Section Report 2018.7.12

It’s ironic that, after an autumn and winter when clear skies were a rarity, the summer should provide so many clear nights at a time when  it hardly gets dark! Judging by the increase in the number of images sent in to the Lunar Section many members chose to turn their telescopes on the brighter objects that were visible and these, of course, include the Moon.

Two such observers were Dave Finnigan and Steve Norrie. Steve being up in Scotland was experiencing even shorter nights than those of us down south and on  June 21st imaged features on the lunar terminator. These included the craters Eratosthenes and Deslandres and Ptolemaeus and Rupes Recta, the last two of which are shown below.

The 153 km diameter Ptolemaeus, the floor of which shows many ‘ghost’ craters buried under the lava that flowed into it. The most readily seen of these lies below the prominent Ammonius. At 9 km diameter Ammonius is easily the largest of the many craterlets which dot Ptolemaeus’s floor.

Rupes Recta, also known as Straight Wall, a fault that is 110 km in length , rising as high as 300 m. To the right is the simple crater Birt, with Birt A linked to its eastern wall, and to the right is the 57 km Thebit. The western rim of this crater was impacted forming Thebit A which in turn has the smaller Thebit L linked to it.


Dave Finnigan was imaging the following night and sent in three pictures, two of which appear below.  These are of craters Pitatus and Archimedes.

Ninety-senven km diameter  Pitatus is on on the southern border of Mare Nubium.  It is fascinating  for the number of rilles which are close to its internal walls.


Archimedes. The largest crater in the Mare Imbrium. Lava has flooded the crater, no doubt burying a central peak.  as there are no breaches in Archimedes wall this lava must have welled up through fractures in its floor.




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