Welcome to my new blog :) For my first post, I’d like to talk a little about ice halos. Here’s a paraphrased description from Wikipedia’s article:
An ice halo is an optical phenomenon consisting of colored or white arcs and spots in the sky. They are produced by the ice crystals in cirrus clouds high in the upper troposphere. The crystals behave like prisms and mirrors, refracting and reflecting sunlight between their faces. The particular shape and orientation of the crystals determines the type of halo observed.
Here is a beautiful example of multiple ice halos (photo by solarthermienator, Creative Commons license):
I first become interested in ice halos in August 2010, when I saw a beautiful one just before sunset. I now actively look for ice halos in the sky, and take photos of them whenever I can.