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K. W. Larsen, A. I. F. Stewart, L. W. Esposito (Univ. of Colorado), R. A. West (JPL), D. E. Shemansky (USC), Cassini UVIS Team
The Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft has observed Titan during six fly-bys during the first year in orbit around Saturn. Using the Far Ultraviolet (FUV) detector (1100 – 1900 nm) Titan has been imaged with 1.5 milliradian spatial resolution under a variety of observational geometries. Spectral resolution varies based on instrument set-up, with a resolution of either 2.75 or 4.8 nanometers. We report on the first year of imaging observations, focusing on the spatial and temporal variability of several facets of Titan’s atmosphere. Low phase angle observations of reflected sunlight from Titan’s disk show spatial variability of the Titan’s clouds. Observations from early fly-bys are compared to later observations that cover the same locations on Titan to assess temporal variability on the scale of months, whereas image sequences taken during individual fly-bys examine variability on the scale of a few hours. High phase angle observations allow characterization of the variable nature of the ubiquitous haze layers through the forward scattered sunlight. Determination of spatial variability is limited by the resolution of the instrument whereas temporal variability may be evaluated on scales as small as a few hours.
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.