kazihu

I got a laser and test my refractor. The reflection was in the center even if the spot on the objective was a little bit off. I tried perfecly center the spot on the objective but not so easy to find out where is the issue.

The laser has a play in the 1,25 adapter, the adapter has a play in the drawtube and the rawtube may not well aligned...

 Even with compression ring design when i tighten a tumbscrew, it moves the spot.

And the laser itself is needed to be collimated. I tried to rotate, and saw it "circling" a little, but i can only rotate it with loose thumbscrew so when i touched the laser, the spot moved...

At last my method to collimate the laser:  I mark the spot position when everything is tight then loose a thumbscrew and rotate the laser 90 degerees, tight and mark again . I adjust the laser until the spot stays on the same  mark. I hope that after each "loose and tight" the laser was the same position...

The second  is only a "what if" case. When the objective is not collimatable.

Back on the first: The laser point is in the center of the objective doesn't  necessarily mean that the drawtube is paralell with the optical axis (because the drawtube has a play). If it doesn't that may cause the off center reflection. At least IMO. 

If the reflection is off on the pointer plate and the lens cell is not collimatable which is the right setting? 

1. The spot centered on the objective and off on the pointer plate

2. The spot off on the objective and centered on the pointer plate