title: Lens systems: aplanatic anastigmatic two and three element.
abstract: In some optical applications, such as thermal imagery, chromatic aberration, correction may not be necessary. The various forms of aplantic doublet are compared with respect to high order aberrations. A set of equations is described, which generates aplanatic anastigmatic two-element single aspheric systems with any specified lens separation and back focus and, as a corollary, three-element systems with two elements in contact. The method is applied to germanium Petzval, telephoto, and inverse telephoto systems.
authors.forename: T H
authors.initials: TH
authors.lastname: Jamieson