                        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.

                                 2023 May 27
      The picture shows the planet Neptune and its moon Triton, both in
     crescent phases, as captured by the passing Voyager 2 spacecraft in
       1989. Please see the explanation for more detailed information.

                         Crescent Neptune and Triton
                        Image Credit: NASA, Voyager 2

   Explanation: Gliding through the outer Solar System, in 1989 the
   Voyager 2 spacecraft looked toward the Sun to find this view of most
   distant planet Neptune and its moon Triton together in a crescent
   phase. The elegant image of ice-giant planet and largest moon was taken
   from behind just after Voyager's closest approach. It could not have
   been taken from Earth because the most distant planet never shows a
   crescent phase to sunward eyes. Heading for the heliopause and beyond,
   the spacecraft's parting vantage point also robs Neptune of its
   familiar blue hue.

                   Tomorrow's picture: an unexpected moon
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                      A service of: ASD at NASA / GSFC
                             & Michigan Tech. U.

