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PEC request

 

Hi,
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I had cause to redo my G11G (with all latest firmware) PEC training and my OFF/ON PemPro logs seem to indicate the PEC training was a success. The only problem is that my PHD2 Guiding Assistant logs (with tracking off) show the periodic error is still there. I double checked PEC is enabled in the Gemini Telescope driver at startup.
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Maybe I am reading something wrong so hoping someone could review the logs below for a second opinion. There appears to be other things at play also but just hoping for an opinion on the PE work.
?
Thanks,
Ken
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PS - BTW, how is the new Gemini PEC work progressing?
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PEMPro-2025-05-08-224417-OFF.txt
PEMPro-2025-05-08-224417-OFF.txt
PEMPro-2025-05-09-205929-ON.txt
PEMPro-2025-05-09-205929-ON.txt
PHD2_GuideLog_2025-05-10_090045.txt
PHD2_GuideLog_2025-05-10_090045.txt

 
Edited

Hi Ken,
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The PEMPro ON data appears to show a fairly large reduction in periodic error. There's a bit of a rotation error in the data, which may mean the PEMPro calibration wasn't as good as it could be. But overall, after derotating the data, worm PE was measured at less than an arcsecond. I can't tell what happened with your PHD2 guide log. There doesn't seem to be any improvement, but I would expect (from the PEMPro plot) that the improvement should be significant.
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There is something wrong with the worm or your measurement, despite PEC being able to correct for it. That large peak is very unusual, and well exceeds any other periodic error I've seen from Losmandy mounts. At the very least, I'd try to clean, regrease, and adjust the worm/gear mesh, but also, possibly swap the DEC and RA worms to see if you get a better result with another worm.
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On Sun, May 11, 2025 at 01:42 PM, Oberon510 wrote:

Hi,
?
I had cause to redo my G11G (with all latest firmware) PEC training and my OFF/ON PemPro logs seem to indicate the PEC training was a success. The only problem is that my PHD2 Guiding Assistant logs (with tracking off) show the periodic error is still there. I double checked PEC is enabled in the Gemini Telescope driver at startup.
?
Maybe I am reading something wrong so hoping someone could review the logs below for a second opinion. There appears to be other things at play also but just hoping for an opinion on the PE work.
?
Thanks,
Ken
?
PS - BTW, how is the new Gemini PEC work progressing?
?
?
 

Hi Paul,
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Thanks for the suggestions and I have ordered the clean/regrease kit from Losmandy to do some clean up work. I also adjusted the backlash on the Dec sprung worm gear to see if will clean things up before looking at swapping them over. I am getting some strange movements in Dec during the PHD2 calibration so something is amiss per your comment - will look into it more after the regrease work.
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I will also retry activities when the weather clears in a few days - on a night when the moon is not blowing out the tracking too.
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Thanks,
Ken

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