A Full Double Rainbow

On my ride home from work yesterday I saw a nice rainbow. It only stretched about a third of the way across the sky, but I stopped to enjoy it. As I looked the sun became less obscured and the rainbow stretched into its full arc. Above it was another rainbow, also a full arc, but much less intense. I was thinking about rushing home to grab the camera when I realized it was in my backpack, which was conveniently on my back. I didn't have the F4 with the 20 mm lens, so I couldn't fit the whole thing into one frame, but here's a couple of the nicest shots: