First-Order Optics of the General Optical System

Abstract

First-order imagery by rays in the neighborhood of some base ray traversing an arbitrary optical system is anamorphotic and characterized by the presence of astigmatism and image rotation. The relationships among these three attributes is discussed; in particular, the effects of requiring that there exist one or more pairs of conjugate points on the base ray. Some inaccuracies in the literature pertaining to the torsion of the image by a general system are cleared up.