When is the best time to observe Caldwell 50?

Caldwell 50 is best observed from November through January, with peak visibility during December when it transits around midnight in the Northern Hemisphere.

Where is Caldwell 50 located in the sky?

Caldwell 50 lies in the constellation Monoceros at right ascension 06h 32m and declination +04° 54′.

What telescope do I need to see Caldwell 50?

At magnitude 4.8, Caldwell 50 is visible to the naked eye from dark skies, easy in any binoculars.

Caldwell 50 — Open Cluster in Monoceros

NGC 2244

Open Cluster Showpiece (82/100)

Magnitude 4.8^m OpenCluster Monoceros Visible

Credit: Stephen Rahn. License: CC0. (Wikimedia Commons)

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About C50

Description

NGC 2244 is the bright open cluster at the center of the Rosette Nebula (C49) in Monoceros, about 5,200 light-years away. It contains about 16 hot, luminous OB-type stars arranged in a rectangular pattern, spanning about 24 arcminutes.

Observing Tips

An easy and attractive cluster even without the nebula. Binoculars show several bright stars in a distinctive rectangle. A telescope at 30-50x frames it nicely. To see the surrounding Rosette Nebula, add an OIII filter. Best in winter.

History

Discovered by John Flamsteed around 1690. The cluster is only about 2 million years old and its massive stars are responsible for illuminating and sculpting the Rosette Nebula.

Fun Facts

The most massive star in NGC 2244 is the O5 star HD 46223, which is about 50 times more massive than the Sun and 400,000 times as luminous. These stars will end their lives as supernovae within the next few million years.

Observe

1Properties

Magnitude 4.8

Angular Size 24 arcmin

Distance 5,200 ly

Description

Open Cluster [Distance: 5200 ly]

Position & Identifiers

RA 06h 31m 52.1s

Dec +04° 54' 00.0"

Constellation Monoceros

Catalog C50

Also known as NGC 2244

Physical size

34 light-years across — about 3.9× the Sun-to-Sirius distance

2How easy to spot?

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Easy
150 mm Newton 150mm Newt.	Easy	Easy	Easy
Celestron C8 (203 mm SCT) 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 79 of 458 members.

3Visibility

Set a location in User Settings to see visibility data.

Best season Nov – Jan (peak: Dec)

4 Eyepiece View

Telescope Eyepiece

50x TFOV: 1.0° Lim. mag: 13.6

C50 · 24.0′ diameter

5 Best Magnification

6Where this cluster sits in time

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.