M39 (also known as NGC7092) is an open cluster embedded within a rich star field in the constellation of Cygnus.
M39 has an estimated age of 200 to 300 million years. All of its confirmed members are still on the main sequence, still burning hydrogen in their core, and have yet to evolve into red giants.
It is a relatively loose cluster, with 30 confirmed members occupying an area about 7 light years in diameter.
M39 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 this star. The cluster can be resolved in 7×50 binoculars, which reveal its triangular shape, with three bright stars marking the corners.
It is one of the nearest Messier objects to Earth, at a distance of about 1,000 lightyears, and is approaching us at 28 km/s. Eeek!!
Imaged in LRGB, with 25x5sec through a Luminance filter and 25x15sec each through Red, Green and Blue filters. Total integration, 20 minutes.