Hi,
I've been using Ekos for 1,5 years now and I haven't had any real issues with guiding before now. I did quite a bit of imaging in 2020 without problems, then had nothing but bad weather etc until February 2021 where I finally got around to do some imaging again - Nothing had been updated in Ekos in between. However, this time I had soooo many problems with guiding, with RMS way over 4, then dropping to 1.5 or so and then spiking again over 3 or 4. Most problems in R.A but also in DEC. I tried going back from SEP to Smart algorithm and that helped a little, but I still had spikes well over 3 in R.A. My Polar Alignment error was 11".

I managed to get a decent result none the less, but I wasn't happy with my equipment. I decided to update Ekos to the latest in the repository and then test it out when the weather was behaving again. Tonight the weather is good, but my guiding (once again) sucks! I'm back on SEP, but it really isn't working out for me.

The guide star is lost quite often and the RMS is again looking bad. My Polar Alignment error tonight is 4".

My pulse setting is currently at 600 (also tried 400), exposure at 3s (also tried 1s and 2s) and box size is 8 (also tried 16). I've included a screenshot of the guide tab.

Any ideas on what has suddenly happened with my system?

Kstars/Ekos: 3.5.0, RP4 4 GB, HEQ5 mount (belt modded), QHY 5L-IIC guide camera on a 50mm guide scope. Using eqmod as "Via" option.

Hi
Two weeks ago I experienced exactly the same scenario with the guiding of my rig. Last year I never spent even one thought about guiding: It worked straightforward with the default of KStars 3.5.1. Now with 3.5.2. I'm not able to finish only one picture within a couple of minutes! Guiding gets so worse I can't believe it.
Did You make some progress in analyzing the reason for the bad guiding? I'm very interested in Your results! I have a sneaking suspicion what the cause could be, but I have to investigate more.

I'm working with the Skywalker AOK DDM mount. This device has a dedicated controller for which I wrote the driver. The interface of this controller follows substantially the LX200 standard.

Antonio

Hi,
I haven't figured out yet what's wrong. I've been imaging the last couple of nights. I've focused on targets high on the night sky and here the guiding wasn't as bad as before. Still RMS between 2 and 3 (sometimes higher), but if I try on a target lower on the southern night sky I get terrible guiding (RMS between 3 and 6). My PA is dead on with 9" error. I suspect that some of the error can be caused by balancing issues (eventhough nothing has changed on my setup!), but it's still very weird.

@escriban, what's your suspicion leaning towards?

Anders

Is there a reason your BOX setting is so small? It should encompass the main guide star, however it looks like its too small.

Maybe that's why?

Hi Anders
As I stated above I had to write a driver for the AOK Sykwalker DDM. I adapted some code from Avalon including the guiding part. I confess that I didn't understand pulse guiding in depth then, I simply transposed the code for the AOK Skywalker controller.
After the disastrous guiding fiasco I had a look at the code that controls the guiding. I was really astonished by the fact that there is some code (coming from the basic driver lx200) that mimics pulse guiding even when the pulse guide commands are deactivated. So I had look at my settings and realized that somehow the switch "Use PulseCmd" was set to OFF!!!
Alas I didn't have the opportunity to check the guiding with pulse commands ON until now, so it's a pure suspicion. But there is a high probability that this could be the culprit!
I didn't notice the state of that switch, because there was indeed some sort of reaction from the "mimic code", only a really bad one! As you stated before sometimes there were no reaction even when the guiding module emitted several correction pulses. So my suspicion is that this "mimic code" doesn't handle the pulse command (especially the time span) correctly. The mentioned code is based heavily on a timer implemented in the core. If there is a heavy load on the main loop I can imagine that the timers go crazy! Sometimes I get some stuttering in other modules of EKOS.
Next step here will be to check the behaviour of the guiding with "Use Puls Cmd" set to ON!
I don't know if the driver of you mount does have this switch. If you're guiding via your mount, check if the switch is ON.

Hi Anders
A couple of days ago I had the opportunity to check the guiding with dedicated pulse commands ("Use PulseCmd" = ON) with the Skywalker. It was a big relief to see the guiding working again! I can confirm now that there are indeed big problems if the driver is using the "alternative" timer based solution ("Use PulseCmd" = OFF). As you described above the guiding does have big problems because of the failing responsiveness. It seems that very often the timers cannot be started (due to an overloaded main loop?). After they can be finally activated an overreaction is inevitable!
In fact I don't understand the benefit of this piece of code (at least for lx200 compatible mounts with the pulse command option). For my share I will remove the PulseCmd switch in the Skywalker driver as it doesn't make any sense.
Sincerly
Antonio

Sorry if my last message appears in duplicate: The forum is extremly slow at the moment and I thought it threw me out.