Sun Halo

Sometimes it looks like the Sun is being viewed through a large lens. In the above case, however, there are actually billions of lenses: ice crystals.  Photographer Peter Rosén

As water freezes in the upper atmosphere, small, flat, six-sided, ice crystals might be formed. As these crystals flutter to the ground, much time is spent with their faces flat, parallel to the ground. An observer may pass through the same plane as many of the falling ice crystals near sunrise or sunset. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our view and creating phenomena like parhelia, the technical term for sundogs.

A Sun Halo Over Cambodia

Sun Halo2

via apod