As I was looking into the clouds on our way to Budapest airport, I noticed something on the left bottom corner. It looked like a rainbow but very circular one. Took a few pictures and color enhanced one of them. Sure enough it looked like a circular rainbow.

What I am not sure of is whether it is a true rainbow or something to do with the window of the airplane. I checked thru two other windows – I could still see the “rainbow”. And after a few minutes it went away – although the clouds were still there.

Can anybody throw some light on this? (sorry for the pun). Is this a real rainbow? Can rainbows be of this shape?