Space Lobster! You are going to need big hammer for this one! And a lot of butter.
This is one of those objects that actually look enough like its name to keep you from scratching your head and wondering what everyone was thinking. But for those that like catalog numbers, this is Sh2-157.
This is a large nebula, the field is about 2.2 degrees across horizontally. It’s an emission nebula and like all emission nebula, it’s much stronger in hydrogen. The SII isn’t bad but the oxygen was fairly weak although that was heavily influenced by a sky that wasn’t great even though it was clear. Of 101 OII frames I ended up keeping only 29 thanks to humidity, smoke and the moon. But, with all the clouds we’ve had I had to take the few clear nights I could get or I’d never get any imaging time in at home.
The oxygen was strongest on the left side of the nebula but compared to many nebula this one seemed more chaotic for lack of a better word. I don’t know what the significance of that is (or even whether it is real or an artifact of my processing) but it did not seem as structured as many nebulae do.
You can find all the technical detail on astrobin.