Recreations in astronomy : with directions for practical experiments and telescopic work (1879)
Warren, Henry White, 1831-1912 · New York : Harper & Brothers · leaf 59
his is the grand principle of the refractingtelescope. Difficulties innumerable arise as we attemptto enlarge the instruments. These have been over-come, one after another, until it is now felt that thebest modern telescope, with an object lens of twenty-sixinches, has fully reached the limit of… … Fig. 14.—Reflecting Telescope. reflects it to the focus F, producing the same result asthe lens of the refracting telescope. Here a mirrormay be placed obliquely, reflecting the image at rightangles to the eye, outside the tube, in which case it iscalled the Newtonian telescope; or a mirror at R…
Astronomy
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