On my way into work this morning I noticed some very pretty sundogs in the sky. Fortunately I had my camera with me so I was able to pull over and snap a few shots. This first picture gives you an idea of the overall scene. (Make sure and click on the thumbnail so you can see the full size image). The sundogs are the bright arcs on either side of the sun. Note that in the image, the sun appears much larger than in real life. This is due to the cameras sensor being saturated by the brightness (or, more accurately, me not knowing how to truly use the cameras features!)
Sundogs (technically called parhelia) are atmospheric phenomenon formed by plate-shaped hexagonal ice crystals in high and cold cirrus clouds. These crystals act as prisms, bending the light rays passing through them by 22°. If the crystals are randomly oriented, a complete ring around the sun is seen --- a halo. But often, as the crystals sink through the air they become vertically aligned, so sunlight is refracted horizontally -- as in this case, and sundogs are seen. These two shots are zoomed in images of the sun dog that was on the right side of the sun.
This is a picture of some very bright sundogs taken in Fargo, North Dakota in the February of 2009...I am cold just looking at at! If you would like to explore more about Sundogs and other similar atmospheric phenomenon, I would recommend you visit this webpage on atmospheric optics.