| 1824 - 452 páginas
...is THE ASTRONOMICAL TELESCOPE. An astronomical telescope consists of two convex lenses, placed in a tube at a distance from each other equal to the sum of their focal distances. That lens which is nearest the object is called the objectglass, and that nearest... | |
| William Mullinger Higgins - 1829 - 202 páginas
...purposes, but by the addition of two convex glasses of the same power, as the eye lense, and fixed at a distance from each other equal to the sum of their foci, the image is erected, and a terrestial telescope formed. " The properties of this instrument,"... | |
| John Lee Comstock - 1830 - 308 páginas
...eonvex lenses, the one having a long, and the other a short focal distance. (The focal distance of a convex lens, it will be remembered, is nearly the...equal to the sum of their two focal distances. Fig. 169. Thus, if the focus of the object glass a, fig. 169, be eight inches, and that of the eye glass,... | |
| John Lee Comstock - 1832 - 308 páginas
...astronomical and nautical purposes. Refracting Telescope. The most "simple refracting teles* scope consists of a tube, containing two convex lenses,...equal to the sum of their two focal distances. Fig. 169. place of the object lens, that of the microscope having a short, while that of the telescope has... | |
| John Lee Comstock - 1835 - 308 páginas
...instruments differ chiefly in respect to the m Refracting Telescope. The most simple refracting telesacope consists of a tube, containing two convex lenses,...equal to the sum of their two focal distances. Fig. 169. place of the object lens, that of the microscope having a short. while that of the telescope has... | |
| Francis Joseph Grund - 1836 - 308 páginas
...astronomical telescope. This consists of two convex lenses, of unequal focal lengths (§ 286, 6th), placed at a distance from each other, equal to the sum of their focal lengths. The lens of greater focal length forms the objectglass ; the other lens forms the eye-glass.... | |
| William Mullinger Higgins - 1838 - 532 páginas
...throwing the ravs tnwvrJ" J — -J-"i uie same form and size as the eye glass, and these are fixed at a distance from each other equal to the sum of their foci. Thus let us take the same lengths as we did in the former case, let the focus of the object glass... | |
| John Lee Comstock - 1841 - 348 páginas
...resembling so many huge serpents. TELESCOPE. 211 TELESCOPE. 712. The Telesr.ope is an optical instrument, employed to view distant bodies, and, in effect, to...and that of the eye glass b, two inches, then the distance of the sums of the foci will be ten inches, and, therefore, the two lenses must be placed... | |
| John Lee COMSTOCK (and HOBLYN (Richard Dennis)), John Lee COMSTOCK - 1846 - 506 páginas
...distances, and, as a consequence, of the heights of mountains, &c. 500. " REFRACTING TELESCOPE.—The most simple refracting telescope consists of a tube,...other equal to the sum of their two focal distances. Thus, if the focus of the object glass A, telescope will be readily comprehended after what has been... | |
| John Lee Comstock, Richard Dennis Hoblyn - 1846 - 154 páginas
...the one having a long, and the other a short, focal distance. (The focal distance of a double-convex lens, it will be remembered, is nearly the centre...other equal to the sum of their two focal distances. Thus, if the focus of the object glass A, Fig. 69. Fig. 69, be eight inches, and that of the eye glass... | |
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