A small aperture.
"Optical", in this case, simply means that they work with light.
INvisible light
Currently, the largest optical telescope is the Gran Telescopio Canarias in the Canary Islands, Spain.
Space Telescope such as the Hubble Space Telescope
Mirrors and telescopes use light reflection.
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.
"Optical", in this case, simply means that they work with light.
me
INvisible light
Radio telescopes collect radio waves. Optical telescopes capture visible light waves.
An optical telescope focuses and concentrates visible light; radio telescopes focus and concentrate electromagnetic radiation (which means, "light") in the radio part of the spectrum.
As far as I know, there is no "optical radio telescope". There are, separately, optical telescopes (which work with visible light), and radio telescopes (which work with radio waves).
Optical!!
Currently, the largest optical telescope is the Gran Telescopio Canarias in the Canary Islands, Spain.
Allows you to gather more light from a distant object.
an optical telescope
They don't. All earth bound telescopes, optical or not, must deal with a number of issues. But what do you mean by "better"? A radio telescope is better suited to pick up radio waves than an optical telescope, but an optical telescope is better for visible light. They each serve their purpose better than the other.