OK, so I've got the back focus of my Orion Starshoot G21 figured out with my EON 110 refactor. In addition I've been successful in a quick and accurate polar alignment with the pole-master (Best astronomy tool product ever!!) and my hyper-tuned CGX-L is now spot on when slewing to DSO after a multi-star alignment and calibration. I do the normal two star setup then add 4 more for good measure. Now the new problems
I seem to have what seem to be dust spots in all my images - I believe the solution for this is to take flat frames after each imaging session, problem is i don't know exactly what would be a good flat frame? I know the temp doesn't matter, the image train needs to be the same focus and all, and i need a even white light source which I'm getting a dimmable led panel. How do i calculate the ADU or what light luminescence/color settings should i have on the panel, in general i have researched this and all i can find is the histogram should be 2/3rds to the right.
Next I'm in Bortle 6/7 skies and i believe a light pollution filter might help on my current targets M81/M82, M42, M51,M101 and M13. I have an old Broadfilter i had from ten years ago in my visual C6R days, it is a Thousand Oaks Optical Broadband Filter LP-1B 2inch, would this be any good i know filter tech has greatly advanced i've been suggested to buy either a Optolong or Astronomik