Moon Dog-- moondog, or mock moon, (scientific name paraselene, plural paraselenae, meaning "beside the moon") is a relatively rare bright circular spot on a lunar halo caused by the refraction of moonlight by hexagonal-plate-shaped ice crystals in cirrus or cirrostratus clouds.
Shadow Chaser 0476 - A sun pillar chases the shadow of Mt Hood across the sky. We're overlooking the Sandy River Basin which is frequently covered in fog in the early mornings. Sun pillars happen when rising or setting sun rays reflect off high altitude ice crystals in cirrostratus clouds.
Good picture taken today at the NWS Spokane office. Some cirrostratus clouds have led to a noticeable ring around the sun.
Sun Halo - an optical phenomenon produced by ice crystals creating colored or white arcs and spots in the sky. They are produced by the ice crystals in cirrostratus clouds high in the upper troposphere. Light is reflected and refracted by the ice crystals and may split up into colors because of dispersion. The crystals behave like prisms and mirrors, refracting and reflecting sunlight between their faces, sending shafts of light in particular directions. www.indigodivers.com