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N. J. Chanover (New Mexico State University), D. A. Glenar (NASA/Goddard Space Flight Center)
The surface and atmosphere of Titan were probed in November 1999 using AImS, a NASA/GSFC-built Acousto-optic Imaging Spectrometer, at the Mount Wilson 100'' telescope. This telescope has been equipped with a natural guide star adaptive optics system since 1995, and therefore allowed us to improve upon uncorrected ground-based imaging observations of Titan using a modest-sized telescope. Using this camera, whose spectral resolution is nearly an order of magnitude greater than a narrow-band filter, we observed Titan's surface in the 0.94 \mum methane window. We also observed at wavelengths sensitive only to absorption and scattering in Titan's atmosphere. The temporal coverage of our data set allowed us to view nearly an entire hemisphere of Titan, including the large bright region previously seen on Titan's leading hemisphere as well as the Cassini/Huygens probe landing site. The images were deconvolved to optimize the spatial resolution on Titan's disk.
The analysis of the images attempts to address several questions. Firstly, we will discuss the temporal stability of the observed contrast of Titan's surface by comparing our reflectivity measurements to those made by other investigators, looking in the same wavelength region, using the Hubble Space Telescope. Secondly, we will address the spectral dependence of the bright and dark regions of Titan's surface by comparing our reflectivity measurements with those made at longer wavelengths. Based on our findings, we will offer suggestions as to the nature of Titan's surface topography and/or composition. This results of this work are based on observations from the Mount Wilson Observatory, which is operated by the Mount Wilson Institute under an agreement with the Carnegie Institution of Washington.