First-class precision instruments based on Klevzov's original advanced optical system design, for the advanced amateur astronomer who desires high resolution and excellent light passing power in a highly portable telescope. The Klevzov-Cassegrain non-aspherical system presents a radial new form of catadioptric telescope that combines the compactness of a Schmidt-Cassegrain with similar enviable high resolution image quality and contrast of modern Maksutov designs. Klevsov's revolutionary catadioptric design employs a sub-aperture meniscus correcting lens, combined with a Mangin mirror-lens secondary. Their fast focal ratios, flat field and excellent correction of coma, spherical aberration and astigmatism (14 micron star images at a distance of 10mm from the optical axis!!) makes these superb instruments for astrophotography, as well as for the observation of planets and deep-sky objects.