Astrophotography – Green Flash

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(Photo: Cecille Kennedy ~ View at EarthSky Community)

Green Flash
The green flash is a fleeting optical phenomenon,
sometimes seen at sunset or sunrise,
where a small green spot or ray of light is briefly visible
just above the disappearing or appearing solar disk.
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This occurs because of atmospheric refraction and dispersion of sunlight, separating the colours of the spectrum. 
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