"Ron Button" wrote in message
...
This is amazing
I can't help but wonder whether there was a tertiary bow around the sun
when that photo was taken! 'Tis a shame that most people wouldn't think of
looking behind them for what is presumably a pretty rare effect...

The tertiary bow has never been reliably observed. See
http://www.sundog.clara.co.uk/rainbows/ord34.htm

It is around the sun in the opposite direction to the primary and
secondary. It is heavily masked by light that passes through
raindrops without an internal reflection.