                        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.

                              2020 September 21

                                Omega Sunrise
                Image Credit & Copyright: Juan Antonio Sendra

   Explanation: Capturing this sunrise required both luck and timing.
   First and foremost, precise timing was needed to capture a sailboat
   crossing right in front of a rising Sun. Additionally, by a lucky
   coincidence, the background Sun itself appears unusual -- it looks like
   the Greek letter Omega (W*). In reality, the Sun remained its circular
   self -- the Omega illusion was created by sunlight refracting through
   warm air just above the water. Optically, the feet of the capital Omega
   are actually an inverted image of the Sun region just above it.
   Although somewhat rare, optical effects caused by the Earth's
   atmosphere can make distant objects near the horizon -- including the
   Sun and Moon -- look quite unusual. This single exposure image was
   taken over the Mediterranean Sea just over two weeks ago near Valencia,
   Spain.

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