I've had my scope for years and made a collimation cap out of a film cannister way back when (remember those?). According to that, my scope never went out of alignment, even after a drive along bumpy dirt roads, so I never did it, though I did check it semi-regularly ('is it out of alignment
yet?').
More recently I figured I should get a Cheshire eyepiece just to be sure so I can eek a little more performance out of my scope and found that it was every so slightly off.
So after years of owning a telescope, I decided to have a crack at collimating. Followed the instructions, after a few attempts I got it pretty exact.
BUT - no matter what I do, the Cheshire cross-hair in the eyepiece itself (not a reflection, in RED on the diagram) will not line up with the center. Every collimation I have attempted has wound up with the cross hairs displaced in the same direction.
http://markusstone.com/hosted_files/...tion_issue.jpg
What I don't understand is how the rest of the telescope's optical axes can be perfectly aligned, yet the cross-hair at the bottom of the eyepiece obstinately refuses to comply. If I rotate the eyepiece in situ, the center of the cross hairs stays put.
I've adjusted the tilt
and rotation of the secondary and tilt of the objective; in short all the adjustments available to me. At this point I'm sufficiently stumped that it's overcome my embarrassment about asking such a basic question, even if I do get the wooden spoon award.
At this point, I wonder if I need to tweak the alignment of the focuser to the tube of the telescope? Has anyone else had this problem? I'm scratching my head here...
Thanks
Markus
PS, I honestly can't remember whether the Cheshire cross was off in the beginning before I started tweaking because I was following the instructions and looking at the reflections in the mirrors.