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NGC 2423 — Open Cluster in Puppis

Open Cluster Excellent (65/100)
Magnitude 6.7m OpenCluster Puppis (Pup) Visible
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1Properties

Magnitude 6.7
Angular Size 11.7′
Cl, vL, Ri, pC, st vS

Position & Identifiers

RA 07h 37m 06.0s
Dec -13° 52' 00.0"
Constellation Puppis (Pup)
Catalog NGC 2423
Physical size
10 light-years across — about 1.2× 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 148 of 406 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 2423 · 11.7′ 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 2423 1.1 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.

Explore

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.

M47
NGC 2422
Easy
Rich open cluster
Open Cluster mag 4.4 0.6° Puppis
NGC 2438
Hard+
Planetary nebula — try an OIII filter
Planetary Nebula mag 10.0 1.4° Puppis
M46
NGC 2437
Easy
Open cluster
Open Cluster mag 6.0 1.5° Puppis
Melotte 71
Easy
Open cluster
Open Cluster mag 7.1 1.8° Puppis
NGC 2414
Easy
Open cluster
Open Cluster mag 7.9 1.8° Puppis
R CMa
Medium
Eclipsing binary, period 1.1d
Variable Star mag 5.70 4.9° Canis Major
Show on Map

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