AMU Editor's Pick Original Space

Good Morning Moon: The Crescent in the Pre-Dawn Sky

There is very little more inspiring than seeing a beautiful crescent moon rising above the Georgia pines on a crisp winter’s morning. The accompanying photograph was taken from my observatory on the morning of February 8, just before sunrise. I used my trusty RASA 8 telescope with its ASI294 color camera to capture a series of 2300 images over a few minutes’ time that were then stacked, combined, and processed into the image presented here.

Technically, astronomers call this phase of our moon a “waning crescent.” This means that the amount of the moon we see each day wanes or decreases. The moon shines in the sky because of sunlight reflected off its surface.

One of the oddities of spotting a crescent moon in the sky is that you can see the entire globe of the moon – not just the illuminated crescent. Appearing somewhat like a three-dimensional ball in the night sky, the moon’s “night-side” is faintly lit not by the Sun but by our Earth. This phenomenon is called Earthshine, which results from sunlight being reflected or bounced off the Earth and then onto the moon.

Although very little of the moon presents itself at this slender phase, observers can still make out its most basic features, which include the smooth dark-maria near the top and cratered highlands at the bottom. The northwestern edge of the crescent is known as Oceanus Procellarum, the “Ocean of Storms,” an area covered by dark volcanic flows. In contrast, ancient craters more than four billion years old scoured the southern crescent’s limb.

When I gaze at the moon, I often think about the 12 Apollo-era astronauts who walked on its surface more than 50 years ago. However, with NASA’s Project Artemis leading the way, it is stirring to think that humanity will soon return to our nearest neighbor in space. Before the end of this decade, both men and woman will gaze across the quarter-million mile gap from the moon to Earth, perhaps seeing our very own planet as a giant waning blue crescent in their black sky.

Dr. Ed Albin is an Associate Professor and Program Director of Space Studies in the School of STEM (Science, Technology, Engineering and Math) at American Military University. His academic credentials include a Ph.D. in Planetary Geology from the University of Georgia, an M.S. in Geology from Arizona State University and a B.S. in Earth Science from Columbus State University. Ed is an astrophotographer and held positions as a planetarium lecturer, a commercial helicopter pilot, and a planetary geologist.

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