What is "letronne"

Letronne is the lava-flooded remnant of a lunar crater. The northern part of the rim is completely missing, and opens into the Oceanus Procellarum, forming a bay along the southwestern shore. The formation is located to the northwest of the large crater Gassendi.To the west-southwest is the flooded crater Billy, and north-northwest lies the smaller Flamsteed.

The surviving rim of Letronne is now little more than a semi-circular series of ridges. The flooded, broken rim of Winthrop overlies the western wall. The rim is the most intact along the eastern stretch, forming a mountainous promontory into the mare. A small cluster of central rises lie at the midpoint of the crater. A wrinkle ridge traverses the floor from north to south, and outline a portion of the missing rim. The crater floor is otherwise nearly smooth and relatively free of craterlets, with the exception of Letronne B near the southeast rim.