The Helmet is an informal term for a highland mass within southern Oceanus Procellarum on the near side of the Moon, southeast of the crater Herigonius. The astronauts of Apollo 16 used the term to refer to the feature during the mission. [1] The name derives from the roughly semicircular shape of the border of the feature, resembling a helmet. The feature is topographically higher and of a higher albedo than the surrounding mare lava plain.
Two mountains within The Helmet are informally named Herigonius Eta (η) and Herigonius Pi (π). Eta is the larger mountain on the northern edge of the Helmet, and Pi is along the southwest edge.
The selenographic coordinates of this feature are 16.8° S, 31.6° W.
Mare Tranquillitatis is a lunar mare that sits within the Tranquillitatis basin on the Moon. It is the first location on another celestial body to be visited by humans.
Mare Marginis ; MAR-jin-iss) is a lunar mare that lies on the very edge of the lunar nearside. The selenographic coordinates of this feature are 13.3° N, 86.1° E, and the diameter is 358 km.
Mare Serenitatis is a lunar mare located to the east of Mare Imbrium on the Moon. Its diameter is 674 km (419 mi).
Eugene Andrew Cernan was an American astronaut, naval aviator, electrical engineer, aeronautical engineer, and fighter pilot. During the Apollo 17 mission, Cernan became the 11th human being to walk on the Moon. As he re-entered the Apollo Lunar Module after Harrison Schmitt on their third and final lunar excursion, he remains the most recent person to walk on the Moon.
Alphonsus is an ancient impact crater on the Moon that dates from the pre-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. To the southwest is the smaller Alpetragius. The crater name was approved by the IAU in 1935.
Copernicus is a lunar impact crater located in eastern Oceanus Procellarum. It was named after the astronomer Nicolaus Copernicus. It typifies craters that formed during the Copernican period in that it has a prominent ray system. It may have been created by debris from the breakup of the parent body of asteroid 495 Eulalia 800 million years ago.
Rille is typically used to describe any of the long, narrow depressions in the surface of the Moon that resemble channels. The Latin term is rima, plural rimae. Typically, a rille can be several kilometers wide and hundreds of kilometers in length. However, the term has also been used loosely to describe similar structures on a number of planets in the Solar System, including Mars, Venus, and on a number of moons. All bear a structural resemblance to each other.
Aristoteles is a lunar impact crater that lies near the southern edge of the Mare Frigoris and to the east of the Montes Alpes mountain range. It was officially named in 1935 after the ancient Greek philosopher Aristotle by the International Astronomical Union, using the classical form of his name.
Dawes is a lunar impact crater located in the wide straight between Mare Serenitatis and Mare Tranquilitatis. To its southwest lies the larger crater Plinius, and to its northeast sits the Mons Argaeus mountain rise. It is named after British astronomer William Rutter Dawes.
Euclides is a small lunar impact crater located near the eastern edge of Oceanus Procellarum, about 30 kilometers to the west of the Montes Riphaeus mountains. The mare in the vicinity is devoid of significant craters, but to the west is an area of low rises. The crater is named after the Greek mathematician Euclid.
Sulpicius Gallus is a small, bowl-shaped lunar impact crater that lies near the southwestern edge of the Mare Serenitatis. The crater is named after the 2nd century BC Roman astronomer Gaius Sulpicius Gallus.
Vitruvius is a small lunar impact crater that lies on the northern edge of the Mare Tranquillitatis. To the east is the crater Gardner, and to the northeast is Fabbroni. To the north-northwest is the elongated Mons Vitruvius mountain, and beyond is the valley where the Apollo 17 mission landed.
Davy is a small lunar impact crater that is located on the eastern edge of the Mare Nubium. It was named after British physicist Humphry Davy. It overlies the lava-flooded remains of the satellite crater Davy Y to the east, a formation which contains a crater chain designated Catena Davy. To the southeast of Davy is the prominent crater Alphonsus.
Bowditch is a lunar impact crater that lies on the far side of the Moon, just beyond the eastern limb. It is located on a region of the lunar surface that is brought into view due to libration, but at such times the area is viewed from the edge and so not much detail can be observed. It lies just to the north of the small Lacus Solitudinis lunar mare, between the craters Titius to the southwest and Perel'man to the east-northeast.
Herigonius is a small lunar impact crater that is located in the southern part of the Oceanus Procellarum, to the northeast of the crater Gassendi. It was named after French mathematician and astronomer Pierre Hérigone. Herigonius is roughly circular, with an inward bulge and narrower inner wall along the northeast. In the interior of the sloping inner walls is a floor about half the diameter of the crater.
Necho is a lunar impact crater on the far side of the Moon, and therefore cannot be seen directly from the Earth. It lies to the northeast of the larger crater Langemak, about a crater diameter to the south-southwest of Bečvář and further east is Love.
In astronomy and spaceflight, a lunar orbit is an orbit of an object around Earth's Moon. In general these orbits are not circular. When farthest from the Moon a spacecraft is said to be at apolune, apocynthion, or aposelene. When closest to the Moon it is said to be at perilune, pericynthion, or periselene. These derive from names or epithets of the moon goddess.
Montes Apenninus are a rugged mountain range on the northern part of the Moon's near side. They are named after the Apennine Mountains in Italy. With their formation dating back about 3.9 billion years, Montes Apenninus are fairly old.
Hadley–Apennine is a region on the near side of Earth's Moon that served as the landing site for the American Apollo 15 mission, the fourth crewed landing on the Moon and the first of the "J-missions", in July 1971. The site is located on the eastern edge of Mare Imbrium on a lava plain known as Palus Putredinis. Hadley–Apennine is bordered by the Montes Apenninus, a mountain range, and Hadley Rille, a meandering channel, on the east and west, respectively.
Rimae Secchi is a system of rilles on the Moon, in northwestern Mare Fecunditatis. They are approximately 40 km long and run along the shore of the mare.