A subhelic arc is a rare halo, formed by internal reflection through ice crystals, that curves upwards from the horizon and touches the tricker arc above the anthelic point. Subhelic arcs are a result of ray entrance and exit through prism end faces with two intermediate internal reflections.
Famous quotes containing the word arc:
“Male urination really is a kind of accomplishment, an arc of transcendance. A woman merely waters the ground she stands on.”
—Camille Paglia (b. 1947)