It's common to see the ring around the sun when there are cirrostratus clouds in the sky.
Last night (February 27, 2018), patchy cirrostratus clouds created this really nice lunar halo that changed in brightness and texture by the minute. Despite the bright moon and the clouds you can stil see some stars shining through. PC: Weather & Sky Photography by Kerry
Cirrostratus with mock sun ~ usually signal the approach of a warm front.
CIRROSTRATUS over Low Clouds A very thin and uniform layer of cirrostratus cloud over low clouds in Ohio. The low clouds are on the edge between cumulus and stratocumulus. Photo by Carolyn Green in Ohio,
CIRROSTRATUS Haze This photo, taken near sunset in Colorado by Kevin Larman, show a very thin and very uniform cirrostratus cloud with streaks of thicker cirrus (perhaps old contrails? Near the horizon some opaque low clouds are visible.
Circumzenithal Arc or Circumzenith Arc (CZA)-- also called the Bravais' arc, is an optical phenomenon similar in appearance to a rainbow, but it belongs to the family of halos arising from refraction of sunlight through ice crystals, generally in cirrus or cirrostratus clouds, rather than from raindrops. The arc is located at a considerable distance (approximately 46°) above the sun & at most forms a quarter of a circle centered on the zenith. It has been called "a smile in the sky", its…
Amazing cloud - Cirrostratus nebulosus, Santa Catarina, Brazil This species of cirrostratus cloud is so light it’s often invisible unless illuminated from a certain angle by the sun, which produces a halo effect.