The Dogs of Sun

By Phil Plait | December 29, 2007 5:00 pm

I forgot to post about this! The other day, after the fam and I were out watching "I Am Legend", we saw a sundog, a bright feature in the clouds caused by ice crystals bending sunlight. I’ve written about these zillions of times.

This one was different though. When I first saw it, I thought it was the Sun! There were low clouds on the horizon, and it looked like the Sun was trying to break through them. But then I saw the actual Sun, quite a bit to the left! It was amazing. The sundog was so bright I could hardly look at it. When I put my polarizing sunglasses on, the glare went away and I was treated to a spectacular rainbow of colors where the sundog was. It was far and away the brightest one I have ever seen. I’m still kicking myself for not having had my camera with me.

Update: my bro-in-law Chris just told me he got a shot of it with his phonecam! So here it is. The sundog is on the right (partially behind the light pole), and the actual Sun on the left. This was when the sundog had already started to fade.

In olden times, sundogs were called "the false Sun". I never understood why, until this week.


Comments (13)

  1. Law Mom

    Coolio. I never knew what these were called, but more than once I almost got in a wreck because I was looking at the sky instead of the road!

    I found this gorgeous picture:

  2. Since we sit in the foothills north of Colorado Springs I see sun dogs fairly frequently in the winter when I go out to feed horses near sunrise. I always get a big kick out of them though it was years before I realized what they were called.

  3. Mark Martin

    Did Phil just say “The Dog & Suds”? They have the world’s best coney dogs.

  4. Scott G.

    This is such a coincidence. While driving from PA to VA today, my family and I saw the most brilliant sun dog ever – the same effect you describe above, Phil – so bright we thought it was the sun behind the clouds until we noticed the somewhat (but not too much) brighter real sun to the left. A huge rainbow effect as well – much more vertical than I have ever noticed before (with better color visibility even without sunglasses). This was about 4 PM Eastern from the lovely southbound lane of Maryland’s I95.

  5. Michael Lonergan

    I used to see these every winter in Edmonton when I lived up there. They always appeared in pairs, one to the left and one to the right, with the sun in the middle. Usually there was a bright halo accompanying it. They were especially bright when ice fog hung heavy in the air.

  6. Michael Amato

    Two years ago I also saw a very bright and colorful sun dog as my friends and I were leaving a Yale football game. It was the most glorious sundog I’ve ever seen and I have seen many. Of course no of us had a camera.

  7. hale_bopp

    One day driving across the cornfields of Illinois on an amazingly cold, clear morning (the high for the day was about -20F!) I was treated to a spectacular sunrise with a wonderful sundog on each side, both looking amazingly like the Sun. It was a freakin’ triple sunrise! It really felt like another planet for a while!

  8. r a varga

    Happy New Year! Sun dogs are fairly common in these parts, I don’t know anyone who has bothered to photograph them with the possible exception of a few news/weather photogs & the usual dedicated local astronomers. The best I’ve ever seen was at noon, mid-Dec/January many years ago, with a sun dog to each side of the sun (East & West) and a halo connecting the dogs, possibly another 2 smaller dogs North & South of the sun, just pups. Spectacular, but I’ve been told, not possible, any comments?.

  9. Edward C

    Happy New Year, Phil.

  10. Perhaps you’ve addressed this before, but I’m too lazy to do a search. Are sun dogs always 23.5 degrees (the Earth’s tilt) from the sun?

  11. I understand that reflections and images of the sun in clouds have likely generated a lot of UFO reports, to the point where I used “sundogs” as a shorthand for the “UFOs-are-natural-phenomena-misunderstood” group of reports. Seeing shouldn’t always be believing; make an effort to check out what you actually saw first.

  12. MandyDax

    @Lugosi: The phenomenon is caused by refraction through or reflection off of ice crystals in the atmosphere and doesn’t have anything to do with the tilt of the earth’s axis. The sun dogs usually form at the horizontal intersection with a 22° circle centered on the sun. Depending on if it is refraction or reflection, it might appear as a bright spot, like the one BA shows here (reflection), or it might look more like a section of a rainbow (refraction).

    I saw moon dogs this summer. Some friends and I were sitting on our dock watching the full moon rise over the lake, and there were thin ice-laden clouds above the horizon. As the moon rose and the clouds moved, the moon dogs (which were the refractive kind) gave us some brilliant rainbow segments on either side of the moon.


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