Ice Halo Lab

Feature / crystal orientation Sun altitude 20° Rays per frame 3000 Dispersion (colour)

Stats

Rays traced0

Min. deviation21.8°

Refractive index n1.310

Sun altitude20°

Prism angle60°

Sunlight bends through the 60° faces of hexagonal ice crystals. The smallest possible bend — the minimum deviation of ~21.8° — is where most rays pile up, so a bright ring forms at 22° from the sun. Random columns give the full halo; flat-floating plates concentrate light into sun dogs left and right of the sun.