Guys,
It is inappropriate to poke fun at people who are having trouble expressing themselves. This has gone too far. Please do not respond when you cannot help. Simply close the browser window and go on to the next topic.
This is a formal warning.
Le Chatran,
Celestia does not use a separate texture for the dark side of Saturn's rings.
It uses a single image (surface texture) to describe rings like those around Saturn. It is not a circular image of the entire set of rings. rather it describes a single radial line extending away from the center of the planet. Celesita expands that radial line into a circle around the planet.
(This assumption that rings are perfectly circular may no longer be appropriate. Cassini has been finding that the structure of Saturn's ring system is extremely complex and irregular and varies with time. But that is for future development.)
The rings' image contains 4 planes (also called channels) containing information. Three of those channels describe the intensity of the colors reflected by the rings: Red, Blue, and Green. The fourth channel is an Alpha channel which describes the opacity of the rings. A lot of careful work has gone into determining the exact color and opacity profile that Celestia uses.
It is the responsibility of Celestia's software to perform the calculations for the optical efffects: both for the reflected light and for the forward scattering that should result from that color and opacity information.
A lot of work also has gone into the algorithm which determines how the rings look on the "dark side," calculating the forward scattering of sunlight by the ring particles. Even so, some improvement is needed, as you've noticed. My understanding is that Chris Laurel, Celestia's primary author, has some thoughts about how it might be improved. However, if you are familiar with the optical effects that are involved, I'm sure he'd be glad for you to describe the improvements that might be made.
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As ElChristou mentions, the shadow cast by the planet on the rings also is calculated, but to see that shadow you need a graphics card which supports "vertex shading routines". A more thorough description of these effects is on the Web at
http://www.lepp.cornell.edu/~seb/celest ... s.html#3.5
Sorry, it's in English. One of the automatic translation sites might help a little.
http://www.google.com/language_tools
http://babelfish.altavista.com/
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This texture will be added for Celestia.