Theon Senior 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 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 craters ...
that is located to the northwest of the crater
Delambre
Jean Baptiste Joseph, chevalier Delambre (19 September 1749 – 19 August 1822) was a French mathematician, astronomer, historian of astronomy, and geodesist. He was also director of the Paris Observatory, and author of well-known books on th ...
, and south of
D'Arrest
Heinrich Louis d'Arrest (13 August 1822 – 14 June 1875; ) was a German astronomer, born in Berlin. His name is sometimes given as Heinrich Ludwig d'Arrest.
Biography
While still a student at the University of Berlin, d'Arrest was pa ...
. It forms a matching pair with
Theon Junior, about two crater diameters to the south-southeast. The satellite crater Theon Senior A can be found to the north. Theon Senior is named for
Theon of Smyrna
Theon of Smyrna ( el, Θέων ὁ Σμυρναῖος ''Theon ho Smyrnaios'', ''gen.'' Θέωνος ''Theonos''; fl. 100 CE) was a Greek philosopher and mathematician, whose works were strongly influenced by the Pythagorean school of thought. His ...
, a 1st-2nd century Greek mathematician and philosopher.
[''Autostar Suite Astronomer Edition''. CD-ROM. Meade, April 2006.][Moore, Patrick (2001). ''On the Moon''. Sterling Publishing Co.. .]
This crater is circular and bowl-shaped, with only a small floor at the center of the steeply sloping interior walls. The crater appears relatively young, as it shows little sign of wear due to impacts. The crater is about 18 kilometers in diameter, and the distance from its rim to the floor is 3470 meters.
Theon Senior is from the
Eratosthenian
The Eratosthenian period in the lunar geologic timescale runs from 3,200 million years ago to 1,100 million years ago. It is named after the crater Eratosthenes, which displays characteristics typical of craters of this age, including a surface ...
period, which lasted from 3.2 to 1.1 billion years ago.
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 Theon Senior.
References
External links
Theon Senior at The Moon Wiki* {{cite web, last = Wood , first = Chuck , date = December 12, 2006 , url = http://www.lpod.org/?m=20061211 , title = How Deep is That Hole , publisher = Lunar Photo of the Day, url-status=dead, archive-url=https://web.archive.org/web/20110614233616/http://www.lpod.org/?m=20061211, archive-date=August 3, 2017 - includes a couple of craters such as Theon Senior
Impact craters on the Moon
Eratosthenian