Hoghton’s camera and telescope

The third-order aberration formulae we have proved in a previous paper, starting from Fermat’s principle and from the idea of stigmatic paths, are here applied to analyze and to project Houghton’s cameras and Houghton–Cassegrain’s telescopes. The final values of the radii of the two-lens corrector are obtained taking into account also the thickness of lenses and the fifth-order aberrations.