Thursday, December 2, 2010

Rosette Nebula

The Rosette Nebula (Caldwell 49) lies in the constellation Monoceros, the Unicorn. It is a faint emission nebula that surrounds open cluster NGC 2244 (Caldwell 50). Both the nebula and the cluster lie between 5,000 and 5,200 light years away. At that distance, the Rosette Nebula is about 100 to 130 light years in diameter. The visible part of the nebula in the image below covers an area slightly larger than the diameter of the full moon, but is so faint that it requires either a very large telescope to see it visually, or long-exposure images.  The Rosette's name comes from the nebula's resemblance to a decorative emblem.

The stars of NGC 2244 are young--only about four million years old--and extremely hot. The pressure of their stellar winds is clearing out a space within the nebula. This action also compresses nebular gas along the outside edges of the cleared space, which triggers additional star formation.

Caldwell 49 (Rosette Nebula), ST80 on Vixen SP, 17x180
The Rosette Nebula is the most visible part of the much larger Rosette Molecular Cloud.


  1. Nice work again, Rory! You've grabbed the whole Rosette! That must be on everyone's list. Yours is nicely framed and the color is well done. The dust lanes are most interesting. By the way, I agree that the thing is tough to see, but I have seen it more than once from dark sites through 20x80 binoculars. It was about the color you have it, though without the hint of red.

  2. Thanks, Val. I've been wanting to image this thing for a long time. My previous attempt with the Epsilon-200 than stellar. I figured that the ST80 was a better scope for the job, though, because it has a wider field of view.

    I've looked at NGC 2244 many times and have never seen the nebulosity around it. But then, I was using telescopes. Also, it's in sort of a bad spot in the sky from my place, as it sits over the light dome of town. I'll give a shot at the observatory some time.

    Yeah, I was surprised at the colors. Nearly every image I've seen has either been false-color or Ha, and my previous attempt came out all red. Imagine my surprise when blues and greens started showing up in processing!