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David Callejas

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January 20, 2019

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Nina Gorenstein
West Lafayette, IN, USA

06/17/2021
11:32 pm

Equipment Details:

Nikon Coolpix P900

Post-processing Details:

Cropped, combined

Image Details:

Growing moon in five consecutive days.
Although every earthly day (24 hours) the position of the terminator shifts along the SPHERICAL surface of the moon by the same distance, the position of the terminator on the lunar DISK (as we see the moon from the Earth) changes unevenly: the moon "grows more slowly" in the first days after the new moon and "grows faster" as approaching the first quarter. In the first days after the first quarter, this "rapid growth" continues, and the "daily gain" decreases in the days before the full moon. Geometry explains this phenomenon.

Posted

January 20, 2019

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David Callejas

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About the Author:

David Callejas, Marketing Director, helps bring EarthSky's content to the world via online ads and other products. He creates strategies that help people around the world find us and appreciate the work we do. He helps manage the EarthSky Store and bring to you the new products that you love. He's the chief liaison between EarthSky.org and the world of commerce. All that, plus he helps post content and populate our pages on Facebook, Google+ and Twitter. Go David!