Since I first saw it, I was inspired by the amazing and famous Hubble/Gendler composite image of this galaxy, which is about 23.5 million light years away. Most spiral galaxies only have one pair of arms, but M106 has an extra set of two arms glowing with Halpha fluorescence. These extra arms are an indirect result of jets of gas from violent churning around the very active supermassive black hole at the galaxy's centre. These extra arms are much more apparent in X-ray and radio emission, while in visible light they are difficult to capture. This galaxy and interior detail is quite asymmetric, presumably either due to the active black hole or interactions with the 16 dwarf satellite galaxies that surround it, or both.

To capture this target, I knew I had to get a lot of RGB data--the core is bright, but the outer reaches are very dim. On the other hand, to get the extra arms and the wonderful blue clusters, I knew my narrow duoband L-eNhance NB filter would be useful to isolate Halpha and OIII from my horrible Bortle 8 skies. The core region was quite well captured with the L-eNhance in 12.6 hr of exposure, but the outer reaches are barely visible. The RGB exposure was about 32 hrs, but given my horrible Bortle 9 sky the outer reaches were still challenging. My plan it to try more L-eNhance next year, I think that would be optimal for my conditions, but this year I ran out of sky real estate.  Unfortunate, as I really do need more exposure still to tease out all the amazing detail in this wonderful target.

A word on processing. Both NB and RGB image stacks were processed separately in Startools. In Photoshop I removed stars on both layers using StarXTerminator, added the two layers together with soft light and masking, added the stars back with screen, followed by APF-R (used by NASA for detail enhancement) and NoiseXTerminator (no detail enhancement, just noise reduction).