Mare Orientale is one of the youngest major impact basins on the Moon, and the visible effects of that gigantic impact are widespread on the extreme western area of the Moon.
Origin: impact and volcanic Size: 640 km Rukl: 50, 39. VII Type: Basin - Mare
Objects: Mare Orientale, Montes Cordillera
Others Identified: Schlüter, Hartwig, Maunder
Date: November 2, 2025
Time: 7:17 PM AST
Equipment: 10" Meade SCT
Eyepiece: 10mm
Magnification: x250
Seeing: Excellent (1)
Transparency: Excellent (1)
I had marked my calendar for November 1 - 3 as ideal to capture this landmark - and I was correct. Easily located this elongated feature on the SW limb.
C1: The Mare had a dark floor compared to surroundings. From the perspective I had during the libration, the Montes Cordillera was low, very well lit and white on the side facing Oceanus Procellarum. The lunar limb was irregular in shape suggesting it was a mountain range on the other side of the Mare - perhaps the Inner Rook Mountains on the lunar far side. The dark oval-shaped crater in the northern portion made me think it could be Maunder.
Not sketched but identified were two craters north of the Montes Cordillera - Schlüter and Hartwig. Schlüter was closer to the rim and darker than Hartwig; both, perhaps because of the libration, appeared oval.
