The western part of Oceanus Procellarum has few bigger craters, but is rich in domes, specially around Marius. This area is of great geological interest, and was going to be the target for an Apollo expedition. Because a number of flights were cancelled due to budget cuts, this was not going to happen.
MAESTLIN - Michael Möstlin (1550 - 1631) German mathematician and astronomer. Teacher of Johannes Kepler. Defended the theory of Copernicus, and popularized Kepler and his heliocentric Copernican theory. Maestlin discovered that the ashen grey Moonlight is actually light reflected back from the Earth.
MARIUS - Simon Mayer. (1570 - 1624) German astronomer, on of the first who used a telescope. Discovered the Andromeda Nebula, and must have seen the moons of Jupiter, for he named them with their present names.Riccioli's Moon Map.
Ocean. (721x488Km / 448x303Mi) (Centre: about 0.0° N, 50.0° W) Procellarum is the largest of the maria, stretching more than 2,500 km (1,600 Mi) across its north-south axis and covering roughly 2,102,000 km2. Larger lunar sea. Very flat to the center. 80m altitude difference in a 400 km diameter circle. Numerous ridges rilles, leftovers of walls. Ghost craters and lava flooded craters, many small hills. The landscape of the area depicted on Chart 41 is basically the same. Rays from Crater Copernicus and other ray craters. The robotic lunar probes Luna 9, Luna 13, Surveyor 1 and Surveyor 3 landed in Oceanus Procellarum. The manned Apollo 12 mission also landed in Oceanus Procellarum, with astronauts Pete Conrad and Alan Bean on board. Their landing site, within 300m of Surveyor 3, has become known as Mare Cognitum. North of Euclides F (5.2 km ø ) (Dept: 1,090m), and in surroundings of Herigonius are ridges which should be counted amongst the most articulated systems on the Moon. In Chart 29 we find the rays of the crater Kepler.