After passing on the darkside of the planet, Mariner 10 photographed the other, somewhat more illuminated hemisphere of Mercury. The north pole is at the top, two-thirds down from which is the equator.
The Mariner 10 spacecraft was launched in 1974. The spacecraft took images of Venus in February 1974 on the way to three encounters with Mercury in March and September 1974 and March 1975. The spacecraft took more than 7,000 images of Mercury, Venus, the Earth and the Moon during its mission.
The Mariner 10 Mission was managed by the Jet Propulsion Laboratory for NASA's Office of Space Science in Washington, D.C.