Calibration error - too far from equator with SGP v4.5 upgrade

[Suzanne Beers]

Since I upgraded from SGP v4.4 (32bit) to SGP v4.5 (64bit) I have been getting an error message in PHD2 - "calibration too far from equator, recalibration needed", primarily when the mount gets close to the meridian, but last night (18Jun2026) I also got it during the initial calibration/start-up (when the target, SH2-129) was at about 30deg.  

  Several nights, when I came out in the morning to end the sequence (~0430MT at astronomical twilight and about 5-10 minutes before the meridian) when I pause the sequence, PHD2 loses the guide star gives the same "too far from the equator" error. (e.g., 16Jun2026) 

  Is there an issue with the SGP 64bit vs. PHD2 32bit, that I should load/use the SGP v4.5 32bit instead?  Or is there something else going on that could be remedied?

I've uploaded the logs for both 16 and 18Jun2026: https://openphdguiding.org/logs/dl/PHD2_logs_7ms9.zip

Thanks!

Suzanne

[Brian Valente]

Suzanne

It has nothing to do with version of SGP or PHD. That is not an error, that is an informational message: You calibrated at declination 60° which is quite far from the celestial equator, so the calibration measurements are not ideal. It still completed the calibration and guided.

It seems like you are calibrating PHD at the target: Why not just calibrate it once at declination 0 using the calibration wizard and when you get a good calibration, just leave it? No need to keep re-doing it.

regarding your 4:30 AM question, it looks like at 4:28 your camera and mount were disconnected. do you have a routine that disconnects hardware at the end of the night?

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Brian Valente

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[Bruce Waddington]

To expand on what Brian said, you shouldn't be letting SGP handle the calibration.  If you have a permanent setup, manually use the Calibration Assistant (Tools menu) to calibrate once, paying attention to everything it tells you to do and looking for an 'acceptable' or 'good' result.  Then keep using that calibration until something in your configuration changes.  In that scenario, you should also choose the option to 'Auto-restore calibration' - you currently have that option reset.  If you set up and tear down frequently, manually run the Calibration Assistant once at the start of your nightly session.  You can often do this before astronomical twilight, so you don't lose any imaging time.  When you get a good calibration result, use it for the rest of the night.  The Calibration Assistant will point the scope to a good sky location and you won't end up with the problem you're having now.

Regards,

Bruce

[Suzanne Beers]

Brian,  Bruce - 

  Thanks for your quick response.  

  Bruce gave me the same advice in March when I was in Chile (about not doing so many calibrations and wasting imaging time).  I misunderstood what he meant,  when I got back I turned on the auto restore after doing a "target- based" calibration.... that didn't work out very well!

  What I don't understand is how I can get to a Dec=0 from my location (latitude = ~40°N) for the calibration wizard to do its best work?? 

  

Thanks, 

Suzanne

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[Brian Valente]

Declination 0 is reachable from latitude 40. I am at lat 43. it's to the south. 

If you use the calibration assistant it will slew to the correct sky position.

Brian

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[Bruce Waddington]

The point is to get as close to Dec=0 as you can, certainly not at Dec=60.  The Calibration Assistant lets you adjust the pointing position to suit your location and you can even save a custom location for future use.  So use the Calibration Assistant and do the best you can from your location - just try to stay at or below Dec=20 degrees if you're working from the northern hemisphere.  

Bruce

[Suzanne Beers]

Okay,  I'll give it a try,  but from my house to it's a LOT of light pollution!

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[Bruce Waddington]

All you need is one usable guide star.

[Suzanne Beers]

Thanks Bruce & Brian - 

  The clouds never cleared here last night, so I wasn't able to give the Calibration Assistant a try.  Theoretically, it's supposed to be clear all night tonight, so I'll give it a try. 

  Just to clarify the other comments in my original email...

1. To Bruce's "you shouldn't be letting SGP handle the calibration."  SGP opens PHD2 when I direct the "connect to all equipment".  Then when SGP is running through the sequence start up after it plate solves, SGP defers to PHD2 to calibrate/start guiding, then pauses PHD2 while the EAF runs for a second time, then waits for PHD2 to say it is settled, and SGP begins the data collection.  
2. To "If you have a permanent setup" - I don't!  When imaging from home, I roll the telescope out on my front porch on a tripod dolly - I have marks for where the legs go, but it's far from "permanent."  When we go to dark skies, it is in our camper - I set up the equipment outside the camper at different locations (depending upon weather).  When I travel to Chile to image the S. Hemi targets, I fly there with my equipment and set up behind the Atacama Lodge where I stay.  
1. So my workflow is: power up equipment, polar align with Polemaster, start SGP sequence (which does EAF#1, plate solve, resume AG, EAF#2, wait for AG to report settled, start data collection).  
2. I will insert the CA in between the Polemaster and SGP sequence start up  (I have already checked the "restore auto calibration" in PHD2 in prep for doing that tonight. 
3. BTW - I also turned "auto meridian flip" back on in SGP - I will give that a try tonight.  Bruce and I had the discussion while I was in Chile in March, about how I have never been able to use the auto meridian flip because PHD2 will not come back from it...he suggested to "stop doing so many calibrations" at that time.  So, we'll see if I solved both problems with better understanding your suggestion WRT the CA. 
3. To Brian's "regarding your 4:30 AM question, it looks like at 4:28 your camera and mount were disconnected. do you have a routine that disconnects hardware at the end of the night?"  I came out at about 0425 to end the sequence (astro twilight).  As soon as I hit the "Pause sequence" in SGP, PHD2 lost its guide stars...  I disconnected the equipment, rather than letting it go through the recovery process.  But my initial question was based upon that happening - ever since I switched to SGP v4.5.0.1642 PHD2 has been losing the guide star at about that point in time (getting very close to the meridian) 

Thanks again for all your help.

Suzanne

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[Brian Valente]

Suzanne

You should probably re-calibrate once for each new setup, after your PA (as you pointed out).  As you pointed out, make sure you have auto-restore calibration enabled in Advanced Settings->Guiding so it will re-use the calibration during the night's sessions.

Otherwise just run it and see how it goes.

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[Suzanne Beers]

Thanks Brian!  That's my plan!!

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[Suzanne Beers]

Everything worked like a charm last night!! I did the CA after the polar alignment, parked the scope,  disconnected the equipment, then started the SGP sequence.  PHD2 came up with the green dot in calibration (and dark library)... and resumed when SGP called it without doing a calibration!

  Also...I came out to watch the auto meridian flip... and it had already happened SUCCESSFULLY! PHD2 was guiding and SGP was collecting the data on the next subframe!  Wooohooo...I have never gotten the auto meridian flip to work successfully!

  Thank you so much!!!   I'm sorry it took me so long to understand what you and the PHD2 hints were telling me!!  

Suzanne

[Brian Valente]

glad to hear it's working well, thanks for the update

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