About 32 km in diameter (assuming an albedo of 0.04), Stephano is a small, dark moon which orbits Uranus in the opposite direction from the regular satellites and the planet's rotation (a retrograde orbit). Its orbital characteristics are similar to those of Caliban, suggesting a common origin.
Stephano was discovered on 18 July 1999 by Brett Gladman, Matthew Holman, John J. Kavelaars, 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 Setebos at the same time.
How Stephano Got its Name:
Originally called S/1999 U2, Stephano was named for a boisterous and often drunken butler of King Alonso in William Shakespeare's play, "The Tempest." He, Trincolo and Caliban plot to kill the island's ruler, Prospero, and Stephano plans to marry Prospero's daughter Miranda and rule the island himself. In his drunken state, he makes promises to Trincolo and Caliban which he cannot keep.
Moons of Uranus are named for characters in Shakespeare's plays and from Alexander Pope's "Rape of the Lock."