Getting back to Mars, just for a bit...
We all know NASA tamper the color of Mars images.
Doesn't mean you won't find a real gem, that shows what the sky might really look like on a Martian sunset:
Notice the hint of blue in there, where did that come from?
http://photojournal.jpl.nasa.gov/catalog/PIA07997
http://photojournal.jpl.nasa.gov/tiff/PIA07997.tif (Full-Res TIFF, 14 meg)