Actually, the initial discovery of the ring system of Uranus was reported by Cornell University astronomer's J. Elliot, E. Dunham and D. Mink in the journal Nature , vol. 277, page 97 in 1979. They reported observing the occultation of a star, SAO 158687 by Uranus on MArch 10, 1977. By monitoring the brightness of the star as it was eclipsed by Uranus, they detected 5 'dips' in brightness. They used an infrared telescope on the Kuiper Airborne Observatory to detect the five rings, called Alpha, Beta, Gamma, Delta and Epsilon.
The above image was obtained by the Hubble Space telescope who note in their caption:
PHOTO RELEASE NO.: STScI-PRC94-50b RELEASE DATE: November 2, 1994
HUBBLE OBSERVES THE PLANET URANUS
This NASA Hubble Space Telescope image of the planet Uranus reveals the planet's rings and bright clouds and a high altitude haze above the planet's south pole.
Hubble's new view was obtained on August 14, 1994, when Uranus was 1.7 billion miles (2.8 billion kilometers) from Earth. These details, as imaged by the Wide Field Planetary Camera 2, were only previously seen by the Voyager 2 spacecraft, which flew by Uranus in 1986. Since then, none of these inner satellites has been further observed, and detailed observations of the rings have not been possible. Though Uranus' rings were discovered indirectly in 1977 (through stellar occultation observations), they have never before been seen in visible light through a ground-based telescope.
Hubble resolves several of Uranus' rings, including the outermost Epsilon ring. The planet has a total of 11 concentric rings of dark dust. Uranus is tipped such that its rotation axis lies in the plane of its orbit, so the rings appear nearly face-on.
Three of Uranus' inner moons each appear as a string of three dots at the bottom of the picture. This is because the picture is a composite of three images, taken about six minutes apart, and then combined to show the moons' orbital motions. The satellites are, from left to right, Cressida, Juliet, and Portia. The moons move much more rapidly than our own Moon does as it moves around the Earth, so they noticeably change position over only a few minutes.
Copyright 1997 Dr. Sten Odenwald
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