                        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.

                                2026 April 21
   A starry sky is seen above snowy mountains. In the sky three arches are
    visible, with the Milky Way on either side and zodiacal light in the
      center. Please see the explanation for more detailed information.

                      Three Sky Arches over Snowy Alps
                     Image Credit & Copyright: Angel Fux

   Explanation: Why are there three arches across the sky instead of two?
   Last month, after being dropped off by a helicopter at a high mountain
   peak in the Alps near the Swiss Italian border, an adventurous
   astrophotographer expected two arches of our Milky Way galaxy to be
   visible during the night. These were the inner arch looking in toward
   the center of our galaxy on the left, visible just before sunrise, and
   the outer arch on the right visible just after sunset. But there were
   three arches. The surprised astrophotographer soon realized that the
   sky was so dark that an entire arc of faint zodiacal light was also
   noticeable -- sunlight scattered by inner Solar System dust. And it
   artfully connected the two Milky Way arches! The next morning a
   helicopter picked the astrophotographer back up, and after 40 hours of
   processing and combining that night's images, the featured triple-arch
   360-degree panorama resulted.

                 Jigsaw Vistas: Astronomy Puzzle of the Day
                       Tomorrow's picture: open space
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

