31st Annual Meeting of the DPS, October 1999
Session 47. Mars Surface: Spectra Posters
Poster Group II, Thursday-Friday, October 14, 1999, , Kursaal Center

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[47.06] Near-IR Imaging Spectroscopy of Mars Using the KPNO Cryogenic Grating Spectrometer (CRSP)

D.A. Glenar, G.L. Bjoraker (NASA-GSFC), D.L. Blaney (JPL), R. Joyce (KPNO), F. Espenak (NASA-GSFC), L. Young (Boston U.)

We used the KPNO Cryogenic Spectrometer (CRSP/SALLY) at the KPNO 2.2 meter telescope to acquire near-infrared spectral images of Mars and several photometric calibration stars over three nights (April 25-27, 1999) near Mars opposition, with Ls~130 and longitudinal coverage extending from 176 to 290 degrees CML. This observing was part of a simultaneous 3-team effort to acquire Mars spectral image data from visible wavelengths to 5 microns, using facilities at KPNO, Lowell and Apache Point observatories (see abstract by Hillman et al., this meeting). CRSP/SALLY uses a 256 x 256 InSb array, and multiple grating, filter and slit settings for moderate resolution slit spectroscopy between 1.0 and ~5.0 microns.

Two-dimensional image cubes were acquired with spectral resolving powers (lambda/Dlambda) ranging from 800-2200, at 5 specific wavelength settings: (I) 2.19-2.32, (II) 2.31-2.43, (III) 2.96-3.56, (IV) 3.55-4.12 and (V) 4.40-4.67 microns. Full-disk images were built up from slit images by tracking Mars at the siderial rate and allowing the planet to drift across the 0.8 arcsec spectrometer slit, which was oriented normal to the planets drift vector (13.3 degrees from celestial North). Slit spectra from each drift scan, about 25 minutes duration, span the entire disk and are transformed into three-dimensional (x, y, wavelength) spectral image cubes, after converting elapsed time into relative position.

Wavelength coverage was chosen to investigate the mineralogy and distribution of clay, carbonate, and sulfate minerals which are important indicators of Martian climate. High spectral resolution allows us to separate atmospheric and surface mineralogic effects more effectively than previous observations collected at these wavelengths.

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