Yes, the CEM60 can be guided while playing back PEC. However, you may not
get a better results (most likely). Because these two methods do not talk
each other when in action."
Well, I heard back from iOptron tech support. You're right! I just don't understand this: "However, you may not
get a better results (most likely). Because these two methods do not talk each other when in action."
Some people say that...but my experience is that it is NOT TRUE. Whether we are talking an imported mount or a top-dollar one, PEC can improve your guiding. You may find my article here of interest: http://uncle-rods.bl...not-to-pec.html
If this were true, AP mounts wouldn't come from the factory PEC trained.
Interesting. I am going to try the experiment with my AP mount. I ran PemPro to get a custom curve, and the periodic error of my Mach1 is weird--it's very low (under 2 arc sec) but it's not totally periodic, it moves up and down the scale. In other words, the periodic error curve sometimes is to the east (varying amounts) sometimes to the west (varying amounts), and sometimes dead even of the RA movement axis.
The net result is that the *fitted* curve is a good approximation for the *combined curves*--but I think a poor one for any single one of them.
As the PE is pretty smooth, I'm going to test whether turning PEC off improves guiding. It's one of my planned experiments this Friday. Half an hour (5 worm periods) each way should give a good enough indication. I'll try twice if I get the time, one time with high hysteresis (25%), and one with low (10%).
Note: I have no doubt that PEC would improve guiding in a mount where the error curve repeats in place (which is sort of what people expect when they hear "periodic") or when there are spikes at points in the worm cycle. But in this case... we'll see. (I don't expect any dramatic improvements, the RMS on medium seeing with PEC on is about 0.73 - 0.80 which I can live with).
Edited by Stelios, 18 July 2017 - 03:25 PM.