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scotopic (daytime) vision, which is of
much higher quality than dark-adapted
photopic vision. Finally, you can use an
aperture mask — a piece of cardboard
that covers the front of your scope with
a small hole cut in it — to turn your tele-
scope into one of much smaller aperture.
All the features shown in the photos
accompanying this story lie along the
terminator around First Quarter. If you
get a string of clear nights, view these
features two or more evenings in a row.
You’ll be surprised at how different they
appear after 24 hours. Compare what
you see with the images.
As practical advice, sit while you
observe. Try different eyepieces of
increasing magnification until the image
starts to deteriorate because of the atmo-
sphere. Note any additional details that
high powers make visible.
Remember, when you observe the
Moon, there’s nothing you need to do
quickly. Take your time and relax. This
is easy observing, so have fun.
Michael E. Bakich is a contributing editor
of Astronomy who points his 4-inch scope
at the First Quarter Moon each month.
8
Stöfler is a large impact crater located in the Moon’s southern highlands. Look for Faraday Crater, which
overlays its western edge. The rim of Stöfler is worn, but its outline remains intact except at Faraday. In a
reverse of Manilius Crater, Stöfler’s floor has a low reflectivity, making the crater easy to identify.
9
Heraclitus is a complex crater in the Moon’s
rugged southern highlands. Licetus Crater forms
the northern end of the formation. Just to the east is
Cuvier Crater, and due south is Lilius Crater. The entire
formation is heavily worn, with features smoothed
down by a long history of impacts.
7
Albategnius Crater is so large that lunar scientists often refer to it as a walled plain or a ring mountain.
Look closely at the most prominent overlapping craters: Klein, which sits to the lower left in this image,
and Albategnius B, just inside the northern rim at the top. Note that Albategnius’ outer wall has a rough
hexagonal shape.