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Aureole around the Moon

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Date:11.12.2000 Instrument:f=135mm, 1/2.8
Place:Schelklingen   Observer:T. Credner

© Copyright by the observers

An extraordinary colorful Corona around the full moon was visible in december 2000 from southern Germany. The image above shows this phenomenon, also called Aureole, how it appeared to the naked eye and in an extremely enhanced way to show also the fainter rings. In a low and thin cloud layer two or three rainbow colored rings were visible to the unaided eye. In the enhanced photography the third ring stands out clearly and even a fourth ring becomes visible.

The Aureole is a diffraction effect of light at tiny atmospheric droplets of the cloud. If all these atmospheric particles have similar sizes it results in systematic interfering rays and ring like diffraction patterns. Since the diffraction effect is a function of wavelength, the resulting minimum and maximum rings have different diameters for different colors. This gives the final effect of colorful rings.

See also:
M.G.J. Minnaert: "Light and Color in the Outdoors", Springer-Verlag
R. Greenler: "Rainbows, Halos, and Glories", Cambridge University Press