Alexander's Dark Band

The brighter sky inside the primary is very noticeable here. There is also a very subtle brightening outside the secondary, corresponding to the brightening inside the primary.

Alexander's dark band

The slightly darker sky between the bows is Alexander's dark band. No light is returned from drops in this direction because it has been totally reflected in other directions.

Bright primary and secondary rainbow

Zooming in shows that the secondary is broader and much fainter than the primary, and with the colours reversed.

Pentax P30t
Wiltshire, England

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