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radio telescope
radio telescope An instrument for collecting and measuring radio waves from astronomical sources. Single-dish radio telescopes can be either used alone or joined into interferometers and arrays. Single-dish telescopes usually have a parabolic reflector, which works in a similar way to the main mirror of an optical telescope. Because radio waves are much longer than light waves, radio reflectors need have only relatively moderate surface accuracy. But, for the same reason, even the largest single-dish radio telescopes cannot match the angular resolution of optical telescopes. Radio interferometers, made of two or more spaced antennas (elements) connected together, are used to achieve high angular resolution. Resolutions better than 0″.001 can be achieved in this way, far exceeding the performance of even the Hubble Space Telescope. Aperture synthesis telescopes are interferometers in which the whole or part of a large, imaginary aperture is built up by the rotation of the Earth and, in some cases, by the movement of the dishes. Parabolic dishes are normally steerable, the larger ones being on altazimuth mountings, but many interferometers consist of arrays of static antennas which either have a fixed beam or can be steered electronically.
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"radio telescope." A Dictionary of Astronomy. 1997. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "radio telescope." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O80-radiotelescope.html "radio telescope." A Dictionary of Astronomy. 1997. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-radiotelescope.html |
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radio telescope
radio telescope Instrument used to collect and record radio waves from space. The basic design is the large single dish or parabolic reflector, up to 100m (330ft) in diameter. The dish reflects radio waves via a secondary reflector to a focus, where they convert into electrical signals. The signals are amplified and sent to the main control room, where there is further amplification before analysis and recording. See also radio astronomy; telescope
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"radio telescope." World Encyclopedia. 2005. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "radio telescope." World Encyclopedia. 2005. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O142-radiotelescope.html "radio telescope." World Encyclopedia. 2005. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-radiotelescope.html |
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radio waves
radio waves Electromagnetic radiation of wavelength longer than about 1 mm (30 GHz). The longest radio waves observable by radio astronomers have a wavelength of about 30 m (10 MHz) (see radio window). The shortest radio wavelengths, from about 1 mm to 30 cm, are known as microwaves.
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Cite this article
"radio waves." A Dictionary of Astronomy. 1997. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "radio waves." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O80-radiowaves.html "radio waves." A Dictionary of Astronomy. 1997. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-radiowaves.html |
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radio telescope
ra·di·o tel·e·scope • n. Astron. an instrument used to detect radio emissions from the sky, whether from natural celestial objects or from artificial satellites. |
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"radio telescope." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "radio telescope." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O999-radiotelescope.html "radio telescope." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-radiotelescope.html |
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radio telescope
radio telescope see radio astronomy . |
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Cite this article
"radio telescope." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "radio telescope." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1E1-X-radiotel.html "radio telescope." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-X-radiotel.html |
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