HI Umop!
I havent tried it on any pure nebulous objects whether emission or reflective, since this is a crude method the Spectra is very faint and small with no absorption or emission lines visible, just a small Rainbow Image on stars are detectable with my prism and that's with a towel over my head!
I will try it on M-42 or M-1 it may not be bright enough!
I would assume that I will not see any rainbow for Nebulas, the Prism technique really just allows me to see which are stars ( they show a small rainbow spectrum) and just what appears to be a point source for the Planetary Nebulas
Dennis
