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 February 5

                         Lunar Eclipse Perspectives
      Image Credit: F. Pichardo, G. Hogan, P. Horálek, F. Hemmerich, S.
                       Schraebler, L. Hašpl, R. Eder;
        Processing & Copyright : Matipon Tangmatitham; Text: Matipon
                            Tangmatitham (NARIT)

   Explanation: Do we all see the same Moon? Yes, but we all see it
   differently. One difference is the apparent location of the Moon
   against background stars -- an effect known as parallax. We humans use
   the parallax between our eyes to judge depth. To see lunar parallax,
   though, we need eyes placed at a much greater separations -- hundreds
   to thousands of kilometers apart. Another difference is that observers
   around the Earth all see a slightly different face of our spherical
   Moon -- an effect known as libration. The featured image is a composite
   of many views across the Earth, as submitted to APOD, of the total
   lunar eclipse of 2019 January 21. These images are projected against
   the same background stars to illustrate both effects. The accurate
   superposition of these images was made possible by a serendipitous
   meteorite impact on the Moon during the lunar eclipse, labeled here
   L1-21J -- guaranteeing that these submitted images were all taken
   within a split second.

                       Tomorrow's picture: open space
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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.

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