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. 2026 February 13 [2]See Explanation. Clicking on the picture will download the highest resolution version available. NGC 147 and NGC 185 Image Credit & [3]Copyright: [4]Chuck Ayoub Explanation: Dwarf galaxies [5]NGC 147 (left) and [6]NGC 185 stand side by side in this deep telescopic portrait. The two are not-often-imaged satellite galaxies of M31, the [7]great spiral Andromeda Galaxy, some 2.5 million light-years away. Their separation on the sky, less than one degree across a pretty field of view toward the constellation Cassiopeia, translates to only about 35 thousand light-years at Andromeda's distance, but Andromeda itself is found well outside this frame. Brighter and more famous satellite galaxies of Andromeda, [8]M32 and M110, are seen much closer to the great spiral. [9]NGC 147 and NGC 185 have been identified as binary galaxies, forming a gravitationally stable binary system. But recently discovered faint [10]dwarf galaxy Cassiopeia II also seems to be part of their system, forming a gravitationally bound group within Andromeda's intriguing population of small [11]satellite galaxies. Tomorrow's picture: floral arrangement __________________________________________________________________ [12]< | [13]Archive | [14]Submissions | [15]Index | [16]Search | [17]Calendar | [18]RSS | [19]Education | [20]About APOD | [21]Discuss | [22]> __________________________________________________________________ Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell ([26]UMCP) NASA Official: Amber Straughn [27]Specific rights apply. [28]NASA Web Privacy, [29]Accessibility, [30]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/2602/N147N185.png 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.youtube.com/chucksastrophotography 5. https://www.nasa.gov/feature/goddard/caldwell-17 6. https://www.nasa.gov/feature/goddard/caldwell-18 7. https://apod.nasa.gov/apod/ap181217.html 8. https://apod.nasa.gov/apod/ap200925.html 9. https://ui.adsabs.harvard.edu/abs/2017MNRAS.466.1764H/abstract 10. https://arxiv.org/abs/1511.08289 11. https://astrobites.org/2013/01/26/the-curious-case-of-andromedas-satellites/ 12. https://apod.nasa.gov/apod/ap260212.html 13. https://apod.nasa.gov/apod/archivepix.html 14. https://apod.nasa.gov/apod/lib/apsubmit2015.html 15. https://apod.nasa.gov/apod/lib/aptree.html 16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 17. https://apod.nasa.gov/apod/calendar/allyears.html 18. https://apod.com/feed.rss 19. https://apod.nasa.gov/apod/lib/edlinks.html 20. https://apod.nasa.gov/apod/lib/about_apod.html 21. https://asterisk.apod.com/discuss_apod.php?date=260213 22. https://apod.nasa.gov/apod/ap260214.html 23. http://www.phy.mtu.edu/faculty/Nemiroff.html 24. http://www.phy.mtu.edu/ 25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 26. http://www.astro.umd.edu/ 27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 28. https://www.nasa.gov/about/highlights/HP_Privacy.html 29. https://www.nasa.gov/general/accessibility/ 30. https://www.nasa.gov/privacy/ 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/