Collimation of AP Starfire 152 f/9

I recently purchased a used 152 Starfire f/9 and find that it is out of collimation--the airy disc is centered on about the 3rd out-of focus diffraction ring when 3 rings are showing. The in-focus image shows all the diffraction rings on one side.
I note that there are 3 pairs of collimation bolts for the lens cell on the outside of the tube, each consisting of a larger and a smaller bolt. Which way do I turn them? What is the easiest way to change the collimation slightly?
Is there ever a problem with the lenses not being centered on each other? I know that some refractors, for example the Borg 101 ED, collimate by sliding one lens laterally with respect to the other.

Bill Patton

I used to have a scope identical to the one you have now. I colllimated it once and made notes. Of the three pairs of screws you noted, the small ones push and the big ones pull. However, note that the outer, curved wall of the lens cell also has screws. There are two rings, and each has three screws. The ones on the rear ring secure the celll to the tube and should not be loosened. The ones on the forward ring lock in the collimation. In other words, unless you first loosen these slightly, the collimation screws will do nothing good!

No one can tell you which way to move the collimation screws. I wouldn't try collimating it on a star; use a Cheshire collimating eyepiece instead. Adjust the push-pull pairs until all the donut reflections you see in the Cheshire are concentric, then tighten up that forward trio of screws.

That's the way it worked for me, anyway...