A colorful nebula

The Dumbbell Nebula (M27) in constellation Vulpecula.

A planetary nebula represents the final stage in a smaller stars life cycle, such as our own Sun. Near the end of its life, the star enters a phase of Helium shell burning that causes the star to blow away its outer atmosphere with strong stellar winds, over a period of about 10,000 years. Finally, only the central white dwarf star remains, with no more exciting prospects than to spend the next billion years slowly cooling off.

This is though luck for the star, but the nebula that is formed from the ejected material makes for a pretty picture from afar. The object is still expanding at about 30 km / second. The red color is from hydrogen gas emitting in the H-alpha region. The blue and green in the center should stem from oxygen, although the lack of actual green probably indicates that I need more practice at color-balancing.

Apart from that, however, it is a true color image taken in the visual spectrum. It was composed from 150 individual frames exposed for 10 seconds each, giving a total exposure time of about half an hour. A 0.5 x focal reducer was used.

I am quite happy about the result because I did not have too much luck with faint nebulous objects until now, and the individual frames did not show much appreciable signal before processing. Now that I got it to work in principle I will try going for longer total exposures, that should get rid of the noisiness that is still quite apparent in this image.

 

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