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indi_skywatcherAltAzMount shown in wrong position

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I'm trying to make a setup using a Raspberry PI and a Skywatcher Virtuoso mount connected through a serial cable using indi_skywatcherAltAzMount.
I set the scope pointing to Polaris and the driver connects to the mount successfully. I can unpark the mount and move it through Ekos Mount Control panel.
When I try to do a Goto to a star in KStars I see the mount indicator moving in a totally wrong direction.
Most interestingly the mount itself moves in the right direction and settles more or less pointing to the requested star, but in Kstars it is indicated on the opposite side of Polaris, exactly in the centrally symmetric position to Polaris.
Checking the coordinates on the Ekos Control panel and Indi control panel as well I found that:
- Declination coordinate is correct
- Right ascension coordinate is off by 12 hours

What can cause this?
Thanks!

INDI Library: 1.8.3
Code v1.8.3-1-geb98b659. Protocol 1.7.
4 years 1 month ago #49540

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I have also a Virtuoso mount and I am the kinda maintainer-author of these drivers.

The indi_skywatcherAltAzMount driver crashes immediately when the serial connection is established at my side. I discourage to use this old driver, I would remove from the stack, but Jasem wanted to keep it around.

Please use the "Skywatcher Alt-Az Wedge" aka indi_skywatcherAltAzSimple driver. I don't see any positioning problem with this driver+Virtuoso. Just make sure in INDI Control Panel/Skywatcher Alt-Az Wedge:
- Wedge Mode set to Disabled.
- Don't use the parking functions if you don't need what I suppose the case.
- Naked eye or DSLR use? If the mount fails to track a star:
1. Raise Tracking Values if it falls behind.
2. Lower the Tracking Values if it goes ahead.
- With DSLR don't expect more than a few seconds of shots with the higher mag. lenses on this mount.

+1: It is very handy to add shortcuts for the slew and sync operations.
The following user(s) said Thank You: Zoltán Belső
Last edit: 4 years 1 month ago by Csaba Kertesz.
4 years 1 month ago #50095

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Hello,
Thanks for answering me!

On my laptop linux the indi_skywatcherAltAzMount driver crashes immediately when the serial connection is established at my side too. It has INDI Library: 1.8.4. I have opened a topic about it first here: indilib.org/forum/mounts/6457-indi-skywa...-fails-to-start.html
I also have a Raspberry PI, on that I have INDI Library: 1.8.3 which does not crash on serial connection, but has this strange "mirrored position" problem.
I have also tried to connect to my mount through WiFi using the SkyWatcher WiFi dongle, but that fails to connect. I have opened a topic about that too: indilib.org/forum/mounts/6467-indi-skywa...andshake-failed.html
It seems to me that the driver tries to handle the wireless connection since I see a good attempt to handshake, but somehow it does not go well.

I have also cloned out and compiled the github indi code on the PI, I got the same result.

I have also tried the indi_skywatcherAltAzSimple but it also crashes on serial connect, this time it does also on the PI, and the fresh github version too. Trying to connect the indi_skywatcherAltAzSimple wireless I got the same handshake failure.

It is rather hard for a newcomer to decide which driver to use. Since the indi_skywatcherAltAzMount has at least a documentation page with basic setup instruction, and I had at least partial success with it, it sounded reasonable for me to suppose that this is the up-to-date one.
I have found nothing about the indi_skywatcherAltAzSimple driver and I got nothing but crash.

I have found a one and a half year old thread about successfully using the AZ GTi mount with the eqmod driver, so I have tried that too. It is kinda works, but only wireless. The eqmod driver does not handle the connected RX-TX line on the Alt-Az mounts, and goes panic hearing back its own chatter....
But it requires to setup the mount in equatorial position which does not work so well with the Virtuoso mount.

I also have a 250 mm Dobsonian mount, my real goal is to use that with INDI. For that it is absolutely impossible to use it in equatorial position, so I need an AltAz solution.

I have also tried the synscan driver, which again, kinda works, but it has some pointing inaccuracy problem. I can see the mount's coordinates on the INDI control panel and also on the EKOS control panel. Strangely enough the two are differing. Not much but about 2 degrees. From here nothing is really works. KStars shows the mount position in the correct place, but when I try to center on the mount position it centers somewhat offset. When I ask to goto to a position, it goes near but again the same offset. It is not the inaccuracy of the mount or some kind of poor alignment, the mount position marker in Kstars is quite accurately shows the mount's actual position. I have also opened a thread about that: indilib.org/forum/mounts/6444-az-synscan...-explain-please.html
I still do not understand what is the difference between the INDI Control panel and the EKOS control panel and how can they show different coordinates? I would think that EKOS gets the coordinates from INDI so it should copy that precisely. Maybe it is some numerical error during calculating back ad force between RA/DEC and ALT/AZ coordiantes?

Zoltán
4 years 1 month ago #50126

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Any traceback from the driver? what causes the crash? It is the only driver in the main INDI stack that make use of the Alignment Subsystem and therefore should be kept as much as possible unless it is completely broken. If it can be fixed then let's work on it.
The following user(s) said Thank You: Zoltán Belső
4 years 1 month ago #50140

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I have included the trace for the indi_skywatcherAltAzMount here: indilib.org/forum/mounts/6457-indi-skywa...-fails-to-start.html
Although it is not much help, since the driver does not crash with an exception gdb can catch, but exits silently instead. Then indiserver tries to restart it futilely.

As far as I remember yesterday evening, indi_skywatcherAltAzSimple does the same, but I will try make a traceback for that too later.
4 years 1 month ago #50151

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I have made a gdb trace and a driver debug log for the indi_skywatcherAltAzSimple driver.
On my PC it is crashing on serial connect. That is what in this log files.

On the Raspberry PI I managed to get some success: the indi_skywatcherAltAzSimple is connecting through serial cable, and the scope position seems to be shown in the right position in Kstars. I was only able to test indoors - it is cloudy tonight, but it seems to slew in the correct direction.
The wireless connect fails exactly the same way as the AltAzMount driver. So it seems the two driver behaves exactly the same connectionwise, but the Wedge driver does not have the positioning problem.

File Attachment:

File Name: indi_skywa...2335.log
File Size:1 KB

File Attachment:

File Name: skywatcher...bout.log
File Size:5 KB
4 years 1 month ago #50170
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Most akkor mi van? :)

Can you elaborate a bit because I am lost what is failing and what is working?...

I tried these drivers only with Virtuoso via a serial connection from my laptop (wedge version: okay, non-wedge: crash), I never use Bluetooth or other wireless solutions because they are not 100 % reliable. However, I daily use the wedge version between a Skywatcher Merlin <-> Raspberry Pi3 via serial connection and connecting to the RaspPi with KStars from my laptop remotely. It works like a charm.

Csaba
Last edit: 4 years 1 month ago by Csaba Kertesz.
4 years 1 month ago #50172

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Ma végre valami működik ;)

So what is failing:

On PC, Ubuntu 18.04, INDI Library: 1.8.4:
- Both indi_skywatcherAltAzMount and indi_skywatcherAltAzSimple crashes (or better to say: exits) on serial connect. Which is causes Kstars to freeze :(((
- Both indi_skywatcherAltAzMount and indi_skywatcherAltAzSimple fails to connect to the Skywatcher wireless adapter. Does not crash, just 'connection failed'. Wireshark trace shows that there is an attemp to communicate, but the driver does not like the answer of the mount :(

On the Raspberry PI, both with INDI Library: 1.8.3 from the package manager and INDI Library: 1.8.4 from github:
- Both indi_skywatcherAltAzMount and indi_skywatcherAltAzSimple fails to connect to the Skywatcher wireless adapter. Does not crash, just 'connection failed'. Wireshark trace shows that there is an attemp to communicate, but the driver does not like the answer of the mount :(

What is working at least partially:

On the Raspberry PI, both with INDI Library: 1.8.3 from the package manager and INDI Library: 1.8.4 from github:
- Serial cable connects.
- The Wedge driver seems to be shown in the correct position and seems to goto to the correct position. But this was only tested indoors.
- The indi_skywatcherAltAzMount shown 12H off position on the RA coordinate (that is: mirrored to Polaris), but the goto command slews the mount to the correct position. Plate solving does not works due to the solver looks for the solution in a totally wrong place.

- The synscan driver works with both the handcontroller+serial cable and Android synscan app+wireless connection, but the coordinates in Ekos off by about 2°. Sync does not help.
- The eqmod driver works with the WiFi module, fail to connect with the serial cable. Even plate solving works. But it is not really a viable solution with the Virtuoso mount, and totally impossible with the big Dobson mount

By the way, today I got back my Dobson 250 mount from repair, and I'm happy to report that the Wedge driver seems to be working the same way with it as with the Virtuoso mount.
4 years 1 month ago #50177

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After quite a lot of debugging I've found some solutions.

I've found that the crash of both the AltAzMount and the AltAzWedge driver is due to null pointer dereference in indidriver.c:IUUpdateSwitch() called from the driver's ISNewSwitch() method.
I did not find the root cause of the problem, and I have no clue why does happen on the PC but does not happen on the Raspberry, but I was able to mitigate it by adding some null pointer check to the code.
I have made a report in the issue tracker of the indi github about my finding.

After that both the AltAzMount and the AltAz Wedge driver able to connect to the mount using serial cable.
The next surprise was that on the PC the AltAzMount driver did not show the problem this topic is about: namely that in Kstars the mount position is shown 12H off RA coordinate.

After a lot of debugging I have found that in SkywatcherAPIMount::ReadScopeStatus() method the "if (TransformTelescopeToCelestial())" goes on the True branch on the PC and report the correct RA/DEC coordinates, but goes on the False branch on the Raspberry, and reports bad RA coordinate.
Examinig the MathPluginManagement::TransformTelescopeToCelestial() method I have fount that on the Raspberry AlignmentSubsystemActive was OFF and that's why the method returned False.

So finally I have found that I have to click on the "Alignment Subsystem Active" button on the INDI control panel Alignment tab to turn it on. This way the mount is shown in the correct position.
I still have no clue why was it ON by default on the PC and OFF by default on the Raspberry. I also don't know why alignment-off code branch does not work, and what is the purpose of this failing code branch in the first place.
The following user(s) said Thank You: Jasem Mutlaq
4 years 2 weeks ago #50678

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Thank you for your investigation! Perhaps in the config it was set it to off? Can you check that? that still does not explain the rest of the issue though.

I use QtCreator to debug some issues on Raspberry PI, so that might help.
4 years 2 weeks ago #50701

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Since I'm new to indi I have no previous config files, I have a fresh installation both on the PC and the Raspberry. I don't really understand how the different components are related, I just try to put the peaces together now, so I have not fiddled with the settings of the Alingment subsystem, at least not intentionally. Telling the truth I thought the alignment subsystem is off initially and it will turn on automatically when I do some sync on stars.

Anyway, I've checked, on the PC the <oneSwitch name="ALIGNMENT SUBSYSTEM ACTIVE"> is On both in .indi/Skywatcher\ Alt-Az_config.xml.default and .indi/Skywatcher\ Alt-Az_config.xml, but it is Off in .indi/Skywatcher\ Alt-Az_config.xml on the RPI.

Maybe there is or is not something in the config file that causes the crash on my PC but prevents on the RPI. That may explain why the AltAz driver does crash for Kecsap too, but the AltAzWedge does not: He use the Wedge driver routinely so He has a working config to it. But He does not use the orig AltAz driver so He tried it now with the default config.

QtCreator is a good idea. I use eclipse for C/C++ development, so I tried that here too, but I did not managed to have a working installation on the RPI, and even on the PC it did not work for me for debugging the forked process. So I did all the debugging using command line gdb.
4 years 2 weeks ago #50706

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