                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                                2026 March 10
   A colorful sky appears above several large telescopes. Prominent in the
   sky is the band of the Milky Way Galaxy which arches across the frame.
     Orange laser beams connect one of the telescopes to the sky on the
   image right. Please see the explanation for more detailed information.

                     Sky Glows over Paranal Observatory
                   Image Credit & Copyright: Julien Looten

   Explanation: Are lasers from giant telescopes being used to defend the
   Earth? No. Lasers shot from telescopes are now commonly used to help
   increase the accuracy of astronomical observations. In some directions,
   Earth atmosphere-induced fluctuations in starlight can indicate how the
   air mass over a telescope is changing, but in other directions, no
   bright star exists. In these directions, astronomers can create an
   artificial star with a laser. Subsequent observations of the artificial
   laser guide star can reveal information so detailed about the changing
   blurring effects of the Earth's atmosphere that much of it can be
   removed by rapidly flexing a telescope's mirror. Such adaptive optics
   techniques allow high-resolution ground-based observations of real
   stars, planets, and nebulas. Pictured here, telescopes at Paranal
   Observatory in Chile study a colorful sky filled with green airglow and
   the Magellanic Clouds on the left, red airglow on the right, and the
   majestic central band of our Milky Way Galaxy arching across the
   center.

                       Tomorrow's picture: open space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

