Geometric optics and rainbows: generalization of a result by Huygens.
In 1652 Huygens derived a formula specifying the rainbow angle for the primary bow (k = 1) in terms of the refractive index only. A generalization of this result for any k >or= 1 is outlined, along with an alternative representation. The details of the derivation can be found in (Adam, Mathematics Magazine, 2008, under review), but the results as stated may be of interest to the atmospheric optics community.
Adam
John A
JA
Department of Mathematics and Statistics, Old Dominion University, Norfolk, Virginia 23529, USA. jadam@odu.edu