Geological Chronicle
Cassini occupies Palus Nebularum at the eastern margin of Mare Imbrium, spanning a diameter of 56.88 kilometers between the solitary peak Mons Piton to the northwest and Promontorium Agassiz to the northeast. Dating to the Lower Imbrian epoch, the impact structure underwent flooding by lava, leaving a floor likely as old as the surrounding mare.
The crater walls are narrow and irregular in form, yet they remained intact despite the lava flooding and rise above a substantial outer rampart. Within the flooded basin sit two significant craters: Cassini A, located just northeast of the crater center with a large interior mound and an adjoining hilly ridge, and Cassini B near the southwestern rim.
For unknown reasons, Cassini was omitted from early maps of the Moon, an absence considered most likely an error by map-makers. In 1791, German astronomer J. H. Schröter introduced the name honoring astronomers Giovanni Cassini and Jacques Cassini, a designation officially adopted by the International Astronomical Union in 1935.