Guiding Problem when PHD2 and Stellarium both communicating with Mach1 mount

[johncd...@gmail.com]

Hello,

   I have been seeing this problem for several months now, and I would like some input as to what the nature of the problem might be.

   To summarize, I am seeing problems with PHD2 guiding - most often the RA tracking - when I am running a guiding session in PHD2 and have the mount also communicating with Stellarium via the Telescope Control plug-in.

What I am seeing is that after I run a full calibration in PHD2, then let the guiding assistant run for 3-4 minutes - apply the suggested parameters, then PHD2 will begin to guide, but after period of time (it varies) - the RA tracking seems to stop and the graph tracks totally off the scale (even set to +- 16").  I stop and re-start, the same thing happens.  

I'm attaching the guiding log and debug log from tonight's session that illustrates the problem.

I'm using 

PHD2 version 2.6.10

Stellarium version 0.21.2 with version 0.4.2 of the Telescope Control plug-in.

Mach1 ASCOM Driver 5.30.10

If this is a known problem - sorry for the long post.  I attempted to search for this problem in prior posts - but I couldn't find this particular issue.

I really like being able to monitor the mount position with Stellarium during a session - so I would really like to get this problem fixed.  Help would be greatly appreciated.

Thanks!

John D.

[johncd...@gmail.com]

Steps from Tonight's session:
1). started up SGP, connected to all the hardware (camera, filter wheel, focuser, mount) and tested the imaging camera.
2). started PHD2 and connected to the mount and guide camera (ASI120mm) to verify that connection.  
3). started Stellarium and connected to the mount.  Using Stellarium I selected a star near the Meridian and Celestial Equator - then had the mount slew to that location using the Telescope Control Interface
4). Had PHD2 autoselect main and other guide stars - and do a calibration run. Everything went fine.
5). After calibration - let it guide for about 30 seconds (guided ok) - then invoked the Guiding assistant.  Let it run for about 4 minutes and then stopped - after the backlash calibration - I accepted the reccomendations and let PHD2 begin guiding.
6). After about 2 minutes - the RA started tracking off of the graph (I see "MountGuidingEnabled = false and MultiStar = false on the Log viewer).  
7). I stopped guiding and re-selected stars - started again - guiding ran a few seconds and the same thing happened again.
8). I started a 3rd time and this time - there were wild swings in the RA guiding and a little in DEC.  I stopped again.
9). I re-ran Calibratoin - it ran fine
10). started guiding again - again the wild fluctuations in RA.

11). I disconnected Stellarium from the mount and shut it down.
12). I disconnected PHD2 from the camera and mount and shut it down
13). I shutdown SGP after disconnecting to all devices
14). I powered down the Mach1 mount and started it back up

15). Restarted SGP and reconnected to all devices.
16). Restarted PHD2 and connected to the guide camera and mount

17). Manually slewed to a location near the meridian and equator... had PHD2 autoselect star and calibrate.
18).  monitored guiding for  90 seconds - no problems - stopped guiding
19). slewed to imaging object - had SGP platesolve and run a sequence.
20). PHD2 guided FINE for 1h 36m until clouds ended the session.

[bw_msgboard]

This is probably a Stellarium problem unless you are connecting that app directly to the ASCOM AP driver. It's not a PHD2 problem.  Judging from a quick web search, support for ASCOM telescope connections in Stellarium has either been a late addition or hasn't been done yet.  Their "telescope control plug-in" is not the same as ASCOM.  You can't have two different drivers trying to control the same mount.  I suggest you move your question to Stellarium or a related forum and get some advice from them.  There may be other choices for you in terms of imaging automation and planetarium software, all of them supporting ASCOM device connections.

 

Good luck,

Bruce

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of johncd...@gmail.com
Sent: Saturday, January 08, 2022 7:02 PM
To: Open PHD Guiding
Subject: [open-phd-guiding] Guiding Problem when PHD2 and Stellarium both communicating with Mach1 mount

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[Brian Valente]

Hi John

>>>and have the mount also communicating with Stellarium via the Telescope Control plug-in.

with 0.21 and later of Stellarium you do not need the plugin, you just need to connect via ASCOM

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/C08F262CEB69438D943B094AEAC8DF94%40HomeDesktop.

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Brian 

Brian Valente

portfolio brianvalentephotography.com 

[johncd...@gmail.com]

I don't think you are correct.  The Telescope Control plug-in IS using ASCOM to communicate with the Mach1.  At least that is the way I have configured the connection for my connection.  The communication is via the Mach1 ASCOM driver.

[johncd...@gmail.com]

Bruce -

     My connection to the mount IS through the ASCOM AP driver.   See attached Screen shot.  I don't think your search gave you the most accurate information.

When I click on "Choose ASCOM Telescope"  I get the standard ASCOM dialog that lets me select the AP ASCOM Driver

And clicking on the Properties... button brings up the AP ASCOM driver configuration dialog.

So - I think this is all done the correct way - if using ASCOM for all connections is the correct way.

[bw_msgboard]

Ok, good to know.  For future reference, if you just tell people you're using (or not using) ASCOM mount connections, that makes it easier to get help.  It's not clear to me at this point that your problem has anything to do with Stellarium.  Please upload your PHD2 DEBUG log file so we can see if Stellarium is doing anything that would affect PHD2.  Please use the Upload function described here:

 

https://openphdguiding.org/getting-help/

 

Bruce

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of johncd...@gmail.com

Sent: Saturday, January 08, 2022 9:30 PM
To: Open PHD Guiding
Subject: Re: [open-phd-guiding] Guiding Problem when PHD2 and Stellarium both communicating with Mach1 mount

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[johncd...@gmail.com]

Hi Bruce,

  Here's the URL for the logs (guide and debug) from the offending session:

https://openphdguiding.org/logs/dl/PHD2_logs_wKz9.zip

Thanks,
John D.

[johncd...@gmail.com]

Bruce:

One more odd thing that I just remembered from last night.  When those wild fluctuations of RA were showing up on the graph - the stars being guided on in the camera window did NOT seem to be moving... also the star display in the star profile window was right in the center of the cross- hairs.  Don't know if that's significant or not, but the behavior of the guiding graph did not seem to match the rest of the feedback.  I should have taken some screen shots - but neglected to do that.

John D.

[bw_msgboard]

What's your site latitude and longitude?  I'm trying to make sense of where the scope was pointing.

 

Bruce

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of johncd...@gmail.com

Sent: Sunday, January 09, 2022 7:38 PM

To: Open PHD Guiding
Subject: Re: [open-phd-guiding] Guiding Problem when PHD2 and Stellarium both communicating with Mach1 mount

Bruce:

One more odd thing that I just remembered from last night.  When those wild fluctuations of RA were showing up on the graph - the stars being guided on in the camera window did NOT seem to be moving... also the star display in the star profile window was right in the center of the cross- hairs.  Don't know if that's significant or not, but the behavior of the guiding graph did not seem to match the rest of the feedback.  I should have taken some screen shots - but neglected to do that.

John D.

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[bw_msgboard]

Ok, here's what I see from the logs - let's pick two glaring examples where you had wild RA excursions (RA in red):

 

 

The scope was pointing about 1 minute west of the meridian, side of pier was west - so just into a counterweights-up position.  This shows a huge excursion to the east but it isn't large enough to show that tracking was actually stopped.  This represented a movement of about 65 arc-sec in a 10-sec period - but if tracking was actually disabled, you would have seen a movement of about 150 arc-sec.  Note that this was during a GA session so guiding was disabled.

 

Here's another one - this time you again had the scope upside-down, in a counterweights-up position:

 

 

Here the RA excursion is in the opposite direction, reinforcing the conclusion that the problem has nothing to do with tracking on or off.  And again, this a GA run, so no guiding was active, PHD2 was just watching how the guide star was moving. 

 

Both of these examples had the scope at a pointing altitude of 46 degrees, both past the central meridian in RA.

 

The next two short guiding sessions, each of which showed large RA excursions, were also done with the scope in a counterweights-up position from the west side of pier (positive hour angle values)

 

When you finally got a decent guiding run - coincidentally when you said you stopped using Stellarium - the scope was still on the west side of pier but pointing 2 hours to the east of the meridian at an altitude of 65 degrees - a normal counterweights-down position.  So you can't draw the conclusion that Stellarium had anything to do with your problems because you moved to a sky location that didn't involve all upside-down calisthenics.  All of this analysis assumes you had the correct longitude and time of day configured, but if you didn't you should have noticed because of slewing errors.  I also notice you're using a guide scope focal length of 120mm which suggests it's one of the flimsy stalk-mounted arrangements that is so prone to shifting around.  Can you please send a photo of your guide scope arrangement?

 

So what are the tentative conclusions from all this:

1.  This is not a guiding problem or a PHD2 problem

2.  It is highly unlikely to be a problem with the mount

3.  The big RA excursions are likely caused by some problem with the guiding assembly - cables that are dragging or pulling or unwanted movement in the whole guiding assembly.  All of this would have been compounded by running in a counterweights-up configuration.  I know the AP mounts will happily do this but it puts a lot of pressure on all the mechanical fittings of the guide scope assembly - all of the gravitational forces are suddenly reversed.

 

This is why I've asked you to send a photo of your guiding setup.  In the meantime, you should stay away from these counterweight-up locations when you're trouble-shooting the problem.

 

Bruce

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of johncd...@gmail.com

Sent: Sunday, January 09, 2022 7:30 PM

To: Open PHD Guiding
Subject: Re: [open-phd-guiding] Guiding Problem when PHD2 and Stellarium both communicating with Mach1 mount

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[johncd...@gmail.com]

I am a totally mobile imager - so I will have to wait until the next time I am out to set up and get a picture.

I appreciate the analysis - I'm somewhat confused about your conclusions... The initial calibrations were done on a star that was very close to the meridian and the equator, so the counterweights-up could not have been more than *slightly* counterweights-up.  But I will be more aware of that in the future.  

Placing the blame on the guiding assembly - cables, etc - is the usual thing to blame any time there is guiding problems.  I get that.  But - this is a Mach1 - has internal cabling, and I was particularly careful with the external cabling that evening.  Also - if it were a cabling problem, why did the guiding work fine - as you noted - for the long session after I re-started and re-calibrated.  NO changes were made in the cabling for the final calibration and for the final guiding session of 1h 36m.  So if cabling was a problem before the final calibration at 18:50, it should have *also* been a problem for THAT calibtration and for the successful guiding session that followed.  That - combined with the fact that this has been observed in multiple sessions with different equipment mounted on the Mach1 - confuses me about the conclusions drawn here.

I do appreciate your help - and I don't mean to argue -- but understand that logically (at least to me) that doesn't follow.  

but I will attempt to do what you are saying and see what happens.

John D.

[bw_msgboard]

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of johncd...@gmail.com

Sent: Monday, January 10, 2022 6:21 AM

To: Open PHD Guiding
Subject: Re: [open-phd-guiding] Guiding Problem when PHD2 and Stellarium both communicating with Mach1 mount

I am a totally mobile imager - so I will have to wait until the next time I am out to set up and get a picture.

I appreciate the analysis - I'm somewhat confused about your conclusions... The initial calibrations were done on a star that was very close to the meridian and the equator, so the counterweights-up could not have been more than *slightly* counterweights-up.  But I will be more aware of that in the future.   

 

I wasn't talking about the calibrations, I was talking about the subsequent guiding runs. Look back at what I said, can you find a place where I even mentioned a calibration?  My point is, if you want to find the source of the problem you will have to start eliminating possible causes, one at a time.  Not running in a counterweights-up configuration is an easy place to start. 

Placing the blame on the guiding assembly - cables, etc - is the usual thing to blame any time there is guiding problems.  I get that.  But - this is a Mach1 - has internal cabling, and I was particularly careful with the external cabling that evening.  Also - if it were a cabling problem, why did the guiding work fine - as you noted - for the long session after I re-started and re-calibrated.  NO changes were made in the cabling for the final calibration and for the final guiding session of 1h 36m.  So if cabling was a problem before the final calibration at 18:50, it should have *also* been a problem for THAT calibtration and for the successful guiding session that followed.  That - combined with the fact that this has been observed in multiple sessions with different equipment mounted on the Mach1 - confuses me about the conclusions drawn here. 

 

I'm not "blaming" anything, I'm trying to help you find the source of your problem.  When I offer advice, I do so on the basis of the data that are in front of me and my many years of experience with this stuff.  I don't randomly look for things to "blame".  Look again at what I actually said:

 

"The big RA excursions are likely caused by some problem with the guiding assembly - cables that are dragging or pulling or unwanted movement in the whole guiding assembly.  All of this would have been compounded by running in a counterweights-up configuration.  I know the AP mounts will happily do this but it puts a lot of pressure on all the mechanical fittings of the guide scope assembly - all of the gravitational forces are suddenly reversed. "

 

I didn't say it was the cables although through-the-mount cabling doesn't guarantee anything.  I asked you to send a photo of your guiding assembly because I'm concerned it may be a device with poor mechanical properties.  I'm not "blaming" that, I don't know what it is so I'm suspicious of it.  For the record, the combination of tiny camera pixels and tiny finderscopes have become, in the past couple of years, the primary source of problems for beginning imagers.

 

The excursion problems don't show up during calibration because that is a fairly quick process - the calibrations were all good.  I'm talking about the longer guiding sessions that came after the calibrations.  A distinguishing property of the successful guiding session at the end was your sky pointing location - that's based on the data in the guide logs, I don't know how much else you changed if anything.  The kinds of problems I'm talking about often depend on pointing position because the guiding assembly and everything that attaches to it are constantly moving.  It's all a matter of basic physics and how various forces are acting on the assembled parts (including the cables) as the whole assembly moves around.  The amounts of movement you're seeing in the worst of the excursions represent 30-40 microns at the guide camera sensor.  That's about 1/2 the thickness of a human hair. Every single fitting, every thumb-screw, every interface point between movable elements is a potential source of trouble.

 

I haven't asserted that I know what your problem is, I labelled my comments as "tentative conclusions".  Perhaps there is a problem related to Stellarium, I have no idea.  To test that hypothesis, you should demonstrate it unambiguously by changing only one variable at a time (which you haven't done to my knowledge):

 

1.  Start a typical guiding session with Stellarium connected and wait until you see a big excursion.  Start by pointing 45 degrees above the eastern horizon.

2.  Disconnect Stellarium, and change nothing else

3.  Resume guiding - without re-calibrating and without moving the scope - and see what happens.  Let it run for 2x the time it took to see an excursion in step 1.

 

If the problem goes away, repeat the demonstration in at least two other, widely separated pointing positions.  Stellarium was not communicating with PHD2 in your last session so if these tests demonstrate the problem, there's nothing we can do here to help you - we can't do Stellarium support because there's no data for us to look at.  How are you physically connecting Stellarium to the mount?  Are you using the same instance of the AP driver or have you made the mistake of using the second serial port on the mount controller box?

I do appreciate your help - and I don't mean to argue -- but understand that logically (at least to me) that doesn't follow.   

 

Keep in mind, we're all volunteers here, we're donating our personal time trying to help you and other users.  You're not dealing with a call center that just wants to close an open ticket.  We can't see your setup, we can't be there to watch what you're doing, and we can't be there to keep you from making mistakes or reaching mistaken conclusions.  But in the end, if our logic doesn't make sense to you, you should seek help elsewhere and we can all get on with other things.

 

Bruce

but I will attempt to do what you are saying and see what happens.

John D.

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[johncd...@gmail.com]

First off - good news (mostly):  I ran an entire session this week without touching Stellarium, and had absolutely NO problem with PHD2 - so worst case I won't use Stellarium to connect to my mount any more.  I can live with that even though I'd rather not.  Now on to your reply to my last email in the thread.

Bruce - sorry if I offended... was not my intent, please accept my apology if I offended in any way.  I understand that because this is open source software - we are all basically "on our own" to deal with problems that come up.  And as I said before I am  greatly appreciative of the fact that you give of your time to try to help out those of us who are users of the software, but not capable of digging into the software or the logs/debug logs to understand everything about how this incredible software does what it does.  

I guess I was confused about the whole focus on the counterweight-up condition related to the problem... the long guiding session at the end was after I had totally shut down my equipment - restarted everything without Stellarium - calibrated PHD2 and went on to run my session, which I am pretty sure would have at least started with the config counterweights down, but I suppose ended with counterweights up.  I do allow SGP to run the Mach1 an hour across the meridian before running the meridian flip.

The problem that I wrote about 1st showed up in the 4 short guiding sessions - 3 after the initial calibration, which were run (I'm pretty sure) at the coordinates where I did the calibration - should have been near the meridian/equator.  Those 1st 3 sessions are where I saw the large RA deviations.  I stopped - recalibrated - and then tried one more short session which produced the same results.  After that was when I restarted everything and left Stellarium out of the mix.

I plan to try to get out during the full moon cycle - if weather cooperates - and do the test that you suggested.  I will also take pictures of my configuration so you can make any suggestions about what could be any cabling problems.  I have tried to be SO careful with that for the last couple of years, since I invested in the incredible Mach1 hardware, so I do need help identifying any issues with that - as I have been trying very hard to make sure that is not a problem.    I do have one photo with my 8" RC so I'm attaching that one.  Will put up another with my 200mm lens after I get out again.

Again - sorry for any offense, and many thanks for your continued help,

John

[bw_msgboard]

Ok, no hard feelings here.  Maybe I should explain why I was quick to assert that Stellarium was unlikely to be causing problems with PHD2.  It comes back to the software architecture and standards that allow all these independent astronomy apps to work together.  From a PHD2 perspective, there are two kinds of astronomy apps in the world:

1.  Those that "know" about PHD2 and communicate with it directly to perform guiding functions.  These are the common imaging automation apps like Sequence Generator Pro, Nina, Voyager, and others.

2.  Apps that don't interact with PHD2.  These include a whole bunch of apps like MaximDL, TheSky, and many others.  These apps may be connected to the mount but they don't communicate with PHD2.  I believe that Stellarium falls into this category

 

For type-1 apps, our logs show all of the communications with PHD2.  So we can know when the app has done something to affect guiding and we can help users who are struggling to figure out why guiding was stopped, why settling didn't finish, etc.  For type-2 apps, there are very few things that can be done to create problems for PHD2:

1.  Park the mount

2.  Slew the mount

3.  Stop tracking

 

PHD2 senses when slewing is being done and stops guiding.  It doesn't sense when tracking is disabled but we can see clear evidence of that in the guide logs - the guide star zooms out of the frame at up to 15 arc-sec/sec while PHD2 is madly issuing guide commands to move the mount west.  None of these things were evident in your log files.  The abrupt excursions I identified for you were in both the east and west directions and the guide star never moved out of the field of view.  Hence, my motivation to suggest other sources of the problem.  Of course, if Stellarium has written its own ASCOM mount drivers or an ASCOM adapter of some kind, then all bets are off and that could definitely be a problem. Why they would do that is beyond me, but I don't know anything about what they are doing.

 

Going back to the architecture picture, PHD2 plays the unfortunately role of being the canary in the gold mine, the messenger of bad news.  It is the only app that is looking at system performance every few seconds and is therefore the first and maybe only app to signal that something has gone amiss.  Imaging apps more often just forge ahead taking exposures and producing poor results, leaving you to figure out why.  That's not always the case, of course, but it happens pretty often.  So when you made comments about "PHD2 is the application that is mis-behaving", I think you were mistaken - we were just delivering some bad news.

 

Regards,

Bruce

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of johncd...@gmail.com

Sent: Friday, January 14, 2022 12:21 PM

To: Open PHD Guiding
Subject: Re: [open-phd-guiding] Guiding Problem when PHD2 and Stellarium both communicating with Mach1 mount

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[Richard T]

Hi John

You mention 200mm lens for your guiding, what is the model of that lens?

Cheers Richard

[jhart]

Have you tried using Device Hub, which is part of the current Ascom platform?  It functions to prevent conflicts when 2 or more applications are connected to the mount via Ascom and try to access it at the same time.

[Michael Bibby]

I seem to be having the exact same problem: I can get PHD2 guiding just fine, but then when I pause guiding, use Stellarium to slew to a different target, platesolve and sync in Sharpcap, and then start guiding on PHD2 it seems to have lost its ability to control the mount-- not only will it not guide, but I can't use the manual controls within PHD2 to move the mount, and it won't calibrate either. It really just looks to me (who knows very little about computers) that somehow Stellarium (and Sharpcap?) is somehow taking away PHD2's control from the mount. The only solution I have found is to close all the programs and reopen them. Even simply disonnecting the mount within PHD2 and then reconnecting it doesn't solve the problem.

Any suggestions greatly appreciated, because this is giving me a lot of headache's and I completely out of ideas. I have made another thread here on Google groups (Here is the link https://groups.google.com/g/open-phd-guiding/c/kYfqRvdmsIY  ), but so far no luck.

Also, if not using Stellarium for slewing the mount, what else should I try Cartes de Ceil?

[Bryan]

This thread is almost one year old.  You would be better served to open a new thread...which you have done.

Bryan

[Jeffery Hart]

Hi Michael,

Some mounts and mount drivers can’t handle multiple applications trying to send instructions to the mount. Could that be the problem you are having? As mentioned previously  Ascom Device Hub is designed to solve that problem.  To try it, don’t connect your apps to your mount driver.  Instead use the Ascom chooser in PHD2, Stellarium, Sharpcap, etc. to select Device Hub for the mount.  You then configure Device Hub to connect to and control the mount. 

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