Close to the edge of the crater are two small craters: Copernicus H with a diameter of 5 km (to the southeast) and Gay-Lussac N, with a diameter of only 2 km (to the north). Both craters are surrounded by dark haloes and lie as if stamped into the Copernicus ejecta. Multispectral investigations show that the dark haloes consist of pulverized mare basalt, which was excavated from beneath the ejecta from Copernicus. Both craters are, admittedly, small, but they must be deep enough to have brought the basalt to the surface. They are included in the class of Dark Halo Craters. Two craters that arose similarly, and with dark haloes of mare basalt, lie southeast of Theophilus. Craters with dark haloes – like the bright ray systems – are best seen under high solar illumination. Because they are generally very small, it is advisable to use magnifications of 150 to 200× for visual observation.

Two smaller, overlapping craters, Fauth (12 km, 6.3°N, 20.1°W) and Fauth A (10 km) lie directly south of Copernicus. Fauth and Fauth A are most probably secondary craters, originating in the gigantic Imbrium impact. The two craters resemble a keyhole, and when taken together with Copernicus, the three craters serve as an indicator of the north-south direction of the lunar coordinate system.