This groovy and psychedelic photograph shows a night of observing the Northern Celestial Pole from the Allgäu Public Observatory in Ottobeuren, Germany. Pictured here is the facility's 0.6-metre Cassegrain reflector telescope, which was installed in 1996.
<p>The brilliant yellow laser beam, which appears to fan out across the sky in this long-exposure image, is ESO's Wendelstein laser guide star unit which was tested at the site in Allgäu. It is a smaller version of the laser guide star that has been installed on the Very Large Telescope in Paranal, Chile.
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A Laser guide star is used to create a bright spot in the sky, which can be used as an artificial reference star, allowing astronomers to measure how the real stars blur or twinkle, as normally seen from the ground. The measurements are then used to correct this blurring and enable sharper images to be taken, in a process is known as adaptive optics.
ESO/M. Kornmesser
CC BY 4.0
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