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.

                               2022 January 2
    [2]The featured image shows four halo arcs surrounding the Moon -- as
      taken Spain in 2012. Please see the explanation for more detailed
                                information.

                    Quadruple Lunar Halo Over Winter Road
                  Image Credit & Copyright: [3]Dani Caxete

   Explanation: Sometimes falling ice crystals make the atmosphere into a
   giant lens causing arcs and halos to appear around the Sun or Moon. One
   Saturday night in 2012 was just such a time near [4]Madrid, [5]Spain,
   where a winter sky displayed not only a bright [6]Moon but four rare
   lunar halos. The brightest object, near the top of the [7]featured
   image, is the Moon. Light from the Moon [8]refracts through tumbling
   hexagonal ice crystals into a somewhat rare [9]22-degree halo seen
   surrounding the Moon. Elongating the 22-degree arc horizontally is a
   more rare [10]circumscribed halo caused by [11]column ice crystals.
   Even more rare, some moonlight refracts through more distant tumbling
   ice crystals to form a (third) rainbow-like arc 46 degrees from the
   Moon and [12]appearing here just above a picturesque winter landscape.
   Furthermore, part of a whole [13]46-degree circular halo is also
   visible, so that an [14]extremely rare -- especially for the Moon --
   [15]quadruple halo was captured. Far in the background is a famous
   winter skyscape that includes [16]Sirius, the [17]belt of Orion, and
   [18]Betelgeuse -- visible between the inner and outer arcs. Halos and
   arcs typically last for minutes to hours, so if you do see one there
   should be time to invite family, friends or neighbors to [19]share your
   [20]unusual lensed vista of the sky.

                    Tomorrow's picture: Saturn moonscape
     __________________________________________________________________

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    Authors & editors: [32]Robert Nemiroff ([33]MTU) & [34]Jerry Bonnell
                                 ([35]UMCP)
          NASA Official: Phillip Newman [36]Specific rights apply.
              [37]NASA Web Privacy Policy and Important Notices
                A service of: [38]ASD at [39]NASA / [40]GSFC
                           & [41]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2201/lunararcs_caxete_1280.jpg
   3. https://kxt.es/
   4. https://youtu.be/fy1lOzAXu2o
   5. https://en.wikipedia.org/wiki/Spain
   6. https://solarsystem.nasa.gov/moons/earths-moon/in-depth/
   7. https://www.flickr.com/photos/danicaxete/8237507462/in/photostream
   8. https://www.atoptics.co.uk/halo/circ1.htm
   9. https://apod.nasa.gov/apod/ap081207.html
  10. https://www.atoptics.co.uk/halo/circum.htm
  11. https://www.atoptics.co.uk/halo/orcol.htm
  12. http://www.flickr.com/photos/danicaxete/8236435325/in/photostream
  13. https://www.atoptics.co.uk/halo/46hal.htm
  14. http://www.quickmeme.com/img/ad/ad7d3b671558c4efc0f540d9265a1825697f52b6e1c64fb713d7500b2e12753a.jpg
  15. https://apod.nasa.gov/apod/image/1212/lunararcs_caxete_labelled.jpg
  16. http://stars.astro.illinois.edu/sow/sirius.html
  17. https://apod.nasa.gov/apod/ap110121.html
  18. https://apod.nasa.gov/apod/ap200101.html
  19. https://apod.nasa.gov/apod/ap151108.html
  20. https://apod.nasa.gov/apod/ap200224.html
  21. https://apod.nasa.gov/apod/ap220101.html
  22. https://apod.nasa.gov/apod/archivepix.html
  23. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  24. https://apod.nasa.gov/apod/lib/aptree.html
  25. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  26. https://apod.nasa.gov/apod/calendar/allyears.html
  27. https://apod.nasa.gov/apod.rss
  28. https://apod.nasa.gov/apod/lib/edlinks.html
  29. https://apod.nasa.gov/apod/lib/about_apod.html
  30. http://asterisk.apod.com/discuss_apod.php?date=220102
  31. https://apod.nasa.gov/apod/ap220103.html
  32. http://www.phy.mtu.edu/faculty/Nemiroff.html
  33. http://www.phy.mtu.edu/
  34. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  35. http://www.astro.umd.edu/
  36. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  37. https://www.nasa.gov/about/highlights/HP_Privacy.html
  38. https://astrophysics.gsfc.nasa.gov/
  39. https://www.nasa.gov/
  40. https://www.nasa.gov/centers/goddard/
  41. http://www.mtu.edu/