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Ptolemaeus is an ancient
The features of Ptolemaeus are highlighted when the Sun is at low angles during the first and last quarter. At full Moon the Sun is directly overhead and the crater contours become more difficult to discern.
The crater has a low, irregular outer rim that is heavily worn and impacted with multiple smaller craters. The rim has a discernibly
The following crater has been renamed by the IAU.
* Ptolemaeus A — ''See'' Ammonius.
Ptolemaeus at The Moon WikiI-556 Ptolemaeus
- USGS ''Geological Atlas of the Moon'', 1966 * * * * * - one of three craters making up a ''Triad'' - that includes Ptolemaeus * * * * * * * {{cite web, last = Wood , first = Chuck , date = September 4, 2014 , url = https://lpod.wikispaces.com/September+4%2C+2014 , title = Nessie , publisher = Lunar Photo of the Day Ptolemy Impact craters on the Moon
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 circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
close to the center of the near side, named for Claudius Ptolemy
Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importa ...
, the Greco-Roman writer, mathematician, astronomer, geographer and astrologer. It measures approximately 154 kilometers in diameter.
Description
To the south-southwest, 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. To the southeast isAlbategnius
Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī aṣ-Ṣābiʾ al-Battānī ( ar, محمد بن جابر بن سنان البتاني) ( Latinized as Albategnius, Albategni or Albatenius) (c. 858 – 929) was an astron ...
and to the north is the smaller but well-defined Herschel.
The features of Ptolemaeus are highlighted when the Sun is at low angles during the first and last quarter. At full Moon the Sun is directly overhead and the crater contours become more difficult to discern.
The crater has a low, irregular outer rim that is heavily worn and impacted with multiple smaller craters. The rim has a discernibly polygon
In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed '' polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two ...
al shape, although overall it remains circular. The largest of the peaks along the rim, designated Ptolemaeus Gamma (γ), has an altitude of 2.9 km and is located along the northwest rim. The crater has no central peak, a lava-flooded floor, and lacks a ray system
A ray system comprises radial streaks of fine ''ejecta'' thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to several times the diameter ...
. Impact sites of this form are often classified as walled plains, due to their resemblance to the maria.
The somewhat dark-hued floor of Ptolemaeus is notable for several ghost craters, formed where lava has covered a pre-existing crater. These leave only a slight rise where the rim existed, and are difficult to detect except at low angles of sunlight. There are also multiple smaller craters across the floor surface, most notably Ammonius in the northeastern quadrant.
On either side of this crater are linear, irregular gashes in the lunar surface, forming valley-like features. These features are approximately parallel to each other and radiate from the direction of Mare Imbrium
Mare Imbrium (Latin ''imbrium'', the "Sea of Showers" or "Sea of Rains", "Sea of Tears") is a vast lava plain within the Imbrium Basin on the Moon and is one of the larger craters in the Solar System. The Imbrium Basin formed from the colli ...
to the north-northwest.
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Ptolemaeus.
The following crater has been renamed by the IAU.
* Ptolemaeus A — ''See'' Ammonius.
See also
*Ptolemaeus (Martian crater)
Ptolemaeus is a crater on Mars, found in the Phaethontis quadrangle at 46.21° south latitude and 157.6° west longitude. It measures approximately 165 kilometers in diameter and was named after Claudius Ptolemaeus (Ptolemy), the Greco-Egyptian a ...
*4001 Ptolemaeus
4001 Ptolemaeus, provisional designation , is a Florian asteroid from the inner regions of the asteroid belt, approximately in diameter. It was discovered on 2 August 1949, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State O ...
References
* * * * * * * * * * *External links
Ptolemaeus at The Moon Wiki
- USGS ''Geological Atlas of the Moon'', 1966 * * * * * - one of three craters making up a ''Triad'' - that includes Ptolemaeus * * * * * * * {{cite web, last = Wood , first = Chuck , date = September 4, 2014 , url = https://lpod.wikispaces.com/September+4%2C+2014 , title = Nessie , publisher = Lunar Photo of the Day Ptolemy Impact craters on the Moon