Irisation forms by light diffracting around waterdrops in clouds and interfering with itself. It is indeed the larger version of corona, but often fragmental.
2003/2/15 15:13 PST. An iridescent cloud above the sun (which itself is visible in the darker cloud). Nikon coolpix 995 digital camera, underexposed. Death Valley, CA.
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All images by Jerry Xiaojin Zhu unless noted otherwise. Feel free to use them for your personal enjoyment. For other usage please contact the author at jerryzhu@gmail.com
