Iapetus
Jet Propulsion Laboratory https://www.jpl.nasa.gov/ May 25, 2000
This narrow-angle camera image of Saturn's mysterious satellite Iapetus was taken through the Clear filter from a distance of 2.5 million km on 15 November 1980. The dramatic brightness change between hemispheres is clearly seen here. Even with the bright side overexposed, the dark surface is still not visible. JPL managed the Voyager Project for NASA's Office of Space Science.