The outer ramparts are irregular and hilly, and there is a bright, fragmented ray system spread across the mare to the west.

On December 30, 1992, Audouin Dollfus of the Observatoire de Paris observed a series of glows on the floor of this crater using the one-meter telescope.

These glows changed form with time, and Dollfus expressed the belief that this was likely a gaseous emission.

[citation needed] Flemish astronomer Michael van Langren was the first person to draw a lunar map while giving names to many of the features, in 1645.

[1] By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Langrenus.