Ross null test for conic mirrors.
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.
Stoltzmann
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Ceravolo
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