                        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 September 20
      The featured image the Sun in many positions above the Callanish
      stones. Please see the explanation for more detailed information.

                     Analemma over the Callanish Stones
                 Image Credit & Copyright: Giuseppe Petricca

   Explanation: If you went outside at the same time every day and took a
   picture that included the Sun, how would the Sun's position change? A
   visual answer to that question is an analemma, a composite image taken
   from the same spot at the same time over the course of a year. The
   featured analemma was composed from images taken every few days at noon
   near the village of Callanish in the Outer Hebrides in Scotland, UK. In
   the foreground are the Callanish Stones, a stone circle built around
   2700 BC during humanity's Bronze Age. It is not known if the placement
   of the Callanish Stones has or had astronomical significance. The
   ultimate causes for the figure-8 shape of this and all analemmas are
   the tilt of the Earth axis and the ellipticity of the Earth's orbit
   around the Sun. At the solstices, the Sun will appear at the top or
   bottom of an analemma. The featured image was taken near the December
   solstice and so the Sun appears near the bottom. Equinoxes, however,
   correspond to analemma middle points -- not the intersection point. In
   two days there will be an equinox ("equal night"), when day and night
   are equal over all of planet Earth. Many cultures celebrate a change of
   season at an equinox.

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                       Tomorrow's picture: open space
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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.

