Update, October 24, 4:33 p.m.: Here’s what Hubble saw:
Update, October 20, 5:19 p.m.: Good, the pictures are starting to come out!
The Mars Reconnaissance Orbiter got some close shots – not visually dramatic in these Rosetta days, but per the text, very informative.
Comet Siding Spring will pass close to Mars, and NASA will move its orbiters over to the other side of the planet during the 22-minute period of greatest risk from comet dust in the tail. I don’t know what the Indian Space Research Organization plans to do for its Mars Orbiter (Mangalyaan). Here’s a video from NASA about the encounter: