15493( 7) - 25-Oct-2018 21:12:30 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15493 Version: 7 Check-in Time: 25-Oct-2018 21:12:30 STScI Edit Number: 6 Title Astrometry of 2014MU69 for New Horizons encounter ------------------------------------------------------------------------------------ Type Cycle GO 26 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Marc W. Buie Southwest Research Institute Y CoI: Stephen Gwyn Dominion Astrophysical Observatory N CoI: Dr. Paolo Tanga Observatoire de la Cote d'Azur N CoI: Dr. William M Folkner Jet Propulsion Laboratory N CoI: Dr. John R. Spencer Southwest Research Institute N CoI: Dr. J. J. Kavelaars National Research Council of Canada N CoI: Dr. Simon Porter Southwest Research Institute N CoI: Dr. Alex Harrison Parker Southwest Research Institute N CoI: Dr. Amanda Marie Zangari Southwest Research Institute N CoI: Dr. Susan D. Benecchi Planetary Science Institute N CoI: Dr. Anne J. Verbiscer The University of Virginia N CoI: Dr. David Tholen University of Hawaii N CoI: Dr. Harold A. Weaver The Johns Hopkins University Applied N Physics Laboratory CoI: Dr. S. Alan Stern Southwest Research Institute N ------------------------------------------------------------------------------------ Abstract We propose 12 orbits of time to make high-precision astrometric measurements of the New Horizons extended mission target, 2014MU69. These observations are in direct support of the navigation of New Horizons leading up to its encounter in Jan 2019. These visits represent an optimized plan for improved orbit estimates that will complete as the target becomes directly observable by New Horizons. This astrometry is a key element leading up to a close investigation of a Cold-Classical Kuiper Belt Object, one of the most primitive members of our solar system. ------------------------------------------------------------------------------------ Observations Description ------------------------ These observations will use the full field of WFC3/UVIS due to its improved broadband PSF and detector sensitivity compared to ACS. This was the HST instrument used to successfully to detect 2014MU69 and our other potential KBO targets in our 2014 search campaign. We are using the F350LP filter for its sensitivity and image quality as well as consistency with the prior observations. Our observing strategy is based on the successful strategy developed for our 2014-2016 HST KBO search and followup campaigns. For each HST orbit we will use WFC3 with the F350LP filter to obtain five 370 second exposures. We will track on the known motion of 2014MU69, which results in trailing of stars, but does not prevent their removal to provide robust 15493( 7) - 25-Oct-2018 21:12:30 - [ 2] detections in single orbits as shown. The formal uncertainty of the position is less than 1 pixel for the entire campaign. Thus, the target can easily be placed near the center of WFC3/UVIS2, and very bright stars can be avoided by adjusting the timing of the observations as necessary. Once preliminary observing windows are available we need to examine the background star field for contamination and final scheduling to avoid field stars. We require acquisition of the full WFC3 field for precise astrometric solutions. The visit timing is designed to get broad time coverage for the orbit estimation needed for New Horizons navigation support. The one week period is chosen to provide ample scheduling flexibility and could be shifted by another day or two if needed. The timing of these weeks is controlled by avoiding the time around quadrature when the sky-plane velocity is below 1 arcsec/hour and the need to get the visits spread out in time throughout the annual observing window. ------------------------------------------------------------------------------------ 15493( 7) - 25-Oct-2018 21:12:30 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 TARGET NAME: 486958-E ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: ASTEROID Kuiper-Belt Object ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 TYPE=ASTEROID, A=44.522607562638, E=0.040269637522, I=2.452265958242, O=158.963182412558, W=174.926199040395, M=315.140003030700, EQUINOX=J2000, EPOCH=15-AUG-2018:00:00:00, EpochTimeScale=UTC ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 27 +/- .3 Ephemeris Center: EARTH ------------------------------------------------------------------------------------------------------------------------------------ 15493( 7) - 25-Oct-2018 21:12:30 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type LINE Pattern_Purpose OTHER Number_Of_Points 5 Point_Spacing .030 Line_Spacing Coordinate_Frame CELESTIAL Pattern_Orient 0 Angle_Between_Sides Center_Pattern YES Pattern_Comments: Objects will naturally dither themselves in a predominantly east-west direction. This dither pattern uses offsets perpendicular to the mean motion of the objects with a two-level pattern so that the dither cannot lead to a false detection with coherent motion. The overall pattern is six positions with 0.75 pixel spacing. ------------------------------------------------------------------------------------------------------------------------------------ 15493( 7) - 25-Oct-2018 21:12:30 - [ 5] Visit: 12 Visit Requirements: SCHED 90%; BETWEEN 25-OCT-2018:00:00:00 AND 15-NOV-2018:00:00:00 On Hold Comments: Additional Comments: The scheduling for this visit must be coordinated with visit 13 from (14450). These two visits are to be sheduled three days apart within the same one week window. We will need to verify the scheduling window for each visit to ensure there are no field star contamination problems. 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 486958-E WFC3/UVI ACCUM UVIS2 F350LP 1 367.0 S GS ACQ SCENARIO BASE1B3; S (1835 S) SEQ 1 NON-INT; PATTERN 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 486958-E 1 WFC3/UVI ACCUM UVIS2 F350LP 1 none none none 1 N/A S 486958-E 1 WFC3/UVI ACCUM UVIS2 F350LP 2 none none none 1 N/A S 486958-E 1 WFC3/UVI ACCUM UVIS2 F350LP 3 none none none 1 N/A S 486958-E 1 WFC3/UVI ACCUM UVIS2 F350LP 4 none none none 1 N/A S 486958-E 1 WFC3/UVI ACCUM UVIS2 F350LP 5 none none none 1 N/A S 15493( 7) - 25-Oct-2018 21:12:30 - [ 6] Summary Form for Proposal 15493 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 25-OCT-2018:00:00:00 AND 15-NOV-2018:00:00:00, GS ACQ SCENARIO BASE1B3, PATTERN 1 1, SCHED 90%, SEQ 1 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F350LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names 486958-E ------------------------------------------------------------------------------------------------------------------------------------