A scarp by any other name…

Beset by clouds and winds for weeks now, I’ve gone back to the superb night March 19/21 when I found Rupes Altai, or the Altai Scarp as us old-timers once knew it, near the terminator showing off many wonderful treats that lie south of Theophilus. First is the anchor of the rupes at the bottom of the image just right of center, Piccolomini (90km diameter) with it’s spectacular stepped or terraced inner walls. To the left of Piccolomini is the smaller Rothman (43km) with the heart shaped Rothman B just below it. Farther on is Linenau (54km). The scarp or rupes itself runs from Piccolomini north for some 495km terminating west or left of the crater Catharina (104km) at the top of the image, and is 1km high for much of its length. Below Catharina is the flat floored crater Polybius (43km) and west of it are two merged craters Polybius C and F (29km and 21km respectively). Notice the straight shared wall between them.

Another dominant feature in this crowded image is the “U” shaped Fracastorius (128km) east (right) of Catharina on the southern shore of Mare Nectaris. With this lighting you can see the skinny rille on it’s floor. The rille is only 1-1.5km across! Between Fracastorius and Catharina is a small copy of Fracastorius, Beaumont (54km) peppered with 1-3km secondary craterlets from the great Theophilus impact event to the north.

There is so much going on west of the scarp that it is impossible to detail it here but you can enjoy it and get out your atlas or go to the LROC QuickMap website and explore away!