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 August 18 [2]A large spiral galaxy appears with stars in the foreground and smaller galaxies far in the background. The picturesque spiral has dark dust lanes between blue arms. Please see the explanation for more detailed information. NGC 1309: A Useful Spiral Galaxy Image Credit: [3]NASA, [4]ESA, [5]Hubble; Processing: [6]L. Galbany, S. Jha, K. Noll, A. Riess Explanation: This galaxy is not only pretty -- it's useful. A gorgeous spiral some 100 million light-years distant, [7]NGC 1309 lies on the banks of the constellation of the River ([8]Eridanus). NGC 1309 spans about 30,000 [9]light-years, making it about one third the size of our larger [10]Milky Way galaxy. Bluish clusters of [11]young stars and dust lanes are seen to trace out NGC 1309's spiral arms as they [12]wind around an older yellowish star population at its core. Not just another [13]pretty face-on spiral galaxy, observations of NGC 1309's two recent supernovas and multiple [14]Cepheid variable stars contribute to the [15]calibration of [16]the expansion of the Universe. Still, after you get over this beautiful galaxy's grand design, [17]check out the array of more distant background galaxies also recorded in [18]this sharp image from the [19]Hubble Space Telescope. Tomorrow's picture: open space __________________________________________________________________ [20]< | [21]Archive | [22]Submissions | [23]Index | [24]Search | [25]Calendar | [26]RSS | [27]Education | [28]About APOD | [29]Discuss | [30]> __________________________________________________________________ Authors & editors: [31]Robert Nemiroff ([32]MTU) & [33]Jerry Bonnell ([34]UMCP) NASA Official: Amber Straughn [35]Specific rights apply. [36]NASA Web Privacy, [37]Accessibility, [38]Notices; A service of: [39]ASD at [40]NASA / [41]GSFC, [42]NASA Science Activation & [43]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2508/Spiral1309_HubbleGalbany_4000.jpg 3. https://www.nasa.gov/ 4. https://www.esa.int/ 5. https://science.nasa.gov/mission/hubble/overview/about-hubble/ 6. https://lgalbany.github.io/ 7. http://en.wikipedia.org/wiki/NGC_1309 8. http://www.hawastsoc.org/deepsky/eri/index.html 9. https://spaceplace.nasa.gov/light-year/ 10. https://science.nasa.gov/resource/the-milky-way-galaxy/ 11. https://apod.nasa.gov/apod/ap140925.html 12. https://pbs.twimg.com/media/GhF-nwZbkAA2UhU.jpg 13. https://apod.nasa.gov/apod/ap080824.html 14. https://apod.nasa.gov/apod/ap960110.html 15. https://lco.global/spacebook/distance/cepheid-variable-stars-supernovae-and-distance-measurement/ 16. https://science.nasa.gov/mission/hubble/science/science-highlights/discovering-a-runaway-universe/ 17. https://esahubble.org/images/potw2530a/zoomable/ 18. https://esahubble.org/images/potw2530a/ 19. https://science.nasa.gov/mission/hubble/ 20. https://apod.nasa.gov/apod/ap250817.html 21. https://apod.nasa.gov/apod/archivepix.html 22. https://apod.nasa.gov/apod/lib/apsubmit2015.html 23. https://apod.nasa.gov/apod/lib/aptree.html 24. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 25. https://apod.nasa.gov/apod/calendar/allyears.html 26. https://apod.com/feed.rss 27. https://apod.nasa.gov/apod/lib/edlinks.html 28. https://apod.nasa.gov/apod/lib/about_apod.html 29. https://asterisk.apod.com/discuss_apod.php?date=250818 30. https://apod.nasa.gov/apod/ap250819.html 31. http://www.phy.mtu.edu/faculty/Nemiroff.html 32. http://www.phy.mtu.edu/ 33. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 34. http://www.astro.umd.edu/ 35. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 36. https://www.nasa.gov/about/highlights/HP_Privacy.html 37. https://www.nasa.gov/general/accessibility/ 38. https://www.nasa.gov/privacy/ 39. https://astrophysics.gsfc.nasa.gov/ 40. https://www.nasa.gov/ 41. https://www.nasa.gov/centers/goddard/ 42. https://science.nasa.gov/learners 43. http://www.mtu.edu/