title: Ross null test for conic mirrors.
abstract: Various refractive null-testing arrangements have been used over the years for testing concave nonspherical mirrors. This paper presents a method for null testing that uses a single plano-convex lens to compensate for the spherical aberration of a concave conic mirror when tested at its center of curvature. This testing method, called the Ross null test, requires a high-quality null lens and a standard Foucault test apparatus. This paper presents graphical and numerical data that provide the necessary parameters for implementing the Ross null test for mirrors with focal ratios ranging from f/3.5 to f/10 and for conic deformations ranging from eccentricities of 0.70-1.50.
authors.forename: D E
authors.initials: DE
authors.lastname: Stoltzmann
authors.forename: P
authors.initials: P
authors.lastname: Ceravolo