Third-Order Rainbow.

A very rare third-order rainbow arc appears amongst the fringes of a passing heavy shower cloud as seen from Edinburgh this afternoon.

The first and second orders are the familiar primary and secondary rainbows seen away from the Sun on the opposite side of the sky after rainfall; third-order rainbows were first shown to exist by Edmund Halley in 1700 but are rarely seen as they rely on a viewing geometry so close to The Sun.

I've been hoping to photograph one for years having seen it only twice before.