Monday, 25 June 2012
When, at nearly 10pm one evening when he was visiting last weekend, David called me very enthusiastically to drop whatever I was doing and bring my camera outside, I was met with one of the most spectacular skies I've ever seen outside of the aurora borealis (which used to seem quite frequent here but which I haven't seen for many years).
I am not aware of ever before having seen a vertical rainbow nor, for that matter, a sunset rainbow either. The latter explains the former.
Sunset rainbows are special [because] the sun's rays are nearly horizontal, so the top of the rainbow will be high in the sky. In fact, a sunset rainbow is the widest arc you'll ever see from the ground: almost half of the full-circle rainbow can become visible....... Sometimes only the end segment of the rainbow appears, and if you see a photo of a vertical rainbow at the horizon, you'll know it was made at sunset (or sunrise). With a little geometry work and a sun angle chart, you can tell time using a rainbow at the horizon.
As we watched the light changed altering the colours of the clouds and the rainbows and the rainbows changed composition too.