Maclear (crater)

Maclear

mosaic of Lunar Orbiter 4 images
Coordinates	10°30′N 20°06′E / 10.5°N 20.1°E / 10.5; 20.1
Diameter	20 km
Depth	0.6 km
Colongitude	340° at sunrise
Eponym	Thomas Maclear

Maclear is a lava-flooded crater on the northwest part of the Mare Tranquillitatis, a lunar mare in the eastern half of the Moon. Its diameter is 20 km.^[1] The crater is located to the southwest of the slightly larger Ross. To the southwest of Maclear is Sosigenes, while farther to the south-southeast is Arago.

With most of its interior submerged in deposits of basaltic lava, all that remains of this crater is a narrow rim projecting above the surrounding mare. The rim is not quite circular, having a flat outward bulge along the western side. But the rim is relatively uniform in width and is not significantly eroded.

The crater rim lies at the southern terminus of a rille belonging to a system that runs along the western edges of Mare Tranquillitatis. The rille system to the north of the crater is designated Rimae Maclear, while the rilles to the south-southwest are named Rimae Sosigenes. The Rimae Maclear stretches for about 100 kilometers, reaching Al-Bakri to the north along the edge of the mare.

It is named after Sir Thomas Maclear,^[1] Her Majesty's astronomer at the Royal Observatory, Cape of Good Hope (Cape Town, South Africa), from 1833 to 1870.