Sharpless, Isaac, 1848-1920, Philips, G. M. (George Morris), 1851-1920, joint author · Philadelphia, J.B. Lippincott company · leaf 290
the eye-piece is placed. The observer looksat right angles to the direction of the object which hewishes to view. Fig. 77 shows the course of the raysof light through a Newtonian telescope. M is the con-cave speculum, and mn the diagonal mirror, or flat/5which reflects to the eye at D. In the… … Fig. 77.—Principle of the Newtonian Keflectob. In the first two the small mirror cuts off a portionof the light which would otherwise fall on the specu-lum ; some light is also lost by the double reflection.In the third the observers head cuts off some light,—less, however, than is lost in the…
Astronomy
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
