365 Days of the Moon -- August 16, 2014

Theophilus, Cyrillus, and Catharina

Here we see one-kilometer resolution in the classic Theophilus-Cyrillus-Catharina area on the northwest rim of Mare Nectaris. Theophilus is the younger looking Erastothinian Epoch crater at the upper right. The Nectarian Epoch crater Cyrillus lies to the left of Theophilus. Since Theophilus overlays the rim of Cyrillus, it is clearly the younger crater. At middle left is Catharina, also a Nectarian Epoch crater. All three of these craters are about 60 miles wide. Look closely and notice the hundreds of small mile-wide Theophilus secondary craters dusted across the landscape. Also notice a number of rilles that fracture the floor of both Catharina and Cyrillus. Within Catharina you can spot the remains of the relatively large crater Catharina P. The wave of ejecta from the Theophilus impact nearly buried Catharina P and heavily modified the floor of adjoining Cyrillus.

Image taken with a Celestron 11 Edge HD, 2.5X Powermate, and Skyris 274M camera.

Image copyright Robert Reeves 2014

Use browser BACK button to return to the Index page