Guiding only working on one side of the meridian

[umasscrew39]

I don't think this is a PHD2 problem, but I am not sure where else to seek help with this unusual problem.  I am imaging from a permanent setup with a C11" EdgeHD and a ZWO OAG with an ASI 174mm mini.  This setup has been used for years with no issues until recently.  Basically, guiding works very well when starting out in the eastern sky.  Once the meridian flip occurs, the PHD2 screen turns bright fuzzy/noisy, preventing the identification of any stars to guide (so no log to provide as there was no guiding).  I looked for loose parts or perhaps light reflections as the cause but am at a loss to date. Also, there are no trees or other physical obstacles in the area.  If anyone has experienced this and has some thoughts on the cause, please let me know.

Thanks,

Bruce

[Bryan]

Bruce

Once, PHD2 is started, there is ALWAYS a Guide and Debug log.  Even if sparse in information, what is there might be useful.

As you may already know, the built-in log uploader is easy,  See http://openphdguiding.org/getting-help/

Bryan

[umasscrew39]

https://openphdguiding.org/logs/dl/PHD2_logs_KZhq.zip

Bryan- here we go.  Hopefully, you can spot something to ID the problem.  

[Brian Valente]

Hi Bruce

You have a number of failures getting the image from the camera but are only 21 during the night. 

Aside from that, It's just not able to find a guidestar. The "PHD2 screen turns bright fuzzy/noisy" is not a cause if this, it's a result of no guidestars found, so the display would normally have a bright star and have a darker background. The guide runs in your data show some pretty variable seeing, are you sure it just wasn't due to that? Later on when you moved to another target, the guide star was acquired and had a nice SNR

A C11 at f/10 on the outer rim where the OAG pickoff mirror resides is quite a dim area. 

You should bin 2 your guide camera, and make sure you have a dark library in use as good practice.

Those are good places to start. 

If you think it's something else, enable diagnostic image logging for finding stars and lost star events and submit those with your log.

As an aside, your RA looks a little rough, when was the last time you redid your PEM on your mount? You alternately try PPEC algorithm for RA with a fixed period of 127 seconds and aggression of around 80 for both reactive and predictive (and disable auto adjust period)

Brian

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Brian 

Brian Valente

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

[Bruce Donzanti]

Hey Brian

Thanks for the feedback and suggestions.

Yes- using the C11 @ f/10 (2800mm FL), can be a challenge, especially at Bortle 7.  That is why I normally pick objects with dense starfields as I can almost always get very good guiding with the OAG. The first object has a weak starfield with only about 25-30 stars in the entire FOV.  So that might be at the root of the problem.  The second object is in a very dense starfield with almost 300 very viewable stars.  I'll set the binning to 2 as you suggest and create a dark library which I seldom do.  As far as PEM goes, I have never done it on this mount which I have had for several years- again, because the guiding was never an issue and I always avoided it since I get such few precious clear nights to image in a year.  I guess I need to find a couple of clear nights to do it.

I appreciate your time in reviewing the log.

Thanks again,

Bruce

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[Brian Valente]

Hi Bruce

sure no problem. you might consider using planetarium features like adding your OAG fov so you can adjust the framing/rotation for an optimal guidestar. For setups like yours that's pretty common practice.

I also suggested you can use the PPEC settings to 'mimic' a PE curve and see if you can improve the RA results. If it does lower your RA RMS (and I suspect it will), you can continue to use the algorithm, but it does point to probably needing to re-do the PEM at some point

Brian 

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