Liljequist parhelion

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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.^[1] 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. ^[2]

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.^[1]

[edit] References

[edit] See also

• Sun dog
• Liljequist subparhelion

[edit] External links

• A fish eye photo by Günter Röttler, Hagen, September 1983^{[dead link]} featuring a parhelic circle with a 120° parhelion and a Liljequist parhelion.
• List of observations (pick Liljequist parhelia as a halo filter.)