Voyager color photometry of Saturn's main rings: a correction

Abstract

We correct a calibration error in our earlier analysis of Voyager color observations of Saturn's main rings at 14° phase angle (Estrada and Cuzzi, 1996, Icarus 122, 251) and present thoroughly revised and reanalyzed radial profiles of the brightness of the main rings in the Voyager green, violet, and ultraviolet filters and the ratios of these brightnesses. These results are consistent with more recent HST results at 6° phase angle, once allowance is made for plausible phase reddening of the rings (Cuzzi et al., 2002, Icarus 158, 199). Unfortunately, the Voyager camera calibration factors are simply not sufficiently well known for a combination of the Voyager and HST data to be used to constrain the phase reddening quantitatively. However, some interesting radial variations in reddening between 6 and 14° phase angles are hinted at. We update a ring-and-satellite color vs albedo plot from Cuzzi and Estrada (1998, Icarus 132, 1) in several ways. The A and B rings are still found to be in a significantly redder part of color-albedo space than Saturn's icy satellites.