Peck, William G. (William Guy), 1820-1892 · New York, Chicago, A. S. Barnes & company · leaf 160
dense glasswith a refracting angle N, equal to about 60°; it can beturned around an axis (not shown in the drawing) parallelto its refracting edge so as to make the angle of incidenceequal to the angle of emergence, a position which is foundto give the best results. The flat beam, in passing… … Fig. 67. The principle of the Spectroscope. Instead, however, of receiving the spectrum on a screenthe deviated rays are allowed to fall upon the objective ofthe view-telescope, C, which differs in no material respectfrom an ordinary refracting telescope of low power. Thetelescope is attached to…
Astronomy
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