The week of September 7-13 takes us from Lunar Day 20 to Day 25. This week we will highlight the crater Clavius, viewable late Tuesday night.
Clavius: [SW/Q8] Sunset over Clavius is something that you don’t want to miss! The crater is so large (140 miles) that the curvature of the Moon pushes the floor’s central regions into the sunlight first, and the shadows will reveal a floor that is strewn 
with craterlets. There is a delightful arc of small craters, artistically and sequentially arranged in order of size, which begins at Rutherfurd, a 34-mile crater just inside the southeast rim, arcs northward and then diminishes toward the west. While the Sun angle is low over Clavius, look for several ridges that extend like fingers northward 
from Rutherfurd. The origin of these ridges remains a mystery. Revisit Clavius often. You will always see something that you missed previously.
OF ADDITIONAL INTEREST IN SPACE:
On Saturday, Venus will be 2.5° south of the Beehive Cluster M44 (you’ll need binoculars).
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It is highly recommended that you get a copy of Sky and Telescope’s Field Map of the Moon, the very finest Moon map available for use at the telescope. It is available for $10.95 at www.skyandtelescope.com and on Amazon. All features mentioned in this blog will be keyed to the grid on the Field Map and will look like this: Plato: [NW/D9]
Credits:
Courtesy of Gray Photography of Corpus Christi, Texas
Lunar photos: NASA / USGS / BMDO / LROC / ASU / DLR / LOLA / Moon Globe. Used by permission
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