Cauchy is a small lunar impact crater on the eastern Mare Tranquillitatis. It is circular and symmetric, with a small interior floor at the midpoint of the sloping inner walls. Due to the high albedo of this bowl-shaped formation, it is particularly prominent at full Moon. Just to the northeast of the rim of this crater is the wide rille named Rima Cauchy, a 210-kilometer-long cleft following a line to the northwest. (wikipedia entry)