It allows us to collect more light than we can with our eyes, thus gathering information we could not otherwise gather.
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.
optical
The most important part of a telescope is the telescope tube. Other parts are the viewfinder or optical finderscope, eyepiece, focuser, reflecting mirrors, refracting lenses, and the mount assembly.
Reflector.
See things that don't shine in the visible spectrum.
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Radio telescopes collect radio waves. Optical telescopes capture visible light waves.
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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.
It contains an objective lens and a lens in the eyepiece of the telescope.
Usually, by using your eye sight, optical telescope, or radio telescope.