Sun dogs light up the sky

My friend Austin took this photograph last week, looking out his office window near the Metrodome in downtown Minneapolis. That flare in the distance isn't Photoshop. Nor is it the nuclear annihilation of St. Paul. Instead, it's a sun dog — an atmospheric phenomenon that happens when light from the Sun is refracted off of ice crystals in the air. The light gets bent as it passes through the crystals and we see the bright flash of a "false sun" to the side of the actual Sun. The same process can also form rings around the Sun. Whether you get a halo or a sun dog depends on which way the ice crystals are oriented in relation to you.

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  1. The sun dog is beautiful, but so are the intricate ice patterns on the window. Cold weather may not always be fun but it can produce some amazing effects.

  2. It took me a short while to figure out that those patterns were on the window, and not smoke/steam from the industrial complex being caught by the light of the sun...

    But yes, patterns in ice (and in nature as a whole) fascinate me. Try to find a beach with lots of shale/broken up slate - it seems to re-arrange itself into the most fascinating of patterns all on it's own.

  3. More than you ever wanted to know about the the optics of ice halos (and other atmospheric optics, too - rainbows and glories and crepuscular rays, oh my!) including simulator software that lets you specify conditions, sun angle, etc., and then calculates the resulting halo(es):

    http://www.atoptics.co.uk/halosim.htm

  4. I suppose you're referring to that bright streak to the right of the sun? I'm afraid that's just a wisp of cloud (perhaps a contrail) being lit up. A proper sundog would appear much further to the right/left. As cbrewer314 already pointed out, what we're seeing here is not a sundog, but a sun pillar.

    To all those who would like to learn more about these phenomena and their proper nomenclature, I can cordially recommend paying a visit to the link glenblank posted. There is also a subreddit dedicated to the subject at www.reddit.com/r/atoptics.

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