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PEC correction in EQMOD telescope driver

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A discussion is ongoing on a french web site "webastro" about the advantage of autoguiding or using the pec correction.
Some people shows that the pec correction is very efficient on the AZ-EQ6. Equal or better than autoguiding for a 1000mm focal.
I don't know where are stored the PEC informations. Is it in a flash memory in the mount or in the pad ?
If it is in the mount it might be very useful to be able to use it.
If it is in the pad, an equivalent PEC training function would be very useful in EKOS and the PEC result could be a part of the mount profile which is saved from EKOS.
Last edit: 7 years 9 months ago by Patrick.
7 years 9 months ago #8866

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Indeed, I'd love to be able to do that. Especially since I have an AZ-EQ6. :)
7 years 9 months ago #8867

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Will research it and see if it is applicable in Ekos.
7 years 9 months ago #8869

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I found some informations about the place where the informations of PEC are stored:

Synscan
AZ-EQ6:
My opinion is that the PEC information is stored on the mount side. So maybe it can be used by other software.
This seems to be different for the EQ6 the PEC information is not stored permanently and lost when the system is powered off. Maybe in this case it is more difficult to store or re-use the PEC information.
7 years 9 months ago #8877

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So, there's a way to do a SPEC (software PEC) with ekos for _all_ mounts with a little routine routine with some autoguiding.
i see something like this on a no windy night : power on your cam, power on your mount, unpark it, target a star (not burn on CCD), launch routine with ekos (that use all autoguiding stuff to calculate)... It will be a serious progress on _all_ mount, even them without PEC inside.
7 years 9 months ago #8881

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Obviously, this is a good idea djibb.
People does it (webastro sourcing): take picture while autoguiding and training PEC (no time lost), at the end of the PEC they continue with PEC and autoguiding.
But it looks like PEC is enough: www.astrobin.com/252529/0
Three constraints:
- Make a very accurate polar alignment
- mount must have a ST4 port. (But I don't know if the training is possible with pulse guiding)
- Be able to park the mount to preserve the PEC informations.
It seems that a PEC training function with memorization exists on ASCOM/EQmod,
Don't know if it can be useful, I found it:
eq-mod.sourceforge.net/docs/PECPrep.pdf
eq-mod.sourceforge.net/docs/eqmod_vs-pec.pdf
Last edit: 7 years 9 months ago by Patrick.
7 years 9 months ago #8882

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This is a topic with lots of potential.

The AZEQ6GT has the functionality of PPEC (permanent periodic error correction).
The values of this PPEC are stored on the controller board just above the motors. It attaches the value of the correction to the position of the encoder. Which means, that when you turn off the mount and restart it, you don't have to redo the PEC-training. Also, if you bump your telescope, or power fails, or something else fails... you keep having a good correction.

You can ONLY use PPEC if you use the synscan-controller manually and choose to track using PPEC. If you use EQMOD from the pc, this is not possible. Not for the windows-version, and probably also not for the linux version.

Having this functionality would be fantastic. But I think the main problem is, is that syntha doesn't want to make the procedure public to program the PPEC yourself.
The following user(s) said Thank You: Jasem Mutlaq
7 years 9 months ago #8912

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I hope some people can someday listen the flow of informations exchanged between the synscan and the mount during pec training, pec storage and pec usage.
7 years 9 months ago #8913

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i think there's clearly 2 pproblematics :
1) howto do PPEC with _one_ mount. (reverse engeniering etc.)
2) How to do SPEC with all mounts supported by indi with autoguiding procedure.

I prefer focusing on '2' ;)
7 years 9 months ago #8914

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Looks like there is a problem which is the reference of the AD position. On the AZEQ6 as said meister there is a encoder position stored. I don't know how it works really because those encoders are not absolute. How is it possible to simulate the same thing by software ?
7 years 9 months ago #8919

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Hi :)

there's no problem if mount is parked. information are stored in driver. (as in EQMOD under windows) When unpark, Motors begin with the good position.

In all other cases, you will have to do another PEC record.
7 years 9 months ago #8923

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I started a discussion on cloudynight about the PPEc on AZ-EQ6.

www.cloudynights.com/topic/540763-how-azeq6-ppec-works/

Looks like the PEC training is a onboard function of the motor controllers which are in the mount.
So for this specific mount and AZ-EQ6 too it could be just necessary to start/stop PEC training and PEC use.
7 years 9 months ago #8929

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