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Thermal infrared observations of Mars (7.5-12.8 microns) during the 1990 oppositionThirteen spectra of Mars, in the 7.5 to 12.8 micron wavelength were obtained on 7 Dec. 1990 from the Infrared Telescope Facility (IRTF). For these observations, a grating with an ultimate resolving power of 120 to 250 was used and wavelengths were calibrated for each grating setting by comparison with the absorption spectrum of polystyrene measured prior to each set of observations. By sampling the Nyquist limit at the shortest wavelengths, an effective resolving power of about 120 over the entire wavelength range was achieved. A total of four grating settings were required to cover the entire wavelength region. A typical observing sequence consisted of: (1) positioning the grating in one of the intervals; (2) calibrating the wavelength of positions; and (3) obtaining spectra for a number of spots on Mars. Several observations of the nearby stellar standard star, alpha Tauri, were also acquired throughout the night. Each Mars spectrum represents an average of 4 to 6 measurements of the individual Mars spots. As a result of this observing sequence, the viewing geometry for a given location or spot on Mars does not change, but the actual location of the spot on Mars's surface varies somewhat between the different grating settings. Other aspects of the study are presented.
Document ID
19920001733
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Roush, T. L. (San Francisco State Univ. CA., United States)
Witteborn, F. (NASA Ames Research Center Moffett Field, CA, United States)
Lucy, P. G. (NASA Ames Research Center Moffett Field, CA, United States)
Graps, A. (Hawaii Univ. Honolulu., United States)
Pollack, J. B. (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1991
Publication Information
Publication: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1990
Subject Category
Lunar And Planetary Exploration
Accession Number
92N10951
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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