title: Formula for the rms blur circle radius of Wolter telescope based on aberration theory.
abstract: A formula for the rms blur circle for Wolter telescopes has been derived using the transverse ray aberration expressions of Saha, Appl. Opt. 24, 1856-1863 (1985), Saha, Proc. Soc. Photo-Opt. Instrum. Eng. 444, 112-117 (1984), and Saha, Proc. Soc. Photo-Opt. Instrum. Eng. 640, 10-19 (1986). The resulting formula for the rms blur circle radius over an image plane and a formula for the surface of best focus are based on third-, fifth-, and seventh-order aberration theory predict results in good agreement with exact ray tracing. It has also been shown that one of the two terms in the empirical formula of VanSpeybroeck and Chase, Appl. Opt. 11, 440-445 (1972), for the rms blur circle radius of a Wolter I telescope can be justified by the aberration theory results. Numerical results are given comparing the rms blur radius and the surface of best focus vs the half field angle computed by skew ray tracing and from analytical formulas for grazing incidence Wolter I-II telescopes and a normal incidence Cassegrain telescope.
authors.forename: D L
authors.initials: DL
authors.lastname: Shealy
authors.forename: T T
authors.initials: TT
authors.lastname: Saha