7181( 5) - 04/09/98 17:56 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7181 Version: 5 Check-in Date: 18-Mar-1998 11:33:14 1.Proposal Title: GRISM SPECTOPHOTOMETRY OF THE URANUS RING ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GTO/NIC 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: BRADFORD A. SMITH INSTITUTE FOR ASTRONOMY CoI: RICHARD TERRILE JET PROPULSION LABORATORY N CoI: ERIC BECKLIN UNIVERSITY OF CALIFORNIA AT LOS ANGELES N CoI: ROLAND MEIER UNIVERSITY OF HAWAII N ------------------------------------------------------------------------------------ 5. Abstract Details of the near-infrared spectral reflectance of the Uranus rings are poorly known, because of problems associated with the scattered light from the planet. Grism spectroscopy of the brightest part of the Epsilon ring will be made with the planet just outside the field of view. To minimize the glare from Uranus, the observations should made when the widest part of the Epsilon ring is at a position angle of approximately 174 degrees. This is one in a series of observations designed to intercompare the near-infrared spectral reflectivity of dark objects in the solar system. Some record of processes that occurred within the Uranus subnebula may be left on the surfaces of the ring particles or the surface coatings of the associated dark inner satellites. ------------------------------------------------------------------------------------ 7181( 5) - 04/09/98 17:56 - [ 2] Observations Description ------------------------ The limb of Uranus is placed 0.5 arcsec outside the FOV, putting the Epsilon ring about 1.38 arcsec from the edge of the field. Spectra are obtained with all three grisms in Camera 3. A wide-band overexposed image is taken before the spectra. This will create diffraction spikes from Uranus within the FOV which can then be used to determine the position of the planet relative to the ring spectra. Because the width of the Epsilon ring varies by a factor of two and is optically thick, the observation is best made when the widest region of the ring appears at the south ansa. Real Time Justification ----------------------- None. Calibration Justification ------------------------- None. Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Rodger I. Thompson*University of Arizona*Steward Obs./NICMOS*933 N. Cherry Ave*Tucson, AZ 85721-0065 Ship Via: Email: thompson@as.arizona.edu ------------------------------------------------------------------------------------ 7181( 5) - 04/09/98 17:56 - [ 3] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: URANUS-RING ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: RING URANUS ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=URANUS | TYPE=TORUS,LONG=90,LAT=+0,RAD=390216,POL | E_LAT=+90 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | H = +18.0+/-5.0 | Will use diffraction spikes to | locate planet which will be outside | FOV. Uranus radius is 1.87 arcsec. Y | -halfwidth of C3 is 26.14 arcsec. | Scale is 13687 km/arcsec. Planet | will be decentered by 1.87 + 0.5 + | 26.14 arcsec = 28.95 arcsec = 390216 | km | ------------------------------------------------------------------------------------------------------------------------------------ 7181( 5) - 04/09/98 17:56 - [ 4] Visit: 01 Visit Priority: Visit Requirements: SCHED 50% ORIENT 37D TO 41D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 URANUS-RING NIC3 MULTIAC NIC3-FI F160W 1.60000 SAMP-SEQ = STEP32,NSAMP = 7 1 DEF PAR 2-3 WITH 1 CUM X ------------------------------------------------------------------------------------------------------------------------------------ 2 ANY NIC1 MULTIAC NIC1 BLANK SAMP-SEQ = STEP32,NSAMP = 7 1 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 3 ANY NIC2 MULTIAC NIC2 BLANK SAMP-SEQ = STEP32,NSAMP = 7 1 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 4 URANUS-RING NIC3 MULTIAC NIC3-FI G096 0.96730 SAMP-SEQ = STEP32,NSAMP = 10, 2 DEF PAR 5-6 WITH 4 CUM X 0 PATTERN = ONE-CHOP,PATTERN-ORIENT = 219,NUM-POS = 2,CHOP-SIZE = 1.3016 ------------------------------------------------------------------------------------------------------------------------------------ 5 ANY NIC1 MULTIAC NIC1 BLANK SAMP-SEQ = STEP32,NSAMP = 10 2 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 6 ANY NIC2 MULTIAC NIC2 BLANK SAMP-SEQ = STEP32,NSAMP = 10 2 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 7 URANUS-RING NIC3 MULTIAC NIC3-FI G141 1.41400 SAMP-SEQ = STEP32,NSAMP = 10, 2 DEF PAR 8-9 WITH 7 CUM X PATTERN = ONE-CHOP,PATTERN-ORIENT = 219,NUM-POS = 2,CHOP-SIZE = 1.3016 ------------------------------------------------------------------------------------------------------------------------------------ 8 ANY NIC1 MULTIAC NIC1 BLANK SAMP-SEQ = STEP32,NSAMP = 10 2 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 9 ANY NIC2 MULTIAC NIC2 BLANK SAMP-SEQ = STEP32,NSAMP = 10 2 DEF CUM ------------------------------------------------------------------------------------------------------------------------------------ 10 URANUS-RING NIC3 MULTIAC NIC3-FI G206 2.06700 SAMP-SEQ = STEP32,NSAMP = 8, 19 DEF CUM X PATTERN = ONE-CHOP,PATTERN-ORIENT = 219,NUM-POS = 2,CHOP-SIZE = 1.3016 ------------------------------------------------------------------------------------------------------------------------------------ 7181( 5) - 04/09/98 17:56 - [ 5] Summary Form for Proposal 7181 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations NIC3 NIC1 NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SAMP-SEQ = STEP32 NSAMP = 7 CHOP-SIZE = 1.3016 NSAMP = 10 NUM-POS = 2 PATTERN-ORIENT = 219 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GTO/NIC ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 50% ORIENT 37D TO 41D PAR 2-3 WITH 1 PAR 5-6 WITH 4 PAR 8-9 WITH 7 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160W BLANK G096 G141 G206 ------------------------------------------------------------------------------------------------------------------------------------ Target Names URANUS-RING ANY ------------------------------------------------------------------------------------------------------------------------------------