 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.