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 69
gle, in a given pro-portion. The incident angle is the angle madeby a ray of light and a line drawn perpendicularto the refracting surface, at the point where thelight enters the surface. The refracted angle isthe angle made by the ray in the refracting mediumwith the same perpendicular produced.… … F G E K ■figure 3. In this figure BC is the incident ray, CE therefracted ray, DG the perpendicular, AD the sine ON THE REFRACTION OF LIGHT. 45 of the angle of incidence ACD, and HR the sineof the angle of refraction GCE. Now, it is a pro-position in optics that,—the sine AD of the angleof…
Astronomy · Astronomical instruments · Telescopes
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