Deslandres (crater)
Encyclopedia
Deslandres is the heavily worn and distorted remains of a lunar
impact crater
. It is located to the southeast of the Mare Nubium
, in the rugged southern highlands of the Moon. In dimension it is the second-largest crater formation on the visible Moon, being beaten only by the 303-kilometer-diameter walled plain Bailly
. The northern and eastern parts of the floor display a relatively level surface, but it is pock-marked with numerous craters. There is a small region of mare material, due to basalt
ic lava
, along the eastern interior floor.
The crater Walther
is attached to the remnant of the eastern rim, and Ball
intrudes into the southwestern rim. The crater remnant Lexell
has broken across the southeastern rim, forming a "harbor" in the crater floor due to the wide gap in its northern rim. The irregular crater Regiomontanus
is attached to the northeast rim of Deslandres. The crater Hell
lies entirely within the western rim.
The satellite crater Hell Q lies at the center of a patch of higher albedo
surface located in the eastern half of Deslandres. Around the time of the full moon
this feature is one of the brightest spots on the lunar surface. The light hue indicates a relatively youthful feature in lunar geological terms. This patch is sometimes referred to as "Cassini's bright spot", as it was first mapped by Cassini
in 1672 at the Paris Observatory
.
This feature is so heavily eroded and degraded by overlapping impacts that it was not actually recognized as a crater formation until the 20th century. The name for this formation was suggested by Eugène M. Antoniadi in 1942, and was passed during the general assembly of the IAU
in 1948.
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...
. It is located to the southeast of the 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...
, in the rugged southern highlands of the Moon. In dimension it is the second-largest crater formation on the visible Moon, being beaten only by the 303-kilometer-diameter walled plain Bailly
Bailly (crater)
Bailly is a lunar impact crater that is located near the south-west limb of the Moon. The oblique viewing angle gives the crater a foreshortened appearance, and the location near the limb can limit visibility due to libration...
. The northern and eastern parts of the floor display a relatively level surface, but it is pock-marked with numerous craters. There is a small region of mare material, due to basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
ic lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
, along the eastern interior floor.
The crater Walther
Walther (crater)
Walther is an ancient lunar impact crater located in the southern highland region of the Moon. It is joined along the western rim to the crater Deslandres...
is attached to the remnant of the eastern rim, and Ball
Ball (crater)
Ball is a lunar impact crater that is located in the rugged southern highlands of the Moon. The formation is circular and symmetrical, and has receive little significant wear. The interior is rough-surfaced, curving downward toward the relatively wide central peak at the mid-point.The crater is...
intrudes into the southwestern rim. The crater remnant Lexell
Lexell (crater)
Lexell is a lunar crater that lies across the southeastern rim of the huge walled plain Deslandres, in the southern part of the Moon. To the northeast is the walled plain Walther, and to the south is Orontius, another walled plain....
has broken across the southeastern rim, forming a "harbor" in the crater floor due to the wide gap in its northern rim. The irregular crater Regiomontanus
Regiomontanus (crater)
Regiomontanus is an ancient lunar impact crater located in the southern highlands region to the southeast of Mare Nubium. It is joined at the chaotic northern rim by the crater Purbach, and to the south-southeast is Walther....
is attached to the northeast rim of Deslandres. The crater Hell
Hell (crater)
Hell is a lunar crater in the south of the Moon's near side, within the western half of the enormous walled plain Deslandres. To the southeast, also within Deslandres, is the larger crater Lexell, and about 9° to the south lies the prominent Tycho crater. The crater received its name in 1935 after...
lies entirely within the western rim.
The satellite crater Hell Q lies at the center of a patch of higher 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...
surface located in the eastern half of Deslandres. Around the time of the full moon
Full moon
Full moon lunar phase that occurs when the Moon is on the opposite side of the Earth from the Sun. More precisely, a full moon occurs when the geocentric apparent longitudes of the Sun and Moon differ by 180 degrees; the Moon is then in opposition with the Sun.Lunar eclipses can only occur at...
this feature is one of the brightest spots on the lunar surface. The light hue indicates a relatively youthful feature in lunar geological terms. This patch is sometimes referred to as "Cassini's bright spot", as it was first mapped by Cassini
Giovanni Domenico Cassini
This article is about the Italian-born astronomer. For his French-born great-grandson, see Jean-Dominique Cassini.Giovanni Domenico Cassini was an Italian/French mathematician, astronomer, engineer, and astrologer...
in 1672 at the Paris Observatory
Paris Observatory
The Paris Observatory is the foremost astronomical observatory of France, and one of the largest astronomical centres in the world...
.
This feature is so heavily eroded and degraded by overlapping impacts that it was not actually recognized as a crater formation until the 20th century. The name for this formation was suggested by Eugène M. Antoniadi in 1942, and was passed during the general assembly of 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...
in 1948.