Quote:
Originally Posted by multiweb
Do you have the corrector's distance spot on? Have you tried moving it in or out. Center field out of focus looks a tiny bit out but not much. The edges might be related to some residual field curvature. Tweaking spacing might fix that.
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Yes the corrector is spot on according to what I have been told. The back focus is 106mm and I am told that is from the rear of the thread. The STXL with filter wheel back focus is 61.84mm. That leaves 44.16mm for adapter. My adapter is 44.2mm. I measured it recent just to make sure.
Collimation could do with a tiny tweak, though I doubt it would have much effect. Perhaps remove the slight elongation to the right side.
I did move the flattener out by 3mm as suggested by TS Optical but it seemed to make the problem worse. I don't have the ability to move it in unfortunately. I don't have a smaller adapter to make that work.
I wonder if the problem is related to the optimum distance of the mirrors. I am within a millimetre or two of that from what I understand, so maybe this is where the problem really lies?