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i, , ye, the final image is, -incipal focus of Sees at ——, if ity, ii,, , le i, Ss, , pfe— fo>|, , , , Fig. 1 :, g. 15.14 (a): Newton's reflecting telescope, , , , , , ---(5), Magnifying Power: The magnifyin, --.(6) (rm) of a telescope is the ratio of angle (8) se toh aati, Fens ee On eye aca ae, , »f a telescope, the f, Z ocal Jen, ould be smallest. The ne ee of wy ended py the object on eye., gn, , , , Secondary, , mirror, , , , , ie, Cee, , This may be calculated just as for refracting, relescope- if fo is the focal length of an objective, mirror and f, the focal length of eyepiece, , Eyepiece, , ry F and that of eyepiece by f£ ie, , f the object is at finite distance, th, , the, concave, and final image is formed at least distance of, “istinct ae on; then magnif ing power, Fig. 15.14 (b): Cassegrain telescope, ofa spherical concave mirror of large - : =, oe as objective and a convex lens of put if the fin ee et f A ri, : u e image is forme at infinity, then, Le ato fo For large magnifying power of telescope, the objective must, magnifying P a have large focal length and eye lens small focal length., e to remove spherical aberration. A very large, d at Mount-Palomet in, , elescope uses a paraboloidal mirror objectiv, 1 to 200 inches (nearly 66 metres). It is place, , Modern reflecting t, f its objective equa, d stars., , scave mirror of large aperture is, telescope has aperture 0, , , , matic aberration is completely, , spherical aberration too, th, , P he om California and used to study distant planets an, 41 length fitted at one end of a 4, The largest telescope in India has a diameter of 2: 34 M. Itis installed in Kavalur, Tamil Nadu., SD aectad towar ds the distant 2. The largest telescope in the world are the pair of Keck telescopes in Hawal USA, of 10 min diameter, am eOs, yl ATES TTon te Reflecting Telescope: :, we Pe eer tor than,that formed by refracting telescope:, nates eeecrn' re(racune, telescope: