Discovery of Setebos

Setebos is a small irregular moon of Uranus, found by a team led by Brett Gladman with a large ground-based telescope. It moves around Uranus on a distant retrograde orbit, opposite to the planet's rotation, indicating that it was captured long ago rather than forming with the planet. It is one of a handful of faint outer moons, along with Prospero and Stephano, that were detected in the same search. Its name comes from Setebos, the god worshipped by the witch Sycorax in Shakespeare's The Tempest, in keeping with the tradition of naming Uranus's moons after literary characters. Like its neighbours, it can be observed only with very large telescopes.

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