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  Green Flash

            The sun slips slowly downwards to a clear ocean horizon. Ever reddening as it sinks, soon only a thin sliver of the once hot disk is left. Then, as that too shrinks and lessens, it shines forth for just a second in a most vivid emerald green. Then it is gone, only the dark ocean remains. That is the green flash of fable.
Flashes like that do occur. A clear atmosphere produces the best ones but it is not absolutely essential. Sometimes the flash is more yellow, very rarely it is even blue. If you are energetic, observe on a hill or dune and run up after the flash has occurred - you could see another one. There are sunrise flashes too if you are alert for the very place and moment that the sun will appear.

There are other types of flash. Some do not need an ocean horizon. The next few pages describe them and the subtle atmospheric conditions that produce their colour and brilliance. There also some clues as to which sunsets will produce them. ↓
Take care of your eyes. Never stare at the sun and never look at it through binoculars, a telescope or the optical viewfinder of an SLR camera - your eyesight could be permanently damaged.

This section owes much to green flash expert Andrew T Young and his site should be consulted for a definitive account. Thanks also to all the photographers
for generously giving permission to use their fine images.

Two types of green flash. That on the left captured from Belgium by Florian Schaaf is an intense flash of emerald green as the last vestige of the sun sinks beneath the horizon. This is the type usually described and seen by eye.   To the right, a detached green fragment on the setting sun, imaged in the Spanish Canary islands by Tony Cook, is the green flash more often photographed. Click images for other versions. ©Florian Schaaf & Tony Cook.