| Encyclopedias and dictionaries - 1823 - 886 pages
...that it will admit of an eye-glass of a/ much shorter focal distance than a refracting telescope ; and consequently it will magnify 'So much the more:...to a true figure, as they are by passing through a convex glassy let it be- ground ever so true. The nearer an object is to the telescope, the more its... | |
| James Ferguson - Astronomy - 1839 - 554 pages
...prevented its useful application. Mir are ""'• r"l"lirt'(l by reflection from a concave mirror, if v"' it be ground to a true figure, as they are by passing...eyes, by bringing the small mirror either nearer to the eye, or removing it farther : by which means, the rays are made to diverge a little for short-sighted... | |
| Thomas Dick - 1845 - 608 pages
...refractors, is, that they will admit of eye glasses of a much shorter focal distance, and consequently, will magnify so much the more, for the rays are not...to a true figure, as they are by passing through a convex glass though figured and polished with the utmost exactness. It will be perceived from the above... | |
| Thomas Dick - Astronomical instruments - 1845 - 644 pages
...refractors, is, that they will admit of eye glasses of a much shorter focal distance, and consequently, will magnify so much the more, for the rays are not...to a true figure, as they are by passing through a convex glass though figured and polished with the utmost exactness. It will be perceived from the above... | |
| Thomas Dick - Educational sociology - 1850 - 586 pages
...refractors is, that they will admit of eyeglasses of a much shorter focal distance, and, consequently, will magnify so much the more, for the rays are not...to a true figure, as they are by passing through a convex glass, though figured and polished with the utmost exactness. It will be perceived from the... | |
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