title: A new derivation of third-order aberration coefficients.
abstract: The Feder expressions for four third-order aberration coefficients, namely, B for spherical aberration, F for coma, C for astigmatism, E for distortion, and the Petzval curvature P, are derived by a new and direct method based on the wavefront concept and with the use of rather elementary means of geometry and algebra. Their relation with the wavefront aberration coefficients is given.
authors.affiliation: Link Group of General Precision, Inc.,Binghamton, New York 13902, USA.
authors.forename: G R
authors.initials: GR
authors.lastname: Rosendahl