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 July 4 [2]See Explanation. Clicking on the picture will download the highest resolution version available. NGC 6946 and NGC 6939 Image Credit & [3]Copyright: [4]Alberto Pisabarro Explanation: Face-on spiral galaxy NGC 6946 and open star cluster NGC 6939 share [5]this cosmic snapshot, composed with over 68 hours of image data captured with a small telescope on planet Earth. The field of view spans spans about 1 degree or 2 full moons on the sky toward the northern constellation [6]Cepheus. Seen through faint interstellar dust clouds near the plane of our Milky Way galaxy, the stars of [7]open cluster NGC 6939 are 5,600 light-years in the distance, near bottom right in the frame. Face-on spiral [8]galaxy NGC 6946 is at top left, but lies some 22 million light-years away. In the last 100 years, 10 supernovae have been discovered [9]in NGC 6946, the latest one seen [10]in 2017. By comparison, the average rate of supernovae in our Milky Way is about 1 [11]every 100 years or so. Of course, NGC 6946 is also known as [12]The Fireworks Galaxy. Tomorrow's picture: squid game __________________________________________________________________ [13]< | [14]Archive | [15]Submissions | [16]Index | [17]Search | [18]Calendar | [19]RSS | [20]Education | [21]About APOD | [22]Discuss | [23]> __________________________________________________________________ Authors & editors: [24]Robert Nemiroff ([25]MTU) & [26]Jerry Bonnell ([27]UMCP) NASA Official: Amber Straughn [28]Specific rights apply. [29]NASA Web Privacy, [30]Accessibility, [31]Notices; A service of: [32]ASD at [33]NASA / [34]GSFC, [35]NASA Science Activation & [36]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2507/N6946N6939pisabarro.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.loscoloresinvisibles.com/ 5. https://www.loscoloresinvisibles.com/galeria?pgid=jze435g7-3da3d0a5-12a2-492f-ac8e-9aad9c85c01d 6. http://www.hawastsoc.org/deepsky/cep/ 7. https://ui.adsabs.harvard.edu/abs/2022AJ....163..191K/abstract 8. https://apod.nasa.gov/apod/ap240726.html 9. https://rochesterastronomy.org/sn2017/sn2017eaw.html 10. https://skyandtelescope.org/astronomy-news/observing-news/possible-bright-supernova-discovered-in-fireworks-galaxy-ngc-6946/ 11. https://www.nasa.gov/mission_pages/chandra/trigger-for-milky-way-s-youngest-supernova-identified.html 12. https://www.nasa.gov/mission_pages/chandra/multimedia/fireworks-galaxy-ngc6946.html 13. https://apod.nasa.gov/apod/ap250703.html 14. https://apod.nasa.gov/apod/archivepix.html 15. https://apod.nasa.gov/apod/lib/apsubmit2015.html 16. https://apod.nasa.gov/apod/lib/aptree.html 17. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 18. https://apod.nasa.gov/apod/calendar/allyears.html 19. https://apod.com/feed.rss 20. https://apod.nasa.gov/apod/lib/edlinks.html 21. https://apod.nasa.gov/apod/lib/about_apod.html 22. https://asterisk.apod.com/discuss_apod.php?date=250704 23. https://apod.nasa.gov/apod/ap250705.html 24. http://www.phy.mtu.edu/faculty/Nemiroff.html 25. http://www.phy.mtu.edu/ 26. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 27. http://www.astro.umd.edu/ 28. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 29. https://www.nasa.gov/about/highlights/HP_Privacy.html 30. https://www.nasa.gov/general/accessibility/ 31. https://www.nasa.gov/privacy/ 32. https://astrophysics.gsfc.nasa.gov/ 33. https://www.nasa.gov/ 34. https://www.nasa.gov/centers/goddard/ 35. https://science.nasa.gov/learners 36. http://www.mtu.edu/