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

FIELD: physics.

SUBSTANCE: telescope has an exit pupil position which does not change when magnification is changed outside the eyepiece and an entrance pupil which is superposed with a first lens during high magnification. The telescope has a positive objective lens which includes a first positive, second and third negative menisci whose concave surfaces face the plane of the exit pupil, and an eyepiece which includes a fourth positive meniscus whose convex surface faces the exit pupil, and a fifth fixed positive meniscus whose concave surface faces the plane of the exit pupil. The third and fourth menisci have two fixed positions each and small displacements in these positions. Parameters of the telescope are related through relationships given in the formula of invention.

EFFECT: simple design, reduced cost price, high transmission coefficient owing to fewer lenses in the system, reduced internal background noise and reduced impact of Narcissus effect.

6 dwg, 6 tbl