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  Light pillars

Multicoloured pillars from low level ice crystals reflecting artificial lights. Shaun Lowe (more of his images) saw these near Bedford Nova Scotia on December '02. ©2002 Shaun Lowe
Unlike the crystals producing sun pillars, those making tall artificial light pillars need not be strongly tilted. The column producing pillars are approximately midway between the eye and the light source. The higher the crystals in the atmsphere, the taller is the pillar. When the crystals are very high - or the light sources are close - the pillars seem to radiate from overhead, the zenith.

 





Columns of light apparently beaming directly upwards from unshielded (and wastefully polluting) lights are sometimes visible during very cold weather. Plate shaped ice crystals, normally only present in high clouds, float in the air close to the ground and their horizontal facets reflect light back downwards.

The pillars are not physically over the lights or anywhere else in space for that matter ~ like all halos they are purely the collected light beams from all the millions of crystals which just happen to be reflecting light towards your eyes or camera.

Artificial light pillars can be much taller than their natural counterparts because rays from the lights are not parallel and plate crystals with small tilts can still reflect them downwards. The crystals producing the pillars are roughly halfway between you and the lights.

When ice crystals float in the air around you, pillars (and other halos) can even be seen around streetlights a few metres away.

More light pillar images 1, 2, 3
Pillars to the zenith 4, 5