M39 is a large, loose open cluster in Cygnus, a sprinkling of bright stars not far from Deneb on the sky, best seen in binoculars or a wide telescope field.
At a glance
| type | open star cluster |
|---|---|
| distance from the Sun | 965 light-years (296 pc) |
| its light left it | 965 years ago |
| size in the piece | about 32 light-years acrossmodel |
Read off the piece’s own catalogue, the same values it draws with. Model marks a property of the piece’s galaxy model rather than a measurement.
About M39
M39 lies in the rich Milky Way of Cygnus and is visible to the naked eye from a dark site as a faint patch. Its bright members are spread so widely that low magnification shows it best, set against the dense star fields behind.
It is a true cluster, its stars born together from the same cloud and moving through space as a group. It is older than very young clusters such as the Pleiades, and Messier added it to his catalogue of objects that could be mistaken for comets.
What you see in the piece
From Earth it is a loose group near Deneb; fly there and the members stay together while the Cygnus star fields around them separate into foreground and background.
Questions
How far away is M39?
M39 is about 965 light-years (296 pc) from the Sun.
Where is M39 in the sky?
In Cygnus, not far from Deneb, in a rich stretch of the Milky Way.