Thanks Ryan, I finally understand. It turns out that I was using the M48 to T thread, but for some silly reason, I screwed it into the 16.5mm adapter so that it would fit onto the coma corrector, rather than on the coma corrector itself
Really appreciate the help. It’s cloudy for the next couple of nights, but hopefully it’ll work now. I have three 1mm spacers if I still get coma, so I can add these one at a time if needed.
Thanks again,
Stéphane