Seeing as I am up at this ungodly hour, I wondered if this image of Iapatus' crater shows something larger than Herschel (Mimas) or Odysseus (Tethys). It is VERY big, though for some reason it was imaged mostly with the GRN (green) filter...
Here is a clear filter image, look at the dark region
http://saturn1.jpl.nasa.gov/multimedia/ ... 006756.jpg
Other images here
http://saturn1.jpl.nasa.gov/multimedia/ ... seLatest=1
Oh I love this Cassini mission
