ARC-1985-A86-7001

Range: 72.3 million km. ( 44.9 million miles ) P-29314B/W This Voyager 2 photograph of Uranus shows the planets outermost, or epsilon, ring. This is a computerized summation of six images shot by the narrow angle camera. It is the first photo to show the epsilon ring unblurred by Earth's atmosphere. The Epsilon ring, some 51,200 km. ( 31,800 miles ) from the planets center, is the most prominent of Uranus' nine known rings. Ground based observations of stellar occulations by the rings have determined that the Epsilon ring is eccentric, or elliptical, with its widest portion about 100 km. ( 60 miles ) wide and its narrowest portion about 20 km. (12 miles ). Estimates of the rings brightness suggest that it is also very dark, with a reflectance of only 1 or 2 percent and a probable composition of carbonaceous material similiar to that on dark asteroids and the dark side of Saturn's moon Lapetus. Because the ring is so narrow and dark, at this range, the Voyager camera could not resolve even the widest part, resulting in long exposure times so obtain a good image. six exposures of 11 or 15 second duration were added together by computer to produce this image. In this image, the central portion is greatly overexposed. Various artifacts due to electronic effects and image proccessing can be seen in the central portion of the frame, including the dark image just above the planets image, the diffuse brightening below it and the small, bright projection from the edge of the planet in the upper left. The ring is distinctly less prominent in the lower left portion and more prominent in the upper right. This is in agreement with the predicted locations of the narrow and wide portions of the ring, respectively.