- a system consisting of an antenna, either parabolic or dipolar, used to gather radio waves emitted by celestial sources and bring them to a receiver placed in the focus.
- an instrument consisting of an antenna or system of antennas connected to one or more radio receivers, used in radio astronomy to detect and analyse radio waves from space
- 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.