a green coloration of the upper portion of the sun, caused by atmospheric refraction and occasionally seen as the sun rises above or sinks below the horizon.
a flash of bright green light sometimes seen as the sun passes below the horizon, caused by a combination of the dispersion, scattering, and refraction of light
Collins English Dictionary - Complete & Unabridged 10th Edition
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The image also captured a so-called green flash near the top of the sun.