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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Internal guider questions

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Sorry Magnus, not much to say. 

I assume you're using PHD2 through KStars/Indi, so they're using the same Indi mount drivers.

I will note that as I understand it, the PHD2 folks recommend calibrating once and leaving it, e.g. not recalibrating for months, unless you change the guiding imaging setup (e.g. rotate the guide camera, remove it, or something like that).  I have taken that to heart, and I personally don't calibrate often either. As you probably know, the internal guider has options to keep use the calibration--e.g. do it once where it works nicely, e.g. near the meridian and the equator, and keep that calibration for a long while instead of recalibrating on every slew.

The calibration scheme simply pulses the mount the amount specified, e.g. 1000ms, every step it takes, without regard for the guide rate, until it sees enough movement. Is it possible you have a lot of backlash, and somehow PHD2 compensates for that better than Ekos? I guess you can measure that with the PHD2 guiding assistant.

Do you have these issues in both RA and DEC?

BTW, now that I think of it, it's also possible that the issue is star detection, not mount movement (e.g. the issue could be improved with improved stellarsolver parameters for guiding).  That would be obvious in a log with debugging enabled for guide and fits.

Hy
 
2 years 10 months ago #71254

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Hi!
Great, thanks! Yes I use PHD2 through Ekos/Indi, so same driver etc. And I use a Losmandy G11 where there is significant DEC backlash - but not RA. It is compensated in PHD2 with compensation around 800 ms, and PHD2 handles it very nicely. This is one thing I was worried about with the internal guider, but it has not yet been a problem. It could play into calibration - however, the scope did not move in RA either... so something else is at play. 

Good thought with star detection! And of course, I did not have logs on... but now I have. :) To adjust the parameters - what to think of there? Is there a good resources somewhere to look at?

I'll try and experiment a bit with this next time clouds part and I am still awake ...

Magnus
2 years 10 months ago #71262

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Greetings guys, I want to ask a question about total error. What is the difference between a total error of 1, 2, 5 or 10 and so on for examples? What really happens to the mount and how is the pulse we send being used? The value of the total error is being multiplied with a number x arcseconds? Thank you very much for your time. Sorry for the "google questions" but I cant really understand what is the happening. I hope plain explanation from fellow observers will help me. Thank you a lot again.

Best regards,
George.
2 years 10 months ago #71264

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Hi!

Unfortunately, George, I have no answer to your question. I have a different problem. 

Tonight, me and the internal guider are not friends. Not at all. 

I can complete calibration tonight. But after calibration, gudiing is just crazy. RA drifts off, far off. So I recalibrate, no help. Some 4 or 5 times. No improvement. So I slew to another area, wait until it is darker and better SNR. No improvement. 

Attached is a guidelog. It looks to me as a Guide Assistant run in PHD2, that is, with no corrections sent to the mount. Kstars log also attached. Anything that makes sense? What did I miss or do wrong?

Directly after this I switched to PHD2. Guiding with RMS 0.54". So it is not a mount issue. And yes, PHD2 runs through Ekos and Indi. 

Any ideas?

Magnus
2 years 10 months ago #71282
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Magnus,

Very sorry about the issues you're having, and I appreciate you sending in logs and raising the issue.

I did look through the log, and it looks like the guider is doing what it should, e.g. it measures error and sends out the appropriate pulses to counter the error.
Unfortunately, it looks like the computed pulses are having no effect at all on the mount, as if it was not even connected.
Yes, very similar to what you said "as a Guide Assistant run in PHD2, that is, with no corrections sent to the mount".
In fact if you view the phdlogview output to the file you sent me, you can see that.

 

I will ask around, but, sorry, I have no idea what could cause the signals from the internal guider to be "not sent to" or "ignored by" the mount.

Hy
2 years 10 months ago #71285
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This was on 3.5.1 which should work but it's better if you use 3.5.3 the latest stable release. Your proportional gains are set to 133.33 and your mount guide rate is 0.5x, correct?
2 years 10 months ago #71287

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Replied by Alfred on topic Internal guider questions

Magnus, I agree this looks like the mount didn't receive the correction pulses at all. This reminds me of my tracking issues. The mount behaves like it never received the commands (and in fact hand controller debug mode confirms they ARE not received). Can this be connectd, by any chance? I haven't guided in months due to bad weather. Should I spot some stars tonight I will try to guide on them and report back.
2 years 10 months ago #71306

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Replied by Alfred on topic Internal guider questions

Sorry, no stars, it's been cloudy with intermittent rain. I'll try to guide as soon as possible, a few minutes should suffice. Do all other commands actually arrive at your mount as expected? My handbox displays the usual :Gm# , :GD#, :GR# etc. traffic. But other commands like :hN, :hW, lunar rate, king rate, etc. are nerver received. Almost never, to be exact.
2 years 10 months ago #71327

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Hi!

Tonight, there is some clear sky here so I try a bit. Yes, it seems that all commands to my mount works well - Gemini 2 and G11. No problems there, that I can see. 

I tried tonight with a 3.5.3, but because of several Kstars-crashes, I switched back to 3.5.1 (anthter R-Pi)

With this, guding works OK-ish tonight - that is, it is guiding. But as you can see in the log, it goes off in some very wild RA bounces, seemingly some resonance (?). So I turned off, switched back to PHD2, and again, nothing of the sort there. 

My settings with internal: I use the GPG RA Guider, have guide rate 0.5, and started out with 133 in proportional. (does that matter when I run GPG?) To try to reduce the swings, I first increased, then decreased the proportional gain, but could not get rid of them. So shut it down. 

What might I do wrong here? What settings should I tweak? (the previous non-guiding situation still being a mystery - did not even upgrade the Kstars-Ekos). 

Magnus
2 years 10 months ago #71330
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Hi Magnus,
there is one thing that looks strange in your logs from the night where the internal guider seem to send no correction signals to the mount: how did you manage it having both running PHD2 AND the internal guider between 22:50 and 22:58? Did you run EKOS with the internal guider and have PHD2 running in parallel?

I haven't tried that, but I would not be surprised if that causes trouble.

Wolfgang
2 years 10 months ago #71331

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Hi!

Interesting. I don't know now, when and how I had PHD2 running. But I switched the Ekos profile between PHD2 and internal. Stopping, changing, restarting it.

I don't see any references to PHD2 btw 22:50 and 22:58 - what makes you think they both ran? What do you see in the log?

Magnus
2 years 10 months ago #71332

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Wolfgang: That log that Magnus included is not a PHD2 log, it is an Ekos internal-guider log, that outputs in PHD2 log format, so that one can view the recording with phdlogview.

Magnus: Do you have any logs or other information related to the 3.5.3 crashes you experienced?

Also, you say that PHD2 worked well after the EKos logging. Can you send me the PHD2 log for that, that comes right after the EKos guide_log on May 15 23:15--23:21 (filename guide_log-2021-05-15T23-15-16.txt)? I'm curious to compare the calibrations used (which are given in the header of the guide log).  For instance, the Ekos one says:  xAngle = 90.1, xRate = 1.651, yAngle = 5.0, yRate = 7.561

Hy
Last edit: 2 years 10 months ago by Hy Murveit.
2 years 10 months ago #71333

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