I am in desperate need for help to understand why I can not see all six primary clips. I can only see the top 3 and no matter what, I can not center the view to see the clips. Why is this happening?
Secondary adjustment doesn't work, I have rotated that thing almost a complete 360.
I ran across this thread and read your post. I had the same problem. Did you manage to fix it? Vic mentioned the solution, I believe, when he talked about the "three circles" in post #4 and others have touched on the solution, too.
This is not a "no matter what" condition, you can and will see the three clips and, more importantly, the entire primary. If you can imagine hand holding a small mirror directly under the focuser, you can rotate and tilt it so all three clips are visible - meaning the entire primary mirror is visible, too. This is where your diagonal needs to be and you get there by tilt and rotation of the secondary (and maybe some longitudinal movement, too, if necessary). However, to me, it's not so much about the clips, they are just along for the ride. It's about seeing the third, innermost circle - the reflection of the primary's edge. If you tilt and rotate the hand held mirror until the entire mirror is visible, you will see all three, four, or six clips and importantly the entire primary mirror. This is where the diagonal needs to be to start, so we need to put it there.
I think the trick is to start small and work up. What I mean is, draw the focuser inward until you can see the entire primary mirror from the peep hole in the collimation cap or site tube. Center the primary reflection as best you can using tilt and rotation. Then back off a little so the image of the primary expands a little, then tweak it again until it's better centered within the secondary edge. Then pull the focuser further out until the primary reflection is very nearly the same size as the secondary and tilt and rotate it again, as needed. At this point, and assuming the secondary is concentric with the bottom of draw or site tube (the first two circles), then the third circle - the primary mirror reflection - will be concentric with them. All three circles will be concentric and you will see the mirror clips (really, you see the clips because the primary reflection is well centered in the secondary).
At this point, if you have a site tube or combo tool, tilt the secondary until the cross hairs hit the (well placed) primary center mark. You might induce some rotation error, just fix it. (A milk jug washer comes in handy for tiny rotation error). Repeat the tilt until the cross hairs are on the center mark with the mirror reflection centered in the diagonal. It should be fine through the full range of focuser motion. If you centered the primary mirror in the diagonal at the maximum focuser outward motion, then it should be very well centered as the focuser is moved inward. The clips will be easily seen all around and you know you have centered the field illumination (where you can see the entire primary mirror.) And with the cross hairs over the center mark, you have good focuser axis alignment.
You're almost done.
Disclaimer: I am new at this, too, about a month into my week long exercise with a combo Cheshire/site tube and some star test confirmation. But, getting results by watching, reading, thinking through, and performing.