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Ground-based Telescope as Sharp as Hubble

Posted by michael on from the corrective-lenses-required dept.

Midnight Thunder writes: "The BBC has an article describing how the Paranal Observatory has been able to take images that are just as sharp as the Hubble Space Telescope. For a ground based telescope the images are of amazing quality."

2 of 36 comments (clear)

  1. This is not new by lanclos · · Score: 3, Informative

    Keck's been capable of "beating" Hubble for a good long while now. Adaptive Optics is wild and crazy stuff.

    Please don't believe that we'll be able to do away with space-based observing because of this innovation. Our atmosphere absorbs an awful lot of interesting wavelengths.

    1. Re:This is not new by Anonymous Coward · · Score: 1, Informative

      Indeed, adaptive optics has been around for a few years at most observatories. However, it is still being developed.

      I have used the adaptive optics systems at both Keck and Lick observatories. They can work very well, but are generally limited to observations near a bright (V~13 or so within ~40 arcsec) guide star. This limit means that only ~1% of the sky is accessible. A laser tuned to a sodium line can be used to create an artificial guide star. In this case, you still need a star for "tip-tilt" correction, but it can be fainter (roughly V~16).
      Laser guide star AO is still in development at Lick (though it does work -- I have a small amount of data obtained with it), and not yet available at Keck.

      There are also issues with the point spread function and dynamic range, especially if you are observing off-axis of the guide star.
      So don't give up on old HST just yet...
      -- Just Another Random Astrophysicist