Early this morning around 01:40, I spent a little time on Messier 39. This is the first time I imaged M39 with my William Optics FLT91 and the ASI2600MCP. The first time I imaged M39 was with my Zenith Star 61 about a year ago.
Messier 39 (M39) is a large open cluster located in the constellation
Cygnus, the Swan. The cluster has an apparent magnitude of 5.5 and lies at a distance of 824.4 light years from Earth. It has the designation NGC 7092 in the New General Catalogue.
Messier 39 is located about 9 degrees to the east and a bit north of the bright star
Deneb, Alpha Cygni. The cluster’s apparent size is 32 arc minutes, making it larger than the full Moon, which means that M39 is best observed in binoculars and small telescopes at the lowest magnifications.Messier 39 can be located by star-hopping from
Deneb to 4th magnitude star Rho Cygni, which lies some 9 degrees to the east. The cluster lies 3 degrees north of the star.
Messier 39 has an estimated age of 200 to 300 million years. All its confirmed members are still on the main sequence, still burning hydrogen in their core, and have yet to evolve into red giants.Messier 39 is a relatively loose cluster with 30 confirmed members occupying an area about 7 light years in diameter. The cluster is approaching us at 28 km/s.Messier 39 is classified as either Trumpler type III,2,m or III,2,p. This means that it is detached from the surrounding star field but with no central concentration (III), that the stars in the cluster have a moderate range in brightness (2), and that the cluster is either moderately rich, with 50 to 100 stars (m) or poorly populated (p), with fewer than 50 stars.
Messier 39 is one of the nearest Messier objects to Earth. Only the
Pleiades (M45),
Winnecke 4 (M40), the
Beehive Cluster (M44), and possibly the
Ptolemy Cluster (M7) are closer to us.The brightest star in M39 is of spectral type A0 and has a visual magnitude of 6.83. Many of the stars in M39 are arranged in pairs.
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