Phew, this was an ordeal!

Firstly, this was the first light for my new Skywatcher 130PDS, an my first time using A real telescope for imaging. It was also my first time using a coma corrector at all an having to deal with back focus, etc. I think i might not be spot on with the backfocus, and perhaps I have a bit of tilt (I do have a tilter in the train, but no adjustment at the moment), but the slow F-ratio and small sensor size is quite forgiving. My stars are much better than I am used to!

I was also a bit worried that I would have problems guiding the much heavier scope with more than double my usual focal length, but I really had no problems. The GEM 28 is now loaded with about half it's nominal capacity and guided at 0.6-0.9 archseconds RMS. With a pixel scale of 1.13 px/arcs, and seeing around 1.5-2.2', it seems adequate. 

I shot the target over several nights (we are having an unprecedented number of clear nights at the moment!) Using several different filters. I started with the CLS light pollution filter - I thought I needed this in my bortle 6 location, but that was based on experience with a DSLR, and obviously the full well capacity of the 533 is much greater. So I could easily take 300s subs with just and UV-IR cut filter. I also did a few sessions with the L-eXtreme to be able to make a HaRGB image.

I have posted the individual stacks for the difference filters her as well, with relatively minimal processing: DBE, EZ denoise, stretch, saturation. I have not often seen such direct comparisons of the same image with the same equipment using different filters (except for single sub comparisons). 

I was very surprised to see how little difference there is between the CLS and the UV-IR cut filters! Almost no colour difference. The contrast is higher in the CLS stack, but that is because some of the actual galaxy light is filtered out, so the total signal is less. But to me, it seems to be a viable option to use a broadband LP filter for galaxies as well, at least when you are in an light polluted zone.  

However even with 15+ hours of broadband data, I still get quite some noise in the final image. I guess you really have to go to a dark sky site to remedy this - it would just take forever to get significantly improved SNR in my bortle 6 skies! 

Anyways, the final image is a combined integration of the broadband data with a bit of a Ha sprinkled in. I did a drizzle integration as I did not get more noise in the image compared to a normal integration (to my surprise!). Drizzling is not needed from a resolution standpoint, as I am not undersampling (for my sky conditions), but I find that for printing, it improves the quality of the print to have the higher resolution file. 

I am happy with this, my first image with a real telescope ;-) Hope you enjoy!