The Straight Wall and Arzachel Crater of the Moon

July 15, 2019


Photographer: John Chumack 
Summary Author: John Chumack 

Featured above is an extreme close-up of the Moon showing the Straight Wall or Straight Cliff (Rupes Recta), at lower right, and the Arzachel Crater, at the upper left. Rima Alpetragius is the crater at lower left, and above the Straight Wall is the crater known as Thebit.

The Straight Wall is a linear, surface fault having a length of 68 miles (110 km), a typical width of between 1.2 and 1.9 miles (2-3 km), and a height of ranging from 787 ft to 984 ft (240–300 m). Although it appears to be a vertical cliff in the lunar surface, in actuality the grade of the slope is relatively shallow.

Arzachel crater is 60 miles (96 km) across and 2.2 miles (3.6 km) deep. The rugged central peak of Arzachel is prominent, rising 0.9 miles (1.5 km) above the crater floor, which is relatively flat, except for some irregularities in the southwestern quadrant (upper right on this image).

Photo Details: Captured from my backyard in Dayton, Ohio with my old orange tube C-11 SCT telescope and QHY290M CMOS camera; 2x Barlow lens; 26 minutes exposure; 650 frames out of 800 stacked in Registax6. I was waiting on Jupiter to get high enough to image along with the Moon when I decided to explore the Moon a bit more.