The Hubble Space Telescope group released an image last week that shows four of Saturn's moons in transit across the face, and rings, of Saturn. This is a fairly rare event, occurring only every fifteen years. This particular image was taken on February 24, 2009. Because the orbits of the larger Saturnian satellites are in the ring plane, or edge-on, it's an exceedingly spectacular event, and the Hubble team succeeded wildly in capturing it for us. </p.

I've linked to a small image of the moons in transit across the face of Saturn in this post; you can click it for a more detailed view, with annotations. You'll see, moving from the top, Saturn's largest moon, Titan (larger even than Mercury), looking faintly orange in color because Titan's nitrogen-rich atmosphere is tinted by the side effects of sunlight on methane and nitrogen. The very dark spot above Titan is actually Titan's shadow. That hard to see spot below Titan, slightly to the left is the moon Mimas. Smaller Saturnian moons that are closer to the planet are lined up along the rings. Further away on the left, off Saturn's disk is the tiny but bright moon Dione, and the much fainter moon Enceledus.

The moons other than Titan are very hard to spot; you'll have much better luck if you watch this annotated video first. Saturn has dozens of moons; only 52 of them have even been named.