A telescope is an instrument that helps in the observation of remote objects by collecting visible light. It is an optical instrument used to view heavenly bodies such moon, stars, planets and distant objects. The objective is a convex lens of large focal length and large aperture. It usually made of two convex lenses in contact with each other to reduce the chromatic and spherical aberrations. The astronomical telescope makes use of two positive lenses: the objective, which forms the image of a distant object at its focal length, and the eyepiece, which acts as a simple magnifier with which to view the image formed by the objective.
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