Glass selection for airspaced apochromats using the Buchdahl dispersion equation

Abstract

The Buchdahl dispersion equation is applied to a system of airspaced thin lenses. The powers, airspaces, and glass dispersion characteristics of a lens system are represented as a series of vectors. The sum of these vectors represents the state of paraxial color correction of the lens system. The vector representation is used as a guide in the selection of glasses for airspaced doublets (dialytes), triplets, and more complex lens systems with apochromatic color correction. Prescriptions and performance data are given.