I never knew much about one of my favorite photos. What caused the colors, this halo?
The mystery and speculation were pleasurable, I'll admit, but only for a while. Searches for an explanation were useless, as I lacked the vocabulary necessary to divine a description of the rings I found so pretty. The quick syntax I submitted is hilarious in hindsight: "airplane rainbow circle", "ring plane spectrum", "corona clouds shadow".
Thanks to the connective magic of Flickr, the word Glory is now of my employ. In a comment posted 4 weeks ago, but unread until today, Permaculture gave me the lead I was looking for; a link to Atmospheric Optics, from which I nicked the above images and solid understanding of what I witnessed from that plexi porthole.
Image 1: Philip Laven
Image 2: Franz Kerschbaum
Image 3: Jonathan Lansey
Image 4: Nik Szymanek