My camera is finally back from the shop and I had to take it out and put it through its paces on a sunset. I keep chasing those green flashes. This sunset looked a little odd and when I downloaded the pics, I got a pleasant surprise. I cropped these pretty close due to the fact that the effect is subtle and difficult to see.
This is a full res pic (now I am wishing I had a higher pixel density or a longer zoom!) Note how the Sun appears nice and yellow on the left. As you progress to the right (where the Sun has just set) you see some green. Further right, you start getting a hint of blue...yes, the even more rare blue flash! This pic is the first time I have caught any hints of blue. Normally, the blue light is scatter by Earth's atmosphere so you don't see it, only the longer wavelength green which is not scattered as much is visible. On rare occasions with a clear atmosphere, you can get the blue. Here are the next two pics in the series.
I have known that blue flashes are a possibility and even seen pics on the web...now I have seen it in my own photos and want a better camera and lens to take it further...I hope I can hold out...this could be an expensive discovery!
Reprinted with permission from the Half-Astrophysicist Blog.