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Lunar Section Reports


During the first three months of 2017 I received several superb images from Dave Finnigan and from Mike Brown.  Mike Hezzlewood sent in a number of excellent observational drawings.  One example from each member is shown below and I hope to feature more in a future issue of Popular Astronomy.  Those who attend the Convention on April 1st will see further examples (And I mean that.  Despite the date you will not be greeted by a banner, on an otherwise bare Lunar Section stall, with the words ‘April Fool!’ emblazoned on it!)

Maurolycus and Barocius : 

This pair of craters is always easily recognised in the intensely cratered southern uplands of the Moon.  Coming into view on about the 6th evening of the lunation, seen through my SCT they always seem to me to be forming a battered letter ‘S’.  Maurolycus is an ancient crater and Dave’s image shows its eroded, terraced walls highest to the east where they reach 4000 m.   The 115 km crater has formed over other, even older, craters and parts of these can be seen in the image.

The wall of 80 km Barocius surrounds a floor containing craterlets and  a ghost crater to the south. We can see what seems to be a low, off-centre mountain, to the east of which Barocius’s wall has be broken by an impact that formed a crater some 30 km in diameter.


Dave’s image was taken via an LX 200 305mm ACF SCT at f25, and a ZWO ASI 120MMS  camera, plus a Baader IR pass filter (685nm).  640 frames out of 800 stacked and processed in Registax 6 and Paintshop Pro 8

Rupes Recta:

Mike Brown’s image of Rupes Recta (Often referred to as Straight Wall) shows the 110 km scarp casting a shadow across the floor Mare Nubium towards the craters Birt and the adoining Birt A.  To the east are the 57 km Thebit and Thebit A, dramatically lit by the low Sun which throws into relief a host of details.


Mike Hezzlewood sent me two drawings of this area close to the eastern limb of the Moon.  One was of the flooded crater Balmer and this one is of nearby Hecataeus, which is closer to the limb and therefore considerably foreshortened.  A casual observer might easily miss this complex crater which at 127 km across is by no means among the smaller of lunar impacts.  It is believed that Hecataeus is actually two joined craters.