PHD2 problems with guiding Open PHD Guiding project PHD2 · Lukas Bauer · ... · 72 · 2342 · 1

Luke-Official 0.00
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Hi, thanks for your response.
How or where can i check if PulseGuiding is enabled? When searching for Ascom i only see a diagnostics window and a user guide.

To calibrate i let the mount slew to where it wants to calibrate (should be the spot you mentioned)

Luke
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Luke-Official 0.00
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PS.: i just looked in EQMOD (which I don't use anymore) it say ASCOM pulse guiding. But I cannot find such a setting in GSS.
The mount is a NEQ6 PRO.
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Bobinius 10.32
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Try to select a minimum SNR for the star, 6 let's say. Minimum HFD in pixels 1.5 or 2 pixels. Check use multiple stars. Verify if RA speed is checked in EQASCOM (the 0.8x sidearal rate) and try to increase the impulse duration 20,30 ms while verifying if during guiding the RA guiding impulses have an effect. 

I prefer Saturation via star profile in Camera settings. Of course check if your Guiding case is checked in the Guiding parameters (lower right).
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Luke-Official 0.00
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Hi, thanks for the help!

I just checked everything you said. The minimum  SNR for the star was already set to 6. I increased the minimum HFD to 2 pixels. Multiple star guiding is checked and the RA rate is set to 0.8. The impulse duration is set to 20ms. The guiding pulses do have an effect - when testing with manual guiding I can see the Ra coordinate change in GSS as well as the impulses shown graphically in GSS. I also hear the mount change the sound, whenever i send a guide pulse - so this should work.

I checked Saturation via star profile in the Camera settings. But where do I check my "Guiding case"?

Luke
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Bobinius 10.32
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Ok, in the Brain and Guiding window, lower right. But I think it should be active, since PHD2 guides your mount.
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Luke-Official 0.00
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Oh, thanks. Yes the "Enable mount guide output" is checked.

But I don't understand, why if this is checked, PHD2 doesn't send guide pulses.
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Bobinius 10.32
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Yes, very puzzling. That's why I told you it is impossible for the Calibration assistant to be able to guide your mount or even the calibration process being able to drive the mount in both directions, and then not being able to guide once the process terminates.

Do you have any flexure between your guidscope and mount axis? Is  the mount synchronised, well polar aligned? I would try the calibration assistant again, see how it does after it applies the settings (I believe I saw some 2,5° axis error) and how it guides after. The only problem is the RA drift, your Dec looks good.
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Luke-Official 0.00
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The guidscope and mount axis should be aligned pretty well. I also questioned the polar alignment, but in sharpcap I usually get <20-30 arcsec. That's why I can take up to 60 sec exposures easily without any star trails. I don't know which programm to trust when it comes to polar alignment, because every programm seems to say something different.

I'm hoping for clear skies soon and I will try it again with the now changed settings.

But I just realised, what if the Dec just looks fine, because with perfect polar alignment you would need only RA. So if the polar alignment is fine, then ideally you wouldn't need any corrections in Dec - right? Because I don't see any guide pulses in Dec either. It's just staying there because maybe the error is too small that PHD2 needs to make corrections.

But when checking manual guiding the Dec workes fine as well.
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Bobinius 10.32
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Lukas Bauer:
The guidscope and mount axis should be aligned pretty well. I also questioned the polar alignment, but in sharpcap I usually get <20-30 arcsec. That's why I can take up to 60 sec exposures easily without any star trails. I don't know which programm to trust when it comes to polar alignment, because every programm seems to say something different.

I'm hoping for clear skies soon and I will try it again with the now changed settings.

But I just realised, what if the Dec just looks fine, because with perfect polar alignment you would need only RA. So if the polar alignment is fine, then ideally you wouldn't need any corrections in Dec - right? Because I don't see any guide pulses in Dec either. It's just staying there because maybe the error is too small that PHD2 needs to make corrections.

But when checking manual guiding the Dec workes fine as well.

No the contrary is true. RA is correlated to the polar alignement, the RA axis is aligned with Earth's rotation. But if you don't see pulses during guiding that's weird. So check the Polar alignment. The Calibration assistant will tell how far off you are with the polar alignement by letting the mount drift.
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Luke-Official 0.00
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But I don't understand why polar alignment should be the problem. Why am I able to take long exosures up to 60 sec with round stars and 120 sek with nearly round stars? 
And I also don't think that my polar alignment is the problem, because if I fix my polar alignment to absolute perfection, of course it's going to help. With perfect polar alignment I wouldn't even need guiding. But then I don't understand why guiding exists.

I am going to try it again but the polar alignment cannot be the solution to my problem, it's just going to help reduce the problem.
That's why guiding even is a thing - right?

But the main problem - PHD2 doesn't send guide pulses - won't be fixed by better polar alignment.

As I already said, I think that my polar alignent can't be that bad, because SharpCap says 20-30 arcsec (most of the time even <10 arcsec) and PHD2 says 2 arcmin, so I don't know who to trust, but I can see that it isn't that bad, because I am able to take long exposures with round stars which means that cannot be the root of my problem.
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Bobinius 10.32
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Lukas Bauer:
But I don't understand why polar alignment should be the problem. Why am I able to take long exosures up to 60 sec with round stars and 120 sek with nearly round stars? 
And I also don't think that my polar alignment is the problem, because if I fix my polar alignment to absolute perfection, of course it's going to help. With perfect polar alignment I wouldn't even need guiding. But then I don't understand why guiding exists.

I am going to try it again but the polar alignment cannot be the solution to my problem, it's just going to help reduce the problem.
That's why guiding even is a thing - right?

But the main problem - PHD2 doesn't send guide pulses - won't be fixed by better polar alignment.

As I already said, I think that my polar alignent can't be that bad, because SharpCap says 20-30 arcsec (most of the time even <10 arcsec) and PHD2 says 2 arcmin, so I don't know who to trust, but I can see that it isn't that bad, because I am able to take long exposures with round stars which means that cannot be the root of my problem.

You're correct of course. If PHD2 does not send pulses, no setting will make any difference. I think the difference between the 2 polar alignment errors is due to using Sharp Cap with the main OTA and PHD2 with the guiding scope (correct me if I'm wrong). So some flexure must exist, if that's the case is pretty big. SharpCap is pretty good, I used it before switching to Polar master. It should be pretty well aligned then (try some 5 min exposures).

Is PHD2  connected successfully to the mount? But if it does not send guide pulses, what happens during calibration? Is PHD able to move the mount?
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Luke-Official 0.00
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No, SharpCap also uses my guide camera on my guide scope. I already did a 5 min exposure, but I don't know if it looks like 2 arcmin error or 20 arcsec error:
5 min exp.zip

PHD2 is connected to the mount and during calibration it can sucsessfully move the mount however it wants - so I think that there might be an issue with PHD2, ASCOM, or maybe the problem could even be eqmod, even if I don't use it anymore, because I use GSS. Maybe these two programms don't want to work together, even if I don't start EQMOD and just use GSS. Maybe there is something wrong in the ASCOM settings (Ascom pulseguiding is activated), but I don't know how to get in the Ascom settings since I can't find a UI for Ascom. I remember that you can change a little bit through EQMOD but I am not sure if these things than carry over to GSS too.
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Bobinius 10.32
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Lukas Bauer:

OK. I don't know GSS, what's that exactly? The 5 min shows a pretty big error. I would recommend to use SharpCap with your main camera. This is how you actually polar align (what you need to align is your mount axis with RA, that's done with the main OTA). Any flexure is then between the guide scope and your main scope. 

Remember we saw on your capture of the guiding log that mount guiding was = false, did you manage to change it to true?  The problem seems to be the communication between PHD and your mount, the mount should have some settings though.
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Gondola 8.11
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You might try dumping EQmod and start using Green Swamp Server. EQMOD is very old software and it seems that other people are having similar problems with it. The other thing that I don't think has been mentioned is, it doesn't sound like you've checked your mount for backlash. Not all problems can be fixed with software if the mechanical bits are not working correctly. I have seen mounts that just completely fail with PHD2 just because of excessive backlash. With a tight mount, PHD2 should work with it's default settings, Push Here….well…..you know! ;)
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Luke-Official 0.00
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@Bogdan Borz GSS is pretty much the same as EQMOD  - a driver for ASCOM. The problem with using my main camera with SharpCap is, that it doesn't detect my Canon camera. Do you think, that the mount guiding = false is something that can be changed in the settings, because I wasnn't able to test it since then because it was always cloudy.


@Gondola You are correct, EQMOD is pretty old and didn't convince me that it is a good programm, so I downloaded GSS and it is much better now (even though the guiding still doesn't work)
I did check the mount for backlash, by following a YouTube tutorial and tightening the necessary screws. When running the guide assistant I hoped to see my Dec backlash, but as you can see in the picture below, it said to look at the graph and the button to open the graph was grayed out.
guiding assistant backlash.zip
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Gondola 8.11
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From the numbers it looks like the excursions were so bad it went beyond certain limits and the test aborted.
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Luke-Official 0.00
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Oh, that doesn't sound particularly great.
I tightened the screws until i couldn't feel any backlash anymore, when trying to move the mount manuall, by hand. I'm going to check again, if I can improve something.
Are there any other methods that I can use to determine how much backlash there is?
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Gondola 8.11
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You don't have to take it that far. Tighten the just enough so that you don't feel any play. Any more will just lead to binding of the worm and wheel and you don't want that.
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Luke-Official 0.00
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That's what I did and it should be fine like that. But for some reason PHD2 says otherwise.
Could there be any other reasons for PHD2 to not complete the backlash measurement?
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Bobinius 10.32
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The mount settings should be changed in some ini file in phd, but it should work using the app. The fact that is shown to be false though is a problem. 

What happens when you start guiding? Is the star visible, is it lost fast? no correction present on the graph? Is it trying to come back to the horizontal axis or not? Why I don't understand are the results of your calibration assistant. It does not detect a problem and your RMS errors are pretty good. 

Maybe you could share on your drive the guide log, or just a short one of a few minutes.
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Luke-Official 0.00
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I can look if I can find something where I can change it to true. 

When I start guiding, phd2 calibrates and starts guiding, sometimes it actually guides for not more than 30 sec, but that's pretty rare. Most of the time though it just doesn't guide at all or just loses the star, because i don't know why. As I already said sometimes it corrects for a little bit but most of the time there are no corrections shown. That means it doesn't try to keep it on the axis.

I already shared a some guide logs, but here is one, where I really tried a few times. This is also the guide log where you can see the Ra drift while the Dec stays the same.

PHD2_GuideLog_2024-08-15_213752.txt

For example, at No. 18 in the guide log, you can see that it does make some corrections in the beginning but then stops.

I also think that No. 35 is really interesting. You can clearly see corrections in the beginning. Then the correction stops and every time the graphs move to 0 on the axis again, I starten guiding over. What's really strange is, that in the beginning it says MountGuidingEnabled = false and after stopping it (5x Star lost) it says MountGuidingEnabled = true.

At No. 37 - the 14 min long one, you can see that it made no corrections in the first place and said MountGuidingEnabled = flase, but after stopping it it wrote MountGuidingEnabled = true (below the calibration assistant data).

(The numbers are the numbers when opening the log in phd2 log viewer)

The only thing I could imagine is that there is something that inverses the MountGuidingEnabled command, because when I start it sets to false and when I stop it becomes true.

Maybe I should try disabling the Enable Mount Guide output option in the brain settings 
Jokes aside... I just have no idea what the problem could be.
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Bobinius 10.32
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What is sure is that you lose the guide star a lot. Is the image on the camera populated with stars and are they in focus? Point like? You could ask on the PHD group on facebook or yahoo if that still exists.
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Luke-Official 0.00
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The image is not noise, the stars are nice and sharp. The guide scope is definitely in focus, because I'm using it in SharpCap too and I can focus it there really well because of polaris (i try to make polaris as small as possible). What I notice is, last time when there were no clouds, I tried it on the Andromeda galaxy and some stars which were there just a second ago in the last frame just disappeared and others just randomly showed up.
Are there like extra troubleshooting groups for phd2 or what can I ask in there?
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Bobinius 10.32
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There is a facebook group that's sure. https://groups.google.com/g/open-phd-guiding That's the Google group.

What you could do is try to see what's going on with the main camera. Keep cycling 2-3 sec frames on the main camera while starting guiding. If the stars begin to look like trails it's clear the guiding turns off completely. 

Or you could revert to EQMOD instead of GSS? Maybe it's the way PHD interacts with it. It would be interesting to give the solution once you have it.
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Gondola 8.11
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Maybe you just need a fresh install of PHD2?
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