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. 2021 September 19 [2]The picture shows Saturn in yearly images taken from 2004 to 2015 from Earth. Please see the explanation for more detailed information. Rings and Seasons of Saturn Image Credit & [3]Copyright: [4]Damian Peach/[5]SEN Explanation: On Saturn, the rings tell you the season. On Earth, Wednesday marks an [6]equinox, the time when the [7]Earth's equator tilts directly toward the Sun. Since [8]Saturn's grand rings orbit along the planet's [9]equator, these rings appear [10]most prominent -- from the direction of the Sun -- when the spin axis of Saturn points toward the [11]Sun. Conversely, when [12]Saturn's spin axis points to the side, an [13]equinox occurs and the [14]edge-on rings are [15]hard to see from not only the Sun -- but Earth. In the featured montage, [16]images of Saturn between the years of 2004 and 2015 have been superposed to show the [17]giant planet passing from southern summer toward northern summer. [18]Saturn was as [19]close as it can get to planet Earth last month, and [20]this month the ringed giant is still [21]bright and visible throughout much of the night Tomorrow's picture: dark nebula 1251 __________________________________________________________________ [22]< | [23]Archive | [24]Submissions | [25]Index | [26]Search | [27]Calendar | [28]RSS | [29]Education | [30]About APOD | [31]Discuss | [32]> __________________________________________________________________ Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell ([36]UMCP) NASA Official: Phillip Newman [37]Specific rights apply. [38]NASA Web Privacy Policy and Important Notices A service of: [39]ASD at [40]NASA / [41]GSFC & [42]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2109/saturn2004to2015_peach_2504.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.damianpeach.com/ 5. https://sen.com/ 6. https://en.wikipedia.org/wiki/Equinox 7. https://www.nationalgeographic.org/encyclopedia/equator/ 8. https://solarsystem.nasa.gov/planets/saturn/in-depth/#otp_rings 9. https://en.wikipedia.org/wiki/Equator 10. https://apod.nasa.gov/apod/ap140622.html 11. https://solarsystem.nasa.gov/solar-system/sun/overview/ 12. https://solarsystem.nasa.gov/planets/saturn/in-depth/ 13. https://en.wikipedia.org/wiki/Equinox#/media/File:North_season.jpg 14. https://apod.nasa.gov/apod/ap111012.html 15. https://apod.nasa.gov/apod/ap191229.html 16. http://www.damianpeach.com/saturn.htm 17. https://apod.nasa.gov/apod/ap110904.html 18. https://apod.nasa.gov/apod/ap200419.html 19. https://media.istockphoto.com/photos/cat-close-up-picture-id1063469124?k=20&m=1063469124&s=612x612&w=0&h=IObywQ-wbwizMUjLgjmXJXIAZw2iWLHSJ6N1u4Cbs7s= 20. https://solarsystem.nasa.gov/skywatching/home/ 21. https://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/ 22. https://apod.nasa.gov/apod/ap210918.html 23. https://apod.nasa.gov/apod/archivepix.html 24. https://apod.nasa.gov/apod/lib/apsubmit2015.html 25. https://apod.nasa.gov/apod/lib/aptree.html 26. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 27. https://apod.nasa.gov/apod/calendar/allyears.html 28. https://apod.nasa.gov/apod.rss 29. https://apod.nasa.gov/apod/lib/edlinks.html 30. https://apod.nasa.gov/apod/lib/about_apod.html 31. http://asterisk.apod.com/discuss_apod.php?date=210919 32. https://apod.nasa.gov/apod/ap210920.html 33. http://www.phy.mtu.edu/faculty/Nemiroff.html 34. http://www.phy.mtu.edu/ 35. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 36. http://www.astro.umd.edu/ 37. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 38. https://www.nasa.gov/about/highlights/HP_Privacy.html 39. https://astrophysics.gsfc.nasa.gov/ 40. https://www.nasa.gov/ 41. https://www.nasa.gov/centers/goddard/ 42. http://www.mtu.edu/