NGC 2244 and NGC 2237-9,46

Diffuse Nebula NGC 2237-9,46, The Rosette Nebula
Open Cluster NGC 2244 (= H VII.2), in Monoceros

[NGC 2244, UKS]

Rosetta Nebula
NGC 2237-9,46
NGC 2244
Right Ascension 06 : 32.3 (h:m) 06 : 32.4 (h:m)
Declination +5 : 03 (deg:m) +4 : 52 (deg:m)
Distance 5.5 (kly) 5.5 (kly)
Visual Brightness ? (mag) 4.8 (mag)
Apparent Dimension 80x60 (arc min) 24 (arc min)

Discovered by John Flamsteed about 1690.

The Rosetta Nebula is a vast cloud of dust and gas, extending over an area of more than 1 degree across, or about 5 times the area covered by the full moon. Its parts have been assigned different NGC numbers: 2237, 2238, 2239, and 2246. Within the nebula, open star cluster NGC 2244 is situated, consisted of the young stars which recently formed from the nebula's material, and the brightest of which make the nebula shine by exciting its atoms to emit radiation.

Although various values for its distance occur in the literature, our adopted distance from the Sky Catalog 2000 implies a true diameter of the nebula of about 130 light years. Burnham quotes a mass estimation of 10,000 (Minkowski 1949) to 11,000 (Menon 1962) solar masses, so it is one of the more massive diffuse nebulae.

Open cluster NGC 2244 was discovered by Flamsteed about 1690. The nebula, however, is not even contained in John Herschel's GC. Nevertheless, it is a splendid object, especially for astrophotography.

Our image was obtained by David Malin with the UK Schmidt Telescope. This image is copyrighted and may be used for private purpose only. For any other kind of use, including internet mirroring and storing on CD-ROM, please contact the Photo Permissions Department of the Anglo Australian Observatory.

  • More information on this image (by David Malin)

    In the SAC 110 best NGC object list. No. 32 in the RASC Finest NGC Objects list. Caldwell 49 (Rosette Nebula) and Caldwell 50 in Patrick Moore's list.

    Bill Arnett's Rosette Nebula and NGC 2244 photo page, info page.

  • Jean-Claude Mermilliod's WEBDA cluster page for open cluster NGC 2244
  • SIMBAD Data of NGC 2244; NGC 2237, NGC 2238, NGC 2239, NGC 2246.
  • Observing Reports for NGC 2244, Observing Reports for NGC 2237, Observing Reports for NGC 2238, Observing Reports for NGC 2239, Observing Reports for NGC 2246 (IAAC Netastrocatalog)

    Hartmut Frommert (
    Christine Kronberg (

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    Last Modification: 27 Jun 1998, 15:30 MET