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Mirror dis-assembly - rookie questions
I pulled the primary mirror out of my GSO 12" dob yesterday to give it a clean and to install my upgraded springs. I marked the mirror on the sides of the support clamps so that I could put it all back together correctly. After getting it all back together I did a laser collimation and tested it out last night. It's great at lower power but when using the 9mm and 6mm higher powered eyepieces I am getting short astigmation tails that extend out to the 2pm position (on the image as seen in the eyepiece). I am assuming that one or more of my mirror clamps is probably to tight; is this a correct assumption? I did a star test and my donut appears to have a bite out of it on the right side (of the image). I did not attempt to fix it last night because the clamps require disassembly, and I didn't want to tackle that in the dark.
Secondly, at the back of the mirror where it sits on the articulated support arms of the support frame, the arms have what seems to be double sided tape pads on the end of each of the triangular arms, two of the three on each arm still have the protective cover on the adhesive and only one on each arm was sticking to the mirror - how important is that? Are they just there to cushion the mirror or should all of them be stuck to the mirror back - admittedly this can make it hard to remove the mirror? And does each triangluar arm have to go back into exactly the same spot, which is what I tried to do?
Finally, GSO (in their wisdom) make both the adjustment knobs and locking knobs the same thread size so it is possible to mis-align the frame in the carrier when remounting the springs. Am I correct in that the locking knobs only go through the holes where only one side is threaded and thus push against the internal mirror support frame to lock it in place; and the spring knobs screw into the internal mirror support frame? Or do I have it wrong way around?
Rookie mistakes I am sure and it's a learning experience. I will take it apart again today to fix the mirror clamp problem, so any advice is appreciated.
Cheers
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