36th DPS Meeting, 8-12 November 2004
Session 18 Outer Planets
Poster I, Tuesday, November 9, 2004, 4:00-7:00pm, Exhibition Hall 1A

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[18.16] Calibration of the IRTF-Galileo Support Dataset

M.B. Vincent, N.J. Chanover, R.F. Beebe (New Mexico State University)

The NASA Infrared Telescope Facility (IRTF), on Mauna Kea, Hawaii, set aside time on almost 500 nights from 1995 to 2002 for a standardized NSFCAM observations of Jupiter (PI: Glenn S. Orton, JPL) in support of the Galileo mission. The program included short, macro-driven observations of Jupiter, with occasional additional observations of calibration stars and flat fields. Data were acquired in four filters: narrow-band filters centered at 1.58 and 2.28 microns and broader L' and M' bands. At the time of the data acquisition, most of the calibration stars were not cross-calibrated against photometric standards. In 2003-2004 we obtained follow-up observations to calibrate the six most frequently observed stars and Jupiter. With the NSFCAM upgrade currently underway, the timing of this effort was crucial for the long-term calibration of the Galileo/Jupiter support data set.

Stellar photometry indicates that NSFCAM's zero point had shifted by up to +/-0.15 magnitudes several times from 1995 to 1997. We present calibrated central meridian scans of the albedos and brightness temperatures of Jupiter between 1995 and 2004. Three calibration methods were applied to the scans: 1) the stellar flux from concurrent observations, 2) nominal zero point magnitudes applied uniformly to all scans taken with the same filter, and 3) normalizing selected latitudes to the calibrated 2004 scans.

All data will be available to the planetary science community through the Planetary Data System Atmospheres Discipline Node at New Mexico State University. We thank the IRTF Division Chief, Alan Tokunaga, for providing the engineering time on the IRTF that allowed us to complete the calibration of this data set.

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.