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 92
C. All the rays which proceedfrom near objects as a window in a room, or anadjacent house or garden are more or less diver-gent. The following figures show the effects of ON THE REFRACTION OF LIGHT. 67 parallel, converging and diverging rays in pass-ing through a double convex lens. Fig. 9, shows… … centre of convexity. It will be observed, thatthey are less refracted as they approach the centerof the lens, and the central ray DEC, which iscalled the axis of the lens, and which passesthrough its center, suffers no refraction. Fig. 10, 68 THE PRACTICAL ASTRONOMER. exhibits the course of…
Astronomy · Astronomical instruments · Telescopes
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