Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 November 23 Credit: NASA, Lunar Orbiter 4 Explanation: Like a target ring bull's-eye, the Mare Orientale is one of the most striking large scale lunar features. Located on the Moon's extreme western edge, this impact basin is unfortunately difficult to see from an earthbound perspective. It is over 3 billion years old, about 600 miles across and was formed by the impact of an asteroid sized object....