Astronomy Picture of the Day

   [1]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 19
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                               Orion in Depth
            Illustration Credit & [3]Copyright: [4]Ronald Davison

   Explanation: [5]Orion is a familiar constellation. The apparent
   positions of its stars in two dimensions create a well-known pattern
   [6]on the bowl of planet Earth's night sky. Orion may not look quite so
   familiar in this 3D view though. [7]The illustration reconstructs the
   relative positions of Orion's bright stars, including data from the
   [8]Hipparcus catalog of [9]parallax distances. The most distant star
   shown is Alnilam. The middle one in the projected line of three that
   make up Orion's belt when viewed from planet Earth, Alnilam is nearly
   2,000 light-years away, almost 3 times as far as [10]fellow belt stars
   Alnitak and Mintaka. Though Rigel and Betelgeuse apparently shine
   brighter in planet Earth's sky, that makes more distant Alnilam
   intrinsically (in absolute magnitude) the brightest of the familiar
   stars in Orion. In the Hipparcus catalog, errors in measured parallaxes
   for Orion's stars can translate in to distance errors of a 100
   light-years [11]or so.

                 Tomorrow's picture: breaking distant light
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    Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell
                                 ([26]UMCP)
          NASA Official: Phillip Newman [27]Specific rights apply.
              [28]NASA Web Privacy Policy and Important Notices
                A service of: [29]ASD at [30]NASA / [31]GSFC
                           & [32]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2009/Orion3Ddavison.png
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. http://om-blog.orbitalmaneuvers.com/author/master2011/
   5. https://apod.nasa.gov/apod/ap191122.html
   6. https://poetrytreasures.wordpress.com/2014/09/29/awake-for-morning-in-the-bowl-of-night/
   7. http://om-blog.orbitalmaneuvers.com/2020/09/13/orion-in-3d-revisited/
   8. https://science.nasa.gov/missions/hipparcos
   9. https://en.wikipedia.org/wiki/Stellar_parallax
  10. https://apod.nasa.gov/apod/ap171123.html
  11. https://ui.adsabs.harvard.edu/abs/2007A%26A...474..653V/abstract
  12. https://apod.nasa.gov/apod/ap200918.html
  13. https://apod.nasa.gov/apod/archivepix.html
  14. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  15. https://apod.nasa.gov/apod/lib/aptree.html
  16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  17. https://apod.nasa.gov/apod/calendar/allyears.html
  18. https://apod.nasa.gov/apod.rss
  19. https://apod.nasa.gov/apod/lib/edlinks.html
  20. https://apod.nasa.gov/apod/lib/about_apod.html
  21. http://asterisk.apod.com/discuss_apod.php?date=200919
  22. https://apod.nasa.gov/apod/ap200920.html
  23. http://www.phy.mtu.edu/faculty/Nemiroff.html
  24. http://www.phy.mtu.edu/
  25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  26. http://www.astro.umd.edu/
  27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  28. https://www.nasa.gov/about/highlights/HP_Privacy.html
  29. https://astrophysics.gsfc.nasa.gov/
  30. https://www.nasa.gov/
  31. https://www.nasa.gov/centers/goddard/
  32. http://www.mtu.edu/