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, to the northwest of the Mare Serenitatis.
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 of slumped material. The rim along the north to east edges has an altitude of over 2 km.
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