                        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.

                                 2022 July 2

                           Solargraphic Analemmas
             Image Credit & Copyright: Dawid Rycabel (Pinholove)

   Explanation: For the northern hemisphere June 21 was the summer
   solstice, the Sun reaching its northernmost declination for the year.
   That would put it at the top of each of these three figure-8 curves, or
   analemmas, as it passed through the daytime sky over the village of
   Proboszczow, Poland. No sequence of digital exposures was used to
   construct the remarkable image though. Using a pinhole camera fixed to
   face south during the period June 26, 2021 to June 26, 2022, the image
   was formed directly on a single sheet of photographic paper, a
   technique known as solargraphy. The three analemmas are the result of
   briefly exposing the photo paper through the pinhole each day at 11:00,
   12:00, and 13:00 CET. Groups of dashed lines on the sides show partial
   tracks of the Sun from daily exposures made every 15 minutes. Over the
   year-long solargraphic photo opportunity clouds blocking the Sun during
   the pinhole exposures created the dark gaps.

                   Tomorrow's picture: doomed moon of Mars
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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