Geological Chronicle
Galilaei is a lunar impact crater positioned in western Oceanus Procellarum, spanning a diameter of 15.99 kilometers. The feature has a sharp-edged rim that exhibits a higher albedo than the surrounding maria. Its inner walls slope down to a ring of debris on the outer edges of the floor, with a small central rise near the midpoint.
The surrounding terrain contains several prominent landmarks, including the crater Reiner to the southeast, Cavalerius to the south-southwest, and a meandering rille named Rima Galilaei to the northeast. Roughly 40 kilometers to the south sits the landing site of Luna 9, the first robotic probe to make a controlled landing on the lunar surface.
The designation carries a complex cartographic history. In 1651, Italian Jesuit Giovanni Battista Riccioli originally applied the name Galilaeus to a bright nearby albedo feature now known as Reiner Gamma. Between 1834 and 1836, Johann Heinrich Mädler and Wilhelm Beer transferred the name to this crater in their Mappa Selenographica because their map did not name albedo features.