Quote:
Originally Posted by bmitchell82
whats more worrying is the focus pattern coming in and coming out its a oblong star that rotates 90 deg on the other side of focus.
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That's astigmatism. You have two good focus points on each side of the sweet spot (that will give you the best of both worlds: a cross). An everything is blurry in the center of your field. In my experience that's a misalignment between the tube axis and the axis going from the center of your primary to the point where your focuser axis intersect the secondary diagonal. Get the tilt and centering of your secondary spot on and that will go.
Now if you have three pinches in your star, it's your primary cell that's holding too tight. That's easily fixed by releasing the clamps. They must only touch the mirror not squeeze it.