ANTHELIC ARC

   The term anthelic arc is indebted to the Greek words anti (against, opposite to) and helios (Sun). It translates loosely as 'arc located opposite to the Sun'. The term is used in meteorology and physics to denote a collection of rare "physical illusions taking the shape of a huge, thin "halo that can be seen against the part of the sky facing the Sun (i.e. the antisolar point). Anthelic arcs can be observed both in the presence and in the absence of "anthelia. They are generally classified as atmospheric effects resulting from the interaction of sunlight and ice crystals with a particular orientation high in the atmosphere.

   References

   Lynch, D.K., Schwartz, P. (1979). Origin of the anthelion. Journal of the Optical Society of America, 69, 383-386.

   Lynch, D.K., Livingston, W. (1995). Color and light in nature. Cambridge: Cambridge University Press.