Cloud Corona and Iridescence Above Curitiba, Brazil

March 16, 2022

EpodIMG_6693 - Copia

Photographer: Fabiano Belisário Diniz

Summary Authors: Fabiano Belisário Diniz; Cadan Cummings

In the late morning on December 12, 2021, I saw a group of cirrocumulus clouds moving across the sky towards the Sun. I quickly grabbed my camera and headed for an open area expecting some beautiful cloud coronae and/or iridescences. Both coronae and iridescences are phenomena produced by optical diffraction when water vapor or ice crystals in the air unevenly scattered the incoming light wavelengths, similar to a prism.

My first sight was fortunately a perfect corona with vivid colors. As the clouds moved through the sky, sometimes the corona turned into an iridescence. After around 20 minutes, the show come to an end. As a note, it is always best practice to take precautions when viewing or photographing near the Sun. During this event, I remembered to shield myself against the intense sunlight close to the zenith, hiding the sun behind the building or some trees.

Photo details: Canon 6D with Canon 28-135mm lens at f/9, ISO 100 and 1/3200s.

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