The telescope lens has a focal length F1 = 25 cm and a diameter of 5 cm, and the eyepiece has a focal length F2 = 5 cm. The telescope is set to infinity. If frosted glass is placed behind the eyepiece, then at a certain position the illuminated circle on the frosted glass has the smallest dimensions and sharply limited edges. What is the distance from the ground glass to the eyepiece and what is the diameter of the circle?

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