Normally, at sunset, the green flash appears at the upper edge of the Sun: atmospheric refraction and dispersion separate the colours, and green remains the last visible component for a moment. In this case, however, the eclipse had ‘cut out’ the solar disc, and the edge that was actually setting was the lower cusp of the crescent, very close to the horizon. It was precisely here, where refraction and dispersion are at their greatest, that the faint green component emerged.
The pronounced distortion of the crescent also reveals significant refraction gradients in the lower atmospheric layers, with a lower mirage component (Omega Sun), capable of further accentuating the colour separation.

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