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Crater on the Moon

Crater on the Moon

One of a group of three craters of comparable size that lie at the southern end of the narrow lunar sea of Sinus Asperitatis where it approaches Mare Nectaris. Theophilus is the northermost of the three craters in the group, with the others being Catharina and Cyrillus to the southwest. Theophilus in fact partially overlays the ring of Cyrillus, showing that it was formed by a later impact.

All three of these craters approach 100 km in diameter, with Theophilus being the largest of the three by a matter of a few kilometres. The inner surface of its crater wall descends in terraces to the floor, some 4,200 km below its rim. From the base of the surrounding wall, the inner surface of the crater is relatively smooth, except for one small interior crater, designated Theophilus B, that lies within Theophilus' southeastern edge.

Theophilus has the common central peak seen in many impact craters, in this case a mountainous mass rising for nearly two kilometres from the crater floor. In Theophilus' case, this is not in fact a single peak, but rises instead into several distinct points. The three most prominent of these have their own specific designations: Alpha Theophilus in the north, Psi Theophilus to the southwest and Phi Theophilus to the southeast.


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