Obere Lichtsäule (EE08)

Description

Light Path
Upper Light Pillar
Crystal Type:
  • Plate Crystals, Column Crystals
Orientation:
  • horizontal
Light Path:
  • Reflection at Lower Base Surface
Occurrence:
  • frequent (20-30 days per year)
A light pillar is a vertical beam of light above or below the sun. Usually, only the upper light pillar is visible. It is about the same width and color as the sun. The upper light pillar is best observed shortly after sunset. Then it looks as if the light from a powerful searchlight is rising vertically above the horizon. During sunset, the color is still orange-white. A few minutes after sunset, the pillar turns more orange-red and fades 20-60 minutes after sunset. When the light pillar is fully developed, a diffusely broadened tip can sometimes be observed. This is the upper tangent arc, whose branches form a sharp angle when the sun is low. The height of the light pillar can be well over 30° in ice fog. However, usually only a 5-10° high pillar is observed. If both the upper and lower light pillar, as well as part of the parhelic circle are visible, a cross appears in the sky. Such an impressive phenomenon was often seen as a sign of God in the Middle Ages.

Origin

The light pillar is created by the reflection of sunlight on the base surfaces of rotating plates and on the prism surfaces of rotating columns. However, a requirement is that the ice crystals oscillate around their vertical axis. Additionally, snow stars can also cause a light pillar. The formation of the pillar is comparable to the path of light that the setting sun creates on a rippling water surface.

Photos

Upper Light Column
Upper Light Column from 18.01.2013 (Photo: Hermann Koberger)
Upper Light Pillar in January
Upper light pillar, taken in Schwedt on 01/19/2013 (Photo: Andreas Möller)
Upper Light Pillar
Upper Light Pillar on 26.06.2009 in Schöneiche (Photo: Andreas Zeiske)

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