About 50,000 Clementine images were processed to produce the four orthographic views of the Moon. The images show albedo variations (normalized brightness or reflectivity) of the surface at a wavelength of 750 nm (just longward of visible red). The image projection is centered at 0 degree latitude and 180 degrees longitude. Mare Moscoviense (dark albedo feature upper left of image center) and South Pole-Aitken Basin (dark feature at bottom) represent maria regions largely absent on the lunar farside. The Clementine altimeter showed Aitken Basin to consist of a topographic rim about 2500 km in diameter, an inner shelf ranging from 400 to 600 km in width, and an irregular depressed floor about 12 km in depth.
http://photojournal.jpl.nasa.gov/catalog/PIA00304