High Quality Content by WIKIPEDIA articles! A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses and curved mirrors. Catadioptric combinations are used in focusing systems such as search lights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric" such as surveillance catadioptric sensors. Catadioptric combinations have been used in many early optical systems. In the 1820s, Augustin-Jean Fresnel developed several catadioptric lighthouse reflectors. Léon Foucault developed a catadioptric microscope 1859 to counteract aberrations of using a lens to image objects at high power. In 1876 a French engineer, A. Mangin, invented what has come to be called the Mangin mirror, a concave glass reflector with the silver surface on the rear side of the glass. The two surfaces of the reflector have different radii to correct the aberration of the spherical mirror. Light passes through the glass twice, making the over all system act like a triplet lens.