Messala is a

lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

impact crater of sufficient dimension to belong to the category of impact features known as walled plains. It is located in the northeastern part of the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, close enough to the rim to appear significantly foreshortened. Nearly attached to the northern rim is the crater

Schumacher Schumacher or Schuhmacher is an occupational surname (German, "shoemaker", pronounced , both variants can be used as surnames, with Schumacher being the more popular one, however, only the variant with three "h"s can also be used as a job descript ...

. To the southwest is the prominent crater Geminus, and due south is the smaller Bernoulli. The outer rim of this formation has received a significant amount of

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

due to minor impacts, but much of the outer wall retains its original shape and a certain degree of terracing. The rim is broken by smaller craters along the south, north, and northwest sides, designated Messala B, J, and K, respectively. Messala J has a narrow gouge in its eastern rim leading one crater diameter to the east. It is attached to a slightly larger crater which lies across the southern rim of Schumacher. The interior floor is relatively level but contains irregularities in the surface at some locations. There are several small craters across the floor, which are now little more than low rims and depressions in the surface. The most notable of these is a

ghost crater A palimpsest , in planetary astronomy, is an ancient crater that has been degraded over time. They may also be referred to as "ghost craters", "degraded craters", "buried craters", or "pathological craters". Palimpsests have been identified on ...

along the western inner wall.

Origin of name

The crater is named after Masha'allah ibn Atharī (c.740-d.815 AD), a Persian Jewish

astrologer Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Dif ...

and

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

from the city of

Basra Basra ( ar, ٱلْبَصْرَة, al-Baṣrah) is an Iraqi city located on the Shatt al-Arab. It had an estimated population of 1.4 million in 2018. Basra is also Iraq's main port, although it does not have deep water access, which is hand ...

(now located in modern-day

Iraq Iraq,; ku, عێراق, translit=Êraq officially the Republic of Iraq, '; ku, کۆماری عێراق, translit=Komarî Êraq is a country in Western Asia. It is bordered by Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq ...

) who was the leading astrologer of the late 8th century. Masha'allah was one of the most prominent members of the commission which decided for

Caliph A caliphate or khilāfah ( ar, خِلَافَة, ) is an institution or public office under the leadership of an Islamic steward with the title of caliph (; ar, خَلِيفَة , ), a person considered a political-religious successor to th ...

al-Mansur Abū Jaʿfar ʿAbd Allāh ibn Muḥammad al-Manṣūr (; ar, أبو جعفر عبد الله بن محمد المنصور‎; 95 AH – 158 AH/714 CE – 6 October 775 CE) usually known simply as by his laqab Al-Manṣūr (المنصور) w ...

(A.D. 754–775) that the propitious moment for the founding of

Baghdad Baghdad (; ar, بَغْدَاد , ) is the capital of Iraq and the second-largest city in the Arab world after Cairo. It is located on the Tigris near the ruins of the ancient city of Babylon and the Sassanid Persian capital of Ctesiphon ...

fell on 30 July 762.

Satellite craters

convention Convention may refer to: * Convention (norm), a custom or tradition, a standard of presentation or conduct ** Treaty, an agreement in international law * Convention (meeting), meeting of a (usually large) group of individuals and/or companies in a ...

these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Messala.

References

* * * * * * * * * * * * {{refend Impact craters on the Moon