                        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 May 9

                          Messier Craters in Stereo
   Image Credit: Apollo 11, NASA; Stereo Image Copyright Patrick Vantuyne

   Explanation: Many bright nebulae and star clusters in planet Earth's
   sky are associated with the name of astronomer Charles Messier from his
   famous 18th century catalog. His name is also given to these two large
   and remarkable craters on the Moon. Standouts in the dark, smooth lunar
   Sea of Fertility or Mare Fecunditatis, Messier (left) and Messier A
   have dimensions of 15 by 8 and 16 by 11 kilometers respectively. Their
   elongated shapes are explained by the extremely shallow-angle
   trajectory followed by an impactor, moving left to right, that gouged
   out the craters. The shallow impact also resulted in two bright rays of
   material extending along the surface to the right, beyond the picture.
   Intended to be viewed with red/blue glasses (red for the left eye),
   this striking stereo picture of the crater pair was recently created
   from high resolution scans of two images (AS11-42-6304, AS11-42-6305)
   taken during the Apollo 11 mission to the Moon.

                    Tomorrow's picture: moonset timelapse
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

