Rosette Nebula and Open Star Cluster (NGC 2244)

The Rosette Nebula is a large cloud of glowing gas and dust located in the constellation Monoceros, surrounding the young open cluster NGC 2244. The hot, massive stars in the star cluster emit ultraviolet radiation that ionises the surrounding gas. When the freed electrons recombine with the atoms or transition between energy levels, the gas emits light at very specific wavelengths, causing the nebula to shine with its characteristic emission-line glow.

The Rosette Nebula lies roughly 1.5 kiloparsecs (or 5000 light-years) from Earth and spans about 40 parsecs (or around 130 light-years) across, making it one of the larger nearby star-forming regions in our galaxy. The strong radiation and stellar winds from the young cluster have carved out the large central cavity visible in the nebula, pushing gas outward and shaping the surrounding clouds into arcs, filaments, and dense knots. Within the darker structures at the edge of the cavity, cold pockets of molecular gas continue to collapse, potentially forming the next generation of stars.

The emission  is captured in narrow-band filters from Hydrogen-alpha, Oxygen-III, and Sulfur-II. By combining these wavelengths into a composite image, subtle variations in the physical conditions of the nebula become visible.

This image was captured from Leysin, Vaud (Switzerland) with a Takahashi TAO-150 refractor telescope using narrowband Hydrogen-alpha, Sulfur-II, and Oxygen-III filters. The telescope has an aperture of 150 mm and a focal length of 1.1 m.
 
Aurel Schneider 2024