telescopes Definition

a usually tubular optical instrument for viewing distant objects by means of the refraction of light rays through a lens or the reflection of light rays by a concave mirror

any of various tubular magnifying optical instruments

radio telescope

to become forced together lengthwise with one part entering another as the result of collision

to slide or pass one within another like the cylindrical sections of a collapsible hand telescope

to become compressed or condensed

a reflecting telescope that has a paraboloidal primary mirror and hyperboloidal secondary mirror, is equivalent in its optical effects to a telephoto lens, and usually has the light brought to a focus through a perforation in the center of the primary mirror

a radio receiver-antenna combination used for observation in radio astronomy

reflector

refractor