TELESCOPIC SYSTEM Russian patent published in 1998 - IPC

FIELD: optical instrumentation engineering. SUBSTANCE: telescopic system objective has two components. First component is made as meniscus lens facing the object with its concavity. Divergent-meniscus lens facing the object with its concavity is positioned in front of first positive component of erecting system. First positive component of erecting system is made in the form of biconvex lens. Difference of dispersion coefficients of glasses of divergent-meniscus lens and the above-indicated component is at least 8. Second component of eyepiece is made as triple-cemented lens the middle member of which is negative, and external members are positive. Difference of refractive indices of positive and negative lenses is not over 0.03, and difference of dispersion coefficients is at least 15. Relation of objective focal distance to erecting system focal distance is within the range of 0.9-1.3, and eyepiece focal distance is at least 0.5 of erecting system focal distance. EFFECT: improved observation process. 1 dwg