Eratosthenes (Moon)

Named after Eratosthenes - Greek astronomer, geographer (c. 276-196 B.C.).

Eratosthenes is a deep lunar impact crater that lies on the boundary. The crater has a well-defined circular rim, terraced inner wall, central mountain peaks, an irregular floor, and an outer rampart of ejecta. It lacks a ray system of its own, but is overlain by rays from the prominent crater Copernicus to the south-west. (wikipedia entry)

A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.