The practical astronomer : comprising illustrations of light and colours, practical descriptions of all kinds of telescopes, the use of the equatorial-transit, circular, and other astronomical instruments, a particular account of the Earl of Rosse's large telescopes, and other topics connected with astronomy (1845)
Dick, Thomas, 1774-1857 · London : Seeley, Burnside, and Seeley · leaf 357
been at least 3 times the focal length,it would have formed an excellent telescope, withthe same aperture. 332 THE PRACTICAL ASTRONOMER. SECT. 6. A REFLECTING TELESCOPE, WITH A SINGLE MIRROR AND NO EYE-PIECE. On the same principle as that by which a refract- .ing telescope may be constructed by… … and C its focus—if an eye be placed at D, about8 or 10 inches within the focal point C, all theobjects in the direction of C, or behind the spec-tator, will be seen magnified by reflection onthe face of the mirror, and strongly illuminated.The magnifying power, in this case, will be nearlyin the…
Astronomy · Astronomical instruments · Telescopes
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