[mynameiscd (Andy)]

Hi all,
Any help on setting the seconary in its corect depth
Perfect night on sunday so I set up and thought i would try my seconary dew heater.
I ended up unscrewing the centre screw to remove the secodary to put the stalk type heater on. I screwed it back to where it was but had a lot of trouble with collimation esp with the depth and twist of the mirror.
I did a check with a laser and it looked ok.
After getting 3 hours of data back and stacking my images are all sharp in the middle, not too bad on the right side, but heaps of paisley comets on the left which means some sort of twist in the mirror.
This part of collimation i have always had trouble with. Ive read lots of info but the secondary offset with f5 scopes goes over my bead a bit.
My scope is a Skywatcher black diamond 150mm f5
Collimating tools are orion 1.25 Collimating eyepiece and 2 lasers which have checked for collimation.
Any help with this exact scope because most info i read is about larger newts or dobs and confusing images of secodary offset etc.
Is there somd sort of tool or method to set the rotation and depth without scratching the mirror?
I thought of using some sort of tube or ruler that touches the mirror but even that could be rotated a little to get a false reading.
Also there's adjustment on the spider to add to my troubles.
Still a bit confused
Cheers
Andy