Shafts of light and shade rendered visible by atmospheric haze are known as crepuscular rays – at least, they are when you see them emanating from the direction of the Sun. But these light effects have a rarer and less familiar counterpart that only appears when you’re looking the other way completely: off towards the horizon with the Sun behind you.

Anticrepuscular rays, like these spotted by Sara Aerssens over the Indian Ocean from Addu Atoll in the Maldives, can appear in the morning or evening with the Sun near the horizon directly behind you. Sara spotted her rays at sunset. They were shadows cast right across the sky by clouds in front of the Sun that was near the horizon behind her. These cloud shadows were being cast right across the sky.

A thin, high layer of ice crystals known as a Cirrostratus cloud likely provided the haze needed to scatter the evening sunlight and reveal the beams of light and shadow. Anticrepuscular rays are in fact parallel but appear to converge at a point opposite the Sun due to the effect of perspective. Sara’s rays were accompanied by small Cumulus in shadow that punctuated the calm evening sky.