* Astronomy

Messier 39 (also M39, NGC 7092, Collinder 438, Melotte 236 and OCL 211) is a magnitude +4.6 open star cluster located 824.4 light-years away in the constellation Cygnus. 

The first discovery was made by Aristotle 325 BC.

With good observing conditions the 30 stars comprising the cluster can be seen with the naked eye. The cluster appears as a triangle with a bright star on each corner. The brightest star is at +6.8
The open cluster was observed by French astronomer Charles Messier using a 8.38 cm (3.3-inch) refracting telescope at the Hôtel de Cluny (now the Musée national du Moyen Age), in Paris, France on the 24th October 1764.

Position (J2000): R.A. 21h 31m 42.0s  |  Dec. +48° 25' 30"

Its age is estimated to be from 200 to 300 million years.
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Credit SDSS