Re: Identifying Peaks in the PECPrep Periodicity Plot In the PHD2 Guide Log - Somewhat #ExploreScientific #iEXOS-100 #EXOS2 #TECHNICAL


Can you quantify what you're seeing as too tight/too loose?  FWIW, I'm getting good results with about 2mm of depression on the belt.
Re: The belt and small pulley.  You know that I put a lot of study into mine, and I found that it really was important to my PecPREP graphs that the belt track down the center of the small pulley, and not pull to one side. The only explanation I can think of for this is that if the belt is rubbing on the pulley's keeper disc, then it must be fluttering a bit from the friction, and the belt teeth will be engaging the pulley at a bit of an angle and perhaps snapping as they seat?  Can't be sure what the mechanics are, but I do know that my graphs cleaned up considerably when made sure that the belt tracked straight. 
Re: Pulley wobble on the shaft, the ones I've seen are a good close fit, but I wondered about that as well. I tighten the two setscrews in turn, hoping to distribute the shaft clearance more, but I've no way of measuring whether it makes any difference - really just makes me feel better.  Visual wobble of the pulley doesn't tell you anything, as all you can really see is the keeper disk, and it's a swedged-on part, and not integral. 
Re: Your question about the post-600s periods...  I don't see an 800s in mine, but I do have various other long ones past that, and they vary depending on whether guiding is on or off.  Basically, I don't think they matter for tracking - if your mount is tuned well enough to handle the short-period waves, it should also take care of the long-period ones.
- Bob
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2-IMX224C
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64

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