                        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.

                                2021 June 17

                        NGC 6888: The Crescent Nebula
    Image Credit & Copyright: Joe Navara, Glenn Clouder, Russell Discombe

   Explanation: NGC 6888, also known as the Crescent Nebula, is a about 25
   light-years across blown by winds from its central, bright, massive
   star. A triumvirate of astroimagers ( Joe, Glenn, Russell) created this
   sharp portrait of the cosmic bubble. Their telescopic collaboration
   collected over 30 hours of narrow band image data isolating light from
   hydrogen and oxygen atoms. The oxygen atoms produce the blue-green hue
   that seems to enshroud the detailed folds and filaments. Visible within
   the nebula, NGC 6888's central star is classified as a Wolf-Rayet star
   (WR 136). The star is shedding its outer envelope in a strong stellar
   wind, ejecting the equivalent of the Sun's mass every 10,000 years. The
   nebula's complex structures are likely the result of this strong wind
   interacting with material ejected in an earlier phase. Burning fuel at
   a prodigious rate and near the end of its stellar life this star should
   ultimately go out with a bang in a spectacular supernova explosion.
   Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000
   light-years away.

                 Tomorrow's picture: The devil didn't do it.
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