The design of objectives for image tubes is discussed with consideration given to the limited resolution of the tubes, the desired resolution in the object plane, and the desired field of view. Particular attention is given to the case of maximum quantum yield for given resolution and field of view. The design of a mirror objective is based on a spherical concave mirror as the main mirror and a plane mirror as the secondary.
H. Koehler, "Objectives for Image Converters and Image Intensifiers," Appl. Opt. 7, 1035-1035 (1968)