PE is not periodic

[Ana Ta]

Why are periodic errors not "periodic" (they are asymmetric, open unguided log), and RA axis has spikes?

iOptron techs do not get such drift of PE, when they evaluate mount without load.

Thanks

Ana

[bw_m...@earthlink.net]

Please post both the PHD2 guide and debug log files using this procedure:  https://openphdguiding.org/getting-help/

 

Regards,

Bruce

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[Ana Ta]

Here it is https://openphdguiding.org/logs/dl/PHD2_logs_UG4j.zip

[Ana Ta]

I am new to this. Does my second post provide info?

Thanks

Ana

[Bruce Waddington]

Hi Ana.  I don't know what you're seeing or being told but these RA tracking errors look quite periodic to me:

I don't know iOptron mount you have and I don't the worm period - different iOptron models seem to have different gearing systems.  But here is a frequency analysis of the graph shown above:

These peaks show up at intervals of about 350 sec, about 175 sec, and about 116 sec in descending order right to left.  These look to me like integer harmonics of the primary frequency, what you'd expect from periodic error.  These graphs are all corrected for drift, which they should be - slow drift is easily guided out and doesn't affect your overall results. 

Regards,

Bruce

[Ana Ta]

Great!

What parameters for PhD2 should I use to guide this off?

Curve that you have shown is result of guiding.

Maybe I need to change some parameters during guiding.

Thanks

Armen

[Bruce Waddington]

No, the curve is NOT the result of guiding, it is showing you the native tracking error of your mount.  The guide corrections have all be extracted from this data.  If you run the Guiding Assistant for 6 minutes, you'll see the mount has a periodic error of 25-30 arc-sec peak-peak.   i don't think this falls within the specs for an iOptron mount and you should try first to get a mechanical improvement.  If you can't get any help from iOptron, you can try using the PPEC guide algorithm for RA, giving it an initial period length the matches the worm period on the mount.  You should find out what that is - 350, 360, or however many seconds.

Bruce