TELESCOPE Russian patent published in 1995 - IPC

FIELD: optical instrument engineering. SUBSTANCE: telescope has mirror-lens objective made in form of two menisci with concave surfaces which surfaces are oriented to image space, primary spherical concave mirror oriented to image space, secondary spherical concave mirror and eye-piece. Three units are mounted inside the telescope one is external and two others are internal. One unit is disposed in front of primary mirror, and secondary internal unit is disposed behind the secondary mirror. Objective builds intermediate direct image in the telescope which image may be observed through eye-piece. The second meniscus of the objective is made with optical power being equal to -0,1 to +0,1 optical power of primary mirror. Difference of specific dispersions of two menisci is equal or higher than 10. The secondary mirror has optical power value equal to -2,4 to -5 optical power of the primary mirror, linear magnification belongs to the limits from -3 to -6 and distance to the primary mirror is equal to 1,2-1,8 focal length of primary mirror. The eye-piece has aberration characteristics corresponding to the third Zeidel sum less than -0,1 and to the fourth Zeidel sum more than 0,5. EFFECT: improved precision. 4 dwg