Neper (crater)

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Neper LROC.jpg
LRO image
Coordinates8°48′N 84°30′E / 8.8°N 84.5°E / 8.8; 84.5Coordinates: 8°48′N 84°30′E / 8.8°N 84.5°E / 8.8; 84.5
Diameter137 km (85 miles)
Depth2.0 km
Colongitude343° at sunrise
EponymJohn Napier
Oblique Lunar Orbiter 4 image
Oblique view from Apollo 10, facing northwest
Oblique view of the central peak from Apollo 11, facing northeast

Neper is an old lunar impact crater located near the eastern limb of the Moon. Due to its location the crater must be viewed during a suitable libration, and is very foreshortened. The crater lies on the south edge of Mare Marginis, to the east of the crater Jansky. To the northwest across the Mare Marginis is the crater Goddard.

The crater inner walls have worn terraces, with low rim edges at the northern and southern extremes. The crater floor is dark and flat, with a central peak and several crater impacts near the west rim. The most notable of these is a small crater near the north-northwestern edge.

It is named after the Scottish mathematician, physicist, astronomer and astrologer John Napier.

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 Neper.

Neper Latitude Longitude Diameter
D 9.2° N 80.8° E 40 km
H 10.4° N 78.2° E 9 km
Q 8.0° N 83.1° E 12 km

The following craters have been renamed by the IAU.


  • Gladstone-Millar, Lynne (March 29, 2003). "Forgotten genius still burns bright". Edinburgh News. Retrieved 2007-09-06.