Proposal 13318 (STScI Edit Number: 0, Created: Thursday, July 11, 2013 1:55:18 PM EST) - Overview 13318 - Giant impacts on giant planets Cycle: 21, Proposal Category: GO (UV Initiative) (Availability Mode: SUPPORTED) INVESTIGATORS Name Prof. Imke de Pater (PI) (Contact) Dr. Michael H. Wong (CoI) (AdminUSPI) (Contact) Dr. Heidi B. Hammel (CoI) Prof. John T. Clarke (CoI) Dr. Amy Simon-Miller (CoI) Dr. Agustin Sanchez-Lavega (CoI) (ESA Member) Dr. Glenn S. Orton (CoI) Institution University of California - Berkeley University of California - Berkeley Space Science Institute Boston University NASA Goddard Space Flight Center Universidad del Pais Vasco Jet Propulsion Laboratory E-Mail imke@berkeley.edu mikewong@astro.berkeley.edu hbh@alum.mit.edu jclarke@bu.edu amy.simon@nasa.gov wupsalaa@bi.ehu.es go@scn.jpl.nasa.gov VISITS Visit Targets used in Visit Configurations used in Visit Orbits Used Last Orbit Planner Run 01 (2) SATURN-IMPACT-SITE WFC3/UVIS 1 11-Jul-2013 14:54:44.0 OP Current with Visit? yes 02 (2) SATURN-IMPACT-SITE WFC3/UVIS 1 11-Jul-2013 14:54:53.0 yes 03 (1) JUPITER-IMPACT-SITE WFC3/UVIS 1 11-Jul-2013 14:55:02.0 yes 04 (1) JUPITER-IMPACT-SITE WFC3/UVIS 1 11-Jul-2013 14:55:10.0 yes 4 Total Orbits Used ABSTRACT 1 Proposal 13318 (STScI Edit Number: 0, Created: Thursday, July 11, 2013 1:55:18 PM EST) - Overview The 2009 impact and recent superbolides on Jupiter caught the world by surprise and cast doubt on impactor flux estimates for the outer solar system. Enhanced amateur planetary imaging techniques yield both high spatial resolution (enabling the 2009 impact debris field detection) and rapid frame rates (enabling the 2010/2012 impact flash detections and lightcurve measurements). We propose a ToO program to image future impacts on Jupiter and Saturn. To remove the possibility of impact cloud non-detections, the program will be triggered only if an existing impact debris field is seen, an object on a collision course with Jupiter or Saturn is discovered, or an impact light curve is measured with an estimated total energy large enough to generate an impact cloud in a giant planet atmosphere (10^20 J). HST provides the only way to image these events in the ultraviolet, providing information on aerosol altitudes and on smaller particles that are less visible to ground-based infrared observations. High-resolution imaging with proper timing (not achievable from the ground) is required to measure precisely both the velocity fields of impact sites and the optical spectrum of impact debris. HST observations of past impacts on Jupiter have also served both as cornerstones of science investigations at other wavelengths and as vehicles for effective public outreach. Large outer solar system impacts are governed by the same physics as in the terrestrial events that dominate the impact threat to humans. Studying the behavior of impactors of various sizes and compositions, as they enter the atmosphere at varying angles and speeds, will better quantify terrestrial impact hazards. OBSERVING DESCRIPTION Observe impact site on target after an impact has been predicted or observed. Target may be Jupiter or Saturn. Quad subarray (2k x 2k) UVIS imaging data will be acquired in quadrants A and D, due to location of important methane-band filters. An event will trigger 2 visits, with visit #2 following visit #1 by one target planet rotation (i.e., 6 orbits later for Jupiter or 7 orbits later for Saturn). Because we include visits to cover both Jupiter and Saturn cases, there are 4 visits in the Phase II even though we were awarded only 2 orbits. Exposure times must be adjusted once the impact is known, to scale with planetary brightness as the target's heliocentric distance changes over time. 2 Solar System Targets Visit Proposal 13318 - SAT-1 (01) - Giant impacts on giant planets Proposal 13318, SAT-1 (01), implementation Diagnostic Status: No Diagnostics Scientific Instruments: WFC3/UVIS Special Requirements: PCS MODE FINE; DROP TO GYRO IF NECESSARY NO REACQ; GYRO MODE 3GOBAD Comments: saturn visit #1 of 2 Thu Jul 11 18:55:18 GMT 2013 NOTE: Date of impact is unknown, so duration of visibilities cannot be predicted at this time. When observations are actually planned, we intend to duplicate or eliminate some exposures to fill the available visibility. Current visit design is for 50-min visibility window. # Name Level 1 Level 2 Level 3 Window Ephem Center (2) SATURN-IMPACT- STD=SATURN TYPE=PGRAPHIC,LONG=0,LAT=0 SEP OF SATURN-IMPACT-SITE EARTH SITE RHEA FROM EARTH GT 19", SEP OF SATURN-IMPACT-SITE TITAN FROM EARTH GT 19" Comments: NEED TO REFINE LEVEL 2 COORDINATES AFTER IMPACT TAKES PLACE (or after impact location is predicted prior to impact) 3 Proposal 13318 - SAT-1 (01) - Giant impacts on giant planets Exposures # 1 Label Target Config,Mode,Aperture FQ889N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, CT-SITE UVIS-QUAD-SUB Spectral Els. FQ889N Opt. Params. CR-SPLIT=NO Special Reqs. Groups Exp. Time (Total)/[Actual Dur.] 300 Secs (300 Secs) [==>] Orbit [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 2 F275W--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F275W CR-SPLIT=NO 140 Secs (140 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 3 F631N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F631N CR-SPLIT=NO 14 Secs (14 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 4 F502N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F502N CR-SPLIT=NO 12 Secs (12 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 5 F343N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F343N CR-SPLIT=NO 20 Secs (20 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 6 F225W--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F225W CR-SPLIT=NO 300 Secs (300 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 7 FQ889N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, FQ889N CR-SPLIT=NO 300 Secs (300 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 8 FQ727N--D (2) SATURN-IMPA WFC3/UVIS, ACCUM, FQ727N CR-SPLIT=NO 30 Secs (30 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 4 Orbit Structure Proposal 13318 - SAT-1 (01) - Giant impacts on giant planets 5 Solar System Targets Visit Proposal 13318 - SAT-2 (02) - Giant impacts on giant planets Proposal 13318, SAT-2 (02), implementation Diagnostic Status: No Diagnostics Scientific Instruments: WFC3/UVIS Special Requirements: PCS MODE FINE; DROP TO GYRO IF NECESSARY NO REACQ; GYRO MODE 3GOBAD; AFTER 01 BY 6 Orbits TO 7 Orbits Comments: saturn visit #2 of 2 Thu Jul 11 18:55:21 GMT 2013 NOTE: Date of impact is unknown, so duration of visibilities cannot be predicted at this time. When observations are actually planned, we intend to duplicate or eliminate some exposures to fill the available visibility. Current visit design is for 50-min visibility window. # Name Level 1 Level 2 Level 3 Window Ephem Center (2) SATURN-IMPACT- STD=SATURN TYPE=PGRAPHIC,LONG=0,LAT=0 SEP OF SATURN-IMPACT-SITE EARTH SITE RHEA FROM EARTH GT 19", SEP OF SATURN-IMPACT-SITE TITAN FROM EARTH GT 19" Comments: NEED TO REFINE LEVEL 2 COORDINATES AFTER IMPACT TAKES PLACE (or after impact location is predicted prior to impact) 6 Proposal 13318 - SAT-2 (02) - Giant impacts on giant planets Exposures # 1 Label Target Config,Mode,Aperture FQ889N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, CT-SITE UVIS-QUAD-SUB Spectral Els. FQ889N Opt. Params. CR-SPLIT=NO Special Reqs. Groups Exp. Time (Total)/[Actual Dur.] 300 Secs (300 Secs) [==>] Orbit [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 2 F275W--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F275W CR-SPLIT=NO 140 Secs (140 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 3 F631N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F631N CR-SPLIT=NO 14 Secs (14 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 4 F502N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F502N CR-SPLIT=NO 12 Secs (12 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 5 F343N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F343N CR-SPLIT=NO 20 Secs (20 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 6 F225W--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, F225W CR-SPLIT=NO 300 Secs (300 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 7 FQ889N--A (2) SATURN-IMPA WFC3/UVIS, ACCUM, FQ889N CR-SPLIT=NO 300 Secs (300 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 8 FQ727N--D (2) SATURN-IMPA WFC3/UVIS, ACCUM, FQ727N CR-SPLIT=NO 30 Secs (30 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 7 Orbit Structure Proposal 13318 - SAT-2 (02) - Giant impacts on giant planets 8 Solar System Targets Visit Proposal 13318 - JUP-1 (03) - Giant impacts on giant planets Proposal 13318, JUP-1 (03), implementation Diagnostic Status: No Diagnostics Scientific Instruments: WFC3/UVIS Special Requirements: PCS MODE FINE; DROP TO GYRO IF NECESSARY NO REACQ; GYRO MODE 3GOBAD; SCHED 100% Comments: jupiter visit #1 of 2 Thu Jul 11 18:55:22 GMT 2013 NOTE: Date of impact is unknown, so duration of visibilities cannot be predicted at this time. When observations are actually planned, we intend to duplicate or eliminate some exposures to fill the available visibility. Current visit design is for 42-min visibility window. # Name Level 1 Level 2 Level 3 Window Ephem Center (1) JUPITER-IMPACT- STD=JUPITER TYPE=PGRAPHIC,LONG=0,LAT=0 SEP OF JUPITER CALLISTO FROM EARTH SITE EARTH GT 50", SEP OF JUPITER IO FROM EARTH GT 50", SEP OF JUPITER EUROPA FROM EARTH GT 50", SEP OF JUPITER GANYMEDE FROM EARTH GT 50" Comments: NEED TO REFINE LEVEL 2 COORDINATES AFTER IMPACT TAKES PLACE (or after impact location is predicted prior to impact) 9 Proposal 13318 - JUP-1 (03) - Giant impacts on giant planets Exposures # 1 Label Target Config,Mode,Aperture FQ727N--D (1) JUPITER-IMPA WFC3/UVIS, ACCUM, CT-SITE UVIS-QUAD-SUB Spectral Els. FQ727N Opt. Params. CR-SPLIT=NO Special Reqs. Groups Exp. Time (Total)/[Actual Dur.] 8 Secs (8 Secs) [==>] Orbit [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 2 FQ889N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, FQ889N CR-SPLIT=NO 60 Secs (60 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 3 F275W--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F275W CR-SPLIT=NO 40 Secs (40 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 4 F631N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F631N CR-SPLIT=NO 4 Secs (4 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 5 F502N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F502N CR-SPLIT=NO 3.4 Secs (3.4 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 6 F395N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F395N CR-SPLIT=NO 9 Secs (9 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 7 F225W--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F225W CR-SPLIT=NO 150 Secs (150 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 8 F343N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F343N CR-SPLIT=NO 5.5 Secs (5.5 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 9 FQ889N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, FQ889N CR-SPLIT=NO 60 Secs (60 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 10 Orbit Structure Proposal 13318 - JUP-1 (03) - Giant impacts on giant planets 11 Solar System Targets Visit Proposal 13318 - JUP-2 (04) - Giant impacts on giant planets Proposal 13318, JUP-2 (04), implementation Diagnostic Status: No Diagnostics Scientific Instruments: WFC3/UVIS Special Requirements: PCS MODE FINE; DROP TO GYRO IF NECESSARY NO REACQ; GYRO MODE 3GOBAD; SCHED 100%; AFTER 03 BY 5.9 Orbits TO 6.1 Orbits Comments: jupiter visit #2 of 2 Thu Jul 11 18:55:23 GMT 2013 NOTE: Date of impact is unknown, so duration of visibilities cannot be predicted at this time. When observations are actually planned, we intend to duplicate or eliminate some exposures to fill the available visibility. Current visit design is for 42-min visibility window. # Name Level 1 Level 2 Level 3 Window Ephem Center (1) JUPITER-IMPACT- STD=JUPITER TYPE=PGRAPHIC,LONG=0,LAT=0 SEP OF JUPITER CALLISTO FROM EARTH SITE EARTH GT 50", SEP OF JUPITER IO FROM EARTH GT 50", SEP OF JUPITER EUROPA FROM EARTH GT 50", SEP OF JUPITER GANYMEDE FROM EARTH GT 50" Comments: NEED TO REFINE LEVEL 2 COORDINATES AFTER IMPACT TAKES PLACE (or after impact location is predicted prior to impact) 12 Proposal 13318 - JUP-2 (04) - Giant impacts on giant planets Exposures # 1 Label Target Config,Mode,Aperture FQ727N--D (1) JUPITER-IMPA WFC3/UVIS, ACCUM, CT-SITE UVIS-QUAD-SUB Spectral Els. FQ727N Opt. Params. CR-SPLIT=NO Special Reqs. Groups Exp. Time (Total)/[Actual Dur.] 8 Secs (8 Secs) [==>] Orbit [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 2 FQ889N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, FQ889N CR-SPLIT=NO 60 Secs (60 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 3 F275W--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F275W CR-SPLIT=NO 40 Secs (40 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 4 F631N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F631N CR-SPLIT=NO 4 Secs (4 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 5 F502N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F502N CR-SPLIT=NO 3.4 Secs (3.4 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 6 F395N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F395N CR-SPLIT=NO 9 Secs (9 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 7 F225W--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F225W CR-SPLIT=NO 150 Secs (150 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 8 F343N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, F343N CR-SPLIT=NO 5.5 Secs (5.5 Secs) CT-SITE UVIS1-2K2A-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 9 FQ889N--A (1) JUPITER-IMPA WFC3/UVIS, ACCUM, FQ889N CR-SPLIT=NO 60 Secs (60 Secs) CT-SITE UVIS-QUAD-SUB [==>] [1] Comments: EXPOSURE TIMES MUST BE REFINED !! exposure time here is preliminary because target's heliocentric distance at time of observations is not known. once the timing of the impact is known, exposure times must be adjusted to maximize s/n ratio, avoid satura tion, and optimize observational efficiency. 13 Orbit Structure Proposal 13318 - JUP-2 (04) - Giant impacts on giant planets 14