Uranus Rings and Two Moons
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Photograph
Uranus Rings and Two Moons
January 21, 1986
Gelatin silver print
Image: 19.4 x 21.6 cm
Overall: 20.2 x 25.6 cm
Gift of NASA and NASA Jet Propulsion Laboratory
Inscriptions verso (applied label, typed): 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-29466 B/W/ U-2-8/ 1/22/86/ Voyager 2 has discovered two "shepherd" satellites associated/ with the rings of Uranus. The two moons - designated/ 1986U7 and 1986U8 - are seen here on either side of the/ bright epsilon ring; all nine of the known Uranian rings are/ visible. The image was taken Jan. 21, 1986, at a distance of/ 4.1 million kilometers (2.5 million miles) and resolution of about 36 km (22 mi). The image was processed to enhance/ narrow features. The epsilon ring appears surrounded by a/ dark halo as a result of this processing; occasional blips/ seen on the ring are also artifacts. Lying inward from the/ epsilon ring are the delta, gamma and eta rings; then the/ beta and alpha rings; and finally the barely visible 4, 5 and/ 6 rings. The rings have been studied since their discovery/ in 1977, through observations of how they diminish the light/ of stars they pass in front of. This image is the first/ direct observation of all nine rings in reflected sunlight./ They range in width from about 100 km (60 mi) at the widest/ part of the epsilon ring to only a few kilometers for most/ of the others. The discovery of the two ring moons 1986U7 and/ 1986U8 is a major advance in our understanding of the/ structure of the Uranian rings and is in good agreement with/ theoretical predictions of how these narrow rings are kept/ from spreading out. Based on likely surface brightness/ properties, the moons are of roughly 20- and 30-km/ diameter, respectively. The Voyager project is managed for NASA by the/ Jet Propulsion Laboratory./ #####
