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.

                               2019 October 14
    [2]See Explanation. Moving the cursor over the image will bring up an
     annotated version. Clicking on the image will bring up the highest
                        resolution version available.

                         Andromeda before Photoshop
                        Image Credit: [3]Kees Scherer

   Explanation: What does the Andromeda galaxy really look like? The
   [4]featured image shows how our [5]Milky Way Galaxy's closest major
   galactic neighbor really appears in a long exposure through [6]Earth's
   busy skies and with a digital camera that introduces normal
   imperfections. The picture is a stack of 223 images, each a 300 second
   exposure, taken from a garden observatory in [7]Portugal over the past
   year. Obvious image deficiencies include bright parallel [8]airplane
   trails, long and continuous [9]satellite trails, short [10]cosmic ray
   streaks, and [11]bad pixels. These imperfections were actually not
   removed with [12]Photoshop specifically, but rather [13]greatly reduced
   with a series of computer software packages that included Astro Pixel
   Processor, DeepSkyStacker, and PixInsight. All of this work was done
   not to [14]deceive you with a [15]digital fantasy that has little to do
   with the real likeness of the [16]Andromeda galaxy (M31), but to
   minimize Earthly artifacts that have nothing to do with the distant
   galaxy and so better recreate [17]what M31 really does look like.

                    Tomorrow's picture: the galaxy above
     __________________________________________________________________

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     __________________________________________________________________

    Authors & editors: [29]Robert Nemiroff ([30]MTU) & [31]Jerry Bonnell
                                 ([32]UMCP)
          NASA Official: Phillip Newman [33]Specific rights apply.
              [34]NASA Web Privacy Policy and Important Notices
                A service of: [35]ASD at [36]NASA / [37]GSFC
                           & [38]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/1910/M31Before_Scherer_4298.jpg
   3. https://www.flickr.com/people/kees-scherer/
   4. https://www.flickr.com/photos/kees-scherer/48847775697/
   5. https://solarsystem.nasa.gov/resources/285/the-milky-way-galaxy/
   6. https://solarsystem.nasa.gov/planets/earth/overview/
   7. https://en.wikipedia.org/wiki/Portugal
   8. https://apod.nasa.gov/apod/ap070825.html
   9. https://apod.nasa.gov/apod/ap080604.html
  10. https://www.eso.org/~ohainaut/ccd/CCD_artifacts.html
  11. https://www.astro.rug.nl/~ndouglas/teaching/JAFFE/reduce.htm#BAD PIXELS
  12. https://en.wikipedia.org/wiki/Adobe_Photoshop
  13. https://apod.nasa.gov/apod/image/1910/AndromedaAfter_Scherer_960.jpg
  14. https://tenor.com/view/confused-dog-who-me-gif-14663746
  15. https://apod.nasa.gov/apod/ap131230.html
  16. https://apod.nasa.gov/apod/ap181217.html
  17. https://apod.nasa.gov/apod/ap190909.html
  18. https://apod.nasa.gov/apod/ap191013.html
  19. https://apod.nasa.gov/apod/archivepix.html
  20. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  21. https://apod.nasa.gov/apod/lib/aptree.html
  22. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  23. https://apod.nasa.gov/apod/calendar/allyears.html
  24. https://apod.nasa.gov/apod.rss
  25. https://apod.nasa.gov/apod/lib/edlinks.html
  26. https://apod.nasa.gov/apod/lib/about_apod.html
  27. http://asterisk.apod.com/discuss_apod.php?date=191014
  28. https://apod.nasa.gov/apod/ap191015.html
  29. http://www.phy.mtu.edu/faculty/Nemiroff.html
  30. http://www.phy.mtu.edu/
  31. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  32. http://www.astro.umd.edu/
  33. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  34. https://www.nasa.gov/about/highlights/HP_Privacy.html
  35. https://astrophysics.gsfc.nasa.gov/
  36. https://www.nasa.gov/
  37. https://www.nasa.gov/centers/goddard/
  38. http://www.mtu.edu/