Celestia Forums

My attempts at colorizing Cassini Rhea pictures:

http://world.std.com/~mmcirvin/rhea_true_color.jpg
RGB visible-light composite. I don't have any means of calibrating these pictures precisely, of course, but I suspect this is pretty close to a natural color view. Rhea is pretty gray.

http://world.std.com/~mmcirvin/rhea_fake_color.jpg
IR3/green/UV3 composite.

Rhea looks a lot like a larger version of Dione, but the colors are more subtle even in the compressed-spectrum picture. Unfortunately, Cassini's closest approach on this flyby was on the leading hemisphere, so we didn't get as close a look at the "wisps" as with Dione; these images don't reveal whether they are also tectonic fractures.

The peculiar straight line (which is really only straight by an accident of perspective) at the lower left is real; Voyager 1 also photographed it and it is in Voyager-derived maps, including the one in the Celestia distro.

Ah, I see everyone's way ahead of me in the "Enceladus" thread... never mind then.

Would the IR3/green/UV3 be what you'd see if you could see Ultraviolet and Infrared as well as normal colours? Because if we could, the visible color spectrum would probably just spread into these types of light.

Michael Kilderry

Michael Kilderry wrote:Would the IR3/green/UV3 be what you'd see if you could see Ultraviolet and Infrared as well as normal colours? Because if we could, the visible color spectrum would probably just spread into these types of light.

I suppose it's a bit like what you'd see if you could see some UV and infrared, but you still only had three cone types in your retina (only with different response curves) and your brain processed colors in something like the way it does now.

It's sometimes fun to think about how it would be to see with more than three primary colors. But it's not possible to create a picture that would show us how it would be to have that sensation... the space of colors would have more than three dimensions, and hues would fall on, say, a color sphere rather than a color wheel...

You explained it better than I did, Rhea probably would look like that if you could see Ultraviolet and Infrared with three cones in your eye (that sounds really painful...).

Michael Kilderry