One faded ray system radiates westward across Mare Fecunditatis from the 132-kilometer-wide crater Langrenus (L85 in the Lunar 100).
Another, even fainter ray system is just detectable on southern Mare Imbrium, radiating from Eratosthenes.
The most unusual ray system on the Moon is also one of the least well known.
The Lunar 100 L Feature name Significance 85 Langrenus rays Aged ray system 93 Dionysius rays Unusual and rate dark keys See Sky & Telescope: April 2004, page 113, or point Web browsers to Sky and Telescop.
The ray systems of Eudoxus, Aristillus, and Pythagoras are examples of old compositional rays.