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A radio telescope in remote Western Australia is helping to build a 3-dimensional map of the night sky, mapping nearby galaxies up to a billion light years away.



  • WALLABY is a radio telescope in Western Australia that is helping astronomers build a three-dimensional map of the night sky.
  • The Widefield ASKAP L-band Legacy All-sky Blind Survey (or WALLABY) is one of two key surveys that are now running on the Australian SKA Pathfinder (ASKAP).
  • It is an innovative imaging radio telescope located in an extremely radio-quiet zone (the Murchison Radio-astronomy Observatory) in Western Australia.


  • To observe three-quarters of the whole sky in the 21-cm line of neutral hydrogen (or HI) at 30-arcsec resolution.
    • thereby detecting and imaging the gas distribution in hundreds of thousands of external galaxies in the local Universe.

The Hydrogen 21-cm Line:

  • The hydrogen in our galaxy has been mapped by the observation of the 21-cm wavelength line of hydrogen gas.
  • At 1420 MHz, this radiation from hydrogen penetrates the dust clouds and gives us a more complete map of the hydrogen than that of the stars themselves since their visible light won't penetrate the dust clouds.
  • It will help the researchers to measure:
    • measure the dark-matter distribution
    • the internal motion of galaxies
    • how these systems evolve and interact

What is radio astronomy and how is it used?

  • The radio telescope is an astronomical instrument consisting of a radio receiver and an antenna system that is used to detect radio-frequency radiation between wavelengths of about 10 meters (30 megahertz [MHz]) and 1 mm (300 gigahertz [GHz]) emitted by extraterrestrial sources, such as stars, galaxies, and quasars.
  • Unlike optical telescopes, radio telescopes can detect invisible gas and, therefore, can reveal areas of space that may be obscured by cosmic dust.
  • Cosmic dust consists of tiny particles of solid material floating around in the space between the stars.
  • In its simplest form a radio telescope has three basic components:
    • One or more antennas pointed to the sky, to collect the radio waves
    • A receiver and amplifier to boost the very weak radio signal to a measurable level, and
    • A recorder to keep a record of the signal.

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