Arzachel (crater)
Encyclopedia
Arzachel is a relatively young lunar
impact crater
located in the highlands in the south-central part of the visible Moon
, close to the zero meridian (the visible center of the Moon). It lies to the south of the crater Alphonsus
, and together with Ptolemaeus
further north the three form a prominent line of craters to the east of Mare Nubium
. The smaller Alpetragius
lies to the northwest, and Thebit
is to the southwest along the edge of the mare
.
It is remarkably clear in its structure and a favorite telescope
viewing subject for advanced amateur astronomer
s. The rim of Arzachel shows little sign of wear and has a detailed terrace structure on the interior, especially on the slightly higher eastern rim. There is a rough outer rampart that joins a ridge running from the north rim to southern rim of Alphonsus.
The rugged central peak of Arzachel is prominent, rising 1.5 kilometers above the floor, and is somewhat offset to the west with a bowed curve from south to north-northeast. The floor is relatively flat, except for some irregularities in the southwestern quadrant of the crater. There is a rille system
named the Rimae Arzachel that runs from the northern wall to the southeast rim. A small crater lies prominently in the floor to the east of the central peak, with a pair of smaller craterlets located nearby.
This crater was named after Abū Ishāq Ibrāhīm al-Zarqālī, Arab astronomer
and mathematician
whose name was Latinized as Arzachel.
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 in the highlands in the south-central part of the visible 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...
, close to the zero meridian (the visible center of the Moon). It lies to the south of the crater Alphonsus
Alphonsus (crater)
Alphonsus is an ancient impact crater on the Moon that dates from the immediate post-Nectarian era. It is located on the lunar highlands on the eastern end of Mare Nubium, west of the Imbrian Highlands, and slightly overlaps the crater Ptolemaeus to the north. The surface is broken and irregular...
, and together with Ptolemaeus
Ptolemaeus (lunar crater)
Ptolemaeus is an ancient lunar impact crater close to the center of the near side. To the south-southeast Ptolemaeus is joined to the rim of the crater Alphonsus by a section of rugged, irregular terrain, and these form a prominent chain with Arzachel to the south...
further north the three form a prominent line of craters to the east of Mare Nubium
Mare Nubium
Mare Nubium is a lunar mare in the Nubium basin on the Moon's near side. The mare is located just to the southeast of Oceanus Procellarum. The actual basin is believed to be of Pre-Nectarian system, with the surrounding basin material being of the Lower Imbrian epoch. The mare material is of the...
. The smaller Alpetragius
Alpetragius (crater)
Alpetragius is a lunar impact crater located on the eastern edge of Mare Nubium, to the southwest of the much larger crater Alphonsus. In the southeast is the prominent crater Arzachel, and to the west lies the flooded Lassell....
lies to the northwest, and Thebit
Thebit (crater)
Thebit is a lunar impact crater located on the southeast shore of Mare Nubium. To the north-northwest is the crater Arzachel, and Purbach lies to the south-southwest. To the southwest is the flooded remnants of Thebit P, which is actually larger in diameter than Thebit itself.The rim of Thebit is...
is to the southwest along 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...
.
It is remarkably clear in its structure and a favorite telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
viewing subject for advanced amateur 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...
s. The rim of Arzachel shows little sign of wear and has a detailed terrace structure on the interior, especially on the slightly higher eastern rim. There is a rough outer rampart that joins a ridge running from the north rim to southern rim of Alphonsus.
The rugged central peak of Arzachel is prominent, rising 1.5 kilometers above the floor, and is somewhat offset to the west with a bowed curve from south to north-northeast. The floor is relatively flat, except for some irregularities in the southwestern quadrant of the crater. There is a rille system
Rille
Rille is typically used to describe any of the long, narrow depressions in the lunar surface that resemble channels. Typically a rille can be up to several kilometers wide and hundreds of kilometers in length...
named the Rimae Arzachel that runs from the northern wall to the southeast rim. A small crater lies prominently in the floor to the east of the central peak, with a pair of smaller craterlets located nearby.
This crater was named after Abū Ishāq Ibrāhīm al-Zarqālī, Arab 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...
and mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
whose name was Latinized as Arzachel.
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 Arzachel.| Arzachel | Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 18.0° S | 1.5° W | 10 km |
| B | 17.0° S | 2.9° W | 8 km |
| C | 17.4° S | 3.7° W | 6 km |
| D | 20.2° S | 2.1° W | 8 km |
| H | 18.7° S | 2.0° W | 5 km |
| K | 18.3° S | 1.6° W | 4 km |
| L | 20.0° S | 0.1° E | 8 km |
| M | 20.6° S | 0.9° W | 3 km |
| N | 20.4° S | 2.2° W | 3 km |
| T | 17.7° S | 1.3° W | 3 km |
| Y | 18.2° S | 4.3° W | 4 km |