TELESCOPE WITH TWO MAGNIFYING POWER VALUES AND REMOTE EXIT PUPIL FOR FAR INFRARED SPECTRUM Russian patent published in 2010 - IPC G02B23/00 G02B13/14 G02B15/16 

FIELD: physics.

SUBSTANCE: telescope has a real and fixed position of the exit pupil outside the eyepiece of the telescope when the magnification changes and has on the beam path a first and a second negative meniscus whose concave surfaces face the plane of the exit pupil and form the objective lens, as well as a movable third biconcave lens having two fixed positions, a fourth biconvex lens, a fifth negative and a sixth positive meniscus whose convex surfaces face each other and form the eyepiece. The third lens has ratio of radii of refracting surfaces whose absolute value is close to 1. Parameters of the telescope are related through relationships given in the formula of invention.

EFFECT: simplification of design owing fewer movable elements with preservation of diffraction limited image quality, low distortion and reduction of magnifying power by three times.

8 dwg, 7 tbl