On eikonal aberrations in axisymmetric double-reflector telescopic systems

A formula describing the eikonal distribution on the surface of the main reflector of a doublereflector system of a general form is derived and its expansion in powers of the offset of the source from the focus up to the fourth-order terms is obtained. The analysis and minimization of aberrations for a doublereflector aplanatic Schwarzschild system are performed.