Some further progress on planetshine . . . Here's an image of Cassini during Saturn orbit insertion in 2004. The spacecraft is illuminated by both the Sun and Saturn--so close to Saturn, the illumination from the planet is very apparent.
This image represents a significant accomplishment: Cassini is defined in its ssc file with an orbit about the Sun. Celestia doesn't just assume that light is reflected between orbitally bound objects any more. I added some new code that does fairly complicated tests to determine what objects may potentially illuminate objects in view. As is frequently the case in Celestia, the complexity arises because of the need to do things very fast, in this case lighting.
With Cassini, secondary illumination can come from a number of different bodies:
- Earth at launch and during gravitational assists
- Venus during gravitational assists
- Saturn during orbit insertion
- Titan and other Saturnian moons during encounters
It's really neat to watch the orange glow of Titan appear on the spacecraft as it performs a flyby of the Moon.
--Chris