thanks for the info Rich, yeah I'm pretty good on my drift alignment
. I'm not sure if I mentioned that I've got a FR in train of the WO/dmk so I'm guiding at around 300mm. The VC itself has a losmandy D plate top and bottom to help with rigidity of the tube and mounting. The whole scope has just come back from Japan for a complete reworking of the mirror so I would hope the clips have been tensioned correctly.
I think I might just have nailed it tonight though (I really hope so). I did a focus with the button just snug, and was getting the usual diagonal trailing, though to a much lesser degree than normal. I tightened the button up (stuff the focus) and everything is looking pretty good. Its strange though that this problem is only occuring in one part of the sky.
