Winter in Sweden

Martin Grosshög pictured a diamond dust halo display in a form beloved of artists - A cross through the sun and a circle studded by mock suns.

©Martin Grosshög, shown with permission.
A HaloSim ray tracing reproduces the display's main features.

Horizontal column crystals produced the impressive upper tangent arc. They also contributed to the upper and lower sun pillars. Internal and external reflections from their hexagonal end faces helped light the parhelic circle.

Plate crystals gave the bright 'mock suns' or sundogs. They too contributed to the pillars and parhelic circle.

Randomly oriented crystals of some form made the encircling 22 degree halo

Atmospheric
Optics
About - Submit Optics Picture of the Day Galleries Previous Next Today Subscribe to Features on RSS Feed
               
In this full size view we see the individual glints of the ice crystals.

Extending downwards from the sun, hexagonal plate crystals glint to form a sun pillar. More randomly oriented crystals refract rays to form the outer 22° halo.