14931( 13) - 14-Aug-2017 17:47:45 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14931 Version: 13 Check-in Time: 14-Aug-2017 17:47:45 STScI Edit Number: 12 Title Energy balance in Saturn's upper atmosphere: Joint Lyman-alpha airglow observations with HST and Cassini ------------------------------------------------------------------------------------ Type Cycle GO/DD 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Lotfi Ben Jaffel CNRS, Institut d'Astrophysique de Paris Y CoI: Dr. Gilda E. Ballester University of Arizona Y CoI: Dr. Kevin H. Baines Jet Propulsion Laboratory N CoI: Dr. Jay B. Holberg University of Arizona N CoI: Dr. Tommi Koskinen University of Arizona N CoI: Dr. Robert A. West Jet Propulsion Laboratory N CoI: Dr. Roger V. Yelle University of Arizona N CoI: Dr. Julianne I. Moses Space Science Institute N ------------------------------------------------------------------------------------ Abstract This proposal is for HST UV spectroscopy of Saturn's disk-reflected Lyman-alpha line (Ly-a) at the same time as Cassini airglow measurements. Saturn's Ly-a emission is composed of solar and interplanetary (IPH) Ly-a photons scattered by its upper atmosphere. The H I Ly-a line probes different upper atmospheric layers down to the homopause, providing an independent way to investigate the H I abundance and energy balance. However, this is a degenerate, multi-parameter, radiative-transfer problem that depends on: H I column density, scattering process by thermal and superthermal hydrogen, time-variable solar and IPH sources, and instrument calibration. Our joint HST-Cassini campaign should break the degeneracy in the Saturn airglow problem. First, line-integrated fluxes simultaneously measured by HST/STIS (dayside) and Cassini/UVIS (nightside), avoiding solar variability, should resolve the solar and IPH sources. Second, high-resolution spectroscopy with STIS will reveal superthermal line broadening not accessible with a low-resolution spectrometer like UVIS. Third, a second visit observing the same limb of Saturn will cross-calibrate the instruments and, with the STIS linewidth information, will yield the H I abundance, a key photochemical parameter not measured by Cassini. Finally, the STIS latitudinal mapping of the Ly-a linewidth will be correlated with Cassini's latitudinal temperature profile of the thermosphere, to provide an independent constraint on the thermospheric energy budget, a fundamental outstanding problem for giant planets. Implementing the proposed UV campaign before the end of the Cassini mission is a unique opportunity that may not return for decades. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will perform two joint HST and Cassini, cross-calibration observations of the Saturn Lyman-alpha (1216 A, Ly-a) emission: Visit 1 (5 HST orbits with STIS), DOY 238 2017, corresponding to August 26, when Cassini will observe at 10:34 - 18:34 UT, and Visit 2 (5 HST orbits with STIS), DOY 245 2017, corresponding to September 02, when Cassini will observe at 01:59 - 08:46 UT. 14931( 13) - 14-Aug-2017 17:47:45 - [ 2] The HST/STIS visits should be scheduled as close as possible (simultaneous or within a day or less) to the Cassini observations. This time-critical requirement will keep the solar Ly-a flux parameter nearly unchanged between the HST and Cassini observations (within ~10%), making the brightness comparison useful. The selected dates for the coordinated observations were also chosen because the IPH and geocoronal Ly-a lines will be at their weakest (solar minimum activity) and furthermore Doppler-shifted to the blue, leaving the red-wing of Saturn's Ly-a free of sky background contamination. No other Cassini sequences can fulfill our joint science goals before Cassini plunges into Saturn on Sep 15. The simultaneous HST/Cassini observation will greatly enhance the science return. We greatly appreciate the effort from the staff at STScI in helping achieve this scheduling. In Visit 1, Aug 26, we will point near the center of the disk of the planet. In Visit 2, Sep 02, we will target the north bright limb of Saturn. The long spectroscopic slit(s) will be placed inside the disk and crossing the limb, to measure the brightness variation across the limb with a disk reference. (We will no longer place the long slit(s) almost parallel to the limb.) Both pointings will avoid Saturn's high-latitude auroral regions poleward of +65 degrees latitude to prevent cross-order contamination from the auroral H2 FUV emissions (Clarke et al. 2005). Each visit will consist of: -- Orbit 1: ACQ on one of Saturn's moons (e.g., Titan, NUV) for accurate pointing. -- Orbits 1, 2, 3: High-resolution STIS/E140H Echelle exposures with the long 52x0.5'' slit (time-tagged) of Saturn. This mode is allowed but not fully supported for full pipeline calibration at STScI because of potential contamination of the spectral window by other Echelle orders falling along the width of the MAMA detector. However, our team has successfully built a full calibration pipeline for this mode that has been applied to study the Jovian (non-auroral) and the interplanetary Ly-a emissions (Ben-Jaffel et al., Icarus, 190, 504, 2007; Vincent et al., ApJ, 738, 135, 2011). -- Orbit 4: Three exposures of Saturn using different modes: one with the STIS/G140M (1222) grating and the long 52x0.1'' slit, where the pointing will be the same as in orbits 1-3; and two FUVMAMA images centered on Saturn, one with the 25MAMA clear filter and the other with the F25SRF2 filter. The data will serve to cross-check the derived E140H absolute fluxes with the well calibrated STIS/G140M medium resolution spectroscopy and FUVMAMA imaging. (The F25SRF2 image will be subtracted from the 25MAMA clear image to yield the net Ly-a flux.) -- Orbit 5: A sky-background exposure in the same high-resolution STIS/E140H, 52x0.5'' slit mode used for Saturn, for detailed evaluation of the background. ------------------------------------------------------------------------------------ 14931( 13) - 14-Aug-2017 17:47:45 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: SATURN-DISK ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Planet Saturn's disk. ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=SATURN ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS NOT ECL P PARTIAL OF SATURN-DISK BY TITAN FROM EARTH, SEP OF SATURN-DISK RHEA FROM EARTH GT 10", SEP OF SATURN-DISK TITAN FROM EARTH GT 10" ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 1.3 +/- 0.3 Moving Target. Point at/near planet center (CML). (Mv SURF-LINE(1216)=2+/-1E-13 W-LINE(1216)=0.1+/-0.02 from JPL Horizons.) Ephemeris Center: EARTH Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 TARGET NAME: SATURN-LIMB ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Planet Saturn's bright limb. ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=SATURN TYPE=POS_ANGLE, RAD=13.0, ANG=245, REF=NORTH ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS NOT ECL P PARTIAL OF SATURN-LIMB BY TITAN FROM EARTH, SEP OF SATURN-LIMB RHEA FROM EARTH GT 10", SEP OF SATURN-LIMB TITAN FROM EARTH GT 10" ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 1.3 +/- 0.3 Moving Target. Point near sunlit, equatorial-west limb on SURF-LINE(1216)=2+/-1E-13 W-LINE(1216)=0.1+/-0.02 the sky (celestial coordinates). (Mv from JPL Horizons.) Ephemeris Center: EARTH Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ 14931( 13) - 14-Aug-2017 17:47:45 - [ 4] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 TARGET NAME: SATURN-SKY-OFFSET ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET Offset from Saturn by ~ 120 arcsec ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=SATURN TYPE=POS_ANGLE, RAD=90, ANG=0, REF=NORTH ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS NOT ECL P PARTIAL OF SATURN-SKY-OFFSET BY TITAN FROM EARTH, SEP OF SATURN-SKY-OFFSET RHEA FROM EARTH GT 10", SEP OF SATURN-SKY-OFFSET TITAN FROM EARTH GT 10" ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 1.3 +/- 0.3 Stis 52x0.5 long slit 2 arc min from Saturn. Observe Lya SURF-LINE(1216)=10+/-5E-13 W-LINE(1216)=0.1+/-0.02 line profile from sky background and interplanetary emissions. We list ANG=0 from North but any other angle Ephemeris Center: HUBBLE is fine. Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 4 TARGET NAME: TITAN ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Satellite Titan for acquisitions. ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=SATURN STD=TITAN ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS SEP OF TITAN SATURN FROM EARTH GT 45", SEP OF TITAN RHEA FROM EARTH GT 10" ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 8.77 +/- 0.3 Mv from JPL Horizons. Ephemeris Center: EARTH Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ 14931( 13) - 14-Aug-2017 17:47:45 - [ 5] Visit: 01 (HST+Cassini-disk (Aug 26)) Visit Requirements: BETWEEN 26-AUG-2017:01:45:00 AND 26-AUG-2017:02:40:00 On Hold Comments: Additional Comments: Visit 1 coordinated with Cassini observations on August 26, 2017 at 10:34 - 18:34 UT. We have set the HST special timing requirement to expand the Cassini observing window by an additional +/- 12 hours. HST will observe the dayside disk, and Cassini the nightside. HST observing as close as possible to Cassini window will highly enhance the cross-calibration and science return. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TITAN STIS/CCD ACQ F28X50LP MIRROR CHECKBOX=9, ACQTYPE=DIFFUSE, 1 0.5 S (0.5 GS ACQ SCENARIO BASE1B3 DIFFUSE-CENTER=GEOMETRIC-CENTE S) R Comments: The Titan STIS ACQ exposure parameters were taken from the GO# 9745 program (Lemmon et al.) that included STIS ACQ exposures of Titan. See their Visit 02, exposure 1 of TITAN-ANY (observed in Jan 3, 2004). ------------------------------------------------------------------------------------------------------------------------------------ 2 SATURN-DISK STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 1880 S GS ACQ SCENARIO BASE1B3 -MAMA G see below (1861 S) Comments: The exposure time is similar to that of previous E140H/52x0.5" exposures of the interplanetary hydrogen (with similar ~1 kR brightness than Saturn) that never had problems with local or global count rates (GO 12800, 12947, 13183, 13628). Since the 52x0.5" slit is not available for ETC runs with E140H, the ETC run provided is for the 6x0.2" slit, for Saturn's 0.1 A wide Ly-a line with 2.e-13 ergs/cm2/s integrated flux, average geocorona, 2500s. (A x10 larger aperture will not exceed global rate limit; STIS.sp.996406.). Please update the slit to 52x0.5'', an option that is not available in the APT. ------------------------------------------------------------------------------------------------------------------------------------ 3 SATURN-DISK STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 2910 S -MAMA G see below (2941 S) Comments: See comments for Exposure 2 (the 1st E140H exposure). ------------------------------------------------------------------------------------------------------------------------------------ 14931( 13) - 14-Aug-2017 17:47:45 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 4 SATURN-DISK STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 2910 S -MAMA G see below (2898 S) Comments: See comments for Exposure 2 (the 1st E140H exposure). ------------------------------------------------------------------------------------------------------------------------------------ 5 SATURN-DISK STIS/FUV TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=350 1 600 S -MAMA G see below (597 S) Comments: ETC run for Saturn's 0.1 A wide Ly-a line with 2.e-13 ergs/cm2/s integrated flux, average geocorona, 2500s. ------------------------------------------------------------------------------------------------------------------------------------ 6 SATURN-DISK STIS/FUV TIME-TA 25MAMA MIRROR BUFFER-TIME=100 1 700 S -MAMA G see below (697 S) Comments: Clear 25MAMA image of Saturn - based on previous imaging of Saturn in the same mode for which 1000s exposures were safe (e.g., GO 6854, GO 13396). For example, for the data-set o4bd04voq (exposure time of 1000 sec), we could observe a global rate of 13088 cts/s, which for the 700 sec required in our program leads to a global rate of 9160 cts/s. ------------------------------------------------------------------------------------------------------------------------------------ 7 SATURN-DISK STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=360 1 910 S -MAMA G see below (907 S) Comments: Continuum F25SRF2 image of Saturn - based on previous imaging of Saturn in the same mode for which 1000s exposures were safe (e.g., GO 6854, GO 13396). For the data-set o4bd04vmq (exposure time of 1000 sec), we could observe a global count rate of 3102 cts/s, which for the 900 sec required in our program leads to a global rate of 2792 cts/s ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ TITAN 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SATURN-DISK 2 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 1 1861.0 S -MAMA G 14931( 13) - 14-Aug-2017 17:47:45 - [ 7] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-DISK 3 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 2 2941.0 S -MAMA G SATURN-DISK 4 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 3 2898.0 S -MAMA G SATURN-DISK 5 STIS/FUV TIME-TA 52X0.1 G140M 1222 none none none none 4 597.0 S -MAMA G SATURN-DISK 6 STIS/FUV TIME-TA 25MAMA MIRROR none none none none 4 697.0 S -MAMA G SATURN-DISK 7 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 4 907.0 S -MAMA G 14931( 13) - 14-Aug-2017 17:47:45 - [ 8] Visit: 02 (HST+Cassini-limb (Sep 02)) Visit Requirements: BETWEEN 01-SEP-2017:23:00:00 AND 02-SEP-2017:00:00:00 On Hold Comments: Additional Comments: Visit 2 coordinated with Cassini observations on September 02, 2017 at 01:59 - 08:46 UT. We have set the HST special timing requirement to expand the Cassini observing window by an additional +/- 12 hours. Both HST and Cassini will observe the same bright limb. HST observing as close as possible to the Cassini window will highly enhance the cross-calibration and science return. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 TITAN STIS/CCD ACQ F28X50LP MIRROR CHECKBOX=9, ACQTYPE=DIFFUSE, 1 0.5 S (0.5 GS ACQ SCENARIO BASE1B3 DIFFUSE-CENTER=GEOMETRIC-CENTE S) R Comments: The Titan STIS ACQ exposure parameters were taken from the GO# 9745 program (Lemmon et al.) that included STIS ACQ exposures of Titan. See their Visit 02, exposure 1 of TITAN-ANY (observed in Jan 3, 2004). ------------------------------------------------------------------------------------------------------------------------------------ 2 SATURN-LIMB STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 1880 S GS ACQ SCENARIO BASE1B3 -MAMA G see below (1861 S) Comments: The exposure time is similar to that of previous E140H/52x0.5" exposures of the interplanetary hydrogen (with similar ~1 kR brightness than Saturn) that never had problems with local or global count rates (GO 12800, 12947, 13183, 13628). Since the 52x0.5" slit is not available for ETC runs with E140H, the ETC run provided is for the 6x0.2" slit, for Saturn's 0.1 A wide Ly-a line with 2.e-13 ergs/cm2/s integrated flux, average geocorona, 2500s. (A x10 larger aperture will not exceed global rate limit; STIS.sp.996406.). Please update the slit to 52x0.5'', an option that is not available in the APT. ------------------------------------------------------------------------------------------------------------------------------------ 3 SATURN-LIMB STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 2910 S -MAMA G see below (2941 S) Comments: See comments for Exposure 2 (the 1st E140H exposure). ------------------------------------------------------------------------------------------------------------------------------------ 14931( 13) - 14-Aug-2017 17:47:45 - [ 9] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 4 SATURN-LIMB STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 2910 S -MAMA G see below (2898 S) Comments: See comments for Exposure 2 (the 1st E140H exposure). ------------------------------------------------------------------------------------------------------------------------------------ 5 SATURN-LIMB STIS/FUV TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=350 1 550 S -MAMA G see below (547 S) Comments: ETC run for Saturn's 0.1 A wide Ly-a line with 2.e-13 ergs/cm2/s integrated flux, average geocorona, 2500s. ------------------------------------------------------------------------------------------------------------------------------------ 6 SATURN-DISK STIS/FUV TIME-TA 25MAMA MIRROR BUFFER-TIME=100 1 610 S GS ACQ SCENARIO BASE1B3 -MAMA G see below (607 S) Comments: Clear 25MAMA image of Saturn - based on previous imaging of Saturn in the same mode for which 1000s exposures were safe (e.g., GO 6854, GO 13396). For example, for the data-set o4bd04voq (exposure time of 1000 sec), we could observe a global rate of 13088 cts/s, which for the 700 sec required in our program leads to a global rate of 9160 cts/s. ------------------------------------------------------------------------------------------------------------------------------------ 7 SATURN-DISK STIS/FUV TIME-TA F25SRF2 MIRROR BUFFER-TIME=360 1 787 S -MAMA G see below (784 S) Comments: Continuum F25SRF2 image of Saturn - based on previous imaging of Saturn in the same mode for which 1000s exposures were safe (e.g., GO 6854, GO 13396). For the data-set o4bd04vmq (exposure time of 1000 sec), we could observe a global count rate of 3102 cts/s, which for the 900 sec required in our program leads to a global rate of 2792 cts/s. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ TITAN 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SATURN-LIMB 2 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 1 1861.0 S -MAMA G 14931( 13) - 14-Aug-2017 17:47:45 - [ 10] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-LIMB 3 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 2 2941.0 S -MAMA G SATURN-LIMB 4 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 3 2898.0 S -MAMA G SATURN-LIMB 5 STIS/FUV TIME-TA 52X0.1 G140M 1222 none none none none 4 547.0 S -MAMA G SATURN-DISK 6 STIS/FUV TIME-TA 25MAMA MIRROR none none none none 4 607.0 S -MAMA G SATURN-DISK 7 STIS/FUV TIME-TA F25SRF2 MIRROR none none none none 4 784.0 S -MAMA G 14931( 13) - 14-Aug-2017 17:47:45 - [ 11] Visit: 1A (HST+Cassini-disk (Aug 26)) Visit Requirements: NOTRACK; AFTER 01 BY 3.9 Orbits TO 4.1 Orbits On Hold Comments: Additional Comments: Visit 1 coordinated with Cassini observations on August 26, 2017 at 10:34 - 18:34 UT. We have set the HST special timing requirement to expand the Cassini observing window by an additional +/- 12 hours. HST will observe the dayside disk, and Cassini the nightside. HST observing as close as possible to Cassini window will highly enhance the cross-calibration and science return. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-SKY- STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 2920 S GS ACQ SCENARIO BASE1B3 OFFSET -MAMA G see below (2483 S) Comments: The exposure time is similar to that of previous E140H/52x0.5" exposures of the interplanetary hydrogen (~1 kR brightness) that never had problems with local or global count rates (GO 12800, 12947, 13183, 13628). Please update slit to 52x0.5'', an option that is not available in the APT. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-SKY-OFFSET 1 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 1 2483.0 S -MAMA G 14931( 13) - 14-Aug-2017 17:47:45 - [ 12] Visit: 2A (HST+Cassini-limb (Sep 02)) Visit Requirements: NOTRACK; AFTER 02 BY 3.8 Orbits TO 4.2 Orbits On Hold Comments: Additional Comments: Visit 2 coordinated with Cassini observations on September 02, 2017 at 01:59 - 08:46 UT. We have set the HST special timing requirement to expand the Cassini observing window by an additional +/- 12 hours. Both HST and Cassini will observe the same bright limb. HST observing as close as possible to the Cassini window will highly enhance the cross-calibration and science return. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SATURN-SKY- STIS/FUV TIME-TA 52X0.5 E140H 1234 BUFFER-TIME=1000 1 2920 S GS ACQ SCENARIO BASE1B3 OFFSET -MAMA G see below (2483 S) Comments: The exposure time is similar to that of previous E140H/52x0.5" exposures of the interplanetary hydrogen (~1 kR brightness) that never had problems with local or global count rates (GO 12800, 12947, 13183, 13628). Please update slit to 52x0.5'', an option that is not available in the APT. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SATURN-SKY-OFFSET 1 STIS/FUV TIME-TA 52X0.5 E140H 1234 none none none none 1 2483.0 S -MAMA G 14931( 13) - 14-Aug-2017 17:47:45 - [ 13] Summary Form for Proposal 14931 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 25MAMA, 52X0.1, 52X0.5, F25SRF2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=DIFFUSE, BUFFER-TIME=100, BUFFER-TIME=1000, BUFFER-TIME=350, BUFFER-TIME=360, CHECKBOX=9, DIFFUSE-CENTER=GEOMETRIC-CENTER ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 3.9 Orbits TO 4.1 Orbits, AFTER 02 BY 3.8 Orbits TO 4.2 Orbits, BETWEEN 01-SEP-2017:23:00:00 AND 02-SEP-2017:00:00:00, BETWEEN 26-AUG-2017:01:45:00 AND 26-AUG-2017:02:40:00, GS ACQ SCENARIO BASE1B3, NOTRACK ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140H, G140M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names SATURN-DISK, SATURN-LIMB, SATURN-SKY-OFFSET, TITAN ------------------------------------------------------------------------------------------------------------------------------------