Extremely unusual circumstances were required to get this shot of Enceladus floating in front of a field of stars. The Cassini spacecraft is flying in space, of course, and regularly captures images of star fields. It also regularly captures images of Enceladus. But Enceladus is so brightly reflective that, under normal circumstances, it is impossible to see both features on Enceladus' surface and a dense field of stars in the same image. To see Enceladus' surface, the camera team would select a short exposure setting; to see the stars, they would select a long exposure setting. This photo is possible because Enceladus was actually in Saturn's shadow when it was taken; the only light reaching its surface (and reflecting from there to Cassini's camera) is sunlight that has first been reflected off of Saturn or its rings. A long exposure revealed both Enceladus' surface and the background field of stars.

NASA / JPL / SSI