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NGC 2539 — Open Cluster in Puppis

Open Cluster Excellent (65/100)
Magnitude 6.5m OpenCluster Puppis (Pup) Visible
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1Properties

Magnitude 6.5
Angular Size 12.3′
Cl, vL, Ri, lC, st 11...13

Position & Identifiers

RA 08h 10m 37.0s
Dec -12° 49' 14.5"
Constellation Puppis (Pup)
Catalog NGC 2539
Physical size
14 light-years across — about 1.7× 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 138 of 485 members.

3Visibility

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Best season Dec – Feb (peak: Jan)

4 Eyepiece View

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125x TFOV: 0.4° Lim. mag: 13.6
N E

NGC 2539 · 12.3′ 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 2539 692 Myr

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.

NGC 2525
Hard+
Bright spiral galaxy
Galaxy mag 11.6 1.9° Puppis
C54
NGC 2506
Easy
Open cluster
Open Cluster mag 7.6 3.3° Monoceros
NGC 2479
Easy
Open cluster
Open Cluster mag 10.0 6.2° Puppis
NGC 2509
Easy
Open cluster
Open Cluster mag 9.0 6.7° Puppis
M48
NGC 2548
Easy
Open cluster
Open Cluster mag 5.5 7.1° Hydra
NGC 2438
Hard+
Planetary nebula — try an OIII filter
Planetary Nebula mag 10.0 7.2° Puppis
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