This was a really cool moment I almost missed several years back while in Navarre Beach, FL. The clockwork afternoon thunderstorms were a bit late that day so I had given up on there being any chance at an open sky at sunset. Just so happened to look out the front window and all I could see was purple. Luckily this spot was within walking distance. I was able to get 2 shots and the anti-crepuscular rays disappeared like someone cut off a light switch.