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By Pallab Ghosh
Science correspondent, BBC News
A team of astronomers from the US and the UK has obtained some of the clearest
pictures of space ever taken.
They were acquired using a new "adaptive optics" system which sharpens pictures
taken from the Mount Palomar Observatory in California.
The images are twice as sharp as those from Hubble Space Telescope.
The new system, dubbed "Lucky", is the result of work by a team from Cambridge
University and the California Institute of Technology (Caltech).
Our techniques can do very well when the telescope is bigger than Hubble and
has intrinsically better resolution
Craig Mackay, University of Cambridge
Pictures taken by Hubble are normally much better than images from ground-based
telescopes because the Earth's atmosphere has a distorting effect.
The Lucky camera overcomes this problem in two ways.
First, it uses one of the most sensitive light-detection systems developed to
date. This comprises a chip that has very low electrical noise and so can see
much greater detail.
Secondly, the software system is able to distinguish when the atmospheric
distortion starts and stops.
The inventor of the system, Dr Craig Mackay of the Institute of Astronomy in
Cambridge, says it is rather like looking at an object through a heat haze.
"The object is distorted by the haze most of the time," he explained, "but
every now and again there are moments when the haze drops and you can see it
very clearly."
The Lucky system gathers together all the clear pictures and throws out the
distortions to produce images that Dr Mackay believes are the clearest ever
images from the ground.
"The images space telescopes produce are of extremely high quality but they are
limited to the size of the telescope," Dr Mackay added.
"Our techniques can do very well when the telescope is bigger than Hubble and
has intrinsically better resolution."
Two images have been published to date. One is of the globular star cluster M13
which is at a distance of 25,000 light-years.
Stars that are as little as one light-day apart can be differentiated in the
picture.
The other shows very fine detail in the Cat's Eye Nebula (NGC6543).