UMBRIEL         

PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011 PHOTO CAPTION (TOP) P-29502 C U-2-21 1/25/86

This color photo of Umbriel, the darkest of Uranus' five large moons, was taken by Voyager 2 on Jan. 23, 1986. At the time, the spacecraft was 1.04 million kilometers (650,000 miles) from Umbriel and heading for a Jan. 24 closest approach. This picture, which has a resolution of 19 km (12 mi), was synthesized from frames exposed with the Voyager narrow-angle camera's violet and clear filters. Umbriel is characterized by the darkest surface and smallest brightness variations of any of the large satellites of Uranus. As seen here, the surface is also generally gray and colorless. Nevertheless, at this resolution, considerable topographic detail is revealed, showing that Umbriel's surface is covered by impact craters. The brightest spot (seen at top, near the equator at approvimately 270 degrees longitude) appears as a bright ring. Its geological significance is not yet understood. Umbriel has a diameter of about 1,200 km (750 mi) and orbits 267,000 km (166,000 mi) from Uranus' center. The satellite's name, from Alexander Pope's "Rape of the Lock," means "dark angel." The Voyager project is managed for NASA by the Jet Propulsion Laboratory.


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