Messier 39

Observation Notes:

A bright, large, open cluster with a couple dozen bright stars and many more dimmer ones. It filled the 1.4 degree field of view. The main area fits in about a half degree area. All stars appear to be white. I saw quite a lot of double stars evident throughout the cluster.


M39 is a 230 to 300 million year old cluster that resides about 800 light years away. Within its 7 light year diameter, there are about 30 proven members, with from 50 to 100 stars suspected to be members. It is moving toward us at 28 km/sec.

While Charles Messier catalogued M39 in 1764, there is some contention that Le Gentil discovered it in 1750, and that Aristotle noted it as a cometary object in 325 BC.

Subject M39/NGC 7092
Classification Open Cluster
Position Cygnus [RA: 21:32.2 / Dec: +48:26]*
Size* 32′
Brightness* 4.6
Date/Time 10/14/04 – 10:40 PM
Observing Loc. Flagstaff, AZ – Home
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 32 mm (37X)
Seeing 3/10
Transparency Mag 5.8

* Based on published data.