Diophantus (crater)

Coordinates: 27°36′N 34°18′W / 27.6°N 34.3°W / 27.6; -34.3
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Apollo 15 image
Coordinates27°36′N 34°18′W / 27.6°N 34.3°W / 27.6; -34.3
Diameter19 km
Depth3.0 km
Colongitude34° at sunrise
Oblique view of Diophantus from Apollo 17, at low sun angle, with the smaller Diophantus C at left.
High-resolution view of dark streaks in the wall of Diophantus, showing downslope movement of buried subsurface deposits.
The craters Delisle (above) and Diophantus (below) from Apollo 15. Mons Delisle is to the left of Delisle, and Rima Diophantus lies between Delisle and Diophantus. Note also bright rays extending from the tiny crater Samir.

Diophantus is a lunar impact crater that lies in the southwestern part of the Mare Imbrium. It was named after ancient Greek mathematician Diophantus.[1] It forms a pair with the larger crater Delisle to the north. Diophantus has a wide inner wall and a low central rise. To the north of Diophantus is the sinuous rille designated Rima Diophantus, named after the crater. Diophantus C lies near the exterior of the southwest wall.

Diophantus is a crater of Eratosthenian age.[2]

Rima Diophantus[edit]

This cleft follows a generally east–west path across the Mare Imbrium. It is centered at selenographic coordinates 31.0° N, 32.0° W, and has a maximum diameter of 150 km.

Small craters[edit]

Several tiny craters north of Diophantus have been assigned names by the IAU. These are listed in the table below.

Crater Coordinates Diameter Name source
Isabel 28°12′N 34°06′W / 28.2°N 34.1°W / 28.2; -34.1 1 km Spanish feminine name
Louise 28°30′N 34°12′W / 28.5°N 34.2°W / 28.5; -34.2 0.8 km French feminine name
Samir 28°30′N 34°18′W / 28.5°N 34.3°W / 28.5; -34.3 2 km Arabic masculine name
Walter1 28°00′N 33°48′W / 28.0°N 33.8°W / 28.0; -33.8 1 km German masculine name
1 Not to be confused with the large crater Walther in the southern hemisphere which is misidentified as 'Walter' in some publications
High-resolution image of Samir (left) and Louise from Apollo 15 panoramic camera.

The crater Samir has bright rays that extend for over 70 km.

Satellite craters[edit]

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Diophantus.

Diophantus Latitude Longitude Diameter
B 29.1° N 32.5° W 6 km
C 27.3° N 34.7° W 5 km
D 26.9° N 36.3° W 4 km

The following craters have been renamed by the IAU.


  1. ^ "Diophantus (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
  2. ^ The geologic history of the Moon. USGS Professional Paper 1348. By Don E. Wilhelms, John F. McCauley, and Newell J. Trask. U.S. Government Printing Office, Washington: 1987. Table 12.2.

External links[edit]