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 37
as such prisms, suffi-ciently perfect, both in material and mechanical exe-cution, can rarely if ever be produced, these telescopesare not in use. But the form of this species of telescope which isnow most employed, for astronomical purposes, is theFront View Reflector, figure 16; where A B C D isa… … mysfi Si wiH be formed in the focus of the mirrornear H. The image is thus thrown to the side of thetube that the observer may not shut out light from themirror. In using this telescope the observer, at H,sits with his hack to the object, and views the image,through an eye glass at the mouth of the…
Astronomy
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