Data Set Information
DATA_SET_NAME KECK II ESI IMAGES OF 81P/WILD 2
DATA_SET_ID EAR-C-I0039-2-SBN0007/KECKIIESI-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The Stardust mission required both astrometric and photometric observations from ground-based telescopes to fine-tune the circumstances for the 2004 January 2 UT spacecraft encounter with comet 81P/Wild 2. The astrometric data provided critical third-dimension information that improved the encounter time, while the photometric data provided information on the level of activity for the comet, which was used to decide on a flyby distance. The Stardust project arranged for some of these observations to be made with the Keck II telescope on Mauna Kea using the ESI instrument in imaging mode, which illuminates a subset of the detector with a 2 by 8 arcmin field. The R filter provided by Richard Ellis (the 'Ellis R filter') was used for all observations because it is the only one in the ESI instrument that accommodates the full 2 by 8 arcmin field of view. Altogether, 57 images of the comet were obtained on the nights of 2003 December 19-21 UT, as well as bias frames, flat field frames, and images of Landolt standard stars. The processed images in this data set have had the average value of the overscan region subtracted, a two-dimensional bias pattern subtracted based on an average of several overscan-subtracted bias images, and were divided by a flat field image based on the median of all the overscan-subtracted and bias subtracted twilight sky flat field images. All three nights were photometric. To compute the photometric zero point of the images, a synthetic aperture of radius 40 pixels was utilized on all astrometric reference stars. The pixel size is 0.155 arcseconds.
DATA_SET_RELEASE_DATE 2004-10-18T00:00:00.000Z
START_TIME 2003-12-19T12:00:00.000Z
STOP_TIME 2003-12-21T04:08:56.730Z
MISSION_NAME SUPPORT ARCHIVES
MISSION_START_DATE 2004-03-22T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME CALIBRATION
SKY
81P/WILD 2 (1978 A2)
STAR
TARGET_TYPE CALIBRATION
COMET
STAR
INSTRUMENT_HOST_ID OBS378T2
INSTRUMENT_NAME KECK ECHELLE SPECTROGRAPH AND IMAGER
INSTRUMENT_ID I0039
INSTRUMENT_TYPE IMAGER
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE NONE PROVIDED
CITATION_DESCRIPTION Tholen, D.J., Keck II ESI images of 81P/Wild 2. EAR-C-I0039-2-SBN0007/KECKIIESI-V1.0. NASA Planetary Data System, 2004.
ABSTRACT_TEXT CCD images of comet 81P/Wild 2 taken 2003 December 19-21 UT with the ESI instrument on Keck II in support of the Stardust encounter.
PRODUCER_FULL_NAME DAVID THOLEN
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