[Kokatha man]

Another way of saying that first bit Chris is to imagine you've taken the sec mirror and holder out of the scope and it's in one hand. In your other hand you've got a short length of 1&1/4 inch poly pipe which you hold up to your eye and look down at an angle of 90 degrees at the sec.

You twist/rotate the sec and holder in one hand whilst peering at it through the pipe (with the pipe a couple of inches off the sec mirror surface to avoid poking it and to simulate the "in situ" mode: by twisting/rotating the sec and holder it will arrive at a position of appearing circular as you peer at it through that bit of pipe - this is what you are aiming at as the first step in the collimation of the scope (after, of course, screwing its' central bolt/screw either way to make the sec and holder move up or down the scope tube and thus be centralized physically under the focusser tube if initially required!)

I could just as easily have said "imagine you are peering through that piece of polypipe perpendicularly down at an oval cardboard cut out that is fixed at 90 degrees (with regard to its' radial axis.) As I'm sure you realize, the sec holder has the sec mirror fixed to it at an angle of 45 degrees.

Don't think of it as a mirror, forget about any reflections etc, it's just an oval object that you want to make appear circular at the bottom of the focusser tube: and you achieve this by rotating it and its' holder whilst peering down the focusser tube with whatever - remembering that to rotate this shebang you need to have those 3 screws loosened: when it looks circular, pinch up those 3 screws and the sec mirror will stay in that position!

Post or pm if you can get to that stage, or if something is stalling you before you can achieve this! I had to go through this head-banging myself to arrive at my present understanding Screwie; and even though I've got a simple newtonian I'm a ***** perfectionist pain-in-the butt type that had to intimately understand what I was doing and really get on top of it - my star tests turn out spot on re diffraction rings now as a benefit.

Cheers, Darryl.