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Proclus (crater)
Encyclopedia
Proclus is a young lunar
impact crater
located to the west of the Mare Crisium
, on the east shore of the Palus Somni
. It lies to the south of the prominent, terraced crater Macrobius
, and west-northwest of the lava-flooded Yerkes
. Between Proclus and Yerkes, on the edge of the mare
, are the Promontories named Olivium and Lavinium.
The rim of Proclus is distinctly polygon
al in shape, having the shape of a pentagon
, and does not rise very far above the surrounding terrain. It has a high albedo
, being second only to Aristarchus
in brightness. The interior wall displays some slumping, and the floor is uneven with a few small rises from slump blocks.
The crater has a notable ray system
that extends for a distance of over 600 kilometers. The rays display an asymmetry of form, with the most prominent being rays to the northwest, north-northeast, and northeast. There is an arc with no ejecta to the southwest. These features suggest an oblique impact at a low angle.
The following craters have been renamed by the IAU
.
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 to the west of the Mare Crisium
Mare Crisium
Mare Crisium is a lunar mare located in the Moon's Crisium basin, just northeast of Mare Tranquillitatis. This basin is of the Pre-Imbrian period, 4.55 to 3.85 billion years ago. This mare is in diameter, and 176,000 km2 in area. It has a very flat floor, with a ring of wrinkled ridges...
, on the east shore of the Palus Somni
Palus Somni
Palus Somni is an area on the Moon of relatively level but somewhat uneven terrain that lies along the northeastern edge of Mare Tranquillitatis and the Sinus Concordiae. It has selenographic coordinates 14.1° N, 45.0° E, and has a diameter of 143 km.The surface of this feature has low ridges and...
. It lies to the south of the prominent, terraced crater Macrobius
Macrobius (crater)
Macrobius is a prominent lunar impact crater located to the northwest of the Mare Crisium. It lies on the southeast edge of the Lacus Bonitatis, a small lunar mare. The somewhat smaller crater Tisserand lies just to the east....
, and west-northwest of the lava-flooded Yerkes
Yerkes (crater)
Yerkes is a lunar crater near the western edge of Mare Crisium. In the past the interior of this crater has been almost completely inundated by lava, leaving only a shallow remnant of a rim above the mare. The rim is widest on the western and southern portions, and barely existent to the east,...
. Between Proclus and Yerkes, on the edge of the mare
Lunar mare
The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...
, are the Promontories named Olivium and Lavinium.
The rim of Proclus is distinctly 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, having the shape of a pentagon
Pentagon
In geometry, a pentagon is any five-sided polygon. A pentagon may be simple or self-intersecting. The sum of the internal angles in a simple pentagon is 540°. A pentagram is an example of a self-intersecting pentagon.- Regular pentagons :In a regular pentagon, all sides are equal in length and...
, and does not rise very far above the surrounding terrain. It has a high albedo
Albedo
Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...
, being second only to Aristarchus
Aristarchus (crater)
Aristarchus is a prominent lunar impact crater that lies in the northwest part of the Moon's near side. It is considered the brightest of the large formations on the lunar surface, with an albedo nearly double that of most lunar features. The feature is bright enough to be visible to the naked eye,...
in brightness. The interior wall displays some slumping, and the floor is uneven with a few small rises from slump blocks.
The crater has a notable ray system
Ray system
A ray system comprises radial streaks of fine ejecta thrown out during the formation of an impact crater, looking a bit like many thin spokes coming from the hub of a wheel. The rays can extend for lengths up to several times the diameter of their originating crater, and are often accompanied by...
that extends for a distance of over 600 kilometers. The rays display an asymmetry of form, with the most prominent being rays to the northwest, north-northeast, and northeast. There is an arc with no ejecta to the southwest. These features suggest an oblique impact at a low angle.
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 Proclus.| Proclus | Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 13.4° N | 42.3° E | 15 km |
| C | 12.9° N | 43.6° E | 10 km |
| D | 17.5° N | 41.0° E | 13 km |
| E | 16.6° N | 40.9° E | 12 km |
| G | 12.7° N | 42.7° E | 33 km |
| J | 17.1° N | 44.0° E | 6 km |
| K | 16.5° N | 46.2° E | 16 km |
| L | 17.1° N | 46.4° E | 9 km |
| M | 16.4° N | 45.2° E | 8 km |
| P | 15.3° N | 48.7° E | 30 km |
| R | 15.8° N | 45.5° E | 28 km |
| S | 15.7° N | 47.9° E | 18 km |
| T | 15.4° N | 46.7° E | 21 km |
| U | 15.2° N | 48.0° E | 13 km |
| V | 14.8° N | 48.3° E | 19 km |
| W | 17.5° N | 46.2° E | 7 km |
| X | 17.7° N | 45.1° E | 6 km |
| Y | 17.5° N | 44.9° E | 8 km |
| Z | 17.9° N | 44.7° E | 6 km |
The following craters have been renamed by the IAU
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
.
- Proclus F — See Crile (crater)Crile (crater)Crile is a tiny lunar crater. It is roughly circular and cup-shaped, with interior walls that slope down to the mid-point. The crater lies in the Palus Somni, between the Mare Crisium to the east and Mare Tranquillitatis to the west....
.
External links
- Apollo 17 image AS17-150-23047 using the 70 mm Hasselblad.