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Anyone able to help analyse my PHD2 log? Regular dec dips...


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Hi

I've set my scope up on it's pier in my ROR observatory, done a few drift aligns and started to take some images. 

I've noticed a 'quite' regular dip in my DEC line on several nights. 

Would anyone be able to have a quick scan of my log and offer any insight?

Could it be backlash? Could it be something with each rotation of the gears? Faulty tooth? 

It is quite regular, although not always, and always in the same direction.

It doesn't seem to be adversely affecting imaging yet, but I've not tried anything too taxing.

Thanks

Joe

 

PHD2_GuideLog_2018-09-23_200940.txt

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Hi Joe

I would send the guidelog and the debuglog to the Open PHD Guiding forum, where the PHD developers will give you an expert opinion.

https://groups.google.com/forum/?fromgroups=#!forum/open-phd-guiding

I'd guess you have a lot of Dec backlash - have you measured it with the Guiding Assistant?

If your mount has Backlash Compensation you should disable this as it fights PHD

The dec excursions aren't always in the same direction, the events at 20:44 onwards, where Dec is yoyo-ing back and forth, they could be due to stiction - corrections are sent until the dec unsticks, then it flies over to the other side, and repeats.

Or just large backlash causing over-corrections.

Your PA might be too good !! If you had a gentle PA trend and unbalanced slightly the same way, then Dec correction would only need to be in that direction, avoiding the overshoots and lengthy time correcting.

But like I say, ask the experts !

Michael

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