from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of several optical instruments that combine the functions of a telescope and microscope e.g. projecting a microscope image onto a screen
from The Century Dictionary and Cyclopedia
- n. A magnifying in strument, invented by the Abbé Deschamps, for the observation of small objects, such as insects, from a distance. Its optical system consists of an objective composed of two achromatic lenses that are separated by a distance less than the principal focal distance of the most convergent lens, and therefore act as a single lens, and of a Dollond ocular with four plano-convex lenses. The eye-glass is made as convergent as possible to increase magnification and field without diminishing the definition.
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