Do you remember december molecular trophies? There were hydrogen alpha only band of Melotte 15 open cluster in the middle of the Heart nebula IC1805. I collected some more – oxygen III band and RGB star color and here comes the color result below. It is all pictured with QHY163M camera, 130mm Photoline refractor and EQ6 mount. All from my backyard, and that is total about 15 hours of exposures. Pretty lot, huh?
IC1805 Heart nebula in Cassiopeia is well known hydrogen cloud, very appreciated by astroimagers. This object is placed 6000 light years away. In its apparent center there is very young open star cluster – Melotte 15. Actually the cluster is about 50 light years closer to us than nebula. Average star age in this cluster is only 1.5 million years. Melotte 15 in IC1805 contains few bright stars OB about 50 times more massive than Sun, and pretty many small stars that are much less massive, than Sun.
Three bright stars in the arc at right of Melotte 15 cluster are spectral type O, which are the brightest and most massive stars known. They also live very short, typically 3 to 6 million years. Our Sun for comparison burns already 4.5 billion years, and it is in the middle of its way.