Design Of Null Lens Correctors For The Testing Of Astronomical NnfitÃÂââÃÂìÃÂÃÂC

Abstract

Some design examples are presented that illustrate the design of null correctors for the testing of strong aspherical surfaces such as those that are of interest in astronomical instrumentation. The design and analysis of an Offner corrector for an f/1 paraboloid is given. Also presented are a zoom null corrector and a null lens that can correct positive as well as negative spherical aberration. A configuration for the testing of convex surfaces is suggested.