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.

                                2025 March 29
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                                Stereo Helene
   Image Credit: [3]Cassini Imaging Team, [4]ISS, [5]JPL, [6]ESA, [7]NASA;
                    Stereo Image by [8]Roberto Beltramini

   Explanation: Get out your red/blue glasses and float next to Helene,
   small, icy moon of Saturn. [9]Appropriately named, Helene is a Trojan
   moon, so called because it orbits at a [10]Lagrange point. A Lagrange
   point is a gravitationally stable position near two massive bodies, in
   this case [11]Saturn and larger moon Dione. In fact, irregularly shaped
   ( about 36 by 32 by 30 kilometers) Helene orbits at Dione's leading
   Lagrange point while brotherly ice moon Polydeuces follows at Dione's
   trailing Lagrange point. [12]The sharp stereo anaglyph was constructed
   from two Cassini images captured during [13]a close flyby in 2011. It
   shows part of the Saturn-facing hemisphere of Helene mottled with
   craters and gully-like features.

                     Tomorrow's picture: Ringed Jupiter
     __________________________________________________________________

      [14]< | [15]Archive | [16]Submissions | [17]Index | [18]Search |
   [19]Calendar | [20]RSS | [21]Education | [22]About APOD | [23]Discuss |
                                    [24]>
     __________________________________________________________________

    Authors & editors: [25]Robert Nemiroff ([26]MTU) & [27]Jerry Bonnell
                                 ([28]UMCP)
          NASA Official: Amber Straughn [29]Specific rights apply.
              [30]NASA Web Privacy Policy and Important Notices
                A service of: [31]ASD at [32]NASA / [33]GSFC,
                         [34]NASA Science Activation
                           & [35]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2503/N00172886_92_beltramini.jpg
   3. http://ciclops.org/
   4. http://ciclops.org/iss/iss.php
   5. http://www.jpl.nasa.gov/
   6. http://www.esa.int/
   7. http://www.nasa.gov/
   8. http://space-3d-images.blogspot.com/
   9. https://solarsystem.nasa.gov/moons/saturn-moons/helene/in-depth/
  10. https://science.nasa.gov/resource/what-is-a-lagrange-point/
  11. https://solarsystem.nasa.gov/moons/saturn-moons/overview/
  12. http://space-3d-images.blogspot.com/2011/06/helene-3d-cassini-cattura-la-regina-del.html
  13. https://solarsystem.nasa.gov/missions/cassini/overview/
  14. https://apod.nasa.gov/apod/ap250328.html
  15. https://apod.nasa.gov/apod/archivepix.html
  16. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  17. https://apod.nasa.gov/apod/lib/aptree.html
  18. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  19. https://apod.nasa.gov/apod/calendar/allyears.html
  20. https://apod.nasa.gov/apod.rss
  21. https://apod.nasa.gov/apod/lib/edlinks.html
  22. https://apod.nasa.gov/apod/lib/about_apod.html
  23. http://asterisk.apod.com/discuss_apod.php?date=250329
  24. https://apod.nasa.gov/apod/ap250330.html
  25. http://www.phy.mtu.edu/faculty/Nemiroff.html
  26. http://www.phy.mtu.edu/
  27. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  28. http://www.astro.umd.edu/
  29. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  30. https://www.nasa.gov/about/highlights/HP_Privacy.html
  31. https://astrophysics.gsfc.nasa.gov/
  32. https://www.nasa.gov/
  33. https://www.nasa.gov/centers/goddard/
  34. https://science.nasa.gov/learners
  35. http://www.mtu.edu/