Sunset over a fjord and the Norwegian Sea in the northern Norway. The 22-degree solar halo captured in this image is a luminous ring, sometimes seen around the sun or the moon. It is caused by refraction by small ice particles high in Earth's atmosphere. Sun Pillar is another optical effect which is most commonly seen near sunrise or sunset. The pillar may extend up to 20 degrees above the Sun as seen in this image, and it is caused by reflection of sunlight from the tops and bottoms of tabular ice crystals which are falling with their principal axes aligned vertically.