Parhelia / Sundogs (EE02/03)

Bright patches of light to the right and left of the sun are called sundogs. They are found at the sun's height parallel to the horizon. Their distance from the low-hanging sun is 22°. They are thus on the small circle. With the sun high in the sky, the sundogs increasingly move away from the 22°-ring. When the sun is 40° above the horizon, the sundogs have a distance of about 27.6°. Sundogs often show a very intense coloration. They are red towards the sun and, in full form, have a long white tail pointing away from the sun parallel to the horizon. The brightness of the sundogs can be so strong in exceptional cases that one is almost dazzled.

Parhelia are formed on hexagonal ice prisms with a plate shape. When the plates fall undisturbed, they automatically assume a horizontal position. The sunlight enters one prism face and exits at the next prism face. The connection between the parhelia and the circumzenithal arc is interesting. Both occur in horizontally aligned ice plates. Therefore, when parhelia appear, one can also expect the circumzenithal arc, especially at a sun height between 15° and 25°.