                        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.

                              2020 September 25

                             Moon over Andromeda
       Composite Image Credit & Copyright: Adam Block and Tim Puckett

   Explanation: The Great Spiral Galaxy in Andromeda (also known as M31),
   a mere 2.5 million light-years distant, is the closest large spiral to
   our own Milky Way. Andromeda is visible to the unaided eye as a small,
   faint, fuzzy patch, but because its surface brightness is so low,
   casual skygazers can't appreciate the galaxy's impressive extent in
   planet Earth's sky. This entertaining composite image compares the
   angular size of the nearby galaxy to a brighter, more familiar
   celestial sight. In it, a deep exposure of Andromeda, tracing beautiful
   blue star clusters in spiral arms far beyond the bright yellow core, is
   combined with a typical view of a nearly full Moon. Shown at the same
   angular scale, the Moon covers about 1/2 degree on the sky, while the
   galaxy is clearly several times that size. The deep Andromeda exposure
   also includes two bright satellite galaxies, M32 and M110 (below and
   right).

                    Tomorrow's picture: Observe the Moon
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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