Liljequist parhelion
Encyclopedia
A Liljequist parhelion is a rare halo
, an optical phenomenon
appearing on the parhelic circle
approximately ±150-160° from the sun
between a 120° parhelion
and the anthelion
(opposite to the sun at the antisolar point
).
While the sun touches the horizon, a Liljequist parhelion is located approximately 160° from the sun and is about 10° long. As the sun rises up to 30° the phenomenon gradually moves towards 150°, and as the sun reaches over 30° the optical effect vanishes. The parhelia are caused by light rays passing through oriented plate crystals. Like the 120° parhelia, the Liljequist parhelia displays a white-bluish colour. This colour is, however, associated with the parhelic circle itself, not the ice crystals causing the Liljequist parhelia.
The phenomenon was first observed by Gösta Hjalmar Liljequist
in 1951 at Maudheim, Antarctica during the Norwegian-British-Swedish Antarctic Expedition
in 1949-1952. It was then simulated by Dr. Eberhard Tränkle (1937-1997) and Robert Greenler in 1987 and theoretically explained by Walter Tape in 1994.
Halo (optical phenomenon)
A halo from Greek ἅλως; also known as a nimbus, icebow or gloriole) is an optical phenomenon produced by ice crystals creating colored or white arcs and spots in the sky. Many are near the sun or moon but others are elsewhere and even in the opposite part of the sky...
, an optical phenomenon
Optical phenomenon
An optical phenomenon is any observable event that results from the interaction of light and matter. See also list of optical topics and optics. A mirage is an example of an optical phenomenon....
appearing on the parhelic circle
Parhelic circle
A parhelic circle is a halo, an optical phenomenon appearing as a horizontal white line on the same altitude as the sun, or occasionally the Moon. If complete, it stretches all around the sky, but more commonly it only appears in sections....
approximately ±150-160° from the sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
between a 120° parhelion
120° parhelion
A 120° parhelion is a relatively rare halo, an optical phenomenon occasionally appearing along with very bright sun dogs as ice crystal-saturated cirrus clouds fill the atmosphere...
and the anthelion
Anthelion
An anthelion is a rare optical phenomenon appearing on the parhelic circle opposite to the sun as a faint white halo, not unlike a sundog.How anthelions are formed is disputed...
(opposite to the sun at the antisolar point
Antisolar point
The antisolar point is the imaginary point on the celestial sphere exactly opposite the Sun. It is where anticrepuscular rays appear to converge, and on a moonless night away from city lights, it is often possible to see the gegenschein there. The apex of a rainbow will also form roughly 42...
).
While the sun touches the horizon, a Liljequist parhelion is located approximately 160° from the sun and is about 10° long. As the sun rises up to 30° the phenomenon gradually moves towards 150°, and as the sun reaches over 30° the optical effect vanishes. The parhelia are caused by light rays passing through oriented plate crystals. Like the 120° parhelia, the Liljequist parhelia displays a white-bluish colour. This colour is, however, associated with the parhelic circle itself, not the ice crystals causing the Liljequist parhelia.
The phenomenon was first observed by Gösta Hjalmar Liljequist
Gösta Hjalmar Liljequist
Gösta Hjalmar Liljequist was a Swedish meteorologist.In Sweden, radio broadcast weather forecasts begun in 1926, and, starting in 1941, Liljequist was one of the recurrent meteorologists appearing in Swedish radio for many years...
in 1951 at Maudheim, Antarctica during the Norwegian-British-Swedish Antarctic Expedition
Norwegian-British-Swedish Antarctic Expedition
Norwegian–British–Swedish Antarctic Expedition the first Antarctica expedition involving an international team of scientists...
in 1949-1952. It was then simulated by Dr. Eberhard Tränkle (1937-1997) and Robert Greenler in 1987 and theoretically explained by Walter Tape in 1994.
External links
- A fish eye photo by Günter Röttler, Hagen, September 1983 featuring a parhelic circle with a 120° parhelion and a Liljequist parhelion.
- List of observations (pick Liljequist parhelia as a halo filter.)