Katchalsky is a crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 that lies on the far side of the Moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. It lies to the southeast of the larger crater Lobachevskiy

Lobachevskiy (crater)

Lobachevskiy is a lunar impact crater that is located on the far side of the Moon, beyond the eastern limb. This crater lies to the southeast of the larger crater Fleming. Less than a crater diameter to the east-northeast lies Guyot....

, and to the west of the prominent King

King (crater)

King is a prominent lunar impact crater that is located on the far side of the Moon, and can not be viewed directly from Earth. It forms a pair with Ibn Firnas, which is only slightly larger and is attached to the northeast rim of King...

. Less than a half-crater diameter to the southeast of Katchalsky is Viviani

Viviani (crater)

Viviani is a small lunar impact crater that lies on the far side of the Moon. It is located due west of the prominent crater King, and just to the southeast of Katchalsky....

.

The outer rim of Katchalsky is not quite circular, with outward bulges to the east and north, giving it a flat side along the northeastern edge. The rim is not markedly eroded, and the interior contains only a few tiny craterlets.