A Green Moon

Lunar eclipse

A Green Moon: Total Lunar Eclipse

Much has been made of a Blood Moon, a reddish moon in a total eclipse…and we all know of a blue moon. But how often do you hear of it being green?

I caught the moon in one such view with a Kodak AZ251 at its maximum optical zoom (25X) during the recent total eclipse early Saturday morning. See the greenish tint in the picture above? It doesn’t appear to be a camera or low-light artifact. Another view a few minutes later, with even less light and the very same camera settings, appears correspondingly darker in the picture below.

Silver and reddish brown moon at the cusp of a total eclipse

Silver and reddish brown moon at the cusp of a total eclipse

If you look carefully enough at the very beginning of the total eclipse, as in the second picture above, you may see the rest of the moon colored a faint reddish brown. Beyond this, with a complete absence of direct sunlight shining on the moon, I did see it a brighter red, lasting for a while before direct sunlight began to shine on an edge again. My rather basic digital camera could not capture the red phase at all.

Discussing this with a friend, a professor in optoelectronics at a preeminent university in India, we think the green moon is an opportune capture near the cusp of a total lunar eclipse. Through a combination of refraction (varied bending of different light wavelengths, as in a Prism) and scattering through earth’s atmosphere, that limits the spectrum of sunlight reaching the moon, a mixing of light from the yellow to the blue wavelengths could have given us this greenish tint. This may only occur for a very short period of time before the eclipse, if at all.

It did make me wonder: could there also be a blue tint, for a fleeting moment even? But blue is a color scattered most by the atmosphere – hence the blue skies we see so often – and any such light passing through the atmosphere on to the moon is most likely quite dim… A blue moon is hence highly unlikely, making it an apt indicator for similarly unlikely expectations!


Update (Aug. 1, 2015):  BBC article on a Blue Moon (the second full moon in a calendar month) around the world.


About Rian Nejar

Rian Nejar is an Indian-American author. He trained and worked as an engineer in India, lived briefly in the Middle East, and arrived in America in the early 90's. After a Master’s degree in electrical engineering in America, he worked as an academic instructor, engineer, entrepreneur, and technical writer over the two decades since. Humbling and Humility (http://goo.gl/FKUnCM) is his first mainstream nonfiction. He lives and writes in the Southwest United States.
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