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After much experience doing collimations with an RC and CDK, I can confirm a laser is rubbish for setting collimation. The James Mchugh method works, and now a second method definitely works and is easy. For imaging setups, use the camera to set collimation. Place the scope on a open cluster and defocus camera to donuts all over FOV. Defocused stars must populate the FOV, but should not be a crowed FOV. Watching the result on your laptop whilst adjusting you secondary, aim for central donuts to be round, and outer donuts to be distorted evenly and equally around the centre. Outer donuts need to be pointing inward to the FOV centre. Upon achieving a balanced arrangement of Donuts over the FOV, upon returning the camera to focus, you will have achieved the best collimation from just adjusting the secondary. The process works even under unstable conditions. Only where the primary is seriously misaligned, will you have to centralize the primary to point to the middle of the secondary. Some iterations may be necessary to get that part right.
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