Ellerman (crater)
Encyclopedia
Ellerman 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...

 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...

 on the far side of the Moon
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...

. It lies within the outer blanket of ejecta that surrounds the 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...

 impact basin, and is located to the west of the Montes Cordillera
Montes Cordillera
Montes Cordillera is a mountain range on the Moon. This feature forms the outer wall of peaks that surround the Mare Orientale impact basin, the inner ring being formed by the Montes Rook...

 mountain range. To the northwest of Ellerman is the larger crater Gerasimovich
Gerasimovich (crater)
Gerasimovich is a lunar crater on the far side of the Moon. It lies beyond the western limb, to the west-northwest of the immense Mare Orientale impact basin. The outer blanket of ejecta from this impact reaches nearly to the rim of Gerasimovich...

.

Probably due to its location amidst rugged surroundings, the otherwise circular rim of this crater is somewhat irregular and polygon
Polygon
In geometry a polygon is a flat shape consisting of straight lines that are joined to form a closed chain orcircuit.A polygon is traditionally a plane figure that is bounded by a closed path, composed of a finite sequence of straight line segments...

al in shape. The loose material along the inner walls has slid down to form a ring of talus
Scree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...

 around the base, leaving walls that slope straight down with no terraces. There is a small crater along the northern rim top.
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