each objective may be connected rigidly together and may have equal or unequal focal lengths application_number US 37853582 A description fig1 and 2 illustrate the schmidt optical system 10 of the invention in right angle planar views taken along the x y and x z planes respectively the system is formed of a pair of side by side catadioptic schmidt objectives 12 14 the primary elements of the objectives are a pair of spherical mirrors 16 18 symmetrically positioned side by side on opposite sides of the central x z common plane as shown in fig3 the curvatures of the spherical reflecting surfaces 17 19 of spherical mirrors 16 18 are oriented to diverge outward with their centers 20 22 respectively separated on opposite sides of the common x y plane the orientation of the curvatures of spherical mirrors 16 18 causes incoming paraxial light rays 24 26 to be divergingly reflected away from the common x z plane as rays 28 30 respectively refractor lens plates 32 34 are symmetrically positioned side by side on opposite sides of the common x z plane between the optical axes 36 38 respectively of the objectives to correct for spherical aberrations by introducing spherical aberrations into transmitted light rays equal and opposite to the total of the spherical aberrations caused by the respective spherical mirrors corrector lens 32 34 form dual aperture stops refractive beamsplitters 40 42 are positioned along the optical axes 36 38 at the respective focal planes 44 46 of the objectives concavity of spherical mirrors 16 18 causes focal planes 44 46 to be spherical and backward curving each beamsplitter accepts the image forming energy of a single optical objective 12 14 to maintain the concentricity of the schmidt system 10 the entrance 48 50.