I had to make a few changes to my setup due to some jamming filters (long story) which meant the back focus from the coma corrector altered so have found myself redialing it all in. It wasn't meant to be particularly clear last night (hence the testing) but ended up with a narrowband M20 (3 hours). The back focus might be close now but collimation and tilt were a bit of a mess. Not the happiest of nights but a start. Never intended to do a NB M20 (much rather a nice LRGB version) but my broadband flats also need redoing so LRGB wasn't really a good option to run with at the last minute. All very noisy but I didn't absolutely hate the colour and the reddish cast of the Ha about M20. I did get a bit of M21 too but that was the side with the most tilt/poor collimation/not quite corrected coma
. Best version seemed to be the cropped one anyway.
5nm Ha, 3nm OIII and SII, all 20x180s through the 8" f4 Newt with an ASI1600MM-Pro (200, -10º) on an EQ6-R. Processed in PixInsight.
Astrobin:
https://www.astrobin.com/full/o5jo2t/F/