The Rosette Nebula, cataloged as Caldwell 49 and NGC 2238, is one of the most rewarding wide-field emission nebulae for astrophotographers, spreading its glowing petals across a broad swath of Monoceros. At its heart sits the open cluster NGC 2244 (Caldwell 50, also listed as Melotte 47), whose hot young stars illuminate and sculpt the surrounding gas — a reminder that although the nebula and cluster look like a single target through the eyepiece or in a photograph, the catalogs list them as separate, independent objects with their own designations. The nebula responds beautifully to narrowband imaging in hydrogen-alpha, sulfur and oxygen, which brings out the intricate filaments, dark dust lanes and the dark central cavity carved by the cluster. Its generous angular extent makes it an ideal subject for short-focal-length refractors and camera lenses that can frame the entire rosette in a single field.
Names and Catalog numbers
- Rosette Nebula
- C 49 (Caldwell 49)
- NGC 2238
- C 50 (Caldwell 50) (associated object: C 50)
- NGC 2244 (associated object: C 50)
- Mel 47 (Melotte 47) (associated object: C 50)
Position and the cosmic neighborhood
Positioned at a right ascension of 06h 30m 30s and a declination of +05° 03′, the Rosette Nebula lies in the faint winter constellation Monoceros, tucked between the brilliant stars of Orion and Canis Major. The embedded open cluster NGC 2244 shines from a distance of about 4,710 light-years, and its angular size of 1.5° (88′) — spanning a physical diameter of roughly 121 light-years — helps guide the framing of the whole complex. This region of the Milky Way is rich in ionized hydrogen, and the cluster drifts through it with a measured radial velocity of 33.62 km/s. For imagers, the surrounding star fields of Monoceros provide a colorful, star-studded backdrop that complements the crimson bloom of the nebula.
Nice to Know
- The Rosette carries two catalog labels of its own — Caldwell 49 and NGC 2238 — while its central star cluster is separately cataloged as NGC 2244, Caldwell 50 and Melotte 47.
- The open cluster NGC 2244 lies about 4,710 light-years from Earth, and its young stars power the glow of the entire nebula.
- With an angular size of 1.5° (88′), the region is large enough to require wide-field optics to capture in a single frame.
- NGC 2244 spans a physical diameter of roughly 121 light-years and moves with a radial velocity of 33.62 km/s.
