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PecPrep files to lx200gps

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#1 Wford

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Posted 29 June 2020 - 04:08 AM

IS it possible to analyse your PE with PecPrep and then somehow get that correction curve upload back to meade lx200 gsp



#2 OzAndrewJ

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Posted 29 June 2020 - 04:53 AM

Gday Wayne

Possible? Yes

Easy?   Depends

If you want to simply record the PEC model in EQMod and then play it back to the mount in one session ( using pulse guides ), then its pretty simple, as the whole process is synchronised.

If you want to do a direct load, you need to be able the get the PEC error/direction/phase correct.

That can be done using my PEC editor, but its a very fiddly process, and you also need to have a rough PEC model programmed into the mount to act as a template to synchronise the new data.

Did i mention its very fiddly.

 

Andrew Johansen Melbourne Australia



#3 Wford

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Posted 29 June 2020 - 05:53 AM

HI Andrew

I guess just option one.I just wanted to use PecPrep to analyze the curve and generate a correction curve through it fitting process, and somehow get that back to the mount. 

Would I then just trigger the PEC training on the mount and then playback the correction curve

I have read about how people struggle with this process, hence the reason for asking some advice before I try it at the scope

 



#4 OzAndrewJ

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Posted 29 June 2020 - 06:33 AM

Gday Wayne

 

I guess just option one.I just wanted to use PecPrep to analyze the curve and generate a correction curve through it fitting process, and somehow get that back to the mount.

I believe that is possible, but dont know the low level details, other than it needs to be done in a single session in order to keep synchronisation.

It might pay to ask on the PHD2 forum for the specific details on the procedure to follow.

ie i am not sure if their PEC processing allows for the fact that the Meade mechanisml

requires 3 turns of the worm for a unique PEC model

 

Andrew Johansen Melbourne Australia


Edited by OzAndrewJ, 29 June 2020 - 06:35 AM.


#5 Wford

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Posted 29 June 2020 - 07:05 AM

Is there possibly another option other then PEMPRO to get this done that you can recommend



#6 OzAndrewJ

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Posted 29 June 2020 - 05:18 PM

Gday Wayne

 

For creating a model via FFT then loading, AFAIK, only PEMPro does it ( for the Meade 3 turn model )

For using smoothed or recreated data, my PEC editor can read and average/smooth

multiple datasets then directly reload to the mount,

but it requires you to train the mount several times using std guiding methods

and save the models from the mount after each train.

 

Andrew Johansen Melbourne Australia



#7 Wford

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Posted 30 June 2020 - 04:45 AM

Last night I tried using PHD2 while training the drive but I used pulse guiding. Not sure of it worked yet.It seemed to go through he motion.I then update the curve via the same method. I download the your software and manged to read the load the curve form the mount. If you are willing, I will appreciated it if some one can have a look at it?

Do you perhaps have the help file available, I cant seem to download that?



#8 Wford

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Posted 30 June 2020 - 04:54 AM

Here is the PEC files I managed to get out of the scope.I cant seem to load the .pec file here

Attached Files



#9 OzAndrewJ

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Posted 30 June 2020 - 05:18 AM

Gday Wayne

That data format means nothing to me???

Where did you get it from??

Andrew Johansen Melbourne Australia



#10 Wford

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Posted 30 June 2020 - 07:13 AM

I tried to export out of myscope in .xls and .PEC.I cant seem to upload the .PEC file here. Here is a link to a google drive link to it.Not sure what I am doing yet so it is possible i am just embarrassing mysef at the moment.confused1.gif

 

 https://drive.google...iew?usp=sharing



#11 OzAndrewJ

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Posted 30 June 2020 - 04:31 PM

Gday Wayne

Hmm, if it is an excell export from my app, it appears odd ( but i havent used excel export for 15 years :-)

 

Here is a link to a google drive link to it.

No use to me lol.gif  as Google expects me to create an account before i can access it.

( not going to happen )

I cant see why you couldnt load the pec file here, its tiny.

Maybe its an unknown extension that the site filter doesnt like, so maybe zip it, or rename it to *.txt

i will just rename it to view

Andrew Johansen Melbourne Australia



#12 Wford

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Posted 01 July 2020 - 01:57 AM

I renamed the extention.I hope this works

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#13 OzAndrewJ

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Posted 01 July 2020 - 02:28 AM

Gday Wayne

That data loaded OK waytogo.gif

Will review it in more detail tomorrow morning when my mind is fresh,

but it does look like an LX200 model :-)

 

Andrew



#14 Wford

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Posted 01 July 2020 - 02:43 AM

Thank you appreciated



#15 OzAndrewJ

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Posted 01 July 2020 - 10:16 PM

Gday Wayne

 

Well after looking at your data, it looks like something in the gearbox was causing some rapid spikes at times

but the FFT analysis pulls out harmonics that dont match the gearbox teethcounts.

Not sure why???

Can you waste a moonlit night soon and grab say 1-1/2 hrs of unguided data

( ie 9 revs of the worm = 3 PEC periods )

This might show up some data that doesnt appear in the processed model in the mount.

 

Andrew Johansen Melbourne Australia



#16 Wford

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Posted 02 July 2020 - 02:45 AM

 HI Andrew thank you for taking a look. Yes I can do that.Just a PHD log with guiding outputs disabled?

The DEC drive has an enormous amount of backlash. The Buck's Precision Gears  arrived so I need to install those and see if I can get a better mesh and improved backlash. But that should not have influenced the RA graph I guess?



#17 OzAndrewJ

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Posted 02 July 2020 - 03:24 AM

Gday Wayne

 

Just a PHD log with guiding outputs disabled?

Yep. DEC lash is irrelevant for this test, just grab the unguided data and we can cross check it

against the stored PEC model for consistency.

If the stored model is a close match, we can use several PEC trains that get averaged and smoothed

to backload to the mount, thus bypassing the need to load the "smoothed" curve via guiding.

 

 

 

The DEC drive has an enormous amount of backlash. The Buck's Precision Gears  arrived so I need to install those and see if I can get a better mesh and improved backlash. But that should not have influenced the RA graph I guess?

Depends.

If you have large DEC lash, and PHD has a large lash reversal value,

it can take a long time for it to finish, and whilst it is running, the RA cannot be guided.

All a game of diminishing returns, but that said, have you measured the DEC lash????

 

Andrew Johansen Melbourne Australia



#18 Wford

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Posted 02 July 2020 - 09:17 AM

This is what PHD report after running the guiding assistant for DEC backlash. I will try and do the run tonight  and report the guide log back

   

Attached Thumbnails

  • dec backlash.JPG


#19 OzAndrewJ

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Posted 02 July 2020 - 04:46 PM

Gday Wayne

If they have converted it to be 26 arcsec, then that is quite good for a Meade.

If you do a drive train to measure the lash, the resulting value is the "equivalent" arcsecs of axle movement

that the motor needs tospin to start moving. Normal numbers are 50-70

What you can do is do a proper drive train, then try upping the DEC lash percentage,

to apply a lot of the lash fast on reversing.

Just play with the lash %  till it reverses fast without jumping.

 

Andrew Johansen Melbourne Australia



#20 Wford

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Posted Yesterday, 02:33 AM

I will try the drive train later today and report back.Good to know it is not as bad as I though.I am just not used to it being this large compared to my other mount

Here is the PHD guiding log. I did two runs one with the PEC on in the mount and one without

Attached Files



#21 Wford

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Posted Yesterday, 02:37 AM

Hi Andrew when you refer to spikes  what do you look for? Just trying to educate myself. Attached is the PHD data without PEC 

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#22 OzAndrewJ

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Posted Yesterday, 02:48 AM

Gday Wayne

 

I am just not used to it being this large compared to my other mount

The beauty of Meade datasets is they are consistently inconsistent.

I  have seen some with PE near 100 arcsecs Pk-Pk and others near 5arcsec

They are a chooks lottery in what you get.

 

 

Hi Andrew when you refer to spikes  what do you look for?

Sharp rapid reversals at a higher frequency than the worm period.

 

Andrew Johansen Melbourne Australia



#23 OzAndrewJ

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Posted Yesterday, 04:38 AM

Gday Wayne

 

Here is the PHD guiding log. I did two runs one with the PEC on in the mount and one without

Not sure thats right, as both data sets look pretty similar

ie PEC was off for both, or you didnt have a stored PEC model

 

Andrew Johansen Melbourne Australia



#24 Wford

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Posted Yesterday, 04:59 AM

Hi Andrew

Yes I did have a model loaded. Maybe I made some mistake in loading it or deactivating it?Not sure still try to learn about this.

I just change the setting to PEC off under the RA PEC settings for the second run.

Do you think this is a workable mount?




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