Radio telescope is a device to receive radio-waves from space. Radio-waves are emitted by a variety of astronomical objects such as galaxies, stars including our sun, and even planets such as Jupiter and Saturn. The first radio telescope which picked up the radio-waves was built in 1937 by Grote Reber.
A radio telescope is different from an ordinary telescope as it is not possible to look through it. It consists of a big dish which picks up the radio signals from space. The waves are focussed on a receiving antenna which changes the waves into electrical signals. These signals are processed by computers to generate images of the source of the radio-waves. The dish antenna of a radio telescope can usually be turned in different directions. Using radio telescopes much has been learnt about various stars, planets and galaxies. Pulsars and quasars were discovered by using radio telescopes.
