Miraged Moonset

An almost full moon sets over the Arizona/California desert. A morning sequence taken over 8 minutes by James Newt Perdue.

Overnight the desert has radiated heat away into space. The chilled surface has in turn cooled the lower air layers to create several temperature inversions. Cold air beneath warmer - The stuff of mirages.

The sequence starts with the moon already noticeably flattened. Then the moon sinks into a strong inversion. Its south bulges downwards as refraction across the inversion temperature gradients takes hold.

Then a second inversion shows as a bulge beneath the bulge.

The final sequence is a classical mock mirage with three images. The uppermost descends. The next is inverted and ascends. That nearest the horizon is erect and sinking.

Atmospheric absorption increases towards the horizon and within the inversion layers. The image colours are not manipulated and are realistic. The silvery moon turns to orange and then to reds as the atmosphere scatters more and more short wavelengths elsewhere.

All images ©James Newt Perdue, shown with permission
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