Interesting, it looks like it's being illuminated by the warm light from a star to the bottom left
It goes without saying there's loads of detail in the nebulosity.
I find it odd/distracting that the background darkens immediately adjacent to the nebula before increasing in brightness again towards the periphery. I would normally see this when over-doing the unsharp masking. Or is this a true representation where extra exposure details has been picked up in the periphery?