band between rainbows
known as Alexander’s band
who first described it

What is a double rainbow?
A double rainbow is a wonderful sight where you get two spectacular natural displays for the price of one.
Surprisingly, this phenomenon is actually relatively common, especially at times when the sun is low in the sky such as in the early morning or late afternoon. The second rainbow is fainter and more ‘pastel’ in tone than the primary rainbow because more light escapes from two reflections compared to one.
The secondary rainbow is also dispersed over a wider area of the sky. It is nearly twice as wide as the primary bow.
A key feature of double rainbows is that the colour sequence in the second rainbow is reversed, so instead of red, orange, yellow, green, blue, indigo and violet (ROYGBIV), the colours appear in VIBGYOR order.
The dark band between the two rainbows is known as Alexander’s band, after Alexander of Aphrodisias who first described it in 200AD.
Who knew they were common, cool, reversed and it took until 200AD to see one.