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Calcium arcade

Chris Schur from Payson, Arizona

A magnificent arcade of coronal loops appeared on the Sun’s limb Sept. 1, 2024, captured here with a 3.2-inch refractor, CMOS camera, and a Calcium-K filter. These arcing features are caused by glowing plasma trapped in the Sun’s magnetic field. While often seen in Hα, they are less frequently visible in the Sun’s fainter CaK emission.