Click on the image to see a larger version

 

The open cluster M39 was officially discovered by Le Gentil in 1750, but Aristotle probably observed it describing it as “cloudy, cometary appearance”. This cluster is rather close to us, less than 1,000 ly and is about 250 million years old. All of its stars are main sequence ones with blue A type dominating. It approaches us at a speed of 28 km/sec.

Additional Information

Object

Name(s): M39, NGC 7092

Type: Open Cluster

RA:  21h 31m 47.8s

Dec: +48º 25’ 59”

Constellation: Cygnus

Size (arcmin): 29×29

Magnitude: +4.6

Distance: 1,000

Image

Date: 2012-10-05

Location: Corbera de Llobregat, Barcelona, Catalonia

Size (arcmin): 37×38

Telescope: Celestron 11” HD f/10

Camera: FLI ML6303 (3072x2048pix)

Guiding: Orion SSAG/Nikkor 500mm f/8

Total exposure: 40 min (L: 10min; RGB: 30min)

Processing: PixInsight