NGC 6820 (Sharpless catalog Sh 2-86) is an emission nebula that surrounds the open cluster NGC 6823 in Vulpecula. The center of the open cluster is about two million years old and is predominantly represented by many young, bright blue stars. Open star cluster NGC 6823 is about 50 light years across and is about 6000 light years away (source: wikipedia).
This was a tough object for me to shoot mainly because of location and weather. I hoped to collect over two hours of total exposure but the astrophotography gods wouldn't have it so I had to settle for an hour plus collected over two nights. Most of the data was from the first night before clouds rolled in. I went out again the next but clouds rolled in before I even started. I went out a week later on a supposedly clear night only to have wispy clouds move in just as the autoguider was set. I did wait and it cleared briefly for me to get six more usable subframes.
I experimented with different processing techniques using DSS. I typically convert my raw images to tiff format and then stack using DSS (the older version of DSS would not read my raw files). I stacked the raw images directly and thought it turned out well as the nebula looked pretty good. However, the star field looked dull or faded, especially the smaller stars. So I converted the raw images to tiff files and stacked the images again. The star field was much better but the nebula was not as good. Ultimately, in my opinion, the tiff stacked method gave me a better overall image.
If you are interested in the raw stacked image, click the link to my webpage:
http://kurt-zeppetello.blogspot.com/2017/08/ngc-6823.html
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