Today’s deep-sky sight, located in the constellation, Monoceros, could easily be called “The Christmas Wreath Nebula”. But it’s real name is the Rosette Nebula, and it’s a beautiful blossom of glowing gas and dust where new stars are being born. While hard to see visually, even in large telescopes, the Rosette Nebula contains a fine young open cluster that’s easy to see in binoculars.
The Rosette is an immense nebula, some three times larger than the Orion Nebula, and three times farther away. The nebula and its cluster overlap, and are found not far from the Christmas Tree cluster. You might find them in the same binocular field of view. Click here to get an idea where to find the Rosette in Monoceros (look for NGC 2244).
You won’t see the nebula in binoculars… just the cluster. But it’s a fine cluster. Catalogued as (NGC 2244), it’s only a million years old, having recently formed inside the nebula. This gaggle of blue stars shines at magnitude 4.4, so you can see it without optics in dark sky. Which is impressive, since the stars are some 4,900 light years away. So they must be intrinsically quite bright.
As for the nebula itself… well it’s quite a bit harder to see. It was discovered piecemeal in the 19th century by observers with large telescope, including a 48-inch reflector. The nebula is therefore catalogued in pieces: NGC 2237, NGC 2238, and NGC 2246. These are all parts of the same star-forming complex, which, because of the non-uniform illumination and sinuous dust lanes, displays an astonishing degree of complexity. Here’s a detailed image that shows you the full glory of this nebula:
An image of the Rosette Nebula (courtesy of Terry Hancock, Downunder Observatory). Click to get larger view.
You won’t need a 48-inch scope to see the Rosette. But you will need very clear sky and good relief from light pollution… it’s not an easy object to see. The nebula was barely seen with a 16-inch scope by Ottawa-based amateur Rolf Meier and Fred Lossing in the 1970’s. Others have spotted it with a 4 or 5-inch scope. And the eagle-eyed Stephen James O’Meara has– amazingly– reported seeing it with his unaided eye and in 7×35 binoculars. Good dark sky is essential. And make sure your eyes are fully dark adapted. An OIII or UHC filter may help, too.
While a challenge for visual observers, the Rosette Nebula is a wonderful target for photographic observers. If you want to try your hand at photographing the Rosette and other deep sky sights, check out the Beginner’s Guide to DSLR Astrophotography. It shows you how to get started as an astrophotographer using an off-the-shelf digital camera and a small telescope.