Keplerian telescope

Ray path in Keplerian telescope

Keplerian telescope

(kep-leer -ee-ăn) The first major improvement of the Galilean telescope, developed by the German astronomer and mathematician Johannes Kepler, in which a positive (convex) lens was used as the eyepiece in place of the negative (concave) lens that Galileo used (see illustration). This gave a larger though inverted field of view and much higher magnifications.

Keplerian telescope

[ke′plir·ē·ən ′tel·ə‚skōp] (optics) A telescope that forms a real intermediate image in the focal plane and can be used for introducing a reticle or a scale into the focal plane.