Friday, August 24, 2007

Green flash at last

Back on land after a quick, but extremely good time on board the SSV Corwith Cramer. I have tons of pictures and will post some of them with a recap of the experience early next week.

For now though, I wanted to share that I finally saw the elusive green flash at sunrise Wed. morning while on dawn watch (more on that later too). For those who don't know about the green flash, it's a rare optical phenomenon (a small, brief, green flash of light on the horizon, "on top of" the setting/rising sun) that occurs the instant before sunrise or after sunset. It is best viewed where there is a clear, straight horizon, so it mostly associated with sunrises and sunsets over the ocean.

The green flash occurs because the sun's rays are refracted by the earth's atmosphere, separating the light into its spectral colors. When the sun is below the horizon, the shorter, blue wavelengths tend to bend more and get scattered before they reach an observer's eyes, thus there is no blue flash. The longer red and orange wavelengths bend less and do not scatter, but by the time they reach an observer's eyes the sun is just above the horizon and so get washed out by the sun's own brilliance, thus there is no "red flash". Green light waves sit in the middle of the spectrum and are refracted at a good angle and just the right time so that they reach an observer's eyes without being overwhelmed by the sun itself. Thus, under appropriate conditions, the observer sees a green flash.

I have well over a 1000 hours at sea and until this week had never seen a green flash. Some people deny its very existence because they've never seen it no matter how long they've spend on the ocean. Seeing this brief, but brilliant emerald green flash was certainly one of the highlights on my trip. I was in the right place, at the right time, under the right conditions. Definitely worth the lack of sleep.

Stay tuned for more details about the whole trip...I think I'm going to go sleep for a few days now.

UPDATE 8/31/07 - A reader, Priscilla B. from South Africa, emailed me about how the San people of South Africa call the Green Flash the Green Python and believe it to bring good fortune to those who see it. Apparently, I was supposed to make a wish when I saw it, but alas, I was too excited about actually seeing it to wish for anything, like world peace, universal health care, or a bitchin' 72" plasma, HD TV. Maybe next time.

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