Pier Failed to Flip

I’m chasing some peculiar behavior with with my guiding apparatus. There is PHD2’s odd stopping during an imaging session, and most recently failing to proper interact with SGPro during a pier flip procedure. I’ve attached the SGPro logfile, Sequence and the PHD2 guidelog and debuglog files.

On November 1st SGPro predicted pier flip from west to east at (about) 10:00pm. (it had failed to flip successfully with the same target the previous night).
This time I observed the attempt which started at approximately 9:55pm. The stars in the guider’s screen began to streak in the RA direction, and PHD2 indicated it had lost the guide star. Possibly SGPro failed to pause the guider during this sequence?

I returned the mount to its home position, restarted the sequence The scope then went to the east side of pier. It ran as intended for the rest of the night’s session.

The PHD2 logfile shows the guide star lost at 21:55:11 and the SGPro logfile reported the star lost at 21:55:32.191.

My mount has been pretty reliable on pier flips so I’d appreciate anyone’s insight on what might be the problem.

I recently removed and re-installed both SGPro’s and PHD2’s softwares in an effort to chase down other guiding issues. And I may not have set them back up properly.


My setup:
CEM120 mount carrying a Meade 12”LX200 OTA with 7.5 Reducer/Corrector, Feathertouch Focuser (with Starizona autofocuser), Mitsuboshi OAG5 and Lodestar guide cam, Atik EWS2 and QHY294mmPro CMOS camera.
Scope has effective FL of 2182mm
Guide cam effective FL of 1091mm
SGPro v3.2.0.660
PHD2 v2.5.11dev6

These problems are the worst… I studied the attached logs and, unfortunately, it’s not exactly clear what is happening, but I’ll tell you my thoughts.

As you note, at 21:55:32, the guide star is reported lost. In the near immediate vicinity prior to this even we can see the telescope and observatory tracking together as normal even as close as 21:55:03. So… 30 seconds from then, the mount suddenly slews. SGPro will not ever slew the mount without making note of the even in the logs so it seems like something external to SGPro may be doing this and when you’re in close proximity to the meridian, there are other things that may take some kind of action.

Assuming you don’t have any other software connected to the scope driver, that leaves, as suspects:

  • SGPro in some kind of very odd bug where we are managing to wildly slew the telescope during an exposure.
  • PHD2… maybe? Issuing slews is not really in PHD2s feature set so…
  • The driver itself. When you re-installed SGPro, did you also re-install drivers? And if yes, does your mount driver have any kind of automatic flipping functionality built into it? Im not really familiar with that driver.
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This can also happen when Windows is doing an update in the background.
I had a similar issue years ago under Win7 Prof. The good news is, it never happened again.

Thanks Ken and Mike.
I really appreciate the responses.

Ken, your comment about the mount driver got me looking. I guess due to my fiddling, the driver was back at default which had the mount stopping at meridian. I’ve reset it to track 5 deg (20 min) past meridian and allow the sequence to pier flip at 5 minutes past.

We’ll see tonight.


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