Enceladus flyby pics

It seems there is a lot of public interest in yesterday's flyby of Enceladus by Cassini because I am finding the Cassini website to be almost impossibly sluggish this morning! Still, "too much interest" is exactly the kind of problem I want to see on space missions. With a little help from some folks at unmannedspaceflight.com I can show you a couple of teaser images.

This first one is really amazing. It's not the best quality image of Enceladus ever taken, but you should be astounded when I tell you that nothing in this photo is illuminated directly by the Sun. At the time that this image was taken, Enceladus was sitting in Saturn's shadow -- in other words, Saturn was eclipsing the Sun. But Enceladus' surface is well lit (at least to the very sensitive eye of Cassini's wide-angle camera) by four light sources. I'll explain below.

In the region above the area illuminated by Saturnshine and ringshine, you can see both the left and right limbs are also illuminated, but much more faintly. The left side is illuminated by Rhea, more than 700,000 kilometers away (and itself only a crescent). The right side receives light from Tethys and Dione, 100,000 and 200,000 kilometers away, respectively. There's light bouncing all over the Saturn system! Here's a sketch map of what I'm talking about. I almost certainly have the "crescents" representing illumination from the moons incorrectly oriented, so take this map with a grain of salt.