Upper Tangent Arc Observed over San José Pinula, Guatemala
Photographer: Fabriccio Díaz
Summary Author: Fabriccio Díaz
One morning several weeks ago, I captured this charming upper tangent arc (top center) using a drone, near my home in San José Pinula, Guatemala. These arcs are tangent to the 22-degree halo and can only be seen when the Sun is relatively low in the sky. They take shape when the hexagonal ice crystals that make up cirriform clouds are oriented with their long axes more or less horizontal. So, sunlight that enters one of the crystal’s side faces is refracted and then exits an alternate side face. Note also the sundog to the right of the Sun. Photo taken approximately 6:30 a.m. (local time) on May 6,2021.
Photo details: ISO 100; f10; Mavic 2 Pro; Merged and edited in Adobe Lightroom.
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