“Just as optical telescopes collect visible light, bring it to a  focus, amplify it and make it available for analysis by various  instruments, so do radio telescopes collect weak radio light waves,  bring it to a focus, amplify it and make it available for analysis

“Just as optical telescopes collect visible light, bring it to a  focus, amplify it and make it available for analysis by various  instruments, so do radio telescopes collect weak radio light waves,  bring it to a focus, amplify it and make it available for analysis.”   (The National Radio Astronomy Observatory, 2019)

The biggest difference between the two that I’ve found is that the  wavelength of light that can be observed by a radio telescope is much  longer. The wavelength observed can be from 1 mm to over 10 meters long!  Visible light waves are only a few hundred nanometers long. This means  we are observing at much longer distances with radio telescopes. The  components and telescopes are much larger than viable light telescopes  to get the resolution needed.  They use “a radio receiver and an antenna  system that is used to detect radio-frequency radiation emitted by  extraterrestrial sources.” (Radio Telescope, n.d.) They both use a  curved reflecting surface to focus the incoming waves and concentrates  them to a point of focus.