This test was with a Celestron Nexstar 102GT mount, no guiding, I put the Skywatcher Pro 80ED f/7.5 with the ASI290MM-Cool, the ZWO Mini Filter wheel with ZWO color filters, it is little out of focus plus even with the 10mm spacer it was short 6.5mm for the Orion Field Flattener distance.
I put the Astronomik 2" CLS-CCD in front of the field flattener:
Ha: 14x4s (Astronomik 12nm, 1.25in)
Darks and Bias.
Captured with SIPS, stacked with DSS.
Extended AVI mode=true
Captured with FireCapture, stacked with Autostakkert
Don't face one's fate, can't be a real man;
Don't know manners, can't be gentle;
Don't know meaning behind the words, can't understand man's heart.