10502( 3) - 07/20/05 13:27 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10502 Version: 3 Check-in Time: 20-Jul-2005 17:26:22 Title ACS Imaging of the Uranus Aurora and Hydrogen Corona ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 14 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. John T. Clarke Boston University CoI: Dr. Jody K. Wilson Boston University N ------------------------------------------------------------------------------------ Abstract ACS SBC UV observations of Uranus are proposed with dual purposes that can be achieved with a single set of observations. First, we propose to observe the very unusual auroral of Uranus for the first time since IUE and Voyager in the 1980's. The Uranus aurora are centered on the magnetic poles, corresponding to the 60 deg. tilted magnetic moment, closer to the equator than the rotational poles. The brighter auroral emission appears around the weaker magnetic pole. The auroral emissions are highly variable, as recorded with IUE, and the rotational phase of Uranus is not known. The observations will therefore cover the extent of a Uranus rotation (17.29 hours), and will be repeated one-half solar rotation later to allow for variations in the solar wind at Uranus. The high sensitivity of the ACS SBC at long wavelengths will increase the sensitivity to auroral H2 emissions, and observations in cycle 14 near solar minimum will limit the sky background and reflected solar emissions from the Uranus disc. Secondly, these images will measure the extended hydrogen corona of Uranus, first seen by the Voyager 2 UVS. We propose to model the distribution of the hydrogen corona to determine the source processes in the Uranus upper atmosphere, by comparison with model runs from an exospheric code. ------------------------------------------------------------------------------------ 10502( 3) - 07/20/05 13:27 - [ 2] Observations Description ------------------------ These observations are to make images of the H Ly alpha emisson from the atmosphere and aurora on Uranus, including the extended cloud of superthermal H around the planet. We hope to detect auroral emissions from the planet disc, and since the rotational ephemeris of Uranus has been lost since the Voyager encounter in 1986, images must be taken over a complete Uranus rotation to cover all phases, including when the auroral ovals may be pointing toward the Earth. This proposal is to observe Uranus from 4 sides separated by approx. 90 deg. of rotation, and to repeat this series about 2 weeks later, for a total of 8 orbits. In one 5 orbit ACS SBC visibility period, two quadrants can be observed (Uranus rotation period = 17.24 hours, and 90 deg. rotation takes 4.3 hours) by observations separated by two orbits. If, on day One, Uranus is observed in the 1st and 4th orbits during the 5 orbit ACS visibility period, and on the following day Two during the 2nd and 5th orbits of the next visibility period, this will correspond to relative longitudes on Uranus of 0 and 100 deg. on day One, and 174 and 274 deg. on day Two. This assumes the visibility period starts at approx. the same local time each day. The cycle should be repeated about 2 weeks later, when the solar wind conditions will have passed through 1/2 solar rotation for the most likely change in solar wind conditions at Uranus. The observations also need to be scheduled close to Uranus opposition to minimize the geocoronal Ly alpha background, but only within +/- one month. Under 2 gyro mode, the main period of visibility for any object is the month before Uranus opposition around 5 Sept. 2005, and that is the one that is proposed here. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 10502( 3) - 07/20/05 13:27 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: URANUS ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Planet Uranus ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=URANUS | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 5.8+/-0.2 | | ------------------------------------------------------------------------------------------------------------------------------------ 10502( 3) - 07/20/05 13:27 - [ 4] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 10-AUG-2005:00:00:00 AND 27-AUG-2005:00:00:00 On Hold Comments: Additional Comments: First visit to Uranus, this is the first orbit at the start of a sequence. ACS SBC MAMA observations are limited to 5 orbits/day outside SAA, about the same time each day. It is not important which side of Uranus is observed at the start of this program, as long as all 4 quadrants are observed over 2 days. In this visit 1, observe in 1st orbit in 5 orbit visibility period, then key timing of visits 2-4 to this time. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 360 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 5] Visit: 02 Visit Priority: Visit Requirements: AFTER 01 BY 2.75 Orbits TO 3.25 Orbits On Hold Comments: Additional Comments: Observe Uranus three orbits after start of visit 1, i.e. two orbits have passed since the end of visit 1. This timing lets Uranus rotate 100 deg. between visits 1 and 2, giving the second of the four quadrants needed in two days. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 360 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 6] Visit: 03 Visit Priority: Visit Requirements: AFTER 01 BY 15.75 Orbits TO 16.25 Orbits On Hold Comments: Additional Comments: Observe Uranus one day after visits 1 and 2, to get the remaining two quadrants in the next 5 orbit visibility window. This visit sees Uranus at a longitude 174 deg. (plus one complete rotation) after visit 1. The requested time is 16 orbits after the start of visit 1, this is expected to be the 2nd orbit in the 5 orbit visibility period on the second day. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 300 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 7] Visit: 04 Visit Priority: Visit Requirements: AFTER 03 BY 2.75 Orbits TO 3.25 Orbits On Hold Comments: Additional Comments: Observe Uranus three orbits after start of visit 3, i.e. two orbits have passed since the end of visit 3. This timing lets Uranus rotate 100 deg. between visits 3 and 4, or a longitude of 274 deg. with respect to the start of orbit 1, giving the last of the four quadrants needed in two days. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 300 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 8] Visit: 05 Visit Priority: Visit Requirements: AFTER 01 BY 12 D TO 16 D On Hold Comments: Additional Comments: Repeat series of observations in visit 1-4, approx. two weeks after visits 1-4. Exact start date is not important, but sequence of orbits is laid out as in visits 1-4, and visits 6-8 must start at requested times with respect to the start of visit 5. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 300 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 9] Visit: 06 Visit Priority: Visit Requirements: AFTER 05 BY 2.75 Orbits TO 3.25 Orbits On Hold Comments: Additional Comments: Equivalent to visit 2 in second series of observations, i.e. 3 orbits after visit 5. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 300 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 10] Visit: 07 Visit Priority: Visit Requirements: AFTER 05 BY 15.75 Orbits TO 16.25 Orbits On Hold Comments: Additional Comments: Equivalent to visit 3 in second series of observations, i.e. 16 orbits after visit 5. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 300 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 11] Visit: 08 Visit Priority: Visit Requirements: AFTER 07 BY 2.75 Orbits TO 3.25 Orbits On Hold Comments: Additional Comments: Equivalent to visit 4 in second series of observations, i.e. 3 orbits after visit 7. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS ACS/SBC ACCUM SBC F115LP 3 400 S ------------------------------------------------------------------------------------------------------------------------------------ 2 URANUS ACS/SBC ACCUM SBC F140LP 2 450 S ------------------------------------------------------------------------------------------------------------------------------------ 3 URANUS ACS/SBC ACCUM SBC F165LP 1 300 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 | ------------------------------------------------------------------------------------------------------------------------------------ URANUS 1 ACS/SBC ACCUM SBC F115LP none none 1 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 2 none 1 N/A URANUS 1 ACS/SBC ACCUM SBC F115LP none none 3 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 1 none 1 N/A URANUS 2 ACS/SBC ACCUM SBC F140LP none none 2 none 1 N/A URANUS 3 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10502( 3) - 07/20/05 13:27 - [ 12] Summary Form for Proposal 10502 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures SBC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/SBC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 10-AUG-2005 00 00 00 AND 27-AUG-2005 00 00 00 AFTER 01 BY 2.75 Orbits TO 3.25 Orbits AFTER 01 BY 15.75 Orbits TO 16.25 Orbits AFTER 03 BY 2.75 Orbits TO 3.25 Orbits AFTER 01 BY 12 D TO 16 D AFTER 05 BY 2.75 Orbits TO 3.25 Orbits AFTER 05 BY 15.75 Orbits TO 16.25 Orbits AFTER 07 BY 2.75 Orbits TO 3.25 Orbits ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F115LP F140LP F165LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names URANUS ------------------------------------------------------------------------------------------------------------------------------------