Rosette Nebula (NGC 2237–2239 / NGC 2244 / Caldwell 49)
Coordinates, Gaia DR3 distance (1.42 kpc), central wind-blown cavity around NGC 2244 O-stars, and observing guide for the Rosette Nebula in Monoceros.
Provenance-Backed Scientific Measurements
Every measurement below preserves its unit, uncertainty interval, observational method, reference epoch, quality status, and primary catalog source. See Uncertainty & Provenance for how competing measurements are handled.
| Parameter | Value | Uncertainty | Method & Epoch | Quality Status | Source Archive |
|---|---|---|---|---|---|
| Integrated visual magnitude (V) | 4.8 mag | ± 0.2 mag | Integrated NGC 2244 cluster + nebular aperture photometry | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Heliocentric distance | 4630 ly | ± 100 ly | Gaia DR3 astrometric parallax of NGC 2244 OB stars (1.42 ± 0.03 kpc) (J2016.0) | definitive | ESA Gaia Archive — Data Release 3 |
| Apparent nebular diameter | 80 arcmin | ± 5 arcmin | Optical H-alpha emission wreath (80′ × 60′) | high-confidence | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Central cluster NGC 2244 age | 0.002 Gyr | ± 0.0004 Gyr | O4 V / O5 V main-sequence & pre-main-sequence isochrone (2.0 ± 0.4 Myr) | high-confidence | ESA Gaia Archive — Data Release 3 |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Rosette Nebula (NGC 2237 & NGC 2244 Cluster) at RA 06h 31m 57.00s, Dec +04° 56′ 30.0″ within Monoceros, alongside peak meridian transit altitudes for 40°N and 30°S observers. Use the RA/Dec Coordinate Converter to compute exact culmination altitude for your latitude.
Astrophysical Context & Structure
The Rosette Nebula (NGC 2237, 2238, 2239, and 2246; Caldwell 49) and its central open cluster NGC 2244 (Caldwell 50) form a symmetric cosmic wreath spanning 80 × 60 arcminutes—nearly three times the width of the full Moon, or 110 light-years physically—at a distance of 4,630 light-years (1.42 ± 0.03 kiloparsecs) in northern Monoceros. While John Flamsteed discovered the central star cluster NGC 2244 in 1690, the surrounding ring of nebulosity was discovered piece by piece over the 19th century by John Herschel, Albert Marth, and Lewis Swift—resulting in four separate NGC numbers for different petals of the same rose.
At the center of the wreath sits the ~2-million-year-old cluster NGC 2244, powered by two extraordinarily luminous hot stars: HD 46223 (spectral type O4 V((f)), ~50 solar masses, 400,000 solar luminosities) and HD 46150 (O5 V((f))). Over the past million years, radiation pressure and 2,000-km/s stellar winds from these O stars have evacuated a 30-light-year central cavity filled with 6-million-kelvin X-ray gas detected by Chandra.
Compressed along the inner edge of the expanding ionized ring are dozens of dark, teardrop-shaped Bok globules and radial 'wrench' dust trunks undergoing triggered gravitational collapse.
Practical Visual Observing Guide
- Located 2° east of 4th-magnitude Epsilon Monocerotis, about one-third of the way along the line from Betelgeuse (α Orionis) to Procyon (α Canis Minoris).
- The central cluster NGC 2244 is easily visible to the naked eye at magnitude 4.8 and resolves in 7×50 binoculars into a dual-row 'box' of six 6th-to-8th magnitude stars led by foreground star 12 Monocerotis.
- With an O-III or UHC filter on an 80–150 mm rich-field telescope at 15×–35× under dark skies, the 1.3°-wide circular doughnut of the Rosette Nebula and its dark northern dust lanes frame the central cluster.
Catalog Cross-Identifications & Aliases
Common Aliases: NGC 2237 · NGC 2244 · Rosette Nebula · Caldwell 49 · Caldwell 50
| Catalog Authority | Identifier |
|---|---|
| NGC | NGC 2237 / NGC 2244 |
| SIMBAD | NGC 2237 |
| WIKIDATA | Q108041 |
Related Objects, Comparisons & Guides
Orion Nebula (Messier 42 / NGC 1976)
Coordinates, VLBI/Gaia distance (412 pc), Trapezium ionizing cluster, and visual observing guide for the Orion Nebula (M42) in Orion.
Heart-Shaped Cluster (Messier 50 / NGC 2323)
Coordinates, Gaia DR3 distance (961 pc), magnitude 5.9, crimson giant HD 52938 contrast, and observing guide for Messier 50 in Monoceros.
Heart Nebula (IC 1805 / Melotte 15)
Coordinates, Gaia DR3 distance (2.07 kpc), Melotte 15 O-star cluster, Fishhead Nebula IC 1795, and observing guide for IC 1805 in Cassiopeia.
Surface Brightness & Extended Objects Guide
Why surface brightness (mag/arcsec²) governs nebula and galaxy visibility more than integrated magnitude, and how exit pupil controls eyepiece contrast.
Astronomical Catalogs Explained (M, NGC, Gaia)
How astronomical designations work across the Messier (M), NGC/IC, Bayer/Flamsteed, Henry Draper (HD), Hipparcos (HIP), and Gaia DR3 catalogs.
Scientific Sources & Dataset Provenance
- ESA Gaia Archive — Data Release 3 (DR3 (2022-06-13)): Gaia Collaboration, Vallenari, A., et al. 2023, A&A, 674, A1 (Gaia Data Release 3) — European Space Agency / Gaia DPAC
- Revised New General Catalogue and Index Catalogue (RNGC/IC) (2024/2026 edition): Steinicke, W. 2010, Observing and Cataloguing Nebulae and Star Clusters (Cambridge Univ. Press); Verga, M. OpenNGC (CC-BY-SA 4.0 / data tables) — Wolfgang Steinicke / OpenNGC
- SIMBAD Astronomical Database (CDS) (2026-10 release): Wenger, M., et al. 2000, A&AS, 143, 9 (The SIMBAD astronomical database) — Centre de Données astronomiques de Strasbourg