Object: L 70
Feature Name: Humboldtianum basin
Significance: Multi-ring impact basin

Mare Humboldtianum is a lunar mare located within the Humboldtianum basin, just to the east of Mare Frigoris. It is located along the northeastern limb of the Moon, and continues on to the far side. Due to its location, the visibility of this feature can be affected by libration, and on occasion it can be hidden from view from Earth.

The outer ring of the basin can be seen between the large flooded crater in the centre of the image (Endymion) and the Mare which is within the inner ring. The outer ring is clearly seen heading south-east (bottom right of image).

DMK 21AU-4.AS through 200mm f/4 GSO Newtonian with 2x Barlow.

Best of 1000 frames stacked in Registax. Processed in Astra Image 3.0 and Paintshop Pro.