Bailly 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 An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...

that is located near the south-west limb of the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. It was named after French astronomer Jean S. Bailly. The oblique viewing angle gives the crater a foreshortened appearance, and the location near the limb can limit visibility due to

libration In lunar astronomy, libration is the cyclic variation in the apparent position of the Moon that is perceived by observers on the Earth and caused by changes between the orbital and rotational planes of the moon. It causes an observer to see ...

. The most favorable time for viewing this feature is near the full moon when the terminator is crossing the crater wall.

Description

This is the largest crater on the near side of the Moon. In area it is comparable in size to a small

mare A mare is an adult female horse or other equidae, equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more th ...

. It lies north of the crater

Le Gentil Guillaume Joseph Hyacinthe Jean-Baptiste Le Gentil de la Galaisière (, 11 or 12 September 1725 – 22 October 1792) was a French astronomer who discovered several nebulae and was appointed to the Royal Academy of Sciences. He wrote on the est ...

and east of Hausen. Further west of Bailly are the (unofficially named) Montes Dörfel mountains. Bailly's uneven crater floor has remained free of

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

flooding, and it is covered with a multitude of ridges and craters. The entire crater has been battered and worn, and the outer

rampart Rampart may refer to: * Rampart (fortification), a defensive wall or bank around a castle, fort or settlement Rampart may also refer to: * LAPD Rampart Division, a division of the Los Angeles Police Department ** Rampart scandal, a blanket ter ...

s are eroded and in some places have even been worn away by myriad impacts. If the crater ever possessed a central peak, it is no longer discernible. Due to its current condition, observers have termed this feature a 'field of ruins'. Due to the size and the worn state of this crater, it is estimated to be more than 3 billion years old, and is part of the Nectarian system.

Satellite craters

The south-eastern part of the crater is home to two notable craters, designated Bailly A and Bailly B. These craters overlap, and Bailly A lies across the rim of Bailly's mountainous wall.

Selenographer Selenography is the study of the surface and physical features of the Moon (also known as geography of the Moon, or selenodesy). Like geography and areography, selenography is a subdiscipline within the field of planetary science. Historically, ...

Giovanni Battista Riccioli Giovanni Battista Riccioli (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion of ...

named Bailly B, ''Bartolus'' for fellow Ferrarese Jesuit

Daniello Bartoli Daniello Bartoli (; 12 February 160813 January 1685) was an Italian Jesuit writer and historiographer, celebrated by the poet Giacomo Leopardi as the "Dante of Italian prose" Ferrara He was born in Ferrara. His father, Tiburzio was a chemist as ...

(1608-1685) in his Almagestum novum (1651). Ewen A. Whitaker: ''Mapping and Naming the Moon, a history of lunar cartography and nomenclature'', page 211. The name was not recognized by the

IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

References

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External links

* {{Craters on the Moon: A–B Impact craters on the Moon Nectarian