Calippus (crater)

Calippus is a small lunar impact crater that is located on the eastern edge of the rugged Montes Caucasus mountain range in the northern part of the Moon. It lies to the southwest of the crater remnant Alexander,^[3] to the northwest of the Mare Serenitatis.

Coordinates38.9°N 10.7°E / 38.9; 10.7

Diameter34.03 km (21.15 mi)^[1]

Depth2.69 km (1.67 mi)^[2]

Colongitude350° at sunrise

Quick facts Coordinates, Diameter ...

Calippus

Mosaic of Lunar Orbiter 4 images
Coordinates	38.9°N 10.7°E / 38.9; 10.7
Diameter	34.03 km (21.15 mi)[1]
Depth	2.69 km (1.67 mi)[2]
Colongitude	350° at sunrise
Eponym	Callippus

Close

The outer rim of Calippus has an irregular appearance, with outward bulges to the northeast and particularly to the west where there is an interior shelf resembling slumped material.^[4]: 26 This crater is large enough for slumping to occur, but the remainder of the inner wall is free of slumps.^[5] The rim along the north to east edges has an altitude of over 2 km.^[6]

The exterior has a slight rampart that is surrounded by the rugged terrain of the mountain range. Within the sharp-sided interior walls is a rough and irregular interior floor. This surface may have experienced extrusions.^[5] Two instances of lunar transient phenomenon have been reported for this crater.^[7]

To the southeast of this crater, on the edge of the Mare Serenitatis, is an arcing rille designated Rima Calippus. This cleft follows a path to the northeast for a length of about 40 kilometers.^[8] A pyroclastic deposit has been identified in this area based on its low strength radar signature.^[9]

This crater was named after Greek astronomer Callippus of Cyzicus (c. 370 B.C.).^[1] His name was incorporated into lunar nomenclature by Italian astronomer Giovanni B. Riccioli in 1651, but he assigned it to the crater now known as Alexander.^[10] The designation Callippus was adopted by the International Astronomical Union in 1935.^[1]