Astronomy Picture of the Week – Crescent Neptune and Triton

This is a photo of a crescent Neptune and its largest moon Triton taken by the Voyager 2 probe in 1989. It is unique because such a picture could not be taken from Earth since Neptune never shows a crescent phase to sunward Earth.

Crescent Neptune and Triton taken by Voyager 2

Image Credit: NASA, Voyager 2 mission.