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of Saturn’s spectrum between 4.6 and 5.1 lm where the effects of scattered sunlight diminish; the collision-induced opacity due to H2–He is at a minimum and strong CH4 absorptions are absent. As a result, this wavelength range allows Cassini to probe deeper into Saturn’s troposphere than at any other infrared wavelength. As on Jupiter, this 5-lm window is sensitive to the emission of the gas giant’s internal heat, attenuated by overlying cloud decks mation about dynamical phenomena within Saturn’s cloud decks (e.g., strings of pearls, ribbon waves, the hexagon, polar vortices, annular clouds, and equatorial plumes; see the review by Del Genio et al. (2009)). However, the wavelength dependence of Saturn’s 4.6–5.1 lm spectrum (1950–2220 cm1) has yet to be fully exploited. In this paper, we study the influences of gaseous distri-butions and cloud properties on nightside VIMS spectra (i.e., sensi-tive to thermal emission alone, in the absence of reflected sunlight) to determine the latitudinal distribution of opacity sources in Sat-urn’s troposphere. ⇑ Corresponding author