I agree with your analysis. The gearbox from the pinion gear through to final drive gear generates most of the high frequency noise with the exception of seeing that PHD2 tries to eliminate. When I miss drilled the pinion gear for the 1/8th motor shaft I had a visably noticeable wobble, that generated at least a 0.5 arc sec guide error ?with a period of 9.2s. It was a very distinct sine wave on the guide chart. You can imagine my guiding was pretty bad, but no worse than 1.3 rms arc sec or so. I gained a whole new appreciation for these higher frequency noise components through just that error on my part. Really, I'd like to get ride of the gear box. These high frequencies can not be corrected for.?With a step size resolution of 0.56 arc sec guiding is actually worsened I feel.
