Most of us can revel in the beauty of a rainbow. Fewer get to see the whole 360 degree arc. Still fewer get to see the illusive moon bow. How about the headlamp bow? I couldn't even find a Google hit for this one! But then not many people run (barefoot) along country roads in the dark at 6 a.m. whilst it is raining. In these conditions, when a vehicle approaches from behind, the full 360 degree arc of a headlamp bow is clearly visible as I witnessed this morning. The bow appears white or "colourless" because the angle subtended at one's eye by the headlamps is more than or comparable to the rainbow's couple of degrees angle of dispersion. There was even the suggestion of the second bow around the first.
A similar effect that I have experienced on early misty mornings is the glory phenomenon, again caused by headlamps. The pleasure of seeing these effects makes me wonder why more people do not run in the early morning? But I am glad that they do not. It is bad enough having to share my mornings with the horrendous and wasteful light pollution from unnecessary house lights, bright enough to destroy my night vision unless I keep my eyes closed whilst passing. And it is never truly dark here, it is never necessary to use my flashlight apart from warding off marauding vehicles. And, yes, I do also wear a hi-vis jacket when on the road.
BTW - these pictures are not my own!
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