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Yep, a 12" Skywatcher dob is a serious scope and packs a serious punch. I've had mine for about 2 1/2 years now and I would like to share some improvements to the stock configuration that you could appreciate. Mostly to help with collimation with this scope, which can be a tricky so-and-so because it has a tendency to shift during the night.
First - always make sure the truss poles when extended are full tightened, even the slightest looseness to move them will cause collimation to shift through the motions of altitude with the scope.
Second, make sure your secondary spider is as tight as you can get it. Use multi-grips if you have to, to tighten it. Like the truss poles, even the slightest looseness will make your collimation shift through the altitude motions of your scope. Also, get bobs knobs for your secondary mirror to make adjustments a breeze.
Third - Replace the mirror springs. Head down to Bunnings if you can and pick up 3 x C-702 springs. Remove about 3/4 of an inch off them as they are a bit long. They fit perfectly in the recess in the mirror cell for the springs. These springs completely eliminate the need for the locking screws, so you can straight up remove them. If you then tighten them all up you can collimate with just loosening and tightening 2 collimation knobs. - Easy
Fourth - Get a decent collimator. I've started using a Hotech SCA 2" Laser collimator and its brilliant. Tight beam and an innovative laser alignment process. At $120 from the US its also very well priced. It has given me the most precise collimation I have ever had. It eliminates the need for a Cheshire eyepiece for me, as every time I use the SCA it agrees exactly with the Cheshire eyepiece anyway.
With these adjustments I guarantee you will be able to maintain collimation through out the night - no problem. Regardless of where you point the scope.
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