Lat: 13.8°S, Long: 50.1°W, Diam: 45 km, Depth: 1.29 km, Rükl: 40
(IAU Directions) BILLY.--A ring-plain, 31 miles in diameter, S.W. of Letronne, with a very dark floor, depressed about 1,000 feet below the grey surface on the E., and a regular border, rising more than 3,000 feet above it. There is a narrow gap on the S., and indications of a crater on the N.E. rim. Two small craters stand on the S. half of the interior. The formation is flanked on the S.E. by highlands.
Depth data from Kurt Fisher database
- Westfall, 2000: 1.29 km
- Viscardy, 1985: 1.21 km
- Cherrington, 1969: 1.21 km
Jacques de Billy (March 18, 1602 – January 14, 1679) was a French Jesuit mathematician. Billy produced a number of results in number theory which have been named after him. He published several astronomical tables and was one of the first scientists to reject the role of astrology in science. He also rejected old notions about the malevolent influence of comets.