is a large lunar crater
of the class known as a walled plain. It is located on the far side
of the Moon
and cannot be viewed directly from the Earth
. Nearby craters of note include Joule
to the northeast, Mitra
attached to the western outer rim, and Henyey
to the southwest.
This is a prominent but eroded formation with multiple craters along the rim and interior. The crater Harvey
breaks across the eastern rim, and its outer rampart
spills across the interior floor of Mach. The overall shape of Mach resembles a pear
, with a prominent outward bulge to the northeast. Such a bulge can be caused by a second, merged crater. The northern edge is also the most worn and overlain by impacts.
The interior of Mach is marked by several small craters, particularly in the northeastern bulge. Several craters also lie along the edges to the west and northwest. The remainder of the interior floor is relatively level, when compared to the terrain
that surrounds Mach. There is a formation of central ridges near the mid-point of the crater that create a large number of unexplained magnetic anomalies. (Or at least the center if the northeastern bulge is disregarded.)
By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Mach.