Astronomy for schools; upon the basis of Mons. Arago's lectures at the Royal observatory of Paris .. (1841)
Arago, F. (François), 1786-1853, Haskins, Roswell William, [from old catalog] ed · New York, Robinson, Pratt & co.; · leaf 33
se telescopesare sometimes very powerful: they have been so con-structed as to magnify the object, viewed through them,one thousand times. The cut, fig. 13, will give an idea of this kind oftelescope, with one of the numerous methods of mount-ing it for use. In this figure the tube, a b, and… … it are refracted to a focus within the tube, near cuThe image formed at this focus, is viewed throughthe eye piece a, of which each telescope usually hasseveral, of different magnifying powers. The finderis a small tube, with glasses, and having two wirescrossing each other at right angles, in…
Astronomy
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