! File: 4349C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:22:51:25 coverpage: title_1: THE COMPOSITION OF COMET ENCKE: IS THERE EVIDENCE FOR VOLATILE title_2: DEPLETION sci_cat: SOLAR SYSTEM sci_subcat: COMETS proposal_for: GO pi_fname: HAROLD pi_mi: A. pi_lname: WEAVER pi_inst: STSCI pi_country: USA hours_pri: 4.78 num_pri: 1 wf_pc: Y fos: Y realtime: Y time_crit: Y funds_length: 12 off_fname: HERVEY off_mi: S. off_lname: STOCKMAN off_title: DEPUTY DIRECTOR off_inst: 3470 off_addr_1: SPACE TELESCOPE SCIENCE INSTITUTE off_addr_2: 3700 SAN MARTIN DRIVE off_city: BALTIMORE off_state: MD off_zip: 21218 off_country: USA ! end of coverpage abstract: line_1: Comet Encke has the shortest period and the smallest perihelion line_2: distance of any known comet. Thus, P/Encke should provide an excellent line_3: test of the hypothesis that ``old'' comets have become depleted of line_4: their most volatile constituents. The primary scientific objective of line_5: this proposal is to perform a ``deep'' search for two important line_6: cometary volatiles, CO and CO2. CO can be observed directly via line_7: fluorescence in the 4th Positive Group near 1500 A. The CO2 abundance line_8: will be probed by searching for ``prompt'' emission from the Cameron line_9: bands of CO, a new technique that was discovered during previous HST line_10: observations of comets. HST observations of P/Encke should provide line_11: abundance limits of approximately 3% relative to water for each line_12: species, which means that both species are in the detectable range if line_13: the nucleus is not de-volatilized. Another important objective is to line_14: obtain a comprehensive spectrum from 1150 A to 6820 A with the FOS, line_15: which can be used to compile an inventory of abundances for the most line_16: important C, N, O, and S bearing molecules in the nucleus. By extending line_17: the HST observations into the optical, we can tie ALL of the abundances line_18: derived from the HST observations to the very extensive set of line_19: ground-based data establishing an important perspective that would line_20: otherwise be missing. ! ! end of abstract general_form_proposers: lname: WEAVER fname: HAROLD title: PI mi: A. inst: STSCI country: USA ! lname: A'HEARN fname: MICHAEL mi: F. inst: UNIVERSITY OF MARYLAND country: USA ! lname: ARPIGNY fname: CLAUDE inst: UNIVERSITE DE LIEGE country: BELGIUM esa: Y ! lname: FELDMAN fname: PAUL mi: D. inst: JOHNS HOPKINS UNIVERSITY country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Since the emissions we plan to observe span a broad range of line_2: wavelengths, our program requires taking spectra with five separate FOS line_3: gratings. Generally, we will use the blue digicon for the UV line_4: observations to reduce susceptibility to long-wavelength scattered line_5: light. We will use the 4.3" aperture for the far UV observations for high line_6: throughput and the 1" aperture in the optical/near UV for better spectral line_7: resolution. The improved Moving Target capabilities expected for line_11: Cycle 3 will make this program significantly more efficient than our line_12: Cycle 1 and 2 cometary programs. Specifically, the program outlined line_13: below assumes that the system can support the "Simple GS Handoff" line_14: and "FGS to GYRO" capabilities. If the latter are not available, line_15: then R/T pointing correction uplinks will be required every line_16: spectroscopy orbit. We assume a target visibility window of 50 min. line_17: We estimate that our program will require a total of 10 orbits of HST line_18: time. Seven orbits use the FOS BLUE side and are called the BLUE group, line_19: while four orbits use the FOS RED side and are called the RED group. line_20: If possible, the BLUE group orbits should be scheduled consecutively. line_21: Ditto for the RED group orbits. It is desirable for the entire 10 line_22: orbit program to be scheduled as close together in time as possible. line_23: The detailed observing scenario according to orbit number is: ! question: 3 section: 2 line_1: BLUE GROUP: line_3: 1: GS ACQ + INT ACQ PC IMAGE line_5: 2: GS REACQ + FOS ACQ + G130H (20m) line_7: 3: GS REACQ + G130H (20m) + G270H (2m) line_9: 4: GS REACQ + FOS ACQ + G130H (20m) line_11: 5: GS REACQ + G190H (20m) + G270H (2m) line_13: 6: GS REACQ + FOS ACQ + G190H (20m) line_15: RED GROUP: line_17: 1: GS ACQ + INT ACQ PC IMAGE line_19: 2: GS REACQ + FOS ACQ + G400H (20m) line_21: 3: GS REACQ + FOS ACQ + G270H (20m) line_23: 4: GS REACQ + FOS ACQ + G570H (20m) ! question: 3 section: 3 line_1: If it proves impossible to schedule either 4 or 7 consecutive line_2: orbits, then one or two of the GS REACQs listed above will line_3: have to be changed to GS ACQs. line_4: The exposure times for the FOS ACCUMs assume a nominal target line_5: visibility window of 52 mins and a "pad" of 3-5 mins (i.e., the line_6: total time associated with all activities should be 47-49 mins line_7: using the Resource Estimator values for overheads). Please expand line_8: the exposure times to fill the orbits, if time is available. line_9: We emphasize that it is highly desirable that these line_10: observations be done under FGS control rather than under GYRO line_12: control. However, if the observations prove impossible to schedule line_13: using FGS tracking only, then the "FGS PAUSE TO GYRO" mode should line_14: be used. line_15: Finally, due to the faintness of this P/Encke, the observations line_16: should be scheduled as close to the minimum allowed solar elongation line_17: angle as possible. Specifically, if the observations cannot be line_18: during either the last week in December or the first week in line_19: January, then we will withdraw our proposal. ! question: 4 section: 1 line_1: IUE simply does not have the sensitivity to probe the CO and CO2 line_2: abundances in P/Encke to a limit that is meaningful; a larger aperture line_3: UV telescope like HST is required. Another crucial element of our line_4: program is the ability to perform simultaneous UV and visible line_5: spectroscopy. While technically this is infeasible even with HST, we line_6: propose doing the next best thing by measuring OH frequently during the line_7: course of our observations and "normalizing" each species to the OH line_8: abundance (since the OH emission is so bright it can be measured with line_9: short exposures). A similar program, including all the species line_10: discussed above, is impossible from any other observatory (either line_11: Earth- or space-based). line_13: Because our program concentrates on species whose spatial brightness line_14: distributions are strongly peaked at the nucleus, it takes full line_15: advantage of the high spatial resolution capabilities of HST. IUE line_16: observations of the Earth-grazing Comet IRAS-Araki-Alcock in 1983 line_17: produced one of the more exciting discoveries in cometary science: the line_18: discovery of S2, a molecule which had not been previously observed line_19: in any astrophysical environment. While HST observations of P/Encke line_20: cannot match the spatial resolution achieved by IUE on Comet I-A-A, line_21: HST's resolution will far surpass what IUE achieves on other comets. line_22: Thus, HST will be probing a spatial domain that has been generally line_23: inaccessible to IUE. ! question: 4 section: 2 line_1: The CO(2,0) band at 1478 A is the strongest emission in the 4th Positive line_2: Group (FPG). At this wavelength the FOS can achieve S/N=3 in 90 min line_3: if the average brightness in the 4.3" aperture is 5 R (when used line_4: as a unit "R" stands for Rayleighs). The CO relative abundance line_5: in P/Encke needed to produce this brightness is about 3%. line_6: We assume that all the CO is coming from the nucleus line_7: and use a g-factor for the (2,0) band of 2.4E-07 ph/s/mol. line_8: The H2O production rate should be about 1-2E28 mol/sec. For line_9: comparison purposes, the CO relative abundance deduced for Halley was line_10: about 5% (this is the estimated relative abundance in the nucleus; line_11: the coma abundance was about 15-20%). line_13: The CO Cameron bands have emission rates (ph/s/CO2 mol) line_14: that are comparable to the g-factors for the CO FPG. line_15: Since the FOS throughput for the Cameron bands is a factor of line_16: about 3 higher than that for the FPG, we should be able to measure line_17: a 3% CO2 abundance in P/Encke in about 1 hr. ! question: 4 section: 3 line_1: Both of the above sensitivities have been verified by actual HST line_2: observations of comets. We have already achieved positive detections line_3: of CO Cameron band emission in comets P/Hartley 2 and line_4: Shoemaker-Levy (1991a1). There doesn't seem to be any CO line_5: in P/Hartley 2 at the level of about 1%, but we might have a line_6: marginal detection of CO in S-L. line_8: HST is very sensitive in the region of the S2 bands line_9: near 2957 A. In 1 hr of observing we should be able line_10: to detect an abundance of S2/H2O of about 5E-06, line_11: which is slightly better than what IUE was able to line_12: achieve on the much brighter and more favorably placed line_13: Comet Austin (1990 V) (Budzien and Feldman, Icarus, 1992). line_14: IUE observed P/Encke during its very favorable apparition line_15: in 1980 but could only set an upper limit of line_16: S2/H2O <= 3.7E-04, a factor of 74 less line_17: sensitive than what HST can achieve. ! question: 5 section: 1 line_1: The cometary observations performed with HST during Cycle 1 were line_2: extremely challenging technically and very inefficient. (Despite these line_3: problems, we must hasten to add that the programs were executed line_4: successfully and have provided us with a wealth of unique and line_5: interesting data.) Fortunately, several new Moving Target capabilities line_6: are scheduled for implementation during the latter part of Cycle 3 that line_7: should improve the observing efficiency of cometary programs by at line_8: least 50% and make them comparable in efficiency to other programs. line_10: Nevertheless, spectroscopic cometary programs will almost certainly line_11: require WFPC-assisted R/T acquisitions to remove ephemeris line_12: uncertainty. If it is demonstrated prior to our observations that we line_13: can blind point Comet Encke into the FOS 4.3" aperture, then we line_14: will drop the R/T INT ACQs thereby saving 1-2 orbits from what line_15: is currently being requested. line_17: Our observations are time-critical in that Comet Encke has a very line_18: narrow observability window. For maximum sensitivity we want to line_19: schedule these observations as close to the 50 deg solar line_20: elongation limit as possible. Thus, these observations should be line_21: scheduled during the weeks of December 27, 1993 or January 4, 1994, line_22: if possible. If we miss this window, the comet will not return again line_23: until 1997. ! question: 7 section: 1 line_1: The reduction of the raw spectrometer data into calibrated form can line_2: be done using the standard STScI procedures. We will use line_3: standard astronomical reduction software (e.g., IDL and STSDAS) to line_4: extract band- and line-integrated intensities from the spectra. This line_5: includes subtracting a reddened solar continuum spectrum from the line_6: original calibrated spectrum in order to separate the line and line_7: continuum cometary emission. We also expect to use the data taken line_8: during the FOS ACQs and INT ACQs to analyze the pointing accuracy line_9: attained during the observations. line_11: The scientific analysis involves converting the integrated absolute line_12: intensities for each species into a molecular abundance in the line_13: nucleus. Generally, this means solving the equations of statistical line_14: equilibrium for each species taking into account collisional excitation line_15: (including its variation with position in the coma), radiative pumping line_16: via absorption of solar photons (UV, visible, and IR including the line_17: "Swings" effect), spontaneous radiative decay in electronic, line_18: vibrational, and rotational transitions, and (possibly) optically thick line_19: radiative transfer for some species. In addition, an appropriate line_20: model (e.g., Haser, vectorial, Monte Carlo, etc.) for the spatial line_21: distribution of each species in the coma is needed. ! question: 7 section: 2 line_1: While we take images in order to attain the pointing accuracy required line_2: for our program, these images are also very interesting scientifically line_3: in their own rite. Building on our experience gained from imaging Comet line_4: Levy (1990 XX) with HST in September 1990 (ID no. 3064), we hope to line_5: analyze the target acquisition images to gain insight into the temporal line_6: variability of the dust emission, search for unusual coma morphology, line_7: and determine the dust velocity in the inner coma. line_9: The analysis described above is fairly complex and requires significant line_10: expertise in cometary physics, molecular spectroscopy, and image line_11: processing. All of the investigators in this program are veteran comet line_12: observers with a proven record of solving these types of problems. ! question: 8 section: 1 line_1: This proposal is a natural extension of our successful Cycle 1 line_2: and Cycle 2 programs. Taken together these programs represent line_3: a systematic attempt to bring HST's considerable capabilities line_4: to bear on some of the fundamental problems in cometary line_5: science. line_7: This program does not duplicate any GTO or approved GO programs. ! question: 9 section: 1 line_1: ID no. 3064: HST Observations of Comet Levy (1990c) line_2: (A'Hearn, Arpigny, and Feldman are Co-Is), an imaging-only line_3: program that is only peripherally related to the line_4: current program. line_6: ID no. 2481: HST Observations of Periodic Comets (A'Hearn, Arpigny, line_7: and Feldman are Co-Is), Cycle 1 version of the current proposal. line_9: ID no. 2483: The Volatile Composition of New Comets (A'Hearn, Arpigny, line_10: and Feldman are Co-Is), complementary to this program. line_12: ID no. 2442: Cometary Parent Molecules, P.D. Feldman, PI (A'Hearn line_13: and Weaver are Co-Is), complementary to this program. line_15: Programs accepted for cycle 2: line_17: ID no. 3707: HST Observations of Periodic Comets (A'Hearn, Arpigny, line_18: and Feldman are Co-Is), Cycle 2 version of the line_19: current proposal in which we will observe P/Schaumasse. line_20: in March, 1993. ! question: 9 section: 2 line_1: ID no. 3064: Two sets of WFC images of comet Levy were obtained 6.5 line_2: hours apart on 27 September 1990 in order to investigate its temporal line_3: variability. An arc of large grains was observed propagating line_4: sunward with a projected velocity of 0.16 km/sec. line_6: ID no. 2481: P/Hartley 2 was successfully observed in late 9/91 line_7: These observations produced the first detection of CO Cameron bands in line_8: comets. This emission is essentially a unique tracer of the CO2 line_9: abundance in comets. Additionally we obtained a beautiful spectrum line_10: of the comet covering the entire spectral range 1200-6800 A, from line_11: which we are compiling (still in progress) an inventory of volatiles line_12: in that comet. line_14: ID no. 2483: Comet Shoemaker-Levy (1991a1) was successfully observed line_15: in July 1992. Unfortunately, the comet was not as bright as we had line_16: hoped, but we obtained data of comparable (slightly higher) quality line_17: to that already in hand from P/Hartley 2. We definitely detected line_18: the CO Cameron bands again, but it is much too early to say anything line_19: more at this time. line_21: ID no. 2442: Comet Shoemaker-Levy (1991a1) was successfully observed line_22: in July 1992, but it is too early to say anything more at this time. ! question: 9 section: 3 line_1: ID no. 3064: Inner Coma Imaging of Comet Levy (1990c) with the Hubble line_2: Space Telescope, H. A. Weaver, M. F. A'Hearn, P. D. Feldman, line_3: C. Arpigny, W. A. Baum, J. C. Brandt, R. M. Light and line_4: J. A. Westphal,Icarus}, v. 97, p. 85, 1992. line_6: ID no. 2481: Probing the Nature of Comets with HST, H. A. Weaver line_7: and P. D. Feldman, in "Science with the Hubble Space Telescope", line_8: ESA-NASA CP, in press. line_10: Presentations on both the above programs have been made at several line_11: scientific meetings, including the annual DPS meetings in 1990 line_12: (for 3064), 1991 (for 2481), and 1992 (2481 and 2483). A paper line_13: on our detection of CO Cameron band emission in P/Hartley 2 line_14: will be submitted to a refereed journal shortly. ! question: 10 section: 1 line_1: The STScI has excellent data-analysis capabilities and also maintains line_2: a pool of Science Data Analysts (SDAs) that are available to its staff. line_3: However, SDA support for our program can only be assured if we are line_4: allocated money to cover the SDA's salary. line_6: The other institutions co-sponsoring this program also have excellent line_7: data analysis facilities and access to graduate students and research line_8: assistants. However, funds must be provided by this program in order line_9: for the Co-Is to utilize these resources. ! !end of general form text general_form_address: lname: Weaver fname: Harold mi: A title: Dr. category: PI inst: 3470 addr_1: 3700 San Martin Drive city: Baltimore state: MD zip: 21218 country: USA phone: 410-516-8619 ! lname: Weaver fname: Harold mi: A. title: Dr. category: PI inst: STScI addr_1: 3700 San Martin Drive addr_2: Baltimore, MD 21218 addr_3: USA city: Baltimore state: MD zip: 21218 country: USA phone: 410-516-8619 ! ! end of general_form_address records ! No fixed target records found solar_system_targets: targnum: 1 name_1: ENCKE descr_1: COMET ENCKE lev1_1: TYPE = COMET, lev1_2: Q = 0.3309160, E = 0.8502134, lev1_3: O = 334.72931, W = 186.27079, lev1_4: I = 11.94106, lev1_5: T = 09-FEB-1994:11:24:59, lev1_6: EQUINOX = J2000, lev1_7: EPOCH = 17-FEB-1994, ACQ = 0.25 comment_1: OPTIMUM OBSERVING TIME IS DURING comment_2: THE WEEKS OF DECEMBER 27, 1993 OR comment_3: JANUARY 4, 1994. WE WANT THE COMET comment_4: AS CLOSE TO THE SUN AS POSSIBLE. fluxnum_1: 1 fluxval_1: SURF(V) = 14 +/- 1 fluxnum_2: 2 fluxval_2: SURF-LINE(4315) = 2.5 +/- 1.2 E-14 fluxnum_3: 3 fluxval_3: W-LINE(4315) = 0.029 fluxnum_4: 4 fluxval_4: SURF-LINE(5730) = 2 +/- 1 E-14 fluxnum_5: 5 fluxval_5: W-LINE(5730) = 0.038 fluxnum_6: 6 fluxval_6: SURF-LINE(1478) = 2 +/- 1 E-13 fluxnum_7: 7 fluxval_7: W-LINE(1478) = 0.0099 fluxnum_8: 8 fluxval_8: SURF-LINE(2957) = 1.5 +/- 0.7 E-13 fluxnum_9: 9 fluxval_9: W-LINE(2957) = 0.020 fluxnum_10: 10 fluxval_10: SIZE = 1 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 0.990 sequence_1: DEFINE sequence_2: IMAGE targname: ENCKE config: S/C opmode: POINTING aperture: V1 num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 req_1: CYCLE 3; req_2: POS TARG -119.377, 169.607; comment_1: SPACECRAFT EXPOSURE TO START comment_2: OBSET AT FOS RED APERTURE. comment_3: ASSUME S/C X IS U3, Y IS U2. ! linenum: 1.000 sequence_1: DEFINE sequence_2: IMAGE targname: ENCKE config: PC opmode: IMAGE aperture: PC6 sp_element: F702W num_exp: 1 time_per_exp: 500 S fluxnum_1: 1 fluxnum_2: 10 param_1: PRE-FLASH=YES param_2: CR-SPLIT=NO comment_1: A PC IMAGE IS USED FOR comment_2: ACQUISITIONS. ! linenum: 2.000 sequence_1: DEFINE sequence_2: ACQ-BLUE targname: ENCKE config: FOS/BL opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 70 S comment_1: FOS/BL ONBOARD ACQ EXP. ! linenum: 2.100 sequence_1: DEFINE sequence_2: VER-BLUE targname: ENCKE config: FOS/BL opmode: ACQ aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 200 S comment_1: THE PSEUDO IMAGE WILL BE comment_2: USED TO VERIFY POINTING. ! linenum: 3.000 sequence_1: DEFINE sequence_2: ACQ-RED targname: ENCKE config: FOS/RD opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 20 S comment_1: FOS/RD ONBOARD ACQ EXP. ! linenum: 3.100 sequence_1: DEFINE sequence_2: VER-RED targname: ENCKE config: FOS/RD opmode: ACQ aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 60 S comment_1: THE PSEUDO IMAGE WILL BE comment_2: USED TO VERIFY POINTING. ! linenum: 4.000 sequence_1: DEFINE sequence_2: OH-BLUE targname: ENCKE config: FOS/BL opmode: ACCUM aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 2 M s_to_n: 10 comment_1: SHORT EXP TO MEASURE OH(0,0) comment_2: BAND ON BLUE SIDE. ! linenum: 5.000 sequence_1: DEFINE sequence_2: OH-RED targname: ENCKE config: FOS/RD opmode: ACCUM aperture: 1.0 sp_element: G270H num_exp: 1 time_per_exp: 2 M s_to_n: 10 comment_1: SHORT EXP TO MEASURE OH(0,0) comment_2: BAND ON RED SIDE. ! linenum: 6.000 sequence_1: DEFINE sequence_2: CH targname: ENCKE config: FOS/RD opmode: ACCUM aperture: 1.0 sp_element: G400H num_exp: 1 time_per_exp: 23 M s_to_n: 13 s_to_n_time: 30 M fluxnum_1: 2 fluxnum_2: 3 fluxnum_3: 10 priority: 1 comment_1: ASSUMES NOMINAL VIS WINDOW OF 52M. comment_2: EXP TIME MUST BE SCALED IF WINDOW comment_3: IS LONGER OR SHORTER. IF GS comment_4: PAIR IS LOST DURING WINDOW THEN comment_5: SWITCH TO GYROHOLD FOR REST OF comment_6: WINDOW. ASSUME CH4/H2O IS 1%. ! linenum: 7.000 sequence_1: DEFINE sequence_2: NH2 targname: ENCKE config: FOS/RD opmode: ACCUM aperture: 1.0 sp_element: G570H num_exp: 1 time_per_exp: 23 M s_to_n: 13 s_to_n_time: 30 M fluxnum_1: 4 fluxnum_2: 5 fluxnum_3: 10 priority: 1 comment_1: ASSUMES NOMINAL VIS WINDOW OF 52M. comment_2: EXP TIME MUST BE SCALED IF WINDOW comment_3: IS LONGER OR SHORTER. IF GS comment_4: PAIR IS LOST DURING WINDOW THEN comment_5: SWITCH TO GYROHOLD FOR REST OF comment_6: WINDOW. ASSUME B(NH2)=B(CH). ! linenum: 8.000 sequence_1: DEFINE sequence_2: DIATOMICS targname: ENCKE config: FOS/BL opmode: ACCUM aperture: 4.3 sp_element: G190H num_exp: 1 time_per_exp: 23 M priority: 2 comment_1: ASSUMES NOMINAL VIS WINDOW OF 52M. comment_2: EXP TIME MUST BE SCALED IF WINDOW comment_3: IS LONGER OR SHORTER. IF GS comment_4: PAIR IS LOST DURING WINDOW THEN comment_5: SWITCH TO GYROHOLD FOR REST OF comment_6: WINDOW. ! linenum: 9.000 sequence_1: DEFINE sequence_2: CO targname: ENCKE config: FOS/BL opmode: ACCUM aperture: 4.3 sp_element: G130H num_exp: 1 time_per_exp: 23 M s_to_n: 10 s_to_n_time: 1 H fluxnum_1: 6 fluxnum_2: 7 fluxnum_3: 10 priority: 3 comment_1: ASSUMES NOMINAL VIS WINDOW OF 52M. comment_2: EXP TIME MUST BE SCALED IF WINDOW comment_3: IS LONGER OR SHORTER. IF GS comment_4: PAIR IS LOST DURING WINDOW THEN comment_5: SWITCH TO GYROHOLD FOR REST OF comment_6: WINDOW. ASSUME CO/H2O IS 5%. ! linenum: 10.000 sequence_1: DEFINE sequence_2: S2 targname: ENCKE config: FOS/BL opmode: ACCUM aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 2 M s_to_n: 20 s_to_n_time: 1 H fluxnum_1: 8 fluxnum_2: 9 fluxnum_3: 10 priority: 4 comment_1: ASSUMES NOMINAL VIS WINDOW OF 52M. comment_2: EXP TIME MUST BE SCALED IF WINDOW comment_3: IS LONGER OR SHORTER. IF GS comment_4: PAIR IS LOST DURING WINDOW THEN comment_5: SWITCH TO GYROHOLD FOR REST OF comment_6: WINDOW. ASSUME S2/H2O IS 0.01%. ! linenum: 10.100 sequence_1: DEFINE sequence_2: S2-1 targname: ENCKE config: FOS/BL opmode: ACCUM aperture: 1.0 sp_element: G270H num_exp: 1 time_per_exp: 2 M s_to_n: 20 s_to_n_time: 1 H fluxnum_1: 8 fluxnum_2: 9 fluxnum_3: 10 priority: 4 comment_1: ASSUMES NOMINAL VIS WINDOW OF 52M. comment_2: EXP TIME MUST BE SCALED IF WINDOW comment_3: IS LONGER OR SHORTER. IF GS comment_4: PAIR IS LOST DURING WINDOW THEN comment_5: SWITCH TO GYROHOLD FOR REST OF comment_6: WINDOW. S2 THROUGH 1 ARCSEC FOV. ! linenum: 11.000 sequence_1: USE sequence_2: IMAGE req_1: SEQ 11-17 NO GAP; req_2: CRIT OBS / 11-28; req_3: CYCLE 3 / 11-28; req_4: INT ACQ FOR 12; req_5: GUID TOL 1" / 11-28; comment_1: PC ACQ IMAGE FOR RED GROUP. comment_2: FGS CONTROL IS PREFERRED comment_3: FOR ALL OBSERVATIONS, comment_4: BUT USE GYRO IF GS NOT comment_5: AVAILABLE. ! linenum: 12.000 sequence_1: USE sequence_2: VER-RED req_1: SEQ 12-13 NON-INT; ! linenum: 13.000 sequence_1: USE sequence_2: CH ! linenum: 14.000 sequence_1: USE sequence_2: VER-RED req_3: SEQ 14-15 NON-INT; ! linenum: 15.000 sequence_1: USE sequence_2: OH-RED time_per_exp: X11 ! linenum: 16.000 sequence_1: USE sequence_2: VER-RED req_1: SEQ 16-17 NON-INT; ! linenum: 17.000 sequence_1: USE sequence_2: NH2 ! linenum: 18.000 sequence_1: USE sequence_2: IMAGE req_1: SEQ 18-28 NO GAP; req_2: INT ACQ FOR 19; comment_1: PC ACQ IMAGE FOR BLUE GROUP. comment_2: FGS CONTROL IS PREFERRED comment_3: FOR ALL OBSERVATIONS, comment_4: BUT USE GYRO IF GS NOT comment_5: AVAILABLE. ! linenum: 19.000 sequence_1: USE sequence_2: VER-BLUE req_1: SEQ 19-20 NON-INT; ! linenum: 20.000 sequence_1: USE sequence_2: CO ! linenum: 21.000 sequence_1: USE sequence_2: CO req_1: SEQ 21-22 NON-INT; ! linenum: 22.000 sequence_1: USE sequence_2: OH-BLUE ! linenum: 23.000 sequence_1: USE sequence_2: VER-BLUE req_1: SEQ 23-24 NON-INT; ! linenum: 24.000 sequence_1: USE sequence_2: CO ! linenum: 25.000 sequence_1: USE sequence_2: DIATOMICS req_1: SEQ 25-26 NON-INT; ! linenum: 26.000 sequence_1: USE sequence_2: OH-BLUE ! linenum: 27.000 sequence_1: USE sequence_2: VER-BLUE req_1: SEQ 27-28 NON-INT; ! linenum: 28.000 sequence_1: USE sequence_2: DIATOMICS ! ! end of exposure logsheet ! No scan data records found