Circumhorizon Arc Above Modica, Italy

August 08, 2023


Photographer: Salvatore Cerruto    
Summary Author: Salvatore Cerruto    

Featured above is the wondrous phenomenon known as the circumhorizon arc (CHA) gracing the charming city of Modica, Italy. The circumhorizon arc’s beautiful hues blend harmoniously with Modica's architectural wonders and rich heritage. It's as if nature is paying homage to Modica's cultural significance as a UNESCO world heritage site.

Circumhorizon arcs appear only in locations where the Sun can reach at least 58 degrees of height in the sky -- about a month or so on either side of the summer solstice in the mid-latitudes. As sunlight dances through ice crystals within cirrus type clouds, the ethereal arc suspends itself beneath the solar disk. But the CHA can only be seen when sunlight is refracted and dispersed through prisms (ice crystals) that are aerodynamically oriented with a hexagonal side facing upwards. Photo taken on June 9, 2023.

Modica (Sicily) Italy Coordinates: 36.8790,14.7691

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Salvatore’s Website