I'm thrilled to have finally produced my first narrowband image and I'm definitely hooked! Watching the individual Ha subs come in was magical seeing contrast that I had only been able to dream of in broadband. Of course, the OIII and SII subs were not as dense but they still had a lot of data. We had four clear nights in a row last week and in two years of imaging that has never happened for me so I was glad to take advantage.
I spent the first couple of hours each night grabbing some Ha data on M33 to hopefully add in to my M33 image but then switched to the Rosette until it went behind the neighbor's house around 3am. Over the course of the three nights I managed to get 56 Ha, 56 OIII and 58 SII images at 5 minutes each. I started at gain 139, but switched to gain 200 after the first night because the subs were at about 3xRN^2. I didn't want to increase the sub length any longer to keep the amp glow under control so bumped up to gain 200. That seemed to work out well.
I wasn't sure I'd have enough data, especially on SII but when I did the integration it looked much better than I had expected so decided to go ahead and process it. The details are on astrobin but the first question was going to be how to combine the data. I decided to bypass the Hubble palette not because I have anything against it but I wanted to do something different and I ended up using pixel math to combine like this:
r: 0.8*ha + 0.2*s2
g: 0.2*ha + 0.4*s2 + 0.2*o3
This gave me an image that was somewhat reminiscent of a broadband image with the reddish core but with all that narrowband detail. I decided I liked the warm palette and the sense of menacing energy it provided (I'm likely projecting but that's how it came off to me).
Overall I'm pretty happy with my first attempt. I didn't try to really retain any star color here. The pixel math combination left them reasonably neutral and stretching desaturated them even more. They weren't distracting so that was good enough for me. I tend not to really notice star color in other narrowband images so wasn't really thinking about how I would approach it. I decided to just see where they ended up.
C&C are always welcome!