Lost calibration again?

[Paul Wilson]

https://openphdguiding.org/logs/dl/PHD2_logs_sYbC.zip

Last night I had about a 3 hour window to image from my remote site with no moonlight.

I got distracted paying attention to using the NINA advanced sequencer which I am only just now learning.  So the mount slewed to incorrect position.  I started over and the 2nd time, the target was nicely centered and looked good!

But the guiding looked bad, with the red DEC line spiking.  It was causing the stars to double, and in frustration I shut down the sequence and went for my walk.  While walking I realized that now would be the time to recalibrate and so when I got back to house I did that.  After recalibration, the guiding appeared better.  I think the second session subs I got may be usable.  

I only recalibrated a couple of weeks ago.  Is this something I should do before every session?  Could anything else have caused this problem?

[Brian Valente]

Hi Paul

The guiding before and after your calibration looks basically the same.

The issue appears to me that your polar alignment is pretty poor and causing Dec guiding issues.  All the guide pulses are in one direction and it switches direction based on side of pier.

I also think your exposure time is too short (iirc you have a cem 70 now?) it should more be in the 2-3 second range.

What you can do before each session is run a guiding assistant for a few minutes, it will show you if you have any issues (i noted you did not run any guiding assistant during this session)

I think you should disavow this notion you have of PHD losing calibration: it doesn't happen. If you connect to the wrong camera that will cause an issue, but you will get other error such as dark library is no longer valid. You should review the NINA advanced sequencer start/stop guiding to make sure you understand how guiding is commanded in NINA, that will help avoid future issues. 

I also encourage you to get familiar with reading the guidelogs via the PHD Log Viewer, it will help you reduce your time-to-solution and increase your imaging time
https://adgsoftware.com/phd2utils/

Brian 

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Brian 

Brian Valente

astronomy portfolio https://www.astrobin.com/users/bvalente/ 

[Paul Wilson]

Perhaps I sent the wrong night?  The 60 seconds was the previous night in full moonlight to test the mount slewing.  Subs last night were 180 seconds, 3 minutes.  I will recheck, sorry.

Paul S. Wilson

Continental Airlines

Capt.  IAH

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[Paul Wilson]

If these are same (show calibration) I apologize and either way I will check PA tonight.

Paul S. Wilson

Continental Airlines

Capt.  IAH

[Brian Valente]

the logs are dated 12-9

i don't know about your other questions, you didn't send any other logs, 

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[Paul Wilson]

Ok.  Well I did only 180sec subs last night so I thought I might have flagged the wrong ones.

Paul S. Wilson

Continental Airlines

Capt.  IAH

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