In a freezing winter night of Tänndalen region of Sweden, atmospheric halos and pillars shape around the Moon. Most notable is large 22-degree halo which shapes around the Moon or the sun when high thin clouds containing millions of tiny ice crystals cover much of the sky. Each ice crystal acts like a miniature lens. Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Sun or the Moon Halo. But also visible is a reflection of the halo and strange columns of light occur over street lights, and so likely involve falling ice crystals reflecting back these lights. The air was noted to be quite cold at -34 degrees Celsius and indeed filled with small ice crystals, just the type known to create several awe-inspiring but well known sky phenomena such as light pillars, sun pillars, sun dogs, and moon halos.



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