Interesting result Ric. Thanks for sharing. I don't know many that image galaxies in narrowband. A Ha filter can extract lovely details for the HII regions, but not much else in the way of specific emission lines. Galaxies emit across very broad wavelengths, similar to stars, hence they are best imaged via luminance or traditional RGB. Still, I take my hat off to you for trying. The other item which may have compounded the result is the exposure time. Narrowband filters don't pass much energy (based on nm window size), thus require long exposure times to obtain a good S/N ratio. I don't think 30sec subs would have been sufficient. Perhaps stick to nebulae with those NB filters.
