Giovanni Domenico Cassini scientific map of the moon produced around c. 1679 contains a strange silhouette at Promontorium Heraclides commonly known as the 'Moon Maiden'. The feature is best observed when the terminator is over that region; slightly less than when the moon is 11 days old.
Sinus Iridum (Latin for "Bay of Rainbows") is a plain of basaltic lava that forms a northwestern extension to the Mare Imbrium. It is surrounded from the northeast to the southwest by the Montes Jura range. The protruding part of the range at the southwest end is named Promontorium Heraclides, while that at the northeast end is called Promontorium Laplace. Read more
Giovanni Domenico Cassini moved to Paris and married Geneviève Delaistre in November 1673, changing his name to Jean Dominique Cassini as he took French nationality. His drawing of the moon has, tucked away in the bottom right hand corner, what appears to be a portrait of a woman, known as the 'Moon Maiden'. This is commonly thought to be a portrait of Geneviève. Confirmation of this is tenuous, however, in 1678, Jean Dominique commissioned a pen-and-ink portrait of his wife from Jean Baptiste Patigny, the son of the artist and engraver of Jean Dominique's map of the Moon of 1679, which gives some credence to the possibility. Read more