Don't have a proper collimator at the moment, but I do have the Orion collimation cap included with my XT8. I know that I am supposed to line everything up with the circle on the primary mirror, but I have an issue. Once it appears to be centered, I move my head to a different angle, and it appears to be off. So how do I know when it is correctly centered?
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The Orion collimation cap is actually quite good. If you are looking through the hole in the collimation cap, moving your head should not affect the alignment significantly.