Aidan,
Your results are rather unusual to say the least.
When you used PEMpro, after you collected data on the analysis page what does the graph there say about your peak to peak error? Is this error the same value that you see when pasted into the Bisque TCS? Similar to running PEC in TSX? (Sorry! I missed your post above). It's really curious how you got the curves to align by removing 50% of the points. I'm not sure at all what that means.
I take it that before using PEMpro you went through the mount wizard where you measure the star trail lengths, etc? Then on the first page of the mount/camera settings page you synched the worm period before collecting the data?
I wanted to check on your assertion that the worm periods are the same for the MX and MX+. I found this so that is not the issue (I had a bit of a doubt remaining):
- ME and ME II: 576 cycles in 24h → 2m30s of sidereal time
- MX and MX+: 375 → 3m50.4s
- MYT: 320 → 4m30s
I'm not remembering if this was previously suggested (and I know your scope is remote!) but perhaps you could eliminate some of your concerns re seeing/large aperture by mounting a smaller scope (a refractor?) and guide camera perhaps on top of the RC and measuring PEC. In any case you would have a point of comparison. Either way the results should be very similar.
Another random thought, perhaps for your seeing .45 arc-sec is asking too much. You might try binning 2x2 which still puts you below 1 arc-sec. I also notice that your exposures were around 3 sec. I think you can do better if binned. Try 1 sec.
Finally, if you can't figure out why only 50% of the curve from PEMpro ends up pasted into the Bisque TCS (and why the Peak to Peak vale changes so much) by all means post the question at Ray's forum at CCDWare. He always has answered me quite quickly!
Peter