Sterling Arc-er

Regular readers know that one thing I do whenever I step outside is look up. Always. It's a habit, and a good one: I see a lot of cool stuff going on in the sky I'd otherwise miss. I recently ran an errand in town, and when I stepped out of the store I did that very thing. And when I did look up, I was rewarded with a glimpse of a beautiful circumhorizonal arc. It's so pretty! They're caused by ice crystals in cirrus clouds bending sunlight toward you, and can only occur when the Sun is higher t...