Enceladus again

Many close-ups today of Enceladus, a moon of Saturn that greatly resembles Chelmsford, Massachusetts. The raw image archive is well worth a look today; image haul is much larger than in the previous flyby, and I doubt it's all been transmitted yet. Some of these are natural-color separations, but I doubt assembling them will reveal Enceladus to be anything other than white.

By the way, the "Browse Latest 500 Raw Images" link on the raw image page often produces strangely out-of-date results; to just get the latest pictures, you're better off doing a search with the fields blank.

Cracks and craters

This is one of the many raw images of Enceladus that came back today. All I did was take out the annoying alternate-scanline compression dropouts.

It's interesting that the thin cracks seem to be modified in direction somewhat when they cross a crater, but run right across them rather than being outright radial. I guess they're tectonic fractures of some sort that are younger than the craters.

Another one

Here's another one, showing a large chunk of the visible disc. This time I've increased the contrast as well as removed the dropouts; the original image had the terrain relief kind of washed-out, probably just because the surface of Enceladus is so white, like fresh snow.

I tried making a color composite of this view from IR/green/UV pictures, but it came out pretty bad, so I'll let somebody else do it. Enceladus looks particularly weird in such false-color composites; it seems almost as if the spectral reflectivity of the ice in the infrared and ultraviolet varies with angle.

Fixing dropouts

By the way, in case you were wondering, here is how to fix dropout-stricken Cassini images in GIMP. It is very easy:

1. Select the affected area with the lasso tool. (You can skip this step if you don't care about losing vertical resolution in the rest of the image.)

2. In the image's menus, select Filters->Enhance->Deinterlace.

3. In the dialog, select "Keep Odd Fields" and click OK.