Lunar Halo above Quebec

June 24, 2008

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Provided by: Philippe Moussette, web site
Summary authors & editors: Jim Foster, Philippe Moussette

The photo above showing a conspicuous 22 degree lunar halo was captured from the Observatoire de la Découverte in Quebec, Canada on January 21, 2008. Randomly oriented, pencil-shaped ice crystals in cirrus clouds often produce 22 degree halos (angular distance of 22 degrees from the Sun or Moon). The darkened area within the halo is analogous to Alexander's dark band between the primary and secondary rainbow. In essence, light cannot be scattered into this region by simple refraction.

Photo details: Canon EOS 40D camera, 8 mm Peleng fisheye lens.