Rosette Nebula

This large circular H II (partially ionized hydrogen gas) region is a combination of NGC 2237, NGC 2238, NGC 2239, NGC 2246 and the central star cluster of NGC 2244 (Caldwell 50).This star forming region is also known as Caldwell 49 and is located in the constellation of Monoceros (Unicorn) in the Perseus arm of the Milky Way. The hot, young and blue O and B stars are thought to be exerting a stellar wind that is clearing out the central region. The nebula is roughly 5000 light years away and is about 130 light years in diameter. The Rosette covers over 2-degrees of sky and is only a small part of a larger area of nebulosity.

29 images x 90-second subframes, Total= 43 minutes. Takahashi Epsilon -180, f/2.8, Unmodified Canon 20D DSLR, Astronomik CLS Light Pollution filter, ISO 800, Losmandy Gemini G-11 EQ mount. Acquisition and processing by Images Plus 2.80, Additional processing using PixInsight LT and Photoshop. ATMoB Clubhouse, Westford, MA, 3 December 2011.