This has to be the best full rainbow I have ever seen! In addition, it was double
The original image is a panorama from 6 photos taken by Sony DSLR-A100 (vertical) which came to about 25 megapixels. Kit lens at 18mm, ISO100 and F/8. It was almost impossible to get both of them to fit - this was a pretty massive field of view. I got lucky, I guess! The colours are real, this was 5 minutes before the sun touched the horizon.
I struggled to remove the distortion, which resulted from it being a panorama and some of the houses being relatively near, and finally succeeded today!
Usually, I am the sunset specialist [link]
and this rainbow caught me heading out to get the sunset that day. This [link]
is one of the shots I got of the sunset that day.