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 221
OB is received either on a piece ofoiled paper, or more frequently on a plane un-polished glass, placed in the horizontal situationFG, which receives the images of all objects,opposite to the lens, and on which, or on an oiledpaper placed upon it, their outlines may be tracedby a pencil. The… … Above is shown the most common form of the boxof this kind of Camera Obscura. A is the positionof the lens, BC, the position of the mirror, D,the plane unpolished glass on which the imagesare depicted, GH a moveable top or screen toprevent the light from injuring the picture, andEF, the moveable…
Astronomy · Astronomical instruments · Telescopes
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