Iapetus

A large circular feature about 200 kilometers (120 miles) across with a dark spot in its center is visible in this photograph of Saturn's satellite Iapetus taken Nov. 12, 1980 from a distance of 3.2 million kilometers (1.9 million miles). The satellite's leading hemisphere is to the left, and the trailing hemisphere, which is about four to five times brighter, is to the right. The large circular feature is most probably a large impact structure outlined by dark material, possibly thrown out by the impact. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.