Seeing green flash easier at sunrise
Dr. Young's fine article on green flashes in a recent issue ("Sunset spectacular," Issue No. 83), was fascinating and freighted with interesting data and good references. As a navigator standing four-to-eight watches in the Navy and merchant marine for years, I have seen many green flashes, since I was up and looking at the horizon.
My only substantial amendment to Dr. Young's interesting description and explanations is that it is much easier to catch a green flash at sunrise than at sunset. You must have a good idea of the correct azimuth. This can be done using a compass or a landmark if its bearing is known, and you must have binoculars.
Pre-dawn, low-light conditions greatly facilitate seeing the flash on the upper limb while the dazzling orb itself is still mostly shielded from your widened pupils. I also believe that the cooler night atmosphere intensifies the flash by widening the difference between air and water temperatures.
I tried to photograph green flashes many times before learning the sad fact mentioned by Dr. Young that the short focal length of the ubiquitous 35mm camera is unsuitable for the job and a much longer focal length is a necessity. And then there is the problem of knowing just when to press the shutter.
Dr. Young's rare and admirable photographs, by the way, give only a faint idea of the true brilliance of a live green flash, which is indescribable.
Bruce Allan Bauer is a retired naval officer and the author of The Sextant Handbook, published by International Marine.