Now that I've posted a sun halo, I guess I should show a sundog
|picture from fall 2011|
Since I learned that they exist, I've been seeing them 3 or 4 times a year. Before that, I never saw them, even during the years I worked outdoors, until the end when I knew about them.
This is the best one I've seen.
Update: for best sky pics, especially without a polarizing filter, try lowering your exposure by a stop or even 2 stops. Or, of course, do that afterwards in Photoshop by adjusting the exposure setting.
Aligned hexagonal ice crystals in the upper atmosphere. This one shows the prism-effect of spectral colors too.