Geological Chronicle
Catharina is an ancient impact crater in the Moon's southern highlands. It lies between the Rupes Altai scarp to the west and Mare Nectaris to the east. With Cyrillus and Theophilus to its north, Catharina is the largest of the three. The group is a notable feature when the Sun is at a low angle to the surface.
Its rim is heavily worn and irregular. The ruined, low-walled ring of Catharina P cuts into most of the north wall, and several smaller craters have deeply impacted the northeast wall. No terraces remain on the inner wall, and the outer rampart has been nearly eroded away. The floor is relatively flat but rugged, with a curved ridge formed by Catharina P and the remains of a smaller crater near the south wall. Nothing remains of a central peak.
Crater data from the Moon Mineralogy Mapper indicate an average FeO content of 9.34 wt%, with values ranging from 0.02 to 18.2 wt%. TiO2 averages 2.56 wt% and ranges from 0.2934 to 13.987 wt%.
Italian astronomer Giovanni B. Riccioli added Catharina's name to lunar nomenclature in 1651. The International Astronomical Union officially adopted the designation in 1935. The crater is named for Saint Catherine of Alexandria; the registry identifies her as a Greek theologian and philosopher.