Setebos was discovered on July 18, 1999 by John J. Kavelaars, Brett Gladman, Matthew Holman, Jean-Marc Petit, and Hans Scholl Using the Canada-France-Hawaii Telescope at the Mauna Kea Observatory on the island of Hawaii. They discovered Prospero and Stephano at the same time.
Setebos is a small, dark moon. It is about 30 miles (48 km) in diameter, assuming an albedo of 0.04). The small moon orbits Uranus in the opposite direction from the regular moons and the planet's rotation (known as a retrograde orbit). It is one of the farthest moons from Uranus, orbiting its home planet at a distance of more than 11 million miles (17 million kilometers). Its orbital characteristics are similar to those of Prospero and Sycorax, suggesting a common origin. But its gray color differs from the light red of Sycorax.
How Setebos Got its Name
Originally called S/1999 U1, Setebos was the name of a South American (Patagonian) deity, which William Shakespeare used as the god worshipped by Sycorax the witch and her son Caliban in the play, "The Tempest."