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Re: Pempro session file uploaded to "astroswede" file


Oct 26, 2010

 


----------------------------

#47257 Oct 26, 2010

Mike,(Greg and Jared)

>

> the raw file is now in my folder "astroswede"

> Yes I have noticed the 76s error and it seems to have moved to 80s and it.s high.

> You might say I have to reassemble the OPW but I.m not shure where I went wrong last time.

> (The performance has clearly improved because I can do unguided exposures with 2000mm FL f.r 75 seconds but there is still a lot of improvement to do on both axis.)

>

> Thanks for having a look.

> Timo

>

>

> --- In Losmandy_users@yahoogroups.com, "ma_siniscalchi" helixgate@> wrote:

> >

> > Hi Timo,

> >

> > Can you post a graph with no PEC fitting applied? This will display the raw values. Better yet, if you can upload the PemPro session file for that measurement period I can run it through and have a detailed look. I suspect you should be getting performance especialy with the 76 error which seems high.

> >

> > Thank you,

> > Mike Siniscalchi

> > helixgate.net

> >

> > --- In Losmandy_users@yahoogroups.com, "Astroswede" mybrightstar@> wrote:

> > >

> > >

> > > Hi Mike, welcome back !

> > > If you have time I would appreciate if you could take a look at the FFT analysis of my newly installed OPW. You find it in my Astroswede folder.

> > > tech.groups.yahoo.com/group/Losmandy_users/files/Astroswede/

> > >

> > > Kind regards

> > > Timo Nordberg

> > > Sweden

> > >

> >

>



----------------------------

#47279 Oct 29, 2010

Hi Timo,

I took a look at the PemPro file.

Here is what I noticed when looking at the raw data values (no drift fitting applied)

* Total uncorrected PE = +2.7/-3.2 arc/sec P-P. This is pretty good. My recent PE measurement last night came in at +2.7/-2.2 arc/sec P-P

uncorrected.



* The so called 76 error at fundamental 3 comes in at 1.24 arc sec peak uncorrected. This still seems high. I have found this to be related to preload on the worm bearings being on the high side. I would try to reduce that. Loosen the blocks and slide them only enough until you can see the edge of the worm gear step touch the inner bearing race sleeve. My recent PE measurement last night shows this uncorrected value to be 0.335 arc/sec peak.



* The peak at fundamental 2 comes in at 1.24 arc/sec peak uncorrected.I have found to be directly related to the coupler alignment between the gearbox shaft and worm. This is especially critical with the Ruland coupler used with the OPW. I suggest you recheck your gearbox to worm alignment to minimize this. My last night measurement came in at .733 arc/sec peak.



As a recommendation when selecting a drift fitting is to use the

histogram to get a good defined bell curve. Then compare it with the periodic error graph to ensure the fitted curve is close to the PE.



Happy Tuning!

Mike Siniscalchi

helixgate.net



----------------------------

#47280 Oct 30, 2010

Hi Mike,

Thank you very, very much for analysing my Pempro raw files !

Yes, I saw the 2 peaks that are much higher than those you have on your website.

Now I.m eager to do some "happy tuning".

But I dont really understand you meaning in this sentence." As a recommendation when selecting a drift fitting is to use the

histogram to get a good defined bell curve."

Maybe its too late when reading your post :-)

I.ll try again tomorrow.

Thanks again !

Timo



--- In Losmandy_users@yahoogroups.com, "ma_siniscalchi" helixgate@...> wrote:

>

> Hi Timo,

> I took a look at the PemPro file.

> Here is what I noticed when looking at the raw data values (no drift fitting applied)

> * Total uncorrected PE = +2.7/-3.2 arc/sec P-P. This is pretty good. My recent PE measurement last night came in at +2.7/-2.2 arc/sec P-P

> uncorrected.

>

> * The so called 76 error at fundamental 3 comes in at 1.24 arc sec peak uncorrected. This still seems high. I have found this to be related to preload on the worm bearings being on the high side. I would try to reduce that. Loosen the blocks and slide them only enough until you can see the edge of the worm gear step touch the inner bearing race sleeve. My recent PE measurement last night shows this uncorrected value to be 0.335 arc/sec peak.

>

> * The peak at fundamental 2 comes in at 1.24 arc/sec peak uncorrected.I have found to be directly related to the coupler alignment between the gearbox shaft and worm. This is especially critical with the Ruland coupler used with the OPW. I suggest you recheck your gearbox to worm alignment to minimize this. My last night measurement came in at .733 arc/sec peak.

>

> As a recommendation when selecting a drift fitting is to use the

> histogram to get a good defined bell curve. Then compare it with the periodic error graph to ensure the fitted curve is close to the PE.

>

> Happy Tuning!

> Mike Siniscalchi

> helixgate.net

>



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