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NGC 6940 — Open Cluster in Vulpecula

Open Cluster Excellent (65/100)
Magnitude 6.3m OpenCluster Vulpecula (Vul) Visible
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1Properties

Magnitude 6.3
Angular Size 10.8′
Cl, vB, vL, vRi, cC, st pL

Position & Identifiers

RA 20h 34m 26.7s
Dec +28° 16' 57.7"
Constellation Vulpecula (Vul)
Catalog NGC 6940
Physical size
11 light-years across — about 1.3× the Sun-to-Sirius distance

2How easy to spot?

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Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. Easy Easy Easy
150mm Newt. Easy Easy Easy
C8 203mm Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

Easy on Seestar S50
At 150mm under B5 skies you should resolve about 171 of 571 members.

3Visibility

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Best season Jun – Aug (peak: Jul)

4 Eyepiece View

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125x TFOV: 0.4° Lim. mag: 13.6
N E

NGC 6940 · 10.8′ diameter

5 Best Magnification

6Where this cluster sits in time

1 Myr 10 Myr 100 Myr 1 Gyr 10 Gyr NGC 2362 Pleiades M67 NGC 188 NGC 6940 1.3 Gyr

Open clusters span more than four orders of magnitude in age — from newborn OB associations to ancient, metal-rich survivors.

7 Colour-Magnitude Diagram

A cluster's colour-magnitude diagram reveals its age: the bluer the turn-off point where the main sequence bends into red giants, the younger the cluster.

Loading member data…

Each point is a Gaia-DR3 member. Colour encodes spectral type; size reflects membership probability.

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8 Classification Decoder

Nearby in the Sky

Other targets within a few degrees — pan your scope a little and keep exploring.

Visibility scores assume a 150 mm Newton at Bortle 4.

T Vul
Medium
Pulsating variable, period 4.4d
Variable Star mag 5.77 3.7° Vulpecula
C37
NGC 6885
Easy
Open cluster
Open Cluster mag 6.0 5.2° Vulpecula
NGC 6882
Easy
Open cluster
Open Cluster mag 8.1 5.3° Vulpecula
Network nebula
NGC 6995
Medium+
Supernova remnant
Supernova Remnant mag 7.00 5.7° Cygnus
NGC 6883
Easy
Open cluster
Open Cluster mag 8.0 9.0° Cygnus
NGC 6834
Easy
Open cluster
Open Cluster mag 7.8 9.3° Cygnus
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