Focas (lunar crater)
Encyclopedia
Focas is a small lunar
impact crater
that lies on the far side of the Moon
, just past the southwestern limb. In this location the crater is occasionally brought into view due to libration
, but not much detail can be seen because the crater is viewed from the side.
The crater is situated in the wide valley between the ring-shaped Montes Rook
in the north and Montes Cordillera
range in the south. These ranges form a double-ring around the Mare Orientale
impact basin. The crater is located toward the southern end of this immense feature, just to the north of the Montes Cordillera range. Focas is a relatively isolated crater, with the nearest craters of note being the Wright
–Shaler
crater pair some distance to the east along the same interior edge of the Montes Cordillera.
This is a circular crater with an interior floor about half the total diameter. It is symmetrical in form, with only some slight appearance of wear along the rim. The interior floor contains no features or impacts of note.
Focas Crater is named after Jean-Henri Focas
(1909-1969), a Greco-French astronomer
.
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...
that lies 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...
, just past the southwestern limb. In this location the crater is occasionally brought into view due 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:...
, but not much detail can be seen because the crater is viewed from the side.
The crater is situated in the wide valley between the ring-shaped 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...
in the north and 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...
range in the south. These ranges form a double-ring around 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. The crater is located toward the southern end of this immense feature, just to the north of the Montes Cordillera range. Focas is a relatively isolated crater, with the nearest craters of note being the Wright
Wright (lunar crater)
Wright is a lunar impact crater that is located near the western limb of the Moon. It lies on the irregular plain between the Montes Cordillera and Montes Rook, two ring-shaped mountain ranges that surround the Mare Orientale. To the north of Wright is the crater Pettit.The outer rim of Wright is...
–Shaler
Shaler (crater)
Shaler is a lunar impact crater that lies on the southeast interior edge of the Montes Cordillera mountain ring that surrounds the immense Mare Orientale formation. It is located near the southwest limb of the Moon on the near side, and so is viewed nearly from on edge from the Earth...
crater pair some distance to the east along the same interior edge of the Montes Cordillera.
This is a circular crater with an interior floor about half the total diameter. It is symmetrical in form, with only some slight appearance of wear along the rim. The interior floor contains no features or impacts of note.
Focas Crater is named after Jean-Henri Focas
Jean Focas
Jean-Henri Focas was a Greco-French astronomer. In Greek he was known as Ioannis Focas. He worked at the Pic du Midi Observatory, investigating the surface features of Mars using visual and photographic techniques. The lunar crater Focas and a crater on Mars were named after him....
(1909-1969), a Greco-French astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
.
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Focas.| Focas | Latitude | Longitude | Diameter |
|---|---|---|---|
| U | 32.7° S | 98.5° W | 10 km |