HEQ5 Pro RA / DEC rates vary... // unsteady guiding

[Sebastian A. Niklaus]

Dear PHD2 community,

I am experiencing very unsteady and jumpy guiding with my HEQ5 pro (2020 model) and I'm afraid I don't understand the problem and the information provided by phd2. So I kindly ask for your help and advice.

I got a Skywatcher 200P and I am using the 5x90 viewfinder with a zwo asi 462mc. I run PHD2 on my raspberry pi4 8gb in combination with kstars. Before the 462mc I tried the zwo 120mm mini with the same problem. While waiting for the new camera I got the rowan belt mod, but it din't smooth my problem. I adjusted backlash most carefully (according to astro-baby), also paying attention to binding. The only thing I notice with the mount is while open clutches the RA is much easier to move compared to the DE.

I also tried the guiding assistant, which suggested to lower the minimal rates. But the guiding remains jumpy.

Thank you very much in advance!

Sebastian

https://openphdguiding.org/logs/dl/PHD2_logs_xfxm.zip

[bw_msgboard]

Hi Sebastian.  It’s hard to make much from this, there are very guiding sessions that are long enough to get a clear picture.  But even in shorter time periods, it’s pretty clear that the native RA tracking of the mount is quite poor (RA shown in red):

 

 

These large, abrupt excursions in RA will kill your guiding results and they are probably originating in the RA mount mechanics – they can’t be guided out by PHD2.

 

The peculiar difference between the measured RA and Dec guide rates is equally puzzling.  The mount driver is reporting that both axis guide speeds are set to 0.5x sidereal, but it’s obvious that the effective rate is much higher for Dec.  Look at the difference in the number of steps taken during the calibration:

 

 

Dec is obviously moving at a much higher rate – in fact, the computed rate is 22.5 arc-sec/sec which is faster than sidereal rate!  Are you 100% that your guider focal length is really 180mm ?

 

Bottom line, the mount/mount driver combination isn’t working nearly well enough to support guiding, so I think you should probably try to get help from the mount supplier.  Longer term, I think you should also review our best practices document and incorporate those into your normal operations (especially with regard to doing calibrations):

 

https://openphdguiding.org/phd2-best-practices/

 

 

Good luck,

Bruce

 

 

 

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[bw_msgboard]

Hi again Sebastian.  Just to further confirm that the poor RA tracking behavior is in the mount, here’s a look at the native tracking with no guiding being done at all:

 

 

A lot of this is coming from the unwelcome 13-sec error that is pretty common to many of these private-label Chinese mounts:

 

 

Here’s another forum thread that talks about this.

https://groups.google.com/g/open-phd-guiding/c/xBK_ib-pCMY/m/O6LRBC-pAAAJ

 

Bruce

 

 

---

From: bw_msgboard [mailto:bw_m...@earthlink.net]
Sent: Sunday, November 29, 2020 12:23 PM
To: 'open-phd...@googlegroups.com'
Subject: RE: [open-phd-guiding] HEQ5 Pro RA / DEC rates vary... // unsteady guiding

 

Hi Sebastian.  It’s hard to make much from this, there are very guiding sessions that are long enough to get a clear picture.  But even in shorter time periods, it’s pretty clear that the native RA tracking of the mount is quite poor (RA shown in red):

 

 

These large, abrupt excursions in RA will kill your guiding results and they are probably originating in the RA mount mechanics – they can’t be guided out by PHD2.

 

The peculiar difference between the measured RA and Dec guide rates is equally puzzling.  The mount driver is reporting that both axis guide speeds are set to 0.5x sidereal, but it’s obvious that the effective rate is much higher for Dec.  Look at the difference in the number of steps taken during the calibration:

 

 

Dec is obviously moving at a much higher rate – in fact, the computed rate is 22.5 arc-sec/sec which is faster than sidereal rate!  Are you 100% that your guider focal length is really 180mm ?

 

Bottom line, the mount/mount driver combination isn’t working nearly well enough to support guiding, so I think you should probably try to get help from the mount supplier.  Longer term, I think you should also review our best practices document and incorporate those into your normal operations (especially with regard to doing calibrations):

 

https://openphdguiding.org/phd2-best-practices/

 

 

Good luck,

Bruce

 

 

 

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of Sebastian A. Niklaus
Sent: Sunday, November 29, 2020 11:20 AM
To: Open PHD Guiding
Subject: [open-phd-guiding] HEQ5 Pro RA / DEC rates vary... // unsteady guiding

 

Dear PHD2 community,

--

[seb...@gmx.de]

Dear Bruce,

thank you very much for your quick reply!

I did not measure the focal lenght of the viewfinder, it was named on some spots in the internet (e.g. on the astro.tools website). The phenomenon was the same with gears and belt. The only parts remaining might be motor, worm gear itself or the gear working with the wormgear. Thank you for the link to the best practice, too. I read it yesterday and will keep sticking to it. I watched the "Getting the Most Out of PHD2 Guiding (Video)" about PHD2 before. Today I wrote my mount supplier asking for advice. The mount is only some month old, maybe they will look it through.

Btw. I tried opening the newer log but PHD2 Log viewer crashed on linux. Were you able to open it? The older one was with gears, the newer one with belt. I forgot to mentinon.

So thank you again, I hope to have some good news soon!

Sebastian

[seb...@gmx.de]

Dear Bruce, 

I found a solution. I was guiding through the sky-watcher handcontroller via USB. It seems like the handcontroller is affecting mount commands on guiding speed but not the general slewing. I build a cable like that http://eq-mod.sourceforge.net/eqdirect2.htm and connected directly without the hand controller. Instead of the Indi Synscan driver I use the Indi EQmod driver. Now everything works. 

Thank you again for your kind support!

Regards from Germany

Sebastian

[bw_msgboard]

Hi Sebastian.  Wow, this is very good news!  And it strikes me as being a very nice bit of work on your part, definitely an out-of-the-ordinary problem to figure out.  Congrats!  You probably want to be insure your EQMOD settings follow this guide:

 

https://github.com/OpenPHDGuiding/phd2/wiki/EQASCOM-Settings

 

Bruce

 

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To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/43dd2130-0b53-4fb0-b15b-c603e9844e3dn%40googlegroups.com.

[John Nagy]

Sebastian,

Are you using EQMod as an interface between the scope and computer? If you are, there is a parameter on the setup/advanced screen called drift compensation. I mistakenly set it to something other than zero in early August and that caused my mount to run slightly fast as well. If you're using EQMOD take a look and verify that parameter isn't set. BTW, I just noticed this is a end of Nov. thread but since you replied I guess you might see this. There is a thread from me in August about my issue and the solution if you need to look it up.

Regards,

John

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/43dd2130-0b53-4fb0-b15b-c603e9844e3dn%40googlegroups.com.

[seb...@gmx.de]

Thank you Bruce, for both compliment and link :) I will try a higher guiding speed as advised. Right now I work with 0.5x. I don't think the other values are accessible with my driver right now. My view is like this: https://www.indilib.org/devices/telescopes/eqmod.html I got one windows partition that I could use to connect via EQMOD Ascom for parametrizing. Usually I connect both cameras, focuser and mount to a raspberry pi4 and use indiserver on it. PHD2 runs directly on the raspberry, everything else is sent to my macbook via network. 

Thank you John, I have also not seen this option in the INDI user interface yet. I will pay attention to that and maybe I can check the mounts settings via windows. 

[seb...@gmx.de]

Dear Bruce,

if possible I would like to kindly ask for your opinion on my futher persisting trouble with controlling my heq5 pro mount for guiding. After solving the problem with the synscan driver I switched to indi eqmod. I am trying hard since then but I have intermittend failure in completing calibration as well as the backlash measurement of the guide assistant. The mount sometimes does not respond to south commands during those processes. While experimenting today I also noticed a failure during the star cross test. All these errors just happen in south direction so there is a chance that it is related to the indi eqmod driver but it could also be a command issue. I most carefully adjusted the backlash and when recognized I get around 800ms to 1300ms. I am sure I do not have binding, I turned both axis manually several times. I also tried a second cable via the handcontroller in pc direct mode. Overall I tried phd2 on my raspberry pi as well as in win10 and mac mojave. Goto and long (2,5-5s) phd2 manual guide pulses work usually.

While the star cross test today all commands could be completed. PHD2 commanded west and east movement perfectly as well as the north commands, but when the south movement started I got the debug log of indi redurned:

[2021-03-16T18:04:27.910 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] Timed guide South 1000 ms at rate 13.537 "
[2021-03-16T18:04:27.911 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] StartDETracking() : trackspeed = -13.537 arcsecs/s, computed rate = -0.9 "
[2021-03-16T18:04:27.911 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SetDERate() : rate = -0.9 "
[2021-03-16T18:04:27.912 CET INFO ][ org.kde.kstars.indi] - EQMod Mount : "[WARNING] Warning: Invalid parameter -> Can not change rate while motor is running (direction differs). "

Guiding speed is set to 0.9x on both axis in the driver. I know PHD2 cannot affect the settings usually.

As all three problems affect south movement in combination with phd2 and today I seen that error I wanted to contact you. 

Example for good calibration but bad backlash measurement:

Two nights ago it was a bit windy but right after a perfect calibration I could not complete the backlash measurement:

Example for good backlash measurment, same setup and guide speeds:

I also posted this in the indi eqmod driver forum. I would be very happy to hear from you.

Thank you in advance

Sebastian

[bw_msgboard]

I don’t really have anything to add here.  Certainly the INDI mount errors need to be corrected.  Overall, the Dec axis on your mount doesn’t seem to be moving consistently and reliably even when the INDI errors aren’t being recorded.  I would guess your mount has a huge amount of Dec backlash so you should clear it manually before you start a calibration.  Running kstars is probably counter-productive until you can get all these mechanical problems sorted out – you should be doing all this stuff manually until you have a clear idea of what’s going on.  The mount has to respond consistently, not just “usually”.

 

Bruce

 

---

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/b07a1ed8-dce0-4857-b6f2-af6b108e8370n%40googlegroups.com.

[Sebastian Niklaus]

Dear Bruce, maybe you want to take a look here: https://github.com/indilib/indi-3rdparty/issues/358#issuecomment-806544929. I posted the issue in the Indi/eqmod forum. It would be good if you found the time to check the other side of the interface to phd2. Kind regards Sebastian 

Am 17.03.2021 um 16:00 schrieb bw_msgboard <bw_m...@earthlink.net>:



I don’t really have anything to add here.  Certainly the INDI mount errors need to be corrected.  Overall, the Dec axis on your mount doesn’t seem to be moving consistently and reliably even when the INDI errors aren’t being recorded.  I would guess your mount has a huge amount of Dec backlash so you should clear it manually before you start a calibration.  Running kstars is probably counter-productive until you can get all these mechanical problems sorted out – you should be doing all this stuff manually until you have a clear idea of what’s going on.  The mount has to respond consistently, not just “usually”.

 

Bruce

 

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of seb...@gmx.de
Sent: Tuesday, March 16, 2021 3:16 PM
To: Open PHD Guiding
Subject: Re: [open-phd-guiding] HEQ5 Pro RA / DEC rates vary... // unsteady guiding

 

Dear Bruce,

 

if possible I would like to kindly ask for your opinion on my futher persisting trouble with controlling my heq5 pro mount for guiding. After solving the problem with the synscan driver I switched to indi eqmod. I am trying hard since then but I have intermittend failure in completing calibration as well as the backlash measurement of the guide assistant. The mount sometimes does not respond to south commands during those processes. While experimenting today I also noticed a failure during the star cross test. All these errors just happen in south direction so there is a chance that it is related to the indi eqmod driver but it could also be a command issue. I most carefully adjusted the backlash and when recognized I get around 800ms to 1300ms. I am sure I do not have binding, I turned both axis manually several times. I also tried a second cable via the handcontroller in pc direct mode. Overall I tried phd2 on my raspberry pi as well as in win10 and mac mojave. Goto and long (2,5-5s) phd2 manual guide pulses work usually.

 

While the star cross test today all commands could be completed. PHD2 commanded west and east movement perfectly as well as the north commands, but when the south movement started I got the debug log of indi redurned:

[2021-03-16T18:04:27.910 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] Timed guide South 1000 ms at rate 13.537 "
[2021-03-16T18:04:27.911 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] StartDETracking() : trackspeed = -13.537 arcsecs/s, computed rate = -0.9 "
[2021-03-16T18:04:27.911 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SetDERate() : rate = -0.9 "
[2021-03-16T18:04:27.912 CET INFO ][ org.kde.kstars.indi] - EQMod Mount : "[WARNING] Warning: Invalid parameter -> Can not change rate while motor is running (direction differs). "

 

Guiding speed is set to 0.9x on both axis in the driver. I know PHD2 cannot affect the settings usually.

 

As all three problems affect south movement in combination with phd2 and today I seen that error I wanted to contact you. 

 

Example for good calibration but bad backlash measurement:

Two nights ago it was a bit windy but right after a perfect calibration I could not complete the backlash measurement:

<image001.gif>

<image002.gif>

 

Example for good backlash measurment, same setup and guide speeds:

<image003.gif>

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[Sebastian Niklaus]

Hello Bruce,

the problem in Indi/Eqmod is now confirmed and it will be fixed. Short guiding pulses were causing the error, especially when changing direction. Details are under the GitHub link. 

Thank you again for your kind support!

Best regards

Sebastian 

Am 17.03.2021 um 16:00 schrieb bw_msgboard <bw_m...@earthlink.net>:



I don’t really have anything to add here.  Certainly the INDI mount errors need to be corrected.  Overall, the Dec axis on your mount doesn’t seem to be moving consistently and reliably even when the INDI errors aren’t being recorded.  I would guess your mount has a huge amount of Dec backlash so you should clear it manually before you start a calibration.  Running kstars is probably counter-productive until you can get all these mechanical problems sorted out – you should be doing all this stuff manually until you have a clear idea of what’s going on.  The mount has to respond consistently, not just “usually”.

 

Bruce

 

---

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of seb...@gmx.de
Sent: Tuesday, March 16, 2021 3:16 PM
To: Open PHD Guiding
Subject: Re: [open-phd-guiding] HEQ5 Pro RA / DEC rates vary... // unsteady guiding

 

Dear Bruce,

 

if possible I would like to kindly ask for your opinion on my futher persisting trouble with controlling my heq5 pro mount for guiding. After solving the problem with the synscan driver I switched to indi eqmod. I am trying hard since then but I have intermittend failure in completing calibration as well as the backlash measurement of the guide assistant. The mount sometimes does not respond to south commands during those processes. While experimenting today I also noticed a failure during the star cross test. All these errors just happen in south direction so there is a chance that it is related to the indi eqmod driver but it could also be a command issue. I most carefully adjusted the backlash and when recognized I get around 800ms to 1300ms. I am sure I do not have binding, I turned both axis manually several times. I also tried a second cable via the handcontroller in pc direct mode. Overall I tried phd2 on my raspberry pi as well as in win10 and mac mojave. Goto and long (2,5-5s) phd2 manual guide pulses work usually.

 

While the star cross test today all commands could be completed. PHD2 commanded west and east movement perfectly as well as the north commands, but when the south movement started I got the debug log of indi redurned:

[2021-03-16T18:04:27.910 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] Timed guide South 1000 ms at rate 13.537 "
[2021-03-16T18:04:27.911 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] StartDETracking() : trackspeed = -13.537 arcsecs/s, computed rate = -0.9 "
[2021-03-16T18:04:27.911 CET DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SetDERate() : rate = -0.9 "
[2021-03-16T18:04:27.912 CET INFO ][ org.kde.kstars.indi] - EQMod Mount : "[WARNING] Warning: Invalid parameter -> Can not change rate while motor is running (direction differs). "

 

Guiding speed is set to 0.9x on both axis in the driver. I know PHD2 cannot affect the settings usually.

 

As all three problems affect south movement in combination with phd2 and today I seen that error I wanted to contact you. 

 

Example for good calibration but bad backlash measurement:

Two nights ago it was a bit windy but right after a perfect calibration I could not complete the backlash measurement:

<image001.gif>

<image002.gif>

 

Example for good backlash measurment, same setup and guide speeds:

<image003.gif>

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[Bruce Waddington]

Thanks for reporting back Sebastian.  It pretty much had to be something like this, the interfaces used by PHD2 don’t expose that level of detail for what the driver is actually doing with the mount firmware.

 

Cheers,

Bruce

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/99AD7BC8-B0E9-4389-9020-81EEEB910251%40gmx.de.