Subj : Daily APOD Report
To   : All
From : Alan Ianson
Date : Sat Jun 21 2025 00:53:20

                        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.

                                2025 June 21

                          Two Worlds, Two Analemmas
        Image Credit: (left) Copyright: Tunc Tezel (TWAN) - (right):
                          NASA/JPL/Cornell/ASU/TAMU

   Explanation: Sure, that figure-8 shaped curve you get when you mark the
   position of the Sun in Earth's sky at the same time each day over one
   year is called an analemma. On the left, Earth's figure-8 analemma was
   traced by combining wide-angle digital images recorded during the year
   from December 2011 through December 2012. But the shape of an analemma
   depends on the eccentricity of a planet's orbit and the tilt of its
   axis of rotation, so analemma curves can look different for different
   worlds. Take Mars for example. The Red Planet's axial tilt is similar
   to Earth's, but its orbit around the same sun is more eccentric (less
   circular) than Earth's orbit. As seen from the Martian surface, the
   analemma traced in the right hand panel is shaped more like a tear
   drop. The Mars rover Opportunity captured the images used over the
   Martian year corresponding to Earth dates July 2006 to June 2008. Of
   course, each world's solstice dates still lie at the top and bottom of
   their different analemma curves. The last Mars northern summer solstice
   was May 29, 2025. Our fair planet's 2025 northern summer solstice is at
   June 21, 2:42 UTC.

                Tomorrow's picture: just a bowl of spherules
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

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