Astronomy Picture of the Day

Explanation: This dramatic image of the Moon's edge against a background of distant stars is from a perspective impossible for groundbased telescopes. It was taken by a star tracker camera onboard the Clementine spacecraft. The Solar Corona, the Sun's outer atmosphere, is visible shining brightly behind the lunar limb while the Moon's surface is illuminated by Earthshine, sunlight reflected from the Earth to the Moon. As pictured, the part of the Moon in shadow is the lunar farside, the side not visible from Earth. The highly successful unmanned Clementine probe explored the Moon from lunar orbit during March and April of 1994. Its star tracker cameras were normally used for celestial navigation, producing wide angle images showing relative positions of stars.