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Unless you have some weak adapters that are not strong enough then the tilt can be handled either by adding a tilt adapter to the train if there is backfocus or simply packing out the offending corner with some packing material like brass shim or spark plug adapters.
Step 1. Orientation:
You need to know how the corners of the physical camera relate to the images.
I use a torch and a rag to dim it down and take a 10 second image and illuminate one corner only. Then see where the light is in the image.
Its most likely the image is reversed top to bottom and left to right with a compound mirrored scope. Do this step until you know which corner of the camera relates to which corner of the image.
Step2: Correction.
Pack out the corner on the camera that relates to the out of focus stars in the image. To get an idea of how much to pack it out on my F3.8 Honders its about .7mm thick. I placed a packer between the camera and the filter wheel.
Take another shot of the stars and check the focus in all 4 corners. Is it better or worse or no change?
It should be better. If worse then step 1 needs to be done again as you are packing out the wrong corner.
Keep adjusting until you have all 4 corners sharp.
Your image shows badly out of focus stars on one corner so expect a fairly large packer to correct - at a guess around 1mm+ thick.
I do this step with all my scopes and when I do it as above it takes about 10 minutes.
If you find you have large packers on most corners its best to start again as it probably is only 1 corner or at most 1 side.
Greg.
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