Hi Tony
Can you share the guidelogs from your screen caps?
i'm assuming if you have not yet done the unguided output, the PECPrep is a residual error, and not the raw periodic error of the mount
I have seen the 2x be a function of the coupler. It could be slightly off-kilter but if you've moved to the oldham, it would be the same thing. You can try to measure the distance between the coupler and the plate beneath it using an improvised measurement (like a hex wrench or stick) and just make sure it's consistent all the way across?
Getting a solid 30-45 minute unguided run from guiding assistant in PHD is a great idea (i recommend the latest 2.6.9 dev 4 release). Here are steps for a baseline guiding which I always recommend people start with to eliminate a lot of inadvertent variables in the setup
https://www.dropbox.com/s/os1thorvswmzaul/How%20to%20create%20a%20baseline%20for%20guiding%20results%20using%20OpenPHD2.pdf?dl=0
Brian
