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 December 21 [2]The featured image shows a composite image of the Sun superposed on the Milky Way. The image shows the night sky you would see if the Sun was very dim. Please see the explanation for more detailed information. Solstice Sun and Milky Way Composite Image Credit & [3]Copyright: [4]Stefan Seip ([5]TWAN) Explanation: Welcome to December's solstice, first day of winter in the north and summer for the southern hemisphere. Astronomical markers of the seasons, [6]solstice and equinox dates are based on the Sun's place in its annual journey along the [7]ecliptic, through planet Earth's sky. At [8]this solstice, the Sun reaches its maximum southern [9]declination of -23.5 degrees today at 15:59 [10]UTC, while its [11]right ascension coordinate on the [12]celestial sphere is 18 hours. That puts the [13]Sun in the [14]constellation Sagittarius in a direction near the [15]center of our Milky Way galaxy. In fact, if you could see today's [16]Solstice Sun against faint background stars and nebulae (that's [17]really hard to do, especially in the daytime ...) your view might look something like this composited panorama. To make it, images of [18]our fair galaxy were taken under dark [19]Namibian night skies, then stitched together in a panoramic view. From a snapshot made on [20]2015 December 21, the Sun was digitally overlayed as a brilliant star at today's northern winter solstice position, close to the center of [21]the Milky Way. Discovery + Outreach: [22]Graduate student research position open for APOD Tomorrow's picture: X launch __________________________________________________________________ [23]< | [24]Archive | [25]Submissions | [26]Index | [27]Search | [28]Calendar | [29]RSS | [30]Education | [31]About APOD | [32]Discuss | [33]> __________________________________________________________________ Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell ([37]UMCP) NASA Official: Phillip Newman [38]Specific rights apply. [39]NASA Web Privacy Policy and Important Notices A service of: [40]ASD at [41]NASA / [42]GSFC & [43]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2112/WinterSolsticeMW_Seip_2980.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. http://www.astromeeting.de/ 5. https://twanight.org/profile/stefan-seip/ 6. https://scijinks.gov/solstice/ 7. https://en.wikipedia.org/wiki/Ecliptic#/media/File:Ecliptic_with_earth_and_sun_animation.gif 8. http://earthsky.org/astronomy-essentials/everything-you-need-to-know-december-solstice 9. https://en.wikipedia.org/wiki/Declination 10. https://en.wikipedia.org/wiki/Coordinated_Universal_Time 11. https://en.wikipedia.org/wiki/Right_ascension 12. https://solarsystem.nasa.gov/basics/chapter2-2/#celestial 13. https://apod.nasa.gov/apod/ap210606.html 14. https://chandra.harvard.edu/photo/constellations/sagittarius.html 15. https://apod.nasa.gov/apod/ap190927.html 16. https://apod.nasa.gov/apod/ap210620.html 17. https://static1.bigstockphoto.com/6/0/4/large2/406370303.jpg 18. https://apod.nasa.gov/apod/ap151107.html 19. https://en.wikipedia.org/wiki/Namibia 20. https://apod.nasa.gov/apod/ap151221.html 21. https://www.nasa.gov/jpl/charting-the-milky-way-from-the-inside-out 22. https://asterisk.apod.com/viewtopic.php?f=28&t=41989 23. https://apod.nasa.gov/apod/ap211220.html 24. https://apod.nasa.gov/apod/archivepix.html 25. https://apod.nasa.gov/apod/lib/apsubmit2015.html 26. https://apod.nasa.gov/apod/lib/aptree.html 27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 28. https://apod.nasa.gov/apod/calendar/allyears.html 29. https://apod.nasa.gov/apod.rss 30. https://apod.nasa.gov/apod/lib/edlinks.html 31. https://apod.nasa.gov/apod/lib/about_apod.html 32. http://asterisk.apod.com/discuss_apod.php?date=211221 33. https://apod.nasa.gov/apod/ap211222.html 34. http://www.phy.mtu.edu/faculty/Nemiroff.html 35. http://www.phy.mtu.edu/ 36. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 37. http://www.astro.umd.edu/ 38. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 39. https://www.nasa.gov/about/highlights/HP_Privacy.html 40. https://astrophysics.gsfc.nasa.gov/ 41. https://www.nasa.gov/ 42. https://www.nasa.gov/centers/goddard/ 43. http://www.mtu.edu/