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Sharpest Images With "Lucky" Telescope

Posted by kdawson on from the palomar-ascendent dept.

igny writes "Astronomers from the University of Cambridge and Caltech have developed a new camera that gives much more detailed pictures of stars and nebulae than even the Hubble Space Telescope, and does it from the ground. A new technique called 'Lucky imaging' has been used to diminish atmospheric noise in the visible range, creating the most detailed pictures of the sky in history."

8 of 165 comments (clear)

  1. Lucky Imaging by dlawson · · Score: 5, Insightful

    First post, huh.
    This technique is often used by amateur astrophotographers using newer CCD cameras and even webcams. Astronomy Picture Of the Day http://antwrp.gsfc.nasa.gov/apod/astropix.html is a great site to see this stuff. I haven't checked Googles pictures, but I am sure that there would be a number of them there, too.
    The quality of some of these photos is amazing.
    davel

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    dot-sig.
    1. Re:Lucky Imaging by Anonymous Coward · · Score: 5, Interesting

      Apologies for not having an account - but I would really like to ask a question for someone who understands the process.

      the wikipedia entry on this subject http://en.wikipedia.org/wiki/Lucky_imaging states that new procedures take, '... advantage of the fact that the atmosphere does not "blur" astronomical images, but generally produces multiple sharp copies of the image'.

      Does the correction algorithm apply a single vector to each image (ie the entire frame is shifted in unity) to produce the composite, or is a vector field applied to every pixel point in the image to shift individually the pixels toward their correct centres? Also if it is pointwise what type of transform is being applied, affine , perspective etc.

  2. Re:If they can do this from earth... by Anonymous Coward · · Score: 5, Funny

    Well sure. All you have to do is bounce your laser off of those gas clouds to find out how to compensate for them. That should only take a couple hundred or a couple of thousand years with a laser that would consume more power than all of the Earth uses. Oh, and you better hope that that gas cloud doesn't change in the transit time.

  3. Compared to adaptive optics? by kebes · · Score: 5, Informative

    One of the main limitations to ground-based optical telescopes (and one of the reasons that Hubble gets such amazing images) is that the atmosphere generates considerable distortion. Random fluctuations in the atmosphere cause images to be blurry (and cause stars to twinkle, of course). The technique they present appears to be taking images at very high-speed. They developed an algorithm that looks through the images, and identifies the ones that happen to not-blurry (hence "lucky"). By combining all the least blurry images (taken when the atmosphere just happened to be not introducing distortion), they can obtain clear images using ground-based telescopes (which are bigger than Hubble, obviously). I imagine the algorithm they've implemented tries to use sub-sections of images that are clear, to get as much data as possible.

    Overall, a fairly clever technique. I wonder how this compares to adaptive optics, which is another solution to this problem. In adaptive optics, a guide laser beam is used to illuminate the atmosphere above the telescope. The measured distortion of the laser beam is used to distort the imaging mirror in the telescope (usually the mirror is segmented into a bunch of small independent sub-mirrors). The end result is that adaptive optics can essentially counter-act the atmospheric distortion, delivering crisp images from ground telescopes.

    I would guess that adaptive optics produces better images (partly because it "keeps" all incident light, by refocusing it properly, rather than letting a large percentage of image acquisitions be "blurry" and eventually thrown away), but adaptive optics are no doubt expensive. The technique presented in TFA seems simple enough that it would be added to just about any telescope, increasing image quality at a sacrifice in acquisition time.

  4. You Too Can Get Lucky. by Erris · · Score: 5, Informative

    DIY.

    --
    DMCA, Hollings, Palladium. What might have sounded like paranoia is now common sense.
  5. Spider-sense by BitwizeGHC · · Score: 5, Interesting

    That is really quite amazing, and reminds me a bit of the jumping spiders whose retinas vibrate to increase their optic resolution.

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    N4st0r, trixx0r h0bb1tz0rz! Th3y st0l3 0ur pr3c10uzz!
  6. Comparison to hubble... by Anonymous Coward · · Score: 5, Informative

    TFA mentions that they can achieve images better than Hubble. The sample image they show, of the Cat's Eye Nebula, isn't as sharp as the Hubble image of the same object.

    Probably they can push their technique harder than this initial image suggests (it was mainly comparing the "lucky" image with a conventional, blurry, ground-based image)... But I just thought it would be good to show Hubble's pictures alongside.

  7. Re:But surely... by hazem · · Score: 5, Informative

    Additionally, while they don't mention details in the article, I presume they have a specially designed camera.

    They are using a new kind of CCD that somehow lowers the noise floor. Details are at:
    http://www.ast.cam.ac.uk/~optics/Lucky_Web_Site/LI _Why%20Now.htm

    In fact this site (same basic place) is much more informative than the press release and answers a lot of questions:
    http://www.ast.cam.ac.uk/~optics/Lucky_Web_Site/in dex.htm