ATM Collimation question

[Brad Davy <bdavy@bigdog.fred.net>]

All this recent discussion regarding collimation methods is quite confusing
to the beginner (me).  I've been trying to get my 8"f8 as close as possible
using a sight tube.  I've gone through the steps described on Mels page and
things look good.  But one interesting phenomenon that I don't quite
understand is occurring.  If I point the scope toward an earthbound object
(my neighbors chimney for example), centering the object in the eye-piece,
then remove the eyepiece, I have to move my eye considerably off the axis
of the eyepiece holder to see the object in the primary mirror.  This seems
to indicate the optical axis of the primary and eyepiece are coincident at
the point of focus, but not paralell.  Should I shim the eyepiece holder in
the direction of the visual image and recollimate, or is this a normal
phenomenon?