Sharpless 200, also cataloged as LBN 674 is a small nebula in Cassiopeia. Measuring only 8 arc minutes across it doesn’t take up a log of sky. It’s also very faint. It is visible in a 15 minute exposure. We managed 16 hours of 45 minutes almost equally split between the two filters but we collected more than twice that amount. Unfortunately, smoke in California continues to plague our imaging.
The nebula is about 3,200 light years away and is listed as a planetary nebula in most sources. The nebula is surrounded by hydrogen but I don’t know whether this is just material behind the nebula or actually associated with it.
This took a few tries at processing to get to a result I liked. It’s very faint and that requires the stretch to be aggressive which also brings out a lot of noise. Eventually I got to this version which is probably about as good as I know how to do at the moment. There’s nothing like a challenging image to keep you humble about your own ability.
You can find all the tech details at astrobin.