Last night I spotted a beautiful lunar halo. Time for some astrophotography!
Lunar halos are caused by ice crystals in high cirrus clouds. Since those high-cloud ice crystals can precede low-pressure systems, they sometimes mean rain is coming. And, in fact, that is what the weatherman predicts.
BTW, these halos are quite large, 22 degrees in radius, as my use of my widest angle lens might suggest.
Camera geek info:
- Canon EOS 60D in manual mode set at f/4, 4 second exposure, ISO 400
- Sigma 10-20mm f/4-5.6 lens, set at 10 mm, manual focus at infinity