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What Are the Parts of a Radio Telescope?

Visible light is electromagnetic (EM) radiation of wavelengths between 390 and 750 nanometers, while radio telescopes can study EM radiation between 10 m to 1 mm, a range several orders of magnitude larger. In other words, by using radio waves instead of optical waves, radio astronomers can see cosmic phenomena that are otherwise invisible, vastly increasing our understanding of the universe. While radio telescopes vary greatly in size and function, they all have five basic components: a dish, antenna, receiver, detector and recorder.

Dish and Antenna
- The area of the dish and the efficiency of the antenna have a direct bearing on the telescope's sensitivity; that is its ability to effectively use weak radio signals. The dish is usually very large because most cosmic radio sources produce weak signals and require high sensitivity. The radio reflector telescope, the most common type of radio telescope, catches the incoming signal in a parabolic dish and focuses it on the antenna. The antenna concentrates the waves and passes them to the receiver.
Receiver
- Only the most sensitive radio receivers are used in radio telescopes, and just like a car radio, they only receive the wavelength to which they are tuned. As an indication of their sensitivity, receivers are maintained at very low temperatures (-250 to -290 degrees C) so the thermal noise generated by "the movement of the atoms in the metal" will be kept to a minimum, according to Australia Telescope Outreach and Education. The receiver amplifies the waves and converts them to electrical signals that are carried by conductors to the decoder.
Detector
- Leaving the receiver, the signal from the telescope is represented by a voltage. In order to use the signal to produce images, you need to measure the power density or the amount of energy in the wave. The detector makes this conversion.
Recorder/Analyzer
- Computers can generate remarkable images from radio telescope input.
  
  The recorder is usually an external storage device attached to a computer that can be used to analyze the data. Once analyzed, the computer can build pictures whose level of detail is restricted only by the amount of data collected. Computers are sometimes used to combine the radio frequency input with optical and infrared input to make composites that have proven very useful to astronomers and cosmologists.

Astronomy