Upper light pillar (EE08)

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. Light pillars are not refraction halos but reflection phenomena. They therefore show no spectral colors and take on the color of the low 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. Light pillars also form around the moon and Venus. In winter they can also be seen above artificial light sources such as streetlights in ice fog or diamond dust. If the upper and lower light pillars and part of the parhelic circle are visible, a cross appears in the sky, which is called a halo cross or sun cross. Such an impressive phenomenon was often seen as a sign of God in the Middle Ages.