how cool

Don't see a double rainbow too often.

Great shots! Thanks for sharing.

I've made a study of the physics of the light reflection, and I'm mostly good with it, but I still don't understand the dark band between them. Is it darker because the light has been refracted away from the band, or is it part of the light spectrum invisible to the human eye?

DU physics people, please explain it to me in layman's terms without making me look stupid. Thanks.

It's just that they are rarely bright enough to be seen. When white sunlight enters each raindrop, it bends. The bending breaks light into its rainbow colors. The light then reflects off the back of the raindrop. On leaving the drops the light bends again. (Each raindrop scatters the full spectrum of colors, but you will see only a single color from each drop). Sometimes light reflects twice inside the raindrop. This action will form two rainbows: a primary rainbow that is produced by the first reflection of light and a larger secondary bow above the first, produced by the second reflection. Colors in the secondary bow are in reverse order to those in the primary rainbow, with red on the inside and violet on the outside. Since only a small number of rays experience this double reflection, the secondary bow is always fainter than the primary.

Between the two bows lies an area of unlit sky referred to as Alexander's band. Light which is reflected by raindrops in this region of the sky cannot reach the observer, though it may contribute to a rainbow seen by another observer elsewhere.

I once experienced a brilliant double rainbow while driving due south on a totally flat basin, the apex of the bows were just north of due east. The apex remained the same, but the dimension of the rainbows grew and shrank as I drove parallel to the rain cell. I got to study it for, maybe, ten minutes, with a million questions flashing through my mind, and I was able to answer most.

As I mention in my post, upsthread, I'm well versed in the physics of the light refraction inside a circular raindrop, and why both rainbows are reversed, but I knew NOTHING about that very pronounced dark band between them and it's been bugging me for years. Alexander's band (Alexander of Aphrodisias)! You just never know what you will learn on DU!

He'll never destroy the earth with a flood again.
God is good.

Next time he'll just burn everyone alive instead.

Which group do you plan on being in?

Well quite obviously since this god of yours has no issues with drowning babies and pregnant women en masse, I have no interest in the "obedient" group.

Sunlight being broken up into it's component colors by raindrops, the way a glass prism does.

No God needed.

Ask the larger dinosaurs.

My ancestors were small burrowing mammals.

8th grade Science class, thank you Mr Yandrow. I never forgot.

What a beautiful sight!

Love it.

ConnorMarc, welcome to DU. I am personally an atheist, but I respect you and your spiritual beliefs. I apologize to you for those who don’t. Many atheists have an ax to grind with religion, spiritualism, and anything to do with such belief systems (perhaps some bad experiences in their formative years?)
At any rate welcome aboard, if you support our political beliefs you are one of us.

Great catch!

I found the end of a rainbow once. I kid you not. Well, OK, I think it was the beginning because there was no damn pot of gold. Leave it to me to find the wrong end.