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Two ideas to help you out come to mind. One is get a magnifying finderscope and mount on the celestron and adjust it to the camera live view NOT an eyepiece in the celestron. If you're taking the camera off the scope and putting back you need to adjust each session you use the combo. A good bright finderscope just gives you a visual view and one that is slightly magnified means you can easier see fainter/smaller targets. If it has cross hairs then ideal. So first off you locate something bright in the sky and get it in the center of your cameras Live view, then adjust finderscope to center the same item there. Now when you slew to something you want to photograph you can center it in the finderscope and be confident it should then be centered in the camera. Be as patient and accurate as you can, any tiny shortcut you take ruins it completely.
Similarly there are diagonals that can let you use a camera AND and eyepiece. So again you need to find a way to match the eyepiece view with the camera view. If parts arent tightened and aligned perfectly each session you need to recheck each time where a target is in the eyepiece when its centered in the camera.
Similarly you can get red dot finders that have a hotshoe mount so you can attach to the camera. And again you need to get your target centered in Live view and then adjust the red dot to align them together.
Basically spend a night or two trial and error testing to sort it out or at least refine a method for yourself that gives you better confidence. If your setup is basically permanent you dont have to redo the process too much. Over time and even during a session your gear will expand and contract and stresses change when tracking a target so tightnest of parts and overall alignment can change so its worth doing a recheck after a few hours in a single session to see what drift occurs especially which direction. Then next time you can pre-empt the drift by starting with target slightly off center so the drift carries is through center.
Otherwise, do as I do and just take a test shot with higher iso so I can see where my expected target is within the frame and adjust where I'm pointing if needed.Then go on to take your shots. I usually do my test shots for targeting first, as many as needed, then i take one more with a torch pointed in front to obviously blow out the shot, then I take my actually shot set. This makes it easy for me to see in preview icons where I switch settings or target. When I go to processing later I usually go through my jpgs to find the one with the best centering of my target which should be where optical distortions are at their least, then use the raw for that frame as my registration target. Sometimes I stack a few frames and then crop those broadly around my target and use that as a registration target.
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