Mare Australe

0.002 seconds exposure, SBIG ST-8E CCD.
8" f/10 schmidt-cassegrain at prime focus.

One of the more difficult maria to observe is Mare Australe. This mare is situated on the south-eastern limb of the Moon (longitude 91 degrees) and is only visible at favourable librations, such as occured when this image was taken. The Mare appears as an iregular patch of darker surface. Lunar orbiter images show it to be roughly circular but with many craters degrading the shape.