Is PEC usable with the EQ6-R Pro and INDI, when autoguiding?

I'm looking to upgrade my mount, and the EQ6-R Pro is at the top of my short list. I'm hoping PEC can be used with autoguiding to smooth out the periodic error, so autoguiding doesn't have to work so hard. But I see in the INDI documentation for the EQMOD driver that it may not work with guiding.

Anyone using an EQ6-R Pro with PEC enabled and guiding (either PHD2 or internal guider)?

Thanks!

Similar questions have been asked on this forum several times over the past months. IIRC no conclusive answer has been given by anyone.


Wouter

I searched and didn't find anything. I guess I didn't search well enough. My apologies

I see you list an EQ6-R Pro in your signature. Do you use it with Ekos? How's the guiding with it? Do you like it?

Yes I use an EQ6-R with Ekos for my 8" RC and lately also for my 80 mm Esprit since I leave the mount in the backyard nowadays. It works very well and when using a 60 mm F=260 mm guide scope I can get 0.5" RMS and better. Lately it seems to struggle a lot when guiding and I suspect that the lubricant in the mount has hardened too much. SkyWacther is known for not using a very high quality lubricant in its mounts so I am considering opening it up, cleaning it and lubricating it anew.

By the way, I always use the internal guider. Never PHD2. I have experimented with it this past week and I don't like the bad responsiveness of Ekos when guiding with PHD2. Plus I didn't notice any improvement in guiding whatsoever.

I'm so sick of my Orion Atlas mount (it has almost 40 arc-seconds peak-peak periodic error in RA, and is a ***** to guide that out) , I went ahead and ordered an EQ6-R Pro. It should be here next week. Can't wait!

I saw a thread on Cloudy Nights (www.cloudynights.com/topic/631100-a-well...curve-with-eq6-r-pro) where you could use EQMOD on Windows to train a well-smoothed PEC curve into the permanent PEC on the mount. Windows and ASCOM will only be needed for training the PEC, it will be stored permanently in the motor controller. Then I can go back to the Raspberry Pi.

I poked through the source code for INDI EQMOD driver, and it does disable PEC while issuing guiding pulses. It re-enables as soon as the guiding pulse is done. I don't mind doing some experimentation with that code left intact, versus removing that code, and compare the differences. I will give that a try and see how it works out.

And even if it turns out that PEC isn't reliable with INDI EQMOD, then that shouldn't come as a great loss, since I see people are getting perfectly good guiding without it.

@wvreeven: re: "I am considering opening it up, cleaning it and lubricating it anew." Do you have a good candidate for lubricant? I have a Celestron CGX-L that seems more stiff than I'd like and I've wondered whether I would venture to remove the lube and start over. If you know of a super-lube you would recommend, I'd be interested. Thanks, DougS.

I have the Orion Atlas as well, but generally can't complain about guiding with that. I performed PEC with it using the hand controller and I got round stars with up to 2 min unguided using a 1600 mm FL RC 8".

I always thought the PEC was retained while guiding with EKOS, then someone (may have been Wouter) told me that the PEC data are stored in the handcontroller, not in the mount itself. That would mean that the data are not used by EKOS.
I yet have to perform PEC using EKOS on the Atlas mount. It has the option in the control panel, so why would it not work?

Jo

Doug, I am afraid that I don't have much choice. I live in La Serena, Chile and I moved here only a few months ago. So I don't know the stores here very well yet and the covid-19 restrictions don't help in that respect. I bought a tube of lawn mower lubricant in a Do It Yourself store here and I hope it is good enough for the mount. Fingers crossed!


Clear skies, Wouter

I assume you're referring to the original Orion Atlas EQ-G, and not the new Orion Atlas EQ-G II. The "II" model is the Orion version of the Skywatcher EQ6-R Pro.

I am sorry to inform you, that the PEC in the Orion Atlas is only temporary. It is indeed stored in the hand controller, and is lost when you power off the mount. That is one of the improvements of the EQ6-R Pro, is it now has Permanent PEC (PPEC), which is stored in the motor controller. There is also some type of sensor on the RA axis worm gear that lets the mount know where it is, so it can apply the stored PEC, even after powering off and on again. The Atlas has no such sensor.

I have the Atlas Pro Az/EQ-G mount. This is what the manual says about PPEC. I am still not sure, though, whether that info is stored in the mount or on the hand controller and whether it will automatically be used every time the mount operates or only if I use the hand controller for operations. The description is too ambiguous.


6.7 Permanent Periodic Error Correction
The Atlas Pro mount is equipped with an index on its R.A. worm,
thus the motor controller can keep tracking the current position
of the worm. After a proper PEC training routine, in which the
training data is stored in the motor controller permanently, a
user can start the periodic error correction (PEC) at any time
to improve the tracking performance for astrophotography. A
training process is not required in the next observing session
(assuming that the polar alignment is always accurate), thus
this is a Permanent Period Error Correction (PPEC). A user can
train the mount by guiding either manually or electronically with
auto-guiding. For detailed instructions, please refer to the rele-
vant section in the SynScan hand controller instruction manual.

Ah yes, I forgot about that model of mount. Yes, you're good to go, sorry for misleading you!

The PEC is stored in the motor controller, not the hand controller, so using EQMOD with PEC without a hand controller won't be a problem. It is not automatically enabled, though. You must enable it.