title: Supernumerary Spacing of Rainbows Produced by an Elliptical-Cross-Section Cylinder. II. Experiment.
abstract: We measured the supernumerary spacing parameter of the first- and second-order rainbows of two glass rods, each having an approximately elliptical cross section, as a function of the rod's rotation angle. We attribute large fluctuations in the supernumerary spacing parameter to small local inhomogeneities in the rod's refractive index. The low-pass filtered first-order rainbow experimental data agree with the prediction of ray-tracing-wave-front modeling to within a few percent, and the second-order rainbow data exhibit additional effects that are due to rod nonellipticity.
authors: C L
authors: CL
authors: Adler
authors: D
authors: D
authors: Phipps
authors: K W
authors: KW
authors: Saunders
authors: J K
authors: JK
authors: Nash
authors: J A
authors: JA
authors: Lock