This is 6 hours of Messier 20, the Trifid Nebula through narrowband filters. It was taken during a nearly full moon over two nights, September 16-17, 2016. You can see the same nebula in a recent image but taken on a moonless night in natural colors here. You can click on the image for a wider view. This narrowband image clearly show a band of gases (in blue) just outside the perimiter of the visible nebula. These gases don’t show up in regular light, one of the benefits of narrowband filters.