This one is fresh from the spacecraft! The data were captured yesterday, December 26, by Cassini during its best yet imaging encounter with the small ringmoon Prometheus, and showed up on the Cassini raw images website today.
I love posting animations of Cassini images that I compose from frames grabbed from the mission's raw images website, but they are shoddy compared to the versions that eventually come out from the mission's imaging team.
Iapetus! I'm always interested in Cassini images, but five years ago this month I was refreshing the Cassini raw images website several times a day, eagerly anticipating the mission's first good encounter with Iapetus.
The Cassini mission announced today the first observation of a specular reflection off of a lake on Titan. A specular reflection is a mirror-like flash, and you only get one when you have a mirror-like surface -- very, very smooth.