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The Square Kilometre Array Observatory


On 4th Feb, the Square Kilometre Array Observatory (SKAO) Council held its maiden meeting and approved the establishment of the world’s largest radio telescope.


  • The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, with eventually over a square kilometre (one million square metres) of collecting area,  project being planned to be built in Australia and South Africa.
  • Conceived in the 1990s, and further developed and designed by the late-2010s, when completed it will have a total collecting area of approximately one square kilometre sometime in the 2020s
  • It will operate over a wide range of frequencies and its size will make it 50 times more sensitive than any other radio instrument.
  • It will require very high performance central computing engines and long-haul links with a capacity greater than the global Internet traffic as of 2013
  • If built as planned, it should be able to survey the sky more than ten thousand times faster than before.
  • With receiving stations extending out to a distance of at least 3,000 kilometres (1,900 mi) from a concentrated central core, it will exploit radio astronomy’s ability to provide the highest resolution images in all astronomy. 
  • The SKA will be built in the southern hemisphere, with cores in South Africa and Australia, where the view of the Milky Way Galaxy is the best and radio interference at its least.
  • The SKA will combine the signals received from thousands of small antennas spread over a distance of several thousand kilometres to simulate a single giant radio telescope capable of extremely high sensitivity and angular resolution, using a technique called aperture synthesis.
  • The SKA will provide continuous frequency coverage from 50 MHz to 14 GHz in the first two phases of its construction. A third phase will then extend the frequency range up to 30 GHz.

SKA members

Organisations from 14 countries are members of the SKA Organisation – Australia, Canada, China, France, Germany, India, Italy, New Zealand, Spain, South Africa, Sweden, Switzerland, The Netherlands and the United Kingdom. This global organisation is managed by the not-for-profit SKA Organisation, who have their headquarters at the Jodrell Bank Observatory, near Manchester in the United Kingdom.

Headquartered in the UK.

The SKA will comprise separate sub-arrays of different types of antenna elements that will make up the SKA-low, SKA-mid and survey arrays:

  1. SKA-low array: a phased array of simple dipole antennas to cover the frequency range from 50 to 350 MHz. These will be grouped in 100 m diameter stations each containing about 90 elements.
  2. SKA-mid array: an array of several thousand dish antennas (around 200 to be built in Phase 1) to cover the frequency range 350 MHz to 14 GHz. It is expected that the antenna design will follow that of the Allen Telescope Array using an offset Gregorian design having a height of 15 metres and a width of 12 metres.
  3. SKA-survey array: a compact array of parabolic dishes of 12–15 meters diameter each for the medium-frequency range, each equipped with a multi-beam, phased array feed with a large field of view and several receiving systems covering about 350 MHz – 4 GHz. The survey sub-array was removed from the SKA1 specification following a “rebaselining” exercise in 2015.

Cost and Completion:

  • The completion is expected to take nearly a decade at a cost of over 1.8 billion pounds.
  • Significance:
    • Some of the questions that scientists hope to address using this telescope:
      • The beginning of the universe.
      • How and when the first stars were born.
      • The life-cycle of a galaxy.
      • Exploring the possibility of detecting technologically-active civilisations elsewhere in our galaxy.
      • Understanding where gravitational waves come from.
  • Function:
    • As per NASA, the telescope will accomplish its scientific goals by measuring neutral hydrogen over cosmic time, accurately timing the signals from pulsars in the Milky Way, and detecting millions of galaxies out to high redshifts.                                                                                                                                                                                                                         
Radio Telescopes:

Radio telescope, astronomical instrument consisting of a radio receiver and an antenna system that is used to detect radio-frequency radiation between wavelengths of about 10 metres (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, they 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. Since the first radio signals were detected in the 1930s, astronomers have used radio telescopes to detect radio waves emitted by different objects in the universe and explore it. According to the National Aeronautics and Space Administration (NASA), the field of radio astronomy evolved after World War II and became one of the most important tools for making astronomical observations. The Arecibo Telescope:

The Arecibo telescope in Puerto Rico, which was the second-largest single-dish radio telescope in the world, collapsed in December 2020.

China’s Sky Eye is the world’s largest single-dish radio telescope. The telescope was built in 1963.Because of its powerful radar, scientists employed it to observe planets, asteroids and the ionosphere, making several discoveries over the decades, including finding prebiotic molecules in distant galaxies, the first exoplanets, and the first-millisecond pulsar.    

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