Quote:
Originally Posted by Windston
Ok I didnt know that the bolts would actually impede in the light train that much, I will remove those this afternoon and see if I notice a difference.
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It's not so much a matter of "impeding" (blocking) the light, it's that you've got a couple of straight parallel edges in the light path, which will cast their own diffraction pattern, distinct from the cross created by the spider.
Rather than cutting them off - can you just turn them around so there is just a screw head inside the tube, and the thread extension is outside?
Yes, straightening the twisted spider vane would also help a bit, but I suspect most of the extra diffraction artefacts you're seeing come from the two long screws, and any other objects which may intrude into the light path. (I don't know, but could the inner end of the focuser tube, and the "ragged" edge of the paper flocking, also contribute some diffraction artefacts?) The effect of a slightly twisted vane might be to make one axis of the classic "diffraction cross" a bit stronger than the other axis, but I suspect this effect is quite small, unless your vane is so twisted as to make it noticeably wider than the edge-on thickness of the vane.