Monday, February 05, 2007

Sun dog

When I was researching heiligenschein recently, I also read about Sun dogs a.k.a. parhelia or false suns. I'd heard the term but had never seen the phenomenon, although it's apparently not rare.

OK, so if sundogs are fairly common, I should start seeing them once I started looking for them, right?

Yep.



Sun dog!



Cool.

It looked much brighter in person. There are usually two, spaced evenly on either side, about 22ยบ away and at the same altitude as the sun. I couldn't see the twin on the other side, even when I moved to a vantage point without trees. The clouds on that side looked different. Thicker.

When I first saw it, I thought it was a rainbow, or rather cloudbow. It looked like the lower arc in this picture, with the addition of a bright white spot just to the left. We were almost home from the grocery store, but by the time I rushed in to grab the camera, the long "bow" portion of the parhelic arc had vanished, and never returned. The sun dog got brighter and dimmer as the clouds shifted.

I was a happy camper.

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Parhelia are formed by light passing through horizontal hexagonal plate ice crystals in the clouds. Certain types of clouds produce them more often, and they are most often seen when the sun is low. (See here.)

Another good site for atmospheric optics:
http://www.meteoros.de/indexe.htm

20 comments:

robin andrea said...

That's great looking atmospheric optics. I've been seeing rainbow affects in the clouds lately, too. There was a place in the sky recently, that when the clouds moved past it, each cloud became filled with rainbow colors. I tried to photograph it, but was unsuccessful. Your photographs are fantastic.

James Cooper said...

Hah, neat! Now I've got to keep an eye out for sun dogs. By the looks of it, it doesn't have to be very cloudy for them to make an appearance. I'll have to keep an eye out during my bike commutes :-)

Rachel said...

Interesting! I have learned something new today! Thanks!

Happy and Blue 2 said...

I used to see sun dogs quite often until I started staring at the sun and went blind..

edifice rex said...

Hey Karen! We saw that same sun dog yesterday! Allen and I were working up on the roof and I looked over and there it was....pretty cool! It faded quickly from our view though or maybe I didn't notice it until it was almost gone.

Linda K said...

My Dad used to say seeing one of these was a sign of rain.

Laurie said...

Very, very cool! I learned something new today. Great pictures.

Ontario Wanderer said...

We see sun dogs fairly often but more often in winter than summer. Regardless, your photo is much better than any I have been able to get so far. Well done !

pablo said...

When I was vacationing in the Carribean, I watched and watched for the Green Flash at sunset, but I never saw it. Some people just lead charmed lives.

Rurality said...

Thanks everybody. I had to play with the contrast on these pictures to get them to resemble what I saw with my eyes. (Otherwise they were too washed out.)

Now that I'm aware of sundogs I think I'll try to keep a better eye out for them, and the other halo stuff too.

Clare said...

We see them a lot in the north. When I was growing up we always said that sun dogs were harbingers of colder weather, but that doesn't seem to be the case here.

Ki said...

Great photos. I can't say that I have ever seen a sun dog or at least don't remember seeing one. Now that you've posted these pictures, you've piqued my interest and I'll have to scan the skies more carefully. Thanks.

Mark said...

Sundogs are, indeed, common. Look for them when the sun is near the horizon. The cloud cover has to be just right, not too thin and not too thick, and usually high. Since they are formed in ice clouds they are more common in cold weather, although clouds high enough in the atmosphere are ice at any time of the year. An interesting thing to watch for is other colorful displays near the sun. If the conditions are really good, you can see close to an entire circle around the sun. You might also see bright columns above and below the sun. All of these depends on the particular shape of the ice crystals. Thin plates give sundogs, columns give arcs as well as sundogs.

I once saw the green flash. I happened to be in a car driving along the beach in Hawaii at sunset and happened to look at the right time and there it was, so green and bright I could hardly believe it.

Floridacracker said...

Cool! I see those from time to time. Always special.

The suncat is a much less impressive phenomena of course.

KFarmer said...

Whoa Nelly- now that would be something to see. Wonderful shots. I hope with the addition of this post you are feeling better :)

Cathy said...

Welcome to the Sun Dog fan club! Good to see you posting again.

Rurality said...

Thanks y'all. I am feeling better, but not back to full steam just yet.

Mark, thanks for the technical info. I'm jealous of your green flash!

Now I'll have to look for suncats too. ;) FC always cracks me up!

Cathy said...

I almost missed the grackles! Neat picture.
Hang in there - those back things are usually self-correcting - tincture of time. Hope your feeling bouncy, soon.
BTW - Couldn't find the 'comment' section under your 'Puffed Sky' post.

Rurality said...

Thanks Cathy, I had accidentally turned off the comments on that one.

high hopes gardens said...

Love to share a vertical sundog from today "up north" http://highhopesgardens.com/blog/2007/02/14/

Mark at high hopes gardens