOVSKY fname: LAWRENCE mi: A inst: UNIVERSITY OF WISCONSIN-MADISON country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: The first executable lines in the exposure logsheet, 71.00 to 80.00 inclusive, line_2: constitute a spectral survey of Titan's contrast features from 336 nm to 1042 line_3: nm. The primary purpose of this survey is to compare the current state of the line_4: atmosphere of Titan with earlier epochs, including both previous HST imaging line_5: and Voyage observations from a dozen years ago. This survey is intended to be line_6: completed entirely within two consecutive HST visibility periods. Following line_7: this, different sequences (lines 11.00 to 13.00; 21.00 to 23.00; and 31.00 to line_8: 34.00) are repeated in exposure lines 81.00 to 92.00, at intervals specified line_9: in the REQ statements of each line. Each time a sequence is executed, it is line_10: required that it will be completed entirely within one HST visibility period. line_11: It may be acceptable to alter some of the AFTER REQs in lines 81 to 92. Please line_12: contact the P.I. if the nominal AFTER REQs cause difficulty in scheduling. The line_13: repeating sequences are intended to track atmospheric or surface features seen line_14: in earlier HST images. See question 5 below. ! question: 3 section: 2 line_1: In order to track cloud and surface features on Titan, it is highly desirable line_2: to record the feature 3 times as it moves across the disk on a single transit. line_3: Our goal is to measure 30-60% of all features moving at +/- 50 m/s or less line_4: with respect to the surface. At +50 m/s, a feature moves 40 deg in longitude line_5: in 7.4 hr. Therefore, we propose to space the first 7 observations by this line_6: amount, with leeway up to 1.5 hr to facilitate scheduling HST. line_8: The survey filters (see section 1 above) give the global context of the line_9: atmosphere from the surface to upper level haze. This is executed on two line_10: consecutive HST visibility periods, to begin the program. The next 6 exposure line_11: lines, defined by SEQUENCE 1, regularly spaced by 7.4 hr, include only the line_12: 850, 673 and 619 nm filters, have the greatest chance for seeing down to 20-50 line_13: km above the surface, where the fastest detectable winds are expected. These line_14: are followed alternately by SEQUENCE 2 and SEQUENCE 3, with intervals of 32 hr line_15: between observations. SEQUENCE 2 has the best chance to resolve low-altitude, line_16: slow moving features, because it includes the 1042 nm filter (while dropping line_17: the 673 nm filter to conserve time). SEQUENCE 3 also includes the 889 nm CH4 line_18: filter, which will track any apparent contrast features up to 750 km altitude. line_20: The scientific goals of this program do not allow breaking it into pieces. We line_21: are trying to learn about the evolution of cloud features by creating a time- line_22: lapse series showing temporal change as the features develop. ! question: 4 section: 1 line_1: The HST is required for its high spatial resolution. It should also be noted line_2: that the spectral range of the WFPC2 filter set used here is significantly line_3: broader than the previous Voyager filter set, including high-contrast methane line_4: filters. ! question: 5 section: 1 line_1: The primary concern with scheduling is that the observations be obtained line_2: within +/- 1 month of opposition, if possible. A slight relaxation of this line_3: constraint would be considered. Furthermore, the spacings between various line_4: observations in this time series are calculated to optimize the scientific line_5: value of detections of atmospheric and/or surface features. It is not line_6: possible to anticipate all possible HST environmental constraints on the line_7: schedulability of our preferred time series, but we are prepared to discuss line_8: trade-offs if specific conflicts arise. See question 3 above. ! question: 6 section: 1 line_1: There are no special calibration requirements. We will require flat-fielding line_2: and standard absolute calibrations only. ! ! question: 8 section: 1 line_1: The RESOURCE estimation for this program is done for individual exposure lines line_2: and includes an accurate acounting for the real number of visits required by line_3: the HST. The correct number of GSACQs and GSREACQ (only one of the latter) line_4: are included in the overall RESOURCE total. ! question: 9 section: 1 line_1: Smith and Caldwell have both done previous HST Titan imaging programs. line_2: Caldwell is a GTO with other programs in planetary imaging and spectroscopy. ! question: 10 section: 1 line_1: Computing facilites exist and have previously been used at both the University line_2: of Arizona and at the Institute for Space and Terretrial Science to reduce HST line_3: data. Both institutions have also participated in data analysis and reduction line_4: for numerous other NASA missions, including Galileo, Voyager, et al. There are line_5: no foreseeable technical issues involving scientific analysis capabilities. ! !end of general form text general_form_address: lname: SMITH fname: PETER mi: H category: PI inst: LUNAR AND PLANETARY LABORATORY addr_1: UNIVERSITY OF ARIZONA city: TUCSON state: AZ zip: 85721 country: USA phone: 602-621-2725 telex: PSMITH@LPL.ARIZONA.EDU FAX: 602-621-4933 ! ! end of general_form_address records ! No fixed target records found solar_system_targets: targnum: 1 name_1: TITAN descr_1: SATELLITE TITAN lev1_1: STD = SATURN lev2_1: STD = TITAN fluxnum_1: 1 fluxval_1: V=8.36 fluxnum_2: 2 fluxval_2: B-V=1.30 fluxnum_3: 3 fluxval_3: U-B=0.75 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 11.000 sequence_1: DEFINE sequence_2: SEQUENCE1 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F673N num_exp: 1 time_per_exp: 40S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 ! linenum: 12.000 sequence_1: DEFINE sequence_2: SEQUENCE1 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F850LP num_exp: 1 time_per_exp: 22S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 ! linenum: 13.000 sequence_1: DEFINE sequence_2: SEQUENCE1 targname: TITAN config: WFPC2 opmode: IMAGE aperture: FQCH4N15 sp_element: FQCH4N15 wavelength: 6193 num_exp: 1 time_per_exp: 80S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 ! linenum: 21.000 sequence_1: DEFINE sequence_2: SEQUENCE2 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F850LP num_exp: 1 time_per_exp: 22S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 ! linenum: 22.000 sequence_1: DEFINE sequence_2: SEQUENCE2 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F1042M num_exp: 1 time_per_exp: 200S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 7 ! linenum: 23.000 sequence_1: DEFINE sequence_2: SEQUENCE2 targname: TITAN config: WFPC2 opmode: IMAGE aperture: FQCH4N15 sp_element: FQCH4N15 wavelength: 6193 num_exp: 1 time_per_exp: 80S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 ! linenum: 31.000 sequence_1: DEFINE sequence_2: SEQUENCE3 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F850LP num_exp: 1 time_per_exp: 22S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 ! linenum: 32.000 sequence_1: DEFINE sequence_2: SEQUENCE3 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F1042M num_exp: 1 time_per_exp: 200S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 7 ! linenum: 33.000 sequence_1: DEFINE sequence_2: SEQUENCE3 targname: TITAN config: WFPC2 opmode: IMAGE aperture: FQCH4N15 sp_element: FQCH4N15 wavelength: 6193 num_exp: 1 time_per_exp: 80S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 ! linenum: 34.000 sequence_1: DEFINE sequence_2: SEQUENCE3 targname: TITAN config: WFPC2 opmode: IMAGE aperture: FQCH4P15 sp_element: FQCH4P15 wavelength: 8922 num_exp: 1 time_per_exp: 100S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 7 ! linenum: 71.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F336W num_exp: 1 time_per_exp: 160S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 7 req_1: CYCLE 4; req_2: GROUP 71-80 NO GAP; comment_1: IT IS EXPECTED THAT GROUP 71-80 WILL comment_2: BE COMPLETED ENTIRELY WITHIN TWO comment_3: VISIBILITY PERIODS comment_4: POSSIBLE, CONTACT P.I. ! linenum: 72.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F439W num_exp: 1 time_per_exp: 40S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 req_1: CYCLE 4; ! linenum: 73.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F547M num_exp: 1 time_per_exp: 7S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 req_1: CYCLE 4; ! linenum: 74.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F588N num_exp: 1 time_per_exp: 40S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 req_1: CYCLE 4; ! linenum: 75.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F673N num_exp: 1 time_per_exp: 40S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 req_1: CYCLE 4; ! linenum: 76.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F791W num_exp: 1 time_per_exp: 3S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 req_1: CYCLE 4; ! linenum: 77.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F850LP num_exp: 1 time_per_exp: 22S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 req_1: CYCLE 4; ! linenum: 78.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: FQCH4P15 sp_element: FQCH4P15 wavelength: 8922 num_exp: 1 time_per_exp: 100S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 7 req_1: CYCLE 4; ! linenum: 79.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: FQCH4N15 sp_element: FQCH4N15 wavelength: 6193 num_exp: 1 time_per_exp: 80S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 15 req_1: CYCLE 4; ! linenum: 80.000 targname: TITAN config: WFPC2 opmode: IMAGE aperture: PC1 sp_element: F1042M num_exp: 1 time_per_exp: 200S s_to_n: 10 fluxnum_1: 1 fluxnum_2: 2 fluxnum_3: 3 priority: 1 param_1: ATD-GAIN = 7 req_1: CYCLE 4; ! linenum: 81.000 sequence_1: USE sequence_2: SEQUENCE1 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 7.4H +/- 1H; ! linenum: 82.000 sequence_1: USE sequence_2: SEQUENCE1 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 14.9H +/- 1.5H; ! linenum: 83.000 sequence_1: USE sequence_2: SEQUENCE1 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 22.3H +/- 1.5H; ! linenum: 84.000 sequence_1: USE sequence_2: SEQUENCE1 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 29.8H +/- 1.5H; ! linenum: 85.000 sequence_1: USE sequence_2: SEQUENCE1 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 37.2H +/- 1.5H; ! linenum: 86.000 sequence_1: USE sequence_2: SEQUENCE1 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 44.7H +/- 1.5H; ! linenum: 87.000 sequence_1: USE sequence_2: SEQUENCE3 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 80H +/- 1.5H; ! linenum: 88.000 sequence_1: USE sequence_2: SEQUENCE2 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 112H +/- 1.5H; ! linenum: 89.000 sequence_1: USE sequence_2: SEQUENCE3 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 144H +/- 1.5H; ! linenum: 90.000 sequence_1: USE sequence_2: SEQUENCE2 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 176H +/- 1.5H; ! linenum: 91.000 sequence_1: USE sequence_2: SEQUENCE3 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 208H +/- 1.5H; ! linenum: 92.000 sequence_1: USE sequence_2: SEQUENCE2 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 272H +/- 1.5H; ! linenum: 93.000 sequence_1: USE sequence_2: SEQUENCE3 req_1: CYCLE 4; req_2: NON-INT; req_3: AFTER 71 BY 304H +/- 1.5H; ! ! end of exposure logsheet ! No scan data records found