                        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 February 28
   A picture of the remnant pillars of Poseiden is shown, an ancient Greek
   Temple. In the middle of the ruins, far in the distance, is a crescent
       Moon. Please see the explanation for more detailed information.

                      Crescent Moon Beyond Greek Temple
                  Image Credit & Copyright: Elias Chasiotis

   Explanation: Why is a thin crescent moon never seen far from a horizon?
   Because the only geometry that gives a thin crescent lunar phase occurs
   when the Moon appears close to the Sun in the sky. The crescent is not
   caused by the shadow of the Earth, but by seeing only a small part of
   the Moon directly illuminated by the Sun. Moreover, the thickest part
   of the crescent always occurs in the direction of the Sun. In the
   evening, a thin crescent Moon will set shortly after the Sun and not be
   seen for the rest of the night. Alternatively, in the morning, a
   crescent Moon will rise shortly before the Sun after not being seen for
   most of the night. Pictured two weeks ago, a crescent moon was captured
   near the horizon, just before sunrise, far behind remnants of the
   ancient Temple of Poseidon in Greece.

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