Popov is a crater on the far side , just beyond the eastern limb. It is located along the very edge of the area of surface that is sometimes brought into view of the Earth during periods of favorable libration and illumination. However even at such times it is not prominent and can only be viewed edge-on. This crater lies due south of Dziewulski, and the crater chain designated Catena Dziewulski passes just to the northeast 's outer rim. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.