I have a SkyWatcher Esprit 120ED that I bought used. It came with a Feathertouch focuser and the visual back. I bought the imaging back so I could use the flattener, set it all up with exactly 75mm of backspace to the sensor on an ASI294, and I can't reach focus. I need to add about 40mm more space behind the flattener to get focus but that really messes up my corners.
Does anyone know what I'm missing?
I don't have the original focuser but if I don't get answers here my next stop is to get one from SW.
Thanks for reading!