Light (solar) pole

One of the most frequent types of halo, a visual phenomenon, an optical effect which is a vertical band of light stretching from the sun during sunset or sunrise.

The phenomenon is called flat or hexagonal columnar ice crystals with nearly horizontal parallel planar surfaces. Suspended in the air flat crystals cause the solar poles, if the sun is at the height of 6 degrees above the horizon or behind columnar — if the sun is at an altitude of 20 degrees above the horizon. Crystals tend to occupy a horizontal position when falling in the air, and the view of the light pole depends on their mutual arrangement.

A light pillar occurs when sunlight is reflected from the surfaces of tiny ice crystals, representing the ice plates or rods with hexagonal cross-section, suspended in the air. Such crystals are formed in high Cirrus clouds, most often in cirrostratus. At low temperatures these crystals can also be formed in lower layers of the atmosphere. Therefore, the light poles are observed more frequently in the cold season. When forming a light post light is reflected from either the upper or lower surface of the ice plate, either from the ends or faces of the ice rod.

In rare cases, light pole may be accompanied by so-called prelicence around. It is a bright strip that is visible in the sky at the same height as the Sun. Under favorable conditions it is a vicious circle passing through the Sun and the false Sun.

Light poles often formed around the moon, city lights and other bright light sources. The pillars that extend from the low-lying light sources are usually much longer than the solar or the lunar poles. The closer to the light pole is the observer, the less affects the location of the crystal in space on the exterior of the pole. Usually this phenomenon is called "needle ice" or "ice forest".

Translated by «Yandex.Translator»