Nearing the end of a long summer day, less than an hour from sunset, a sun shower passes through. Out the window we see a remarkable sight: a double rainbow in front of a blue sky! Conditions were basically perfect: bright sun coming in at a low angle against a darkening sky. It was one of largest and brightest rainbows I’ve ever seen.

I grabbed my DSLR and started taking photos. For the first time I had taken a good photo of a rainbow (they tend not to look nearly as dramatic in photos as the look in real life).

As I was looking through the viewfinder, I thought “wow, it kind of looks like there are extra bands beyond the violet on the main arc. And the photo confirmed: there are. It turns out there is more to rainbows that I knew about.

But before we get to that those extra bands: what is a double rainbow? For that matter…