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The Hubble Space Telescope has a number of instruments, but the primary one is an optical telescope.
"Optical", in this case, simply means that they work with light.
The non-optical telescope, primarily radio telescopes, were invented in the 1930s. One of the first and most notable radio telescopes was built by Karl Guthe Jansky in 1931.
optical
Reflector.
See things that don't shine in the visible spectrum.
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The surface of a radio telescope doesn't have to be as flawless as the surface of an optical telescope because the radio telescope is collecting radio waves, something that will not be affected by faults in the glass. Optical telescopes, on the other hand, are collecting light, where faults in the surface can interfere with the image.
Radio telescopes collect radio waves. Optical telescopes capture visible light waves.
you can get the optical components to repair an old telescope at http://www.astromart.com/classifieds/details.asp?classified_id=644695. Another site is www.Fixya.com/Telescope+Repair
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Usually, by using your eye sight, optical telescope, or radio telescope.