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Through an Astronaut's Eye

Craig Wandke & David North

This month's column is a tad different; we got a Moonocentric submission from that tireless and devoted observer Craig Wandke.

He has given several inspiring talks to the club, and pursues the Moon with a doggedness second only (perhaps) to Harold Hill.

Often the question comes up - what do you look for on the Moon? And how? Craig thought the Apollo guidelines seemed to be the best answer around ... so with no further blather:

Apollo 8 Critical Item Checklist by Craig D. Wandke.

When Apollo 8 orbited the moon in December of 1968, it was the first time human eyes gazed down upon the surface of this alien world from so close.

Apollo 8 showcased the very latest technology by the United States, and the mission, flown by highly-trained pilots, had clear and specific directives for lunar observation.

Astronauts Borman, Lovell (later to fly on the ill-fated Apollo 13), and Anders had received training in how to observe and record the lunar scene under their spacecraft, and it interesting to note their guidelines.

Because many of the observational criteria they were required to follow may be used by all of us through our amateur telescopes (obviously with a far less detailed perspective!) it might be fun - on your next lunar observing session - to gaze on the moon as if you were an Apollo 8 astronaut ... and let's assume the last item will not concern you!

If it does, however, notify all of us in the club immediately ... as well as CNN!

Impact Craters

Is it large? Does it have rays? A bright halo? Sharp rimmed? Low-rimmed or high? Is the rim radial or concentric, and can you see flow patterns?

Is the crater circular, asymmetric, polygonal? Is there a terrace?

Look at the walls. Can you see textures, patterns, layers, flows, or channels?

Benches are flat areas below the rim but above the floor. Are there any? Note the rim relation, channels and possible eruptive features.

On the floor: again, can you see textures or flow patterns? Pay special attention to colors and any fracture patterns.

Central Peak: Color, layers and layer orientation can all be important.

If the crater is filled in, note the shape and orientation of the fill: concentric, domed, polygonal, knobby or some combination.

Look also for relief, patterns, color, and especially the filling level (does it make it all the way to the rim?)

Seemingly Uncratered Surfaces

What about the surfaces where there aren't any craters? Note the characteristics: Relief, color, patterns, fractures.

Look for High Relief Structures. Are they knobby, domed, hummocky, or cratered?

Do you see any ridges? Are they parallel, or some other arrangement? Inspect ridges closely. Can you identify superimposed flows? Are they on mare or terra? Do they seem rounded, flat-topped, wrinkly or branching?

In these same areas you might find eruptive features and fine crater fields with a careful look.

Of course, there are also Low Relief Structures. Try to identify their source - can you see an obvious starting point? Is the area smooth, dark, light or very light?

General relief features such as domes, ridges, rimless craters and halo craters, rilles or fractures may also be visible.


Speaking of rilles, you should observe the tails for evidence of alluvial deposits. Observe the heads for any source of erosion agents.

It's particularly important to determine interruptions in continuity (this can be helpful for dating purposes).

Note the shape. Is it sinuous, linear, angular, arcuate, or some combination?

The Terminator

Generally, close attention should be paid to the terminator (where light meets shadow).

Identify flow fronts on low relief surfaces. Note glows or obscurations. Look closely for subtle relief: flows, patterns, or roughness.


Note size, shape, color, reflectivity. Mission threatening or passive? (Craig welcomes comments from observers on all matters relating to the moon. Email

Mail to: David North
Copyright © 2000 San Jose Astronomical Association
Last updated: July 19, 2007

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