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Massive Radio Telescope Starts Observing the Skies 44

New submitter cyachallenge writes with this excerpt from New Scientist: "RadioAstron, effectively the largest radio telescope ever built, is up and running. The telescope's main component, a 10-metre radio dish aboard the spacecraft Spectr-R, launched in July to an oblong orbit that extends between 10,000 and more than 300,000 kilometres from Earth. By coordinating observations with radio telescopes on Earth in a technique called interferometry, the telescope can make observations as sharp as a single dish spanning the entire distance between the two farthest dishes. When Spectr-R is at its farthest from Earth, the system acts like one enormous telescope about 30 times as wide as our planet, boasting about 10,000 times the resolution of the Hubble Space Telescope."
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Massive Radio Telescope Starts Observing the Skies

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  • by Anonymous Coward on Saturday December 10, 2011 @05:46AM (#38324136)

    .. it still "only" has 10m of aperture (+ the aperture from radio telescopes on Earth) so it will have a hard time detecting faint objects near its maximum resolution. It will be excellent at detecting small details of bright objects though.

  • Their Website (Score:5, Informative)

    by bobby1234 ( 860820 ) on Saturday December 10, 2011 @06:41AM (#38324320)
  • Re:Too bad (Score:5, Informative)

    by buchner.johannes ( 1139593 ) on Saturday December 10, 2011 @09:32AM (#38325084) Homepage Journal

    Actually, in radio astronomy you can't really say it's photons. The wavelengths are centimeters to meters (a pretty large photon), and you get wave-effects everywhere.
    It's not true that this or other radio telescopes are no match for Hubble. This satellite links up with ground-based telescopes and does VLBI. The baseline of VLBI -- equivalent to the aperture diameter for optical telescope -- is the distance between the linked telescopes. If you want to have a telescope as powerful as Hubble, you need to compare diameter/wavelength (Hubble example: 2.4m/440nm = 5e6). So for radio (e.g. 21 cm), you need a baseline of 1050 km. Ground-based VLBI networks, like the Australian LBA (3300km Perth-Sydney, 5500km Perth-Auckland) or the European EVN, the VLBA (8000km) reach these lengths. This brings you down to milliarcsecond resolutions, incidentally similar to the optical VLT interferometer.
    RadioAstron will be on an "orbit that extends between 10,000 and more than 300,000 kilometres from Earth".

    So yes, it will be a match for Hubble by a factor of 100. However, this comparison is not really helpful, as optical and radio telescopes see different things and probe different physical processes. To understand the universe, information from all wavelengths is relevant.

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