After centering the secondary using a site tube, I aligned it using a laser
and a center dot on the primary. I then collimated the primary by getting
the return beam to meet the source beam for the laser.

Now, when I look through the cheshire, the reflection of the illuminated
metal piece is offset in the secondary, away from the primary, at a postion
possibly two thirds length of the major axis.

In a star test the images are pretty good close to focus, but racking focus
in and out a far distance shows the shardow of the CO as shifted this same
distance. First on one side of focus it is to the top (away from primary)
and then on the other side of focus it is to the bottom (toward the
primary).

What's up with that?

I've tried moving the secondary both away from and toward the primary and I
can't seem to ever get this centered. Also, if I ignore the laser, and
center the reflection of the cheshire, the collimation in star testing is
way off. Putting the laser back in and aligning, immediately improves the
star images, even though the previous problem persists far outside and
inside focus.

With the cheshire collimation, (where the shifted reflection is also evident
in the the secondary) the laser and the cheshire agree that the mirrors are
lined up on the center axis of the primary (the center dot appears in the
center of the cheshire reflection, as well as returning the laser beam into
the beam at the source).

Where am I going wrong?

Is my secondary too far from the primary? Too close? Or is something else
awry?


--
-Stephen Paul