                        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 September 25

                       The Bubble and the Star Cluster
                   Image Credit & Copyright: Lorand Fenyes

   Explanation: To the eye, this cosmic composition nicely balances the
   Bubble Nebula at the right with open star cluster M52. The pair would
   be lopsided on other scales, though. Embedded in a complex of
   interstellar dust and gas and blown by the winds from a single, massive
   O-type star, the Bubble Nebula, also known as NGC 7635, is a mere 10
   light-years wide. On the other hand, M52 is a rich open cluster of
   around a thousand stars. The cluster is about 25 light-years across.
   Seen toward the northern boundary of Cassiopeia, distance estimates for
   the Bubble Nebula and associated cloud complex are around 11,000
   light-years, while star cluster M52 lies nearly 5,000 light-years away.
   The wide telescopic field of view spans about 1.5 degrees on the sky or
   three times the apparent size of a full Moon.

                  Tomorrow's picture: The Red Square Nebula
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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