Astronomy - USA 2021-04)

Clavius

Porter

RutherfurdRutherfurd

Mare

Imbrium

Montes Teneriffe

Vallis Alpes

Montes

Alpes

Plato

Bliss

Protagoras

Archytas

Mare Frigoris

Fontenelle Timaeus

Montes

Alpes

Short

Simpelius D

Moretus

Curtius

Gruemberger

Klaproth A

Cystatus

Cystatus A

RutherfurdRutherfurd Zach

WWW.ASTRONOMY.COM 53

Moon watchers use two other ways to

cut the Moon’s brightness. Boosting the

magnification reduces the field of view

so less light gets through. New observers,

however, may find identifying features in

such tiny areas difficult. The other way is

to use an aperture mask — a round piece

of cardboard with a hole cut out. It covers

the front of your telescope so less light gets

through, but doesn’t limit the field of view.

Where to start

One of the best ways to learn the Moon

is to have a lunar map or globe with

labeled features next to your telescope

while you observe. Start by finding a

prominent crater that’s currently visible

and work outward from it. You’ll quickly

learn how your telescope’s field of view

differs from your reference. Some scopes

flip the image; others rotate it 180°.

Yours may do both.

You’ll find one great choice for a

Moon globe at MyScienceShop.com. This

12-inch diameter globe, based on images

supplied by the Lunar Reconnaissance

Orbiter (launched in 2009 and still orbit-

ing the Moon), has 1,473 features labeled.

When you do head out, get comfort-

able (I love sitting in a chair), take your

time, and have fun.

1. Arzachel Crater makes a great starting point.
   Examine how different parts of its wall appear.
   The prime target in this region, however, is
   Rupes Recta, also known as the Straight Wall.
   You’ll see it best when it’s in sunlight with the
   terminator nearby. Then identify Thebit Crater
   and Thebit A, Birt Crater, and Nicollet. Finally,
   try to find Rima Birt, a less prominent version
   of Rupes Recta. BRIAN FORD


2. Clavius Crater also is a great target for
   beginning lunar observers. Inside, it features
   a curving line of half a dozen craterlets of
   shrinking size. Porter Crater and Rutherfurd
   Crater sit on its edge. Other significant craters
   nearby are Blancanus, Scheiner, and
   Longomontanus. JAMES EDLIN


3. Plato Crater is one of the most striking
   features on the Moon, so it makes an ideal
   location to begin. The mountains to its lower
   right are the Montes Alpes. Interesting though
   they are, the top target here is Vallis Alpes, a
   100-mile-long (162 km), lava-filled chasm. Take
   your time identifying the many other craters in
   this region. CHRIS SCHUR


4. Moretus Crater, with its central mountain,
   lies near the bottom of the Moon as we see it,
   in what are called the Southern Highlands.
   Many craters pack into this region, so take
   your time identifying them. DAMIAN PEACH

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