After a thorough collimation of one of my reflectors using a laser and Orion precision centration adapter, I noticed that I couldn't get a good star-test pattern without further tweaking- much more than is usually needed before I got the centration device. It turns out that eyepieces then used without the centration adapter are not truly centered, so of course the diffraction pattern was off-center. This tells me that if you want dead-on collimation, either DO NOT use the centration adapter, or use it WITH your eyepieces and camera afterwards. And if the adapter itself is a sloppy fit in the focuser drawtube, you may be chasing your tail. Some focusers are overbored more than others, so YMMV. It may or may not be a problem with your particular scope.