                        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 8

                        The Deep Sky Toward Andromeda
                  Image Credit & License: Stefan Ziegenbalg

   Explanation: What surrounds the Andromeda galaxy? Out in space,
   Andromeda (M31) is closely surrounded by several small satellite
   galaxies, and further out it is part of the Local Group of Galaxies --
   of which our Milky Way galaxy is also a member. On the sky, however,
   gas clouds local to our Milky Way appear to surround M31 -- not unlike
   how water clouds in Earth's atmosphere may appear to encompass our
   Moon. The gas clouds toward Andromeda, however, are usually too faint
   to see. Enter the featured 45-degree long image -- one of the deeper
   images yet taken of the broader Andromeda region. This image, sensitive
   to light specifically emitted by hydrogen gas, shows these faint and
   unfamiliar clouds in tremendous detail. But the image captures more. At
   the image top is the Triangulum galaxy (M33), the third largest galaxy
   in the Local Group and the furthest object that can be seen with the
   unaided eye. Below M33 is the bright Milky-Way star Mirach. The image
   is the digital accumulation of several long exposures taken from 2018
   to 2021 from Pulsnitz, Germany.

                       Tomorrow's picture: open space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                             & Michigan Tech. U.


