Massive guiding excursions with new mount

[Kevin Wisdom]

Hi,

I have recently replaced my reliable Celestron AVX with a Sky-Watcher NEQ6, for which I have Rowan belt modified.

Trouble is, the replacement mount refuses to guide reliably, regardless of payload.

More often than not during a guiding session, massive random guiding excursions (traditionally DEC, but lately RA is affected) are experienced. Often PHD2 does not recover the guide star and if left unattended, the imaging session is ruined.

I have stripped, tuned and rebuilt the mount countless times, dialling out backlash, upgrading bearings. regreasing, but to no avail. I see no obvious mechanical issues to speak of. Cables are neatly secured with no snags.

I've created new profiles from the PHD2 wizard, chopped and changed guiding algorithms, guide cam exposure lengths, run guiding assistant over a worm cycle, calibrated near the meridian or at the point of imaging, swapped from EQMOD to GSS, changed guide rates in RA and DEC but found no cure. 

I use N.I.N.A. for my imaging plans and dither in random pattern every few frames. The dither distance is set correctly for whichever imaging scope I have mounted, as evidenced by past trouble-free AVX imaging sessions.

Needless to say, my polar alignment is more than adequate and I never experienced any of these issues with my AVX. Sometimes HEAVILY unbalancing Dec to be North or South heavy improves things, but not always.

I can't think of any stone I've left unturned, but during my last imaging session I checked the "Reverse Dec output after meridian flip" and "Assume Dec orthogonal to RA" options out of desperation, and it seemed to settle the excursions for the guiding run, but can't be sure if it's a permanent fix, as it was only a single instance.

For reference, I've included some of my most recent guide logs.

Any suggestions, please as I'm at a loss?

Thanks,

Kevin

[Bruce Waddington]

In light of the history of how you've arrived at your current configuration, I think we need to start over.  Please follow all the instructions in the attached document and, even more important, use the PHD2 Upload Logs feature to send us the data we need to help you out.  As an extension to the instructions in the document, we should see a 20-30 minute guiding session on each side of the pier WITH NO CHANGES TO GUIDING PARAMETERS OR ATTEMPTS TO "FIX" SOMETHING.  We're trying to understand what's wrong with your setup before we then determine how to improve it.  You should perform the testing without using NINA or any other session manager, just run PHD2 manually.

Regards,

Bruce

[Kevin Wisdom]

Hi, Bruce

Thanks for your assistance, but I do not see the attached document you speak of?

Unless there's anything else I'm missing, when the skies finally clear I'll upload the log files as instructed.

Regards,

Kevin

--
You received this message because you are subscribed to the Google Groups "Open PHD Guiding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to open-phd-guidi...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/open-phd-guiding/0042f5df-7a6a-419b-b638-4ac36e85785cn%40googlegroups.com.

[Bruce Waddington]

Sorry, this was pretty useless "assistance" I gave you - I forgot to attach the document.  My bad, long day.  The doc is attached to this message now.  Just take your time doing this and don't let yourself start thrashing around.  As I said before, this isn't going to fix anything but it will hopefully tell us what's going wrong.

Good luck,

Bruce