My Dob is an Orion XT-8, my first scope, owned it since January 2003 and am
very pleased with it.

Shortly after I got it, I bought the Tectron collimation tools (sight tube
with crosshairs, "auto-collimator," and Cheshire). I read up on collimation
and spent a couple of hours last February in my below-freezing garage
collimating the scope -- I was quite proud of the results as collimation did
improve the images in the scope.

I recently bought the Orion deluxe laser collimator and have figured out how
to use it.

For the past few weeks, I've been dragging the scope out to pubic Mars
viewings where I and the folks who look through the scope have seen the
polar cap, dark surface features, and the like.

This morning, I decided to check the collimation. The beam from the laser
was not hitting the donut in the center of the mirror and the returned beam
was visible on the reflecting surface of the mirror. I dragged out the
Tectron tools and started from scratch -- the secondary mirror was not
exactly centered in the sight tube so I centered it, checked and re-checked.
I fiddled with the secondary until it was a circle in the sight tube,
centered all the way around. I then installed the laser and adjusted the
secondary setscrews to center the laser dot on the primary mirror after
which I adjusted the primary mirror -- using the laser -- and the scope was
collimated.

I did all this with the focuser bottomed out -- that is, I ran the focuser
all the way in until the part that moves in and out was seated against its
frame.

HOWEVER -- I collimated the scope with the tube tilted at approx 30 degrees.
When I ran the focuser out to where it is when eyepieces are focused, and
elevated the tube to around 60 degrees, the laser beam slipped out of the
donut in the primary. I tried to figure out why this would be happening and
found that there is enough side-to-side slop in the focuser to cause the
laser collimator or an eyepiece to move ever so slightly from side to
side -- it's mighty slight but it's there.

Do I need to worry about this?

As I say, I've been happy with the scope, saw surface features on Mars with
no problems other than those caused by poor seeing; I cleanly split the
Epsilon Lyrae double-double; and stars always dissolve into round concentric
rings -- so -- it may not be a problem. Or, it may be.

What do you folks recommend?

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Joe S.