is a prominent lunar
Impact Crater that lies between
Sinus Asperitatis in the north and
Mare Nectaris to the southeast. It partially intrudes into the comparably-sized
Cyrillus Crater to the southwest. To the east is the smaller
Mädler Crater and further to the south-southeast is
Beaumont Crater . To the west-northwest is
Mons Penck , a peak forming a promontory arm on the ''
Rupes Altai ''.
The d inner surface that shows indications of landslips. The exterior has a wide, wrinkled
Rampart that descends about 1.4
Kilometer s to the surrounding
''maria'' . The largest impact crater of signifance on the wall is the small Theophilus B on the inside of the northwest rim. Most of the
Rays from this crater has been weathered away, although a few are still visible.
The floor of the crater is relatively flat, and it has a large, triple-peaked central crater that climbs to a height of about 2 kilometers above the floor. The western peak is designated Psi (ψ), the eastern Phi (φ), and the northern peak is Alpha (α) Theophilus. The western slopes of this ridge are wider and more irregular, whereas the peaks descend more sharply to the floor on the northern and western faces.
The
Apollo 16 mission collected several pieces of
Basalt that are believed to be ejecta from the formation of the Theophilus crater.
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 Theophilus crater.
