Fogbow & Glory from a col on Piz Lad near the Italian, Swiss and Austrian borders. Imaged by Gangolf Haub (climb) September 8, '08.
Image ©Gangolf Haub, shown with permission.
Gangolf’s shadow in the mist (or ‘Brocken Spectre’) is surrounded by a multi-ringed glory. Further away the much larger rings of a fogbow dominate the scene. The outer, almost colourless, ring is the fogbow primary corresponding to that of a rainbow. Inside are at least four more strongly coloured supernumerary fringes.
Fogbows and glories can be seen when the sun breaks through mist or fog. They are centered on the antisolar point directly opposite the sun.
They are part of the same phenomenon of light scattering and diffraction by tiny water droplets. The corona (next OPOD) seen around the moon or sun is generated at the same time. Diffraction becomes more marked as the scatterers shrink towards the order of size of the wavelength of light.
Diffraction is sometimes thought of as a laboratory curiosity but here it is writ large across the sky.