When I recently imaged M20 the Trifid Nebula in LRGB, I followed up with the full suite of Narrowband (Ha, OII & SII). I used the Forax methodology to combine the NB datasets into this false colour image. The technique produces exquisite detail and a very aesthetically pleasing colour combination, at least to my eye. Funnily enough, with the first foray on this object a couple of years back on the C14, I messed around with the colour combinations, evolving them to something I thought was representative and not too garish. Amazingly, that effort ended up not so very far away from this, https://astrob.in/si3myq/D/ although I feel that this, being a  wider field image is more interesting. In this one the resolution of detail is superior to my previous effort and there is no better evidence of that than the clarity of the Harbig-Haro object HH339. This stood out most clearly in the SII data which is interesting and BlurXTerminator did a great job in bringing that detail out in the final image. Interestingly, the blue reflection nebula doesn't correspond completely with the blue areas (primarily OIII) in this image. Clearly the OIII emission occurs where oxygen atoms are being stimulated by starlight, whereas the blue reflection nebula is simply blue starlight being reflected back of molecular clouds. They do not necessarily correspond.
For comparison purposes, the LRGB version can be accessed via the mouseover.
For those interested here is some further abridged informationfrom Wikipedia: “The Trifid Nebula (catalogued as Messier 20 or M20 and as NGC 6514) is an H II region in the north-west of Sagittarius in a star-forming region in the Milky Way's Scutum–Centaurus Arm. It was discovered by Charles Messier on June 5, 1764. Its name means 'three-lobe'. The object is an unusual combination of an open cluster of stars, an emission nebula (the relatively dense, reddish-pink portion), a reflection nebula (the mainly NNE blue portion), and a dark nebula (the apparent 'gaps' in the former that cause the trifurcated appearance, also designated Barnard 85). Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, and is thus a perennial favourite of amateur astronomers.The Trifid Nebula was the subject of an investigation by astronomers using the Hubble Space Telescope in 1997, using filters that isolate emission from hydrogen atoms, ionized sulphur atoms, and doubly ionized oxygen atoms. The images were combined into a false-colour composite picture to suggest how the nebula might look to the eye.The close-up images show a dense cloud of dust and gas, which is a stellar nursery full of embryonic stars. This cloud is about 8 ly away from the nebula's central star. A stellar jet protrudes from the head of the cloud and is about 0.75 ly long and it is a Herbig-Haro jet (HH399). The jet's source is a young stellar object deep within the cloud. Jets are the exhaust gasses of star formation and radiation from the nebula's central star makes the jet glow.The images also showed a finger-like stalk to the right of the jet. It points from the head of the dense cloud directly toward the star that powers the Trifid nebula. This stalk is a prominent example of evaporating gaseous globules, or 'EGGs'. The stalk has survived because its tip is a knot of gas that is dense enough to resist being eaten away by the powerful radiation from the star.It is about 4100 ly from Earth. Its apparent magnitude is 6.3.”