APRIL 7TH / 8TH - FAVOURABLE LIBRATION BRINGS MARE AUSTRALE INTO VIEW

[paulastro]

I was out last night from about 11 pm and was pleased to find that a very favourable S/SW libration had brought Mare Australe into view.  It's a hugely interesting area and not often seen well.  In the fine Cambridge Photographic Moon Atlas (out of print and very expensive if you can find a used copy), chapter 10 covers Mare Australe very well.  It's  not well shown in most references I had to hand and the two page spread of images and information were invaluable in helping me identify the features I has been looking at.  The craters Oken, Lyot, Hanno and Pontecoulant (visible only because of their darker floors than the surrounding mare areas) were all on show.  I was particularly pleased to observe Lyot, as according to the Cambridge atlas:

Lyot, diam 140 km is a large complex crater and the largest impact structure in Mare Australe.  Observing is a challenge because of the location at the extreme limb and is successful only under the most favourable libration.  (Lyot is situated at 50.2 degrees S, 84.1 degrees E)

This was a fabulous highlight of the session but there was also other fine detail along the terminator, including the area to the S of Bailly.

The single frame below was taken at 00.19 on 8th with the SW 120ED, Olympus E-M5 MK11, 1/1000 sec at 200 asa, and the crops taken from the same frame.