Mare Nubium is in the Nubium basin on the moon's
near side. The mare is located just to the southeast
of Oceanus Procellarum. The actual basin is believed
to be of Pre-Nectarian system, with the surrounding basin
material being of the Lower Imbrian epoch. The mare
material is of the Upper Imbrian epoch. The crater to
the east of the mare is Bullialdus, which is of the
Eratosthenian Epoch. This means the crater is younger
than the mare it sits in The crater that sits on the
southern rim of the mare is Pitatus. You can clearly
see the rays from Tycho at the bottom of the photo.
Mare Cognitum and Fra Mauro are seen toward the top.