
Last night I stumbled across a name I have been looking for since a sailing trip a couple of months ago, when I took this photo. I now know that the unusual phenomenon in this picture is called a ‘fogbow’. It is similar to a rainbow in many ways, but the fog droplets are so small that instead of light being refracted it is instead diffracted, which leads to a white arc instead of the more familiar colours. Coloured and white bows can occasionally be seen at night, if there are the right atmospheric conditions and a bright moon, but these are given the fair name of ‘moonbows’.
Apparently it also has something to do with quantum wavelengths, but that sounds like one for a rainier day than today and it’s pretty wet out there as it is.