The Rosette Nebula (also known as NGC 2237, sh2-275 or Caldwell 49) is a giant emission nebula in the constellation Monoceros at a distance of about 5200light years. It is approximately 130 light years in diameter, significantly larger than the famous Orion Nebula (M42) which is much closer to the Earth. The Rosette Nebula is a region of intense star formation. The open star cluster NGC 2244 is located in the central region of the Rosette Nebula and contains few extremely hot blue stars, including a rare class of stars of the spectral class O4. The X-ray radiation emitted by the stars produces a super-hot plasma with temperatures ranging from 1 to 10 million K, that is much hotter than the 10,000 K plasmas seen in majority of other HII regions. The central hole in the nebula is a result of the shock-heated winds and the radiation blasting away the gas.
Imaged at the Skopje city center (Bortle scale 8) on 15, 19, 22 and 25 November 2020 using my brand-new SharpStar Ascar FRA400 astrograph (with reduced focal length 280 mm), ZWO ASI183MM Pro, (Gain: 111) at -20 Celsius Degrees; Guiding: ZWO ASI174MM Mini with OAG; AsiAir Pro 1.5; iOptron CEM40EC, SII: 22x600", H-alpha: 33x600", OIII: 24x600" (total integration time 13.2 hours). Image processing: PixInsight 1.8.8-5.