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PEC Training Unguided Laptop


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Hi, I have an EQM-35 pro that I use unguided. I'm fine tuning wich software to use, and for now the combination I like best is to use kstars/ekos in linux to align, an control mount/camera, and process in windows. As for imaging, my tracking is suffering from periodic error and for now that is my limiting factor for exposure times. I know with the hand controller I could PEC train my mount, but I would have to track with the hand controller as the info is stored there. Is that right? In windows I read that you could PEC train while guiding. Is there a way to train without a guide camera? Is there any way I could PEC train and track with my linux setup? Thanks.


PS - I Know Autoguiding is the way to go, but for now I have to make the best of what I Have.

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Hi, if your mount - like mine (NEQ6 Pro) - doesn't support PPEC (Permanent), then unfortunately you will not be able to use it with KStars/EKOS. I was using a Windows machine and I managed to record a few correction cycles using EQMOD and then save a PEC curve and load it in EQMOD every time I wanted to use sidereal rate plus PEC. This almost doubled my unguided exposure times. With EQMOD all you had to do was park the mount before switching it off, and the PEC curve was always synchronized with the motor positions.

I had to make the switch to a Raspberry Pi 4 and KStars/EKOS, because Windows laptop died, and since then I haven't been able to take advantage of PEC anymore, because with KStars/EKOS only permanent PEC mounts are supported for the PEC feature to be available (nobody developed a PEC synchronized with motor positions option for that suite).

With Windows/EQMOD, there was definitely the option to train the PEC even without a guide camera: when I did it, I used a joystick (plugged in and configured in EQMOD) to give corrections to the mount and a cross-haired eyepiece with a 2x Barlow with my C8, to keep chosen star in the center of the eyepiece. So, you can do this without a guide camera. But only with EQMOD, under Windows.

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Thank you very much endlessky.

I will have to dig a bit more. I haven't found any information regarding PEC training without guiding, but I will try to explore the software it's self to see if I can figure it out. 

I was polar aligning with the dslr with kstars/ekos polar aligning assistant. If I polar align in linux, park, and get back to windows could I still use the pec curve or is it possible that the parking could be a little different and I could loose sync? Besides sharpcap I don't know more possibilities to polar align with the camera in windows because Sharpcap doesn't support the dslr,  And ekos was working great.

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If you just use KStars/EKOS to polar align, then I guess parking the mount in Linux and restarting it with Windows/EQMOD could work. But, as you pointed out yourself, the two parking positions (the one in EKOS and the one in EQMOD) have to be the same, or you will end up with an offset between when the PEC should apply the correction and the motor position that is actually getting that correction (ahead or behind the correct one of the curve).

A workaround could be parking the mount in EQMOD (after you record your PEC data), turning the mount off, starting EKOS, turning the mount on, and before doing anything (unparking, tracking, anything that moves the mount from the EQMOD parked position) saving the current position under EKOS parking configuration setting - I think this should be doable. Then you should be pretty sure that the two parking positions are the same.

A way to check if this worked could be:

1) park the mount in EQMOD, take note of the motor positions

2) set the current parking position as EKOS parking position, before doing anything that moves the mount from where EQMOD left it (no tracking, no unparking, no slewing, etc.)

3) still under EKOS, unpark the mount, slew randomly a few times, park the mount

4) go back in EQMOD, see if the motor positions are still the ones you recorded in step 1

If they are, then you can be sure that the two parking positions are exactly the same and your PEC curve will be correctly applied even if you switch between the two systems.

I hope this makes sense - and that it works!

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Ok, I Found out how to record the PEC Curve, and I can use my mouse buttons as you used your joystick.

It would be great if I could use everything in the same operating system. I used Kstars/EKOS because it was the solution that I managed to integrate everything. Using Windows I think I will use APT, and Cartes du Ciel. The only thing missing is some kind of Alignment software that supports the DSLR so I don't need do chance SO all the time. Am I correct thinking that most of the time the polar alignment I get from software + camera will be better than with the polar scope and I will benefit more by changing SO to polar align than to use the polar scope to aling and not changing SO?


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Nice that you could manage to record the curve!

Yeah, I agree, it would be nice to have everything under one system. Unfortunately with KStars/EKOS we cannot have PEC, but we can polar align with the DSLR. In Windows it's just the opposite.

To be honest, I have been polar aligning my mount using the polar scope and an Android app that shows me the position to put Polaris in the polar scope (if interested, the app is PolarFinder). I have managed up to 4 minutes exposures with no field rotation, at 300mm focal length and a DSLR. The few times I tried using the polar alignment feature in EKOS, the error according to EKOS was so great that if I corrected for it, Polaris would be off almost by the whole diameter of the circle in the polar scope. I blamed this problem on flexure of the DSLR plus the heavy 300mm lens on the ball head that everything was mounted on. Since then I always polar aligned manually and everything went fine.

If your imaging focal length is in the same ballpark as mine, I wouldn't worry about switching systems just for polar alignment and stick with your Windows setup. PEC would probably benefit you a lot more than a superior polar alignment. You could try polar aligning manually and then taking a few test exposures under Windows - if the stars are nice and round in all the field of view, then you are good to go!

Edited by endlessky
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Maybe you could give PEM PRO a try? There is trial license.

Here is what you should do:

1. record a video of a star being tracked (no guiding). For this you need either web cam or ascom camera. Maybe try to see if your DSLR has ASCOM drivers that can be used for this. Alternatively see if PEM PRO can work with AVI files or other movie file (like ser)

2. Generate PEC curve in PEM PRO

3. PEM PRO says on their website that it can upload PEC curve to most mounts - so I guess it can do that to Eqm-35 as well?

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