Astronomy Picture of the Day

   [1]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
   [2]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: [3]Julien Looten

   Explanation: Are lasers from giant telescopes being used to defend the
   Earth? No. [4]Lasers shot [5]from telescopes are now commonly used to
   help increase the accuracy of astronomical observations. In some
   directions, Earth atmosphere-induced [6]fluctuations in starlight can
   indicate how the [7]air mass over a [8]telescope is changing, but in
   other directions, no bright star exists. In these directions,
   astronomers can create an [9]artificial star with a [10]laser.
   Subsequent observations of the artificial [11]laser guide star can
   reveal information so detailed about the changing blurring effects of
   the [12]Earth's atmosphere that much of it [13]can be removed by
   rapidly flexing a telescope's mirror. Such [14]adaptive optics
   techniques allow high-resolution ground-based observations of [15]real
   stars, [16]planets, and [17]nebulas. [18]Pictured here, telescopes at
   [19]Paranal [20]Observatory in [21]Chile study a colorful sky filled
   with green [22]airglow and the [23]Magellanic Clouds on the left, red
   [24]airglow on the right, and the majestic central band of our
   [25]Milky Way Galaxy [26]arching across the center.

                       Tomorrow's picture: open space
     __________________________________________________________________

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    Authors & editors: [38]Robert Nemiroff ([39]MTU) & [40]Jerry Bonnell
                                 ([41]UMCP)
          NASA Official: Amber Straughn [42]Specific rights apply.
            [43]NASA Web Privacy, [44]Accessibility, [45]Notices;
                A service of: [46]ASD at [47]NASA / [48]GSFC,
                         [49]NASA Science Activation
                           & [50]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2603/TeleSkyLasers_Looten_3000.jpg
   3. https://www.flickr.com/photos/julienlooten/
   4. https://en.wikipedia.org/wiki/Laser
   5. https://apod.nasa.gov/apod/ap090816.html
   6. https://apod.nasa.gov/apod/ap000725.html
   7. https://en.wikipedia.org/wiki/Air_mass_(astronomy)
   8. https://spaceplace.nasa.gov/telescopes/
   9. https://economictimes.indiatimes.com/news/international/us/astronomers-are-creating-fake-stars-on-purpose-and-the-reason-is-surprisingly-practical/articleshow/129141647.cms
  10. https://science.howstuffworks.com/laser.htm
  11. https://en.wikipedia.org/wiki/Laser_guide_star
  12. https://science.nasa.gov/earth/earth-atmosphere/earths-atmosphere-a-multi-layered-cake/
  13. https://www.reddit.com/media?url=https://external-preview.redd.it/4r6uFaV1OY5PZpRyaQyEUG3NEdyytuDsuzFlzSQb2Mg.jpg?width=640&crop=smart&auto=webp&s=ed840ba0c7af96a0994daec2d97b4a507a08712f
  14. https://www.gemini.edu/sciops/instruments/adaptiveOptics/AOPrimer.html
  15. https://apod.nasa.gov/apod/ap000522.html
  16. https://apod.nasa.gov/apod/ap000218.html
  17. https://noirlab.edu/public/images/noirlab2025a/
  18. https://www.flickr.com/photos/julienlooten/55107654448/in/pool-apods/
  19. https://www.eso.org/public/teles-instr/paranal-observatory/
  20. https://www.youtube.com/watch?v=k_LwlwJWZN0&t=115s
  21. https://en.wikipedia.org/wiki/Chile
  22. https://svs.gsfc.nasa.gov/12963
  23. https://apod.nasa.gov/apod/ap230211.html
  24. https://en.wikipedia.org/wiki/Airglow
  25. https://svs.gsfc.nasa.gov/14935/
  26. https://apod.nasa.gov/apod/ap210113.html
  27. https://apod.nasa.gov/apod/ap260309.html
  28. https://apod.nasa.gov/apod/archivepix.html
  29. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  30. https://apod.nasa.gov/apod/lib/aptree.html
  31. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  32. https://apod.nasa.gov/apod/calendar/allyears.html
  33. https://apod.com/feed.rss
  34. https://apod.nasa.gov/apod/lib/edlinks.html
  35. https://apod.nasa.gov/apod/lib/about_apod.html
  36. https://asterisk.apod.com/discuss_apod.php?date=260310
  37. https://apod.nasa.gov/apod/ap260311.html
  38. http://www.phy.mtu.edu/faculty/Nemiroff.html
  39. http://www.phy.mtu.edu/
  40. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  41. http://www.astro.umd.edu/
  42. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  43. https://www.nasa.gov/about/highlights/HP_Privacy.html
  44. https://www.nasa.gov/general/accessibility/
  45. https://www.nasa.gov/privacy/
  46. https://astrophysics.gsfc.nasa.gov/
  47. https://www.nasa.gov/
  48. https://www.nasa.gov/centers/goddard/
  49. https://science.nasa.gov/learners
  50. http://www.mtu.edu/