11656( 7) - 02-Jul-2009 16:30:25 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11656 Version: 7 Check-in Time: 02-Jul-2009 16:30:25 STScI Edit Number: 4 Title A Comprehensive Survey of Neptune's Small Moons and Faint Rings ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Mark R. Showalter SETI Institute CoI: Prof. Imke de Pater University of California - Berkeley N CoI: Dr. Jack J. Lissauer NASA Ames Research Center N ------------------------------------------------------------------------------------ Abstract We will use a subarray of the WFC3/UVIS to study the inner rings, arcs and moons of Neptune with a sensitivity that exceeds that achieved by any previous observations, including Voyager 2 during its 1989 flyby. Our study will reveal any inner moons down to V magnitude 25, corresponding to a radius ~ 20 km (assuming 9% albedo), to address a peculiar, apparent truncation in the size distribution of inner moons and to look for the "shepherds" and source bodies for Neptune's dusty rings. (For comparison, the radius of Neptune's smallest known regular moon, Naiad, is ~ 33 km.) Monitoring of the arcs at fine resolution and sensitivity will reveal their ongoing evolution more clearly and will enable us to assess the role of Galatea, whose resonant perturbations are widely believed to confine the arcs. Our study will also reveal any broad, faint rings with optical depth ~ 10^-6, comparable to those now known to encircle all of the other giant planets. ------------------------------------------------------------------------------------ Observations Description ------------------------ Each of our five orbits contains eight exposures of 275 seconds duration through the F606W filter. The long exposures will provide the finest possible sensitivity to small moons and faint rings, and the sequence will yield "movies" that can be animated to search effectively for small moving targets. The planet will be vastly over-exposed in these frames, but its saturated pixels will bloom along the y-axis and so will not interfere with features oriented close to the x-axis. However, our orientation constraint is only available for a few days around Neptune's opposition. Additional, brief exposures through filters F475W, F625W and F775W will be used for color measurements of the moons and for cross-calibration of the F606W filter. We will use five consecutive orbits targeted at Neptune to obtain the most complete possible coverage in time, because moons and arcs are most detectable if imaged near their maximum elongation from the planet. These five orbits are organized in a set of two consecutive visits, with slightly different ORIENT constraints. By positioning the rings and moons 15-20 degrees off the x-axis, but in opposite directions, we will obtain a better model for the scattered light from the planet and will be able to separate it from any faint, outer rings that might be present. 11656( 7) - 02-Jul-2009 16:30:25 - [ 2] Dithering is accomplished shifting Neptune up and down along the y-axis between (not during) orbits. The rotational change between visits will also allow for a clearer identification of hot pixels and any other reproducible imperfections in the CCD. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11656( 7) - 02-Jul-2009 16:30:25 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET Planet Neptune ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 7.8 Ephemeris Center: EARTH ------------------------------------------------------------------------------------------------------------------------------------ 11656( 7) - 02-Jul-2009 16:30:25 - [ 4] Visit: 01 Visit Requirements: SCHED 100%; ORIENT 309D TO 314 D On Hold Comments: Additional Comments: Neptune's pole is aligned with the columns of the CCD for ORIENT = 114 or 294. For this visit, we rotate the rings 15-20 degrees clockwise. We shift the target upward by 0.2 arcsec (5 pixels) for the second of the three orbits to get the benefits of dithering while retaining stable pointing during each orbit. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F606W CR-SPLIT=NO 8 275 S POS TARG 0, 0; SEQ 1 S 2B-SUB NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F606W CR-SPLIT=NO 8 275 S POS TARG 0, 0.2; SEQ 2-4 S 2B-SUB NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 3 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F625W CR-SPLIT=NO 1 3 S SAME POS AS 2 S 2B-SUB ------------------------------------------------------------------------------------------------------------------------------------ 4 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F775W CR-SPLIT=NO 1 10 S SAME POS AS 2 S 2B-SUB ------------------------------------------------------------------------------------------------------------------------------------ 5 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F606W CR-SPLIT=NO 8 275 S POS TARG 0, 0; SEQ 5-7 S 2B-SUB NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 6 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F475W CR-SPLIT=NO 1 8 S SAME POS AS 5 S 2B-SUB ------------------------------------------------------------------------------------------------------------------------------------ 7 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F775W CR-SPLIT=NO 1 8 S SAME POS AS 5 S 2B-SUB ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 1 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 2 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 3 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 4 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 5 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 6 none 1 N/A S 12B-SUB 11656( 7) - 02-Jul-2009 16:30:25 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 7 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 8 none 1 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 1 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 2 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 3 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 4 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 5 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 6 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 7 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 8 none 2 N/A S 12B-SUB NEPTUNE 3 WFC3/UVI ACCUM UVIS1-C5 F625W none none none none 2 N/A S 12B-SUB NEPTUNE 4 WFC3/UVI ACCUM UVIS1-C5 F775W none none none none 2 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 1 none 3 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 2 none 3 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 3 none 3 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 4 none 3 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 5 none 3 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 6 none 3 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 7 none 3 N/A S 12B-SUB NEPTUNE 5 WFC3/UVI ACCUM UVIS1-C5 F606W none none 8 none 3 N/A S 12B-SUB NEPTUNE 6 WFC3/UVI ACCUM UVIS1-C5 F475W none none none none 3 N/A S 12B-SUB NEPTUNE 7 WFC3/UVI ACCUM UVIS1-C5 F775W none none none none 3 N/A S 12B-SUB 11656( 7) - 02-Jul-2009 16:30:25 - [ 6] Visit: 02 Visit Requirements: SCHED 100%; ORIENT 274D TO 279 D; AFTER 01 BY 270 M TO 300 M On Hold Comments: Additional Comments: Neptune's pole is aligned with the columns of the CCD for ORIENT = 114 or 294. For this visit, we rotate the rings 15-20 degrees counter-clockwise. We shift the target upward by 0.2 arcsec (5 pixels) for the first of the two orbits to get the benefits of dithering while retaining stable pointing during each orbit. This visit is timed to begin on the orbit immediately after Visit 01 finishes. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F606W CR-SPLIT=NO 8 275 S POS TARG 0, 0.2; SEQ 1 S 2B-SUB NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F606W CR-SPLIT=NO 8 275 S POS TARG 0, 0; SEQ 2-4 S 2B-SUB NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 3 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F475W CR-SPLIT=NO 1 8 S SAME POS AS 2 S 2B-SUB ------------------------------------------------------------------------------------------------------------------------------------ 4 NEPTUNE WFC3/UVI ACCUM UVIS1-C51 F775W CR-SPLIT=NO 1 8 S SAME POS AS 2 S 2B-SUB ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 1 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 2 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 3 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 4 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 5 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 6 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 7 none 1 N/A S 12B-SUB NEPTUNE 1 WFC3/UVI ACCUM UVIS1-C5 F606W none none 8 none 1 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 1 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 2 none 2 N/A S 12B-SUB 11656( 7) - 02-Jul-2009 16:30:25 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 3 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 4 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 5 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 6 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 7 none 2 N/A S 12B-SUB NEPTUNE 2 WFC3/UVI ACCUM UVIS1-C5 F606W none none 8 none 2 N/A S 12B-SUB NEPTUNE 3 WFC3/UVI ACCUM UVIS1-C5 F475W none none none none 2 N/A S 12B-SUB NEPTUNE 4 WFC3/UVI ACCUM UVIS1-C5 F775W none none none none 2 N/A S 12B-SUB 11656( 7) - 02-Jul-2009 16:30:25 - [ 8] Summary Form for Proposal 11656 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS1-C512B-SUB ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 270 M TO 300 M, ORIENT 274D TO 279 D, ORIENT 309D TO 314 D, POS TARG 0, 0, POS TARG 0, 0.2, SAME POS AS 2, SAME POS AS 5, SCHED 100%, SEQ 1 NON-INT, SEQ 2-4 NON-INT, SEQ 5-7 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F475W, F606W, F625W, F775W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NEPTUNE ------------------------------------------------------------------------------------------------------------------------------------