Oberon is the outermost and second-largest major moon of the planet Uranus. It is the second-most massive of the Uranian moons, and the tenth-largest moon in the Solar System. Discovered by William He
Oberon, as imaged by Voyager 2, January 1986. A number of bright-rayed craters are visible, with the largest, Hamlet, at center. At the lower left limb rises an 11 km high mountain.