Saturn

Can't argue with you there) I have an IR pass 850 in my filter wheel but haven't tried it yet—thinking it'll cut too hard at f/13. Well, we'll figure it out. The 685 can be unscrewed from the guide scope if I want to give it a shot, plus focusing with a mask and aiming is quite a song and dance) I've aligned the guide scope and main tube almost perfectly and aim by switching the main camera to the guide camera.

One fellow hobbyist suggested it, and it works: focus with a Bahtinov mask on a star as usual, but by eye you can't get the focus—the atmosphere is shifting and it's impossible to tell.

I don't focus by eye) I mean that something is off and I couldn't even do it using a mask.

And I noticed that the higher the magnification, the more demands it places on the atmosphere — most likely, it didn't cooperate for you.