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On the prickly and frustrating subject of collimation - I see in all the how-to diagrams out there on the web that you should see a complete image of your primary in the secondary. I can only see the cell clamps when my drawtube is wound in to the max. Is my secondary possibly undersize or is this normal? (not a freudian slip)
I have a Skywatcher 10" f4.7 Dob so the tolerances for optimal performance are supposed to be very tight (I've read that it's thousandths of an inch!). The manual for the scope suggests you can successfully collimate with a modified 35mm film container - you've gotta be kidding!!! Seriously I'm sorry I didn't do some more research into the problems of fast scopes before I purchased. I just saw aperture and had stars in my eyes (pun intended).
For a start I find I have heaps of slop in the focuser which uses 2 set screws for clamping. These actually move the cheshire off center for collimation but later my ep's are a better fit and locate more central (can't be good for lining up focal planes and maxing performance!). I have seen focusers/adaptors using brass ring clamps. Do these centralise the collimation tool better? They've gotta be easier on the chromework.
So many questions I know but I'm really struggling to crack this black art called 'collimation'.
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