Of a cold winter night one would not be surprised to see a bright 22°halo around the moon, http://en.wikipedia.org/wiki/22%C2%B0_halo But that is winter – and winter is cold after all.
At midday in June the heat of the sun would tend to turn ice crystals into water droplets and that would appear only as an amorphous halo around the sun. It did not today. Lucky us – in Marin and some parts of Sonoma – to see this on a pristine cloudless summer’s day. There must have been a freak layer of moisture at very high altitude.
Here is a gallery of 8 higher resolution pictures http://www.philipchudy.com/galleries//ringaroundthesun
With the sun so high in the sky, it was stunning how bright the ring appeared. The brightness of the ring itself I is the ‘once in a lifetime’ element. I would guess that this is a function of the height of the sun above the horizon. In winter the sun is never that high and one tends to see sun dogs instead https://en.wikipedia.org/wiki/Sun_dog
I accosted a few people I saw wondering down the street and said “look”, pointing up at the sky. Most greeted this with a hint of a scowl at first (who is that crazy!) but it was comical how stunned they were as soon as their eyes were raised a few degrees. And some nearly ducked when they saw it before bursting out laughing. What does not come across in the photos is how big the thing looked in real life. You really would want to duck. I shot the pics mostly on 16mm wide angle because without some trees and buildings, there would be no sense of it at all. But that has the disadvantage of making the ring look small in the shots.