LRunkle,
I don't intentionally rotate the disk. It does it on it's own. It's actually the combination of the standard pattern and that movement that helps you to be able to tell if you're really seeing the disk, or just imagining that you're seeing it. In reality, the disk only rotates a few degrees, clockwise, then counter-clockwise, etc. I suspect that all Secchi users are experiencing this phenomenon to a certain extent.
...but I do see your point.
