PEC training with PPEC - advisable?

[aaron craig]

Wondering if it's ok to use PPEC algorithm while training PEC? For some reason it seems wrong haha

[Brian Valente]

You should not be using guiding at all while training PEC

 

But once you have PEC enabled, yes ppec is great for picking up residual PE

 

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

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[steve]

El 25/01/2018 a las 08:17, Brian Valente escribió:

You should not be using guiding at all while training PEC

Then how does the mount know what to correct?

[steve]

El 25/01/2018 a las 08:15, aaron craig escribió:
> Wondering if it's ok to use PPEC algorithm while training PEC? For
> some reason it seems wrong haha

Hi
Hands on from a non PHD2 specialist. EQ6 and vspec:

Train with hysteresis, guide with hysteresis: OK
Train with hysteresis, guide with PPEC: Better
Train with PPEC, guide with PPEC: Worse.
Mount PEC disabled, guide with PPEC: Best.

HTH, clear skies and good luck,
Steve

[Brian Valente]

Training your Mount is separate from guiding. PEC looks at the mounts internal error and corrects them within the mount by recording the corrections and playing back inside the mount. 

Once that's done it generally makes guiding more effective. 

Ppec algorithm builds its own pe model on the fly. It doesn't look at or know about the mount PEC at all

HTH

Brian

Sent from my iPad

[Aaron Craig]

Hi Brian,

Training PEC is no longer a manual only task. Training while you autoguide is the best and easiest way to do it in my opinion. It removes the human element.

Cheers, 

Aaron 

Brian

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[steve]

El 25/01/2018 a las 09:35, Brian Valente escribió:
> Training your Mount is separate from guiding.

Ah, OK. Didn't realise that. On my EQ6, it's the guiding pulses which
are recorded and then played back. Do other mounts have some way of
knowing what to correct without reference to a star?

I could, e.g. make a PEC file using a PHD2 log file but I can't see how
I'd do that with just a mount...

[Ken Self]

Recording the guide pulses is the quick way but may have a lag and the guide parameters can afffect the accuracy of the recording. An alternative is to record an unguided run of several worm cycles and process in PECPrep for loading into EQMOD. The EQ6 does not respond well to PEC when the 122s period is high as it is not a harmonic of the worm period. With PECPrep it is possible to isolate just the worm period and correct for that but that is the period that guides out most easily. I once encoded PEC into my DIY controller for an SP mount and it didn't have any noticeable effect. I concluded that the correction profile was out of phase with the actual PE and getting it in phase was very difficult. Thats why the lagging effect of guide pulses or even guide correction calculations can be problematic

[Brian Valente]

Steve

 

I think I need to update my comment. I thought you were using a separate program.

 

I think Ken’s advice below is spot on

 

 

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

 

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of Ken Self

Sent: Thursday, January 25, 2018 3:03 AM
To: Open PHD Guiding <open-phd...@googlegroups.com>

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[steve]

El 25/01/2018 a las 17:57, Brian Valente escribió:

Steve

 

I think I need to update my comment. I thought you were using a separate program.

I thought you were saying that you should not be guiding when recording PEC. My misunderstanding.

[peter wolsley]

Aaron and Brian,

PEC training is a very straightforward process.  The user is asked to keep the mount aligned with a star while the mount learns PEC by watching what happens with the mount's RA position.  The user can use any convenient method for keeping the star aligned with the mount.  They can use a high magnification eyepiece and issue manual slews to the mount using the lowest possible slew speed (50% sidereal for my Celestron CGEM).  They can use an automated method to send pulse guiding commands to the mount which would be to use PHD2.  The user can choose any algorithm they wish...including PPEC.  The goal is to have the mount follow the star accurately so that the PEC table has as much detailed RA axis information as possible.

One issue that arises when you try to use PHD2, or any autoguiding method, is how every piece of software needed to learn the PEC table can listen to what is happening.  For my Celestron mount this means having PHD2 and PECTools simultaneously listening to the mount via ASCOM.  It is certainly do-able but it takes some fiddling to get it working.

AFAIK, PEC learning and autoguiding are compatible and can occur simultaneously.

Just my two cents

Peter

On Thursday, January 25, 2018 at 2:15:55 AM UTC-5, aaron craig wrote:

[Brian Valente]

That depends – how are you recording PEC?

 

 

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

 

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of steve
Sent: Thursday, January 25, 2018 10:33 AM
To: open-phd...@googlegroups.com
Subject: Re: [open-phd-guiding] PEC training with PPEC - advisable?

 

 

 

El 25/01/2018 a las 17:57, Brian Valente escribió:

--

[Brian Valente]

>>> AFAIK, PEC learning and autoguiding are compatible and can occur simultaneously.

 

I don’t think that is true?

 

If you are PEC learning with an external app or on the mount itself, autoguiding will adjust the star position which obfuscates the true periodic error, right?

 

Using autoguiding to record the PEC data for uploading into PECPrep is a different application, and there you rely on PHD’s autoguiding and logging to gather that data

 

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

 

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of peter wolsley

Sent: Thursday, January 25, 2018 10:40 AM
To: Open PHD Guiding <open-phd...@googlegroups.com>

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[steve]

El 25/01/2018 a las 19:39, Brian Valente escribió:

That depends – how are you recording PEC?

I could be keeping a star on cross hairs in an eyepiece or guiding using PHD2. I don't think it matters.
Cheers and clear skies
Steve

[roswella...@gmail.com]

Brian,

just jumping in on this conversation as I have been monitoring. Are you saying to run the PEC training WITHOUT PHD2 and just keep the star in the cross hairs of eyepiece and adjust manually and THEN run playback when you start guiding with PHD2? You would make adjustments in RA ONLY correct?

CJ

[Brian Valente]

I apologize, things seem to be getting a bit convoluted, so let me try to break down my understanding

 

The main question is how are you recording your Period error data:

 

1.       If you are doing it manually (in PHD or elsewhere), you would turn off PHD guiding and adjust star position by hand. Presumably you take the guidelog from PHD and plug that into a program such as PECPrep and it will use that data to create the PE correction curve for the mount.

I think it’s generally understood this isn’t the most accurate approach, and probably not worth the time when you have much better options available (below)

2.       If you are using PHD to automatically track the guidestar, then yes turn ON guiding and guide as you normally would. Next steps are same as above: you take your guidelog from PHD, plug it into PECPrep or whatever app you use for PEC, and go from there.

I think it’s generally understand this is a preferred approach to 1. above

3.       If you are using an external application to generate PE data such as PEMPro, you turn guiding OFF. These programs do their own calculations to track periodic errors and create their own data files and resulting mount corrections

 

Once you have the PEC programmed into the mount, then use guiding/PHD as you normally would (i.e., turn it on). PPEC remains a great algorithm because there will likely still be residual periodic error it can help guide out more effectively.

 

 

That is my understanding

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

 

[roswella...@gmail.com]

Brian,

if I recall from the original page concerning the Beta, you are using a G11 with G2 as well. Or maybe just a G11. Either way, how are you doing it? I apologize for the ignorance but being a new G11 owner with RA issues and trying to get better guiding seems to be aloof. I thought you ran the PEC in the Gemini 2, once trained, you played back after rebooting the G2, then turned on guiding. Now with PPEC, it should then figure it out(?)

I'm not using PEMPro pr PECPREP as I didnt think they were compatible unless running Maxim or other programs.

CJ

[Brian Valente]

Hey CJ

 

Yes I have the G11T with G2.

 

Mostly you got it right except the built-in PEC of the gemini isn’t too good imho.

 

There’s also a 2 worm cycle PE error that I don’t think built-in PEC handles, but I’m not sure

 

I can’t speak for PECPrep, but PEMPro works really well with Gemini 2 mounts from Losmandy, no other stuff is needed

[Aaron Craig]

Recording PEC by hand or through PhD, aside from the technical differences (machine computed reaction vs human reaction) either method will suffice.

I think people are confused with terms here.

PEC training is the act of recording slew/guide movement commands to the mount. These slew/guide commands boil down to two elements: direction (n/s/e/w) and period (how long to move the mount in that direction). Again, aside from the obvious difference of human (slower, imprecise) vs computed (fast, precise) it doesn't matter where the movement commands come from. 

Same with using a live view and using your pc to send the movement commands.. The software you use to watch the star and issue movement commands manually to keep it centered will have those movements recorded by whatever you are training your PEC with. 

If you are doing anything PEC related on you computer while connected to your mount, the movement commands will be no different than PhD, which is what the program you are working on your PEC will capture.

If you are doing PEC without a computer, then your mount must be capable of storing the movement pulses from your hand control and playing that back.

My question was,  will using PhD's PPEC have an ill effect I'm training /recording my mounts PEC, and looks like it won't. 

Aaron 

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[roswella...@gmail.com]

I believe you are correct on the 2 cycle. I've timed the PEC training in G2 and it takes about 4 minutes which is one cycle. When I've loaded PEC before on playback, it seemed it fought with PHD2 but I had never kept the star in crosshairs until I just recently learned that you have to or PEC doesnt record.

CJ

[Brian Valente]

Yeah sounds like you have the G11 – the worm period is around 312 secs so that makes sense

 

I do think there’s a way to set the worm period for longer than one – it’s in the ASCOM interface under PEC options

[Brian Valente]

>>> will using PhD's PPEC have an ill effect I'm training /recording my mounts PEC, and looks like it won't. 

 

If you are using PHD logs as your recording, then no

 

I use PEMPro so any sort of guiding turned on would screw up it’s recording of the star movements, and probably make the mount’s PE look far less than it actually is.

 

So I turn off guiding while recording that data

 

 

I hope that additional clarification makes sense and where I agree with you in some circumstances

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

 

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[roswella...@gmail.com]

I'm trying to get to the ccdware website and it doesn't seem to be up and running. So two questions if the website comes up and before I invest money here....

- I assume ccdware is just the name and a CMOS camera will work fine?

- Does anyone know of any videos showing how it works and operations? Not seeing anything on Youtube.

CJ

[Brian Valente]

CJ are you referring to PEMPro?

 

Any camera with ASCOM interface is fine

 

Regarding operation, again if it’s PEMPro just drop me an email I’d be happy to explain it

[roswella...@gmail.com]

Yeah. Googled PEMPro, takes me to a CCDWARE.com link, click on it and the web page is down.

CJ

[Brian Valente]

It’s pretty straightforward if you know what buttons to push.

 

Does a great job of walking you through things and spitting out a well calibrated curve correction, just mho

[roswella...@gmail.com]

Hi Brian,

question. I uploaded the free trial of PemPro and ran it. Was pretty simple and the help guide  worked well. However, I ran it for 35 minutes and when I went to analyze the data, it came up with all "0's". I cannot believe I have a perfect mount. Is the trial version not allowed to record/analyze the data? Do you need the full version for this?

Also, should you run and record PEC in the mount and play back to PHD2 and also run PPEC or is PPEC ran onto itself?

CJ

On Thursday, January 25, 2018 at 2:15:55 AM UTC-5, aaron craig wrote:

[Brian Valente]

Hi DJ

 

Yeah, all zeros is probably not realistic ;) I don’t believe you need the full version I think the trial is fully working for a limited tiem

 

When you train the mount, make sure you are following all the instructions including calibrating the mount. all the details re: resolution, mount type, etc. are all important so make sure they are correct

 

When you are gathering data make sure you are not guiding, it should be running on its own without any assistance

 

hth

 

Thanks

 

Brian

 

 

Brian Valente

Brianvalentephotography.com

 

From: open-phd...@googlegroups.com [mailto:open-phd...@googlegroups.com] On Behalf Of roswella...@gmail.com

Sent: Wednesday, March 14, 2018 7:07 AM
To: Open PHD Guiding <open-phd...@googlegroups.com>

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[Andy Galasso]

On Wed, Mar 14, 2018 at 10:06 AM, <roswella...@gmail.com> wrote:

question. I uploaded the free trial of PemPro and ran it. Was pretty simple and the help guide  worked well. However, I ran it for 35 minutes and when I went to analyze the data, it came up with all "0's". I cannot believe I have a perfect mount. Is the trial version not allowed to record/analyze the data? Do you need the full version for this?

a good question for the Pempro forum

 

Also, should you run and record PEC in the mount and play back to PHD2 and also run PPEC or is PPEC ran onto itself?

Check out this informative recent post from Bruce regarding PEC + PPEC. In a nutshell, they work independently of each other and both will improve your RA tracking. PEC, if done correctly, results in smoother RA tracking before PHD2 sees it. In some cases you may be able to use one or the other, but generally the recommendation is to use both: first use your PEC application to train the mount's PEC. Then, use PHD2's Predictive PEC to correct any residual error.

In some cases you can skip using PEC in the mount and just use PPEC. For example, my mount has a problem with PEC where the PE profile is different on either side of the the meridian.  If I train PEC on the east, it makes my east side tracking very smooth (<1" PE amplitude) but on the west side the tracking is worse than if PEC is not used at all.  For this reason I cannot use PEC with this mount and only use PPEC, and PPEC does a wonderful job of removing the PE on both sides of the meridian.

Andy