title: Best-fit sphere approximation to a general, aspheric surface.
abstract: In manufacturing an aspheric lens or mirror, it is often convenient to generate a spherical surface as a starting point. The radius of the sphere should be such that the volume of glass which must be removed to achieve the final aspheric is a minimum. Equations for this best-fit sphere are developed and arranged in a form well suited for computer programming.
authors.affiliation: American Optical Company, SpaceDefense Division, Pittsburgh, Pennsylvania, USA.
authors.forename: T W
authors.initials: TW
authors.lastname: Unti