An instrument that consists of a radio receiver and antenna system mounted on a wide, bowl-shaped reflector, used to detect radio-frequency emissions from astronomical objects. The reflector and receiver form a parabolic antenna ; incoming radio waves are focused by the reflector onto the receiver, where the radio signals are translated into electrical signals for further processing or electronic display. Due to the long wavelengths of radio waves, the reflectors of radio telescopes must be very large to focus the waves at a good resolution. Separate reflectors are sometimes linked in fixed arrays to act as a single collector.