Another great shot from the soon to be gone Hubble Space Telescope: a Transit of Saturn by its four largest moons. From left to right Enceladus and her shadow, Dione and her shadow, Titan,by far the largest moon in the Solar system. It is even large than Luna, and over just at the edge of the planet Mimas. We can see these because of the angle of the rings. Taken from APOD.