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The Triangulum Galaxy

was discovered by Charles Messier in1764 and is a member of our 'Local Group' of galaxies. This Sc-type is small compared to the Andromeda galaxy M31and to our Milky Way galaxy, but is of average size for spiral galaxies in the universe. M33 is approaching our Solar System at 182 km/s.The red knot at 7 o'clock in the galaxy is one of the largest H II regions known and has a diameter of nearly 1,500 light-years and a spectrum similar to the Orion nebula M42. M33 was among the first 'Spiral Nebulae' identified by William Parsons, the Third Earl of Rosse. It was also among the first 'nebulae' identified as a galaxy in which Cepheid variable stars were found. The current distance is about 3 million light-years from Earth. The distance of M33 from M31 is about 750,000 light-years and M33's diameter may be at least 60,000 light-years. The pronounced arms exhibit numerous reddish HII regions as well as blueish clouds of young stars. Beautiful isn't it?