CEM60-EC problem- mount moving about

[cbbella]

hi, does anyone know what could be wrong with my cem60ec mount. the last time i used it all was working fine.  now it jumps about. i've never changed any settings and i'm still using the same equipment - a skywatcher 200p with a qhy163m camera with filter wheel and 9x50 finderscope with a qhy5L-II guide camera attached.

in the phd2 video dated 2nd August i haven't even selected a star and you can see it jumping about in the star profile and when i put my qhy163m imaging camera on a star in sharpcap it does the same. everything is balanced and i've got excellent polar alignment using sharpcap.

ioptron support sent me a pdf on how to adjust the RA_Play_Fixing but there was very little movement in it. i've adjusted the play in RA and it is still the same, i've also re-calibrated the EC encoder.  i've emailed ioptron support and i'm waiting for a response from them but in the meantime i just wondered if anyone else has this problem

please view videos here, , they’re only short videos of 30-50 secs: https://1drv.ms/u/s!ArXyy_OLav56qHnZBMh43pHli30i?e=kuZ89K

regards

[michael8554]

Found this on the PHD2 Help Forum.

Although it relates to a CEM40EC, the problem is probably the same for the 60EC:

"I struggled to guide a CEM40EC for quite a while before learning that iOptron EC mounts suffer from "sub-divisional error" on the encoders. In my CEM40EC, this resulted in the mount oscillating in RA with a 6-second period and a peak-to-peak amplitude of 0.6 arc seconds. There was no way to guide this out. The best I could do was use a long interval (3 or 6s) to try to average out the wobble so it didn't inject noise into the guiding. Eventually, I bought a CEM60 (no EC) and sold the CEM40EC to someone who was imaging at a larger scale."

Michael

[cbbella]

thanks for that Michael but my problem isn't guiding related.  As i wrote in my 1st post the mount jumps about even when not guiding. In the phd2 video it is only looping exposures selected and in sharpcap with my main imaging camera you can see it moving about even though i haven't got phd2 open

regards

Edited August 15, 2021 by cbbella

[michael8554]

My take on the message was that this behaviour was while Tracking?

Which makes Guiding difficult.

Could be wrong......

Michael