Tuesday, October 27, 2009

Big Telescopes Get Lucky (Imaging)

Over lunch I read a cool article in the November Optics and Photonics News. The article is called "High Resolution Imaging with Large Ground-Based Telescopes" by Craig Mackay, and it's not available online yet, though there is quite a lot of material on the subject at the "Lucky Imaging WebSite," hosted by the University of Camridge, where Mackay is an astronomer. The home page includes a good overview of the subject as well as many links to more detailed articles and even a Ph.D. thesis if you want lots of detail.

I'll let you read elsewhere for the details, but "Lucky Imaging" takes advantage of the statistical properties of atmospheric turbulence in combination with fast, low-noise, electron-multiplying CCD's and some very clever techniques to achieve diffraction-limited imaging from ground-based telescopes in visible wavelengths, where adaptive optics methods (AO) have not been especially successful (AO works better in the infrared). We're talking Hubble quality resolution or better, especially when this technique is implemented on the latest very large telescopes. It has already been demonstrated on the Palomar 5 meter telescope in combination with an AO system. The animated GIF above compares an uncorrected Palomar image of the Cat's Eye Nebula (NGC6543) with the same object using the AO plus Lucky Imaging technique (Hubble's Cat's Eye images look better than this due to several factors including longer exposures, but this gives an idea of the improvement Lucky Imaging makes possible).

1 comment:

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