Thales (crater)

Thales is a small crater located in the northeast part of the Moon, just to the west of the larger crater Strabo. To the southeast is a walled plain called De La Rue.

Thales has a sharp, circular rim that has received little erosion. The lunar surface around Thales has a ray system that extends for over 600 kilometers, and it is consequently mapped as part of the Copernican System.^[1] However, an area to the north-northwest of the crater is free of rays, indicating that the crater may have been formed by a low-angle impact from that direction. The inner wall of Thales has some terraces, particularly along the southern side. The sides have a higher albedo than the typical lunar terrain.

This crater has been noted for transient lunar phenomena. In 1892, E. E. Barnard observed a pale haze fill the crater interior, while the surroundings remained clear and sharply visible.