Strange PEC Curve / EQ6R-Pro

[MikeeJC]

Hi all!

I'm running a EQ6R-Pro mount and am getting a strange EQMOD PEC curve all of a sudden (see image below).  Does anyone know what could cause this?

Previously I've been getting a smooth Sine wave curve, equal top and bottom.  The only thing I've done recently is to remove a bit of play in the dec axis, being very careful not to overtighten.  After the adjustment I re-ran PEC training which then gave me this strange shaped curve.  Although I was sure at the time there was no stiction I will double check this.

Also, this may be a daft question, but how do I ensure EQMOD's PEC is properly sync'd to the mount so it's not running out of phase?  Or do I not need to worry about this?

Many thanks!

[david_taurus83]

The EQ6R and AZEQ6 both have optical encoders on the RA axis so that's how it probably knows where to start the PEC corrections but I couldn't say how accurate it is. I use GSS and was happy with PPEC correction at first but I've found it to be too unreliable and the mount can behave strangely with it on. Now I just use PHD's algorithm which kicks in after a couple of revolutions of the axis each time you start it.