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Originally Posted by Stu Ward
although i can never quite get the laser beam into the middle of the donut on the primary.
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Why? Are some of your Bob's knobs getting too tight which prevents you from moving the beam further to the center?
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But what bugs me is that if i look at a star totally out of focus the shadow of the secondary cast on the blurry star is nowhere near the middle ( as basic collimation methods say it should be )
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It sounds you are defoucsing too much. In this case, the secondary shadow will indeed look shifted especially for fast scopes. To evaluate collimation, you are suppose to defocus by a small amount at high magnification -- enough to see only few rings .
Jason