Moon of Uranus Diameter: 1169 km Distance: 265970 km (mean) Period: 4.144 days Eccentricity: 0.004 Inclination: 0.13° Magnitude: 14.5
Discovered in 1851, Umbriel is the darkest of Uranus' largest moons. There is a curious bright ring about 140 km in diameter on the moon's dark surface. Umbriel's numerous craters measure up to 210km across. Most of the moon consists of water ice, while the surface is slightly blue in color. Near Umbriel's equator lies the most prominent surface feature, the Wunda crater, about131 km across.