Third Order Rainbow

Matěj Grék caught this view of the fabled 3rd order rainbow at Ostrava, Czech Republic on August 18, 2014.

Unlike the well-known 1st and 2nd order bows, the 3rd order is sunwards. The low sun is at left just hidden by the building.

Mouse over the image for a colour subtraction enhancement

©Matěj Grék, shown with permission
5th and 6th order bows overlap the primary and secondary. Search for part of the 5th order in Alexander's dark band.

This Bowsim ray tracing is an all sky view centred on the zenith. The sun is on the horizon at right.

The upper half is shown 20X brighter and is filtered to remove rays reflected less than three times inside raindrops.

A different view of higher order bows here.

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The tertiary bow was first photographed in 2011 by Michael Grossmann. There have been several images captured since but it remains a hard object.

"I did not see anything visually. I just thought that I could take a picture and then try to enhance the photo to actually see it.. ..It was during a moderate rain shower passing overhead and eventually leaving towards north-east. Both primary and secondary bows were visible, along with primary supernumeraries."

The tertiary bow is bright - 24% of the primary - and it is almost the same size. But it is broader and easily swamped by bright sky near the sun. The superimposed zero order glow from sunlight passing through raindrops with no internal reflection also interferes.
Three internal reflections produce the tertiary.