High Quality Content by WIKIPEDIA articles! Wallach is a tiny lunar impact crater located in the eastern Mare Tranquillitatis. It is a circular, bowl-shaped feature with a negligible interior floor; the inner walls just slope down to the mid-point of the crater. Wallach is located to the northeast of the crater Maskelyne, near some low ridges in the lunar mare. It was previously identified as Maskelyne H before being given a name by the IAU.