Messier 17 (M17) – The Swan Nebula

Messier 17 (M17 and Sh2-45), popularly known as the Swan Nebula or the Omega Nebula, is a very bright emission region in the Sagittarius constellation approximately 5,500 light years distant.

It’s one of the largest star-forming regions in the Milky Way and contains some very young stars at less than a million years in age. These young, hot stars are primarily responsible for the ionization of the gasses that makes this interesting formation so bright. They release an unfathomable torrent of ultraviolet radiation that sculpts and churns the gasses in the nebula.

The nebula, while primarily comprising hydrogen, also contains copious amounts of ionized sulfur and oxygen gasses. The primary image on this page is a true-color (LRGB) image. But if you play the slideshow, you will see a narrowband version where I’ve used specialized filters to isolate the aforementioned gasses. The narrowband image reveals hidden structures and chemical interactions that are not visible in the true-color image.

Nearby, you can find the much smaller emission nebula Sh2-47 in the lower left corner of the image, which is actually across the constellation border in Serpens. It sits about twice as far away as M17.