Target Type R. A. Dec. Constellation Magnitude Size M24 (IC 4715) Open Cluster 18h 18m 48s -18° 33′ 00″ Sagittarius +4.59 90.0 arcmin Overview Other than the Andromeda Galaxy, the Sagittarius star cloud is the largest of all the Messier objects visible in our night sky. At ninety arcminutes wide, it occupies an area of …
Target Type R. A. Dec. Constellation Magnitude Size M21 (NGC 6531) Open Cluster 18h 04m 13s -22° 29′ 00″ Sagittarius +5.90 14.0 arcmin Overview Less than 1° away from the Trifid Nebula, M22, is this compact open cluster. Discovered by Messier in June, 1764, this rich little cluster is 4,200 light-years away from us. The …
Target Type R.A. Dec. Constellation Magnitude Size M18 (NGC 6613) Open Cluster 18h 19m 58s -17° 06′ 00″ Sagittarius 6.90 5.0 arcmin Overview This cluster is sparsely populated with just a few dozen bright stars. It’s a young cluster, aged just 33 million years, and is seventy light-years off the galactic plane, almost 5,000 light-years …
Target Type R. A. Dec. Constellation Magnitude Size M4 (NGC 6121) Globular Cluster 16h 23m 35s -26° 31′ 33″ Scorpius 5.6 36.0 arcmins Overview Located relatively close to the center of the Milky Way, M4 is currently believed to be the third closest globular cluster to our solar system, being only 7,200 light-years away from …
Target Type R. A. Dec. Constellation Magnitude Size M107 (NGC 6171) Globular Cluster 16h 31m 32s -13° 03′ 14″ Ophiuchus +7.9 13.0 arcmin Overview Pierre Méchain discovered this loose globular cluster in April 1782, but it wasn’t added to Messier’s catalog until Helen Sawyer Hogg did so in 1947 based on the argument that Méchain …
Challenge #4 – M107, Globular Cluster in Ophiuchus Read More »
Target Type R. A. Dec. Constellation Magnitude Size M62 (NGC 6266) Globular Cluster 17h 01m 13s -30° 06′ 49″ Ophiuchus +6.44 15.0 arcmin Overview Messier discovered this fabulously odd cluster in 1771. He described it as resembling a small comet. Today, we know that that’s because, unlike most globular clusters, M62 is asymmetrical. Even today, …
Challenge #3 – M62, Globular Cluster in Ophiuchus Read More »
Target Type R. A. Dec. Constellation Magnitude Size M40 (WNC 4) Multiple Star 12h 22m 16s +58° 05′ 04″ Ursa Major +9.6 n/a Overview This is a strange one, and it almost feels like cheating you, dear member, to include it. But, we need a complete collection of Messier object guides inside the Virtual Astronomy …
Target Type R. A. Dec. Constellation Magnitude Size M23 (NGC 6494) Open Cluster 17h 57m 04s -18° 59′ 00″ Sagittarius +5.50 29.0 arcmins Overview This open cluster in Sagittarius is the home of 150 or so stars. Discovered by Charles Messier in June 1764, he correctly identified it as a star cluster from first glimpse. …
Target Type R. A. Dec. Constellation Magnitude Size M90 (NGC 4569) Spiral Galaxy 12h 36m 50s +13° 09′ 48″ Virgo +9.36 9.1×3.8 arcmin Overview On one night, 18 March 1781, Charles Messier discovered eight separate galaxies. M90 is one of those eight. At the time, astronomers weren’t aware of galaxies and so he classed it …
Target Type R. A. Dec. Constellation Magnitude Size M89 (NGC 4552) Elliptical Galaxy 12h 35m 40s +12° 33′ 22″ Virgo +9.67 8.1×8.0 arcmin Overview This bright, compact galaxy was discovered by Charles Messier on 18 March 1781, the same day that he discovered seven others. He didn’t know at the time what it was he’d …
