Phoebe

I did hours of detective work recently, trying to find which little smudge on my processed images corresponded to Saturn's outer moon Phoebe. Both my sky chart programs were completely wrong with its position and I had to follow-up with some more images 3 days later. It's a rather lovely name for a very porous, dim, reddish rock that orbits in a 550 day retrograde orbit. She spins in 9 hours, so is not tidally locked like the other moons (and our own), leading astronomers to think it could be a captured asteroid. I'm amazed it was detected in 1898; it's only 16.45 magnitude! Take a look at the hi-res Cassini pictures to see how unbelievably full of holes it is. It was a case of taking 4 x 15 second exposures for each area around Saturn and stacking them to reduce noise. Here is the labelled version of the Tuesday night (Weds morning) when more moons were visible. The planet is rather overexposed (if you were wondering where the rings are).