I haven't had my CPC1100 out for quite a while and had to remove the corrector plate to get some toys my grandson dropped through the eyepiece opening. After putting it back together, I couldn't get it to focus on anything. Just got a wedge of light when looking at Jupiter, for instance. I tried to collimate it using Robert Piekiel's book on the subject, but can't get it anywhere near the ballpark. I have no reason to think the primary is out of alignment, and a visual check from the front seems to verify this. I set up an artificial star over 100 feet away and tried collimating on it, but after backing out 2 of the adjustment knobs all the way (so they were completely out of the thread), I still couldn't even get an out of focus doughnut. The images when I try to focus on anything show a LOT of astigmatism. When I defocus the artificial star, I just get a pair of parabolas that I can overlap by adjusting the focus. Both parabolas are pointing so they are opening to the lower left when viewed through my diagonal. I've tried doing this with several eyepieces of varying diameter. I can't seem to make these parabolas change in any way by adjusting the collimation knobs. The only way I can move the parabolas is by turning the focus knob. BTW: When I put the corrector plate back in, I was careful to place the cork shims in 4 positions at the 12, 3, 6, and 9 o'clock locations so it would be centered. I've never separated the secondary mirror assembly from the corrector plate. The etched number on the corrector plate is at the 3 o'clock position.
Does anyone have a clue as to what is going wrong here? Is there some way for me to get the secondary collimation knobs set so they are at a known position so I know which direction I need to go to get to correct collimation?
I'm at my wits end trying to figure this out. Any help would be greatly appreciated.
Edited by dudleyjohn, 13 September 2021 - 06:59 PM.