Kevin_A ... I see a flat comb shape but huge over corrections from something too.
Hmmm, where did you see that, Kevin? I was looking for correction pulses, and did not find any (my browser may not be showing blue that prominently either) -- I was about to ask him to turn on the correction pulses the next time he see this oscillation. What I had been calling a "comb" refers to a comb of saturated correction pulses (i.e., max duration pulses sent in a long sequence and still not sufficient to correct the mount's slope error), and not to a constant amplitude oscillation of the RA error itself.
@CHriss
When you ask for recommendations from folks who are not at your computer, please include all autoguiding information that you can. I suspect, for example that your problem comes from an RA Aggressiveness setting (loop gain) that is set too high, and that caused the RA pulses to alternate in sign (i.e., oscillation caused by the autoguider software, and not the mount). However, you did not show the aggressiveness setting for RA, nor turned on correction pulses on your chart -- so there is no way we can tell with even 1% certainty what is happening, except that we see abnormal rapid oscillations (that is usually associated with applying too long a pulse to the mount, together with aggressive numbers -- basically the loop gain, if you are familiar with feedback loops -- that are too large). Actually, I am also surmising that the oscillations are rapid -- I was looking for the abscissa scale and didn't find that either.
The other important thing -- you will find that in general, strain wave gear mount autoguides about as well as a worm gear mount that is 1/3 the price of the strain wave mount. It is just the nature of the beast -- the market for strain wave gears are the people who are willing to pay the extra for portability (no need to lug around heavy counterweights, or for that matter the weight of the mount), and no need to worry about balancing (especially not having to worry about "third axis" balancing). Part of the market is for old folks like me who can't handle weights, even though I don't take any telescope out of the home anymore.
If you had bought these mounts on the premise (or promise) that they can autoguide as well as worm geared mounts, that is false advertising, and you should remedy that.
I have been using strain wave geared mounts for some 4 years now and still slowing trying to get them to work to my satisfaction (part of it due to my OCD -- most people would be happy with a 0.5" error). At least I have gotten mine to now guide to the 0.35" region by applying everything that I know about the behavior of these mounts, and the autoguiding software.
So, patience is required to learn your mount (each mount is so different from another one from the same manufacturer) that you can't just depend on what other people use to tune their autoguiding parameters.
There is a large variance in the sample you get (luck of the draw). Just because I can get 0.35" from my RST-135 does not mean that a different owner can get the same performance -- his/hers might be better, or it might be worse. But it appears like ZWO mounts have much larger variance (bigger lottery) from one sample to another.
You need to be patient (just like other aspects of this hobby) and slowly learn your own mount. Or simply buy a nice traditional mount. An Avalon M-zero for example will wipe the floor with these strain wave mounts when it comes to configurability and autoguiding performance.
Chen
