Caldwell 49 — Emission Nebula in Monoceros
NGC 2237
About Rosette Nebula
Description
The Rosette Nebula (NGC 2237) is a large, circular emission nebula in Monoceros, about 5,200 light-years away. It spans 1.3 degrees (over 2 full Moons) and surrounds the open cluster NGC 2244 (C50), whose hot young stars ionize the hydrogen gas and create the rose-shaped glow.
Observing Tips
Due to its large size, best in binoculars or a wide-field telescope at very low power. An OIII or UHC filter is almost essential to see the nebulosity visually. The embedded cluster C50 is easy without a filter. Best in winter evenings.
History
The nebula was discovered in different parts by John Herschel and others in the 1830s. Lewis Swift observed additional sections. The full rosette shape was only appreciated through photography.
Fun Facts
The Rosette Nebula contains enough gas to form about 10,000 solar-mass stars. The central hole is being carved out by the stellar winds and radiation from the hot OB stars in cluster C50. Eventually the gas will be completely dispersed.
Observe
1Properties
Position & Identifiers
2How easy to spot?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Medium | Medium | Hard+ |
| 150 mm Newton 150mm Newt. | Medium+ | Medium+ | Medium |
| Celestron C8 (203 mm SCT) C8 203mm | Medium+ | Medium+ | Medium+ |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
With O-III filter
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Easy | Medium+ | Medium+ |
| 150 mm Newton 150mm Newt. | Easy | Easy | Easy |
| Celestron C8 (203 mm SCT) C8 203mm | Easy | Easy | Easy |
3Visibility
Set a location in User Settings to see visibility data.
4
Filter Response Guide
5
Eyepiece View
Rosette Nebula · 80.0′×50.0′ · N up, E left
Explore
6
Surface Brightness
Discover
7
Light Travel Time Machine
8
Relativistic Travel
Community Photos (1)
Credit: Siderevs nuncivs. License: CC BY-SA 4.0. (Wikimedia Commons)
Skybred Mar 2, 2026
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.
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