Japetus

Sunlight strikes the terminator (the boundary between day and night) Region on Saturn's moon Iapetus at nearly horizontal angles, making visible the vertical relief of many features.
This view is centered on terrain in the Southern Hemisphere of Iapetus. Lit terrain visible here is on the moon's Leading Hemisphere.
In this image, a large, central-peaked crater is notable at the boundary between the dark material in Cassini Regio and the brighter material on the Trailing Hemisphere.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 22, 2006, at a distance of approx. 1,3 MKM (such as about 800.000 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 67°. Resolution in the original image was 8 Km (about 5 miles) per pixel. The image has been magnified by a factor of two and contrast-enhanced to aid visibility.