Full-Res GIF (193 kB)
Compare these images of the Uranian ring system. Voyager 2 acquired the upper one the day before it passed Uranus in January 1986; at the time sunlight striking the ring particles was reflected back toward the camera. Computer enhancement makes the rings appear much brighter than they really are. (To see the faint lambda ring, put your eye close to the page bottom and look toward the arrow.) In the lower image, taken somewhat later, Voyager 2 was looking almost directly back toward the Sun’s direction (the phase angle is 172.5 deg). This backlighting of the rings dramatically enhanced the visibility of any micron-size dust particles they contain. Voyager 2’s motion during the exposure caused some smearing of the detail, especially near the bottom edge. The nine rings discovered from Earth can be discerned with relative ease (note the poor segment match for the markedly eccentric epsilon ring). However, many other ringlets visible here do not correspond to known features in the system.
Figure 16-14 of Burns, J. A. 1998. Planetary Rings. In The New Solar System, 4th Edition_ (J. K. Beatty, C. C. Peters, and A. Chaikin, Eds.), Cambridge University Press. Used by permission.