Nicholson (lunar crater)
Encyclopedia
Nicholson is a lunar
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 located at the western limb. In this position it is subject to libration
Libration
In astronomy, libration is an oscillating motion of orbiting bodies relative to each other, notably including the motion of the Moon relative to Earth, or of Trojan asteroids relative to planets.-Lunar libration:...

, which can limit observation. The crater is also viewed at a very oblique angle, so it is seen from the side when observed from the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. It is an irregular, somewhat pear-shaped formation that has an uneven rim due to its location amidst rugged ground. The rim is sharp-edged and the inner wall varies in thickness, being narrower along the northern side and wider at the southern end. The interior floor is rough, small and uneven, with no impacts of significance. There is a small central ridge.

Nicholson is located in the Montes Rook
Montes Rook
Montes Rook is a ring-shaped mountain range that lies along the western limb of the Moon, crossing over to the far side. It completely encircles the Mare Orientale, and forms part of a massive impact basin feature...

, a ring-shaped mountain formation that encircles the immense Mare Orientale
Mare Orientale
Mare Orientale is one of the most striking large scale lunar features, resembling a target ring bull's-eye. Located on the extreme western edge of the lunar nearside, this impact basin is difficult to see from an Earthbound perspective.Material from this basin was not sampled by the Apollo program...

 feature. It lies to the northwest of Pettit
Pettit (lunar crater)
Pettit is a lunar impact crater that lies near the western limb of the Moon. In this location the crater is viewed nearly from the side by observers on Earth, and visibility can be significantly affected by libration effects....

.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK