Re: [ap-gto] 10arcsec oscillation: Re: AP900GTO - Factory PEC Curve


Sep 24, 2009

 


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

#25781 Sep 24, 2009

Have there been issues with the PEC curves that are supposed to be customized to the new mount... or did I do something wrong? I just setup the mount, computer, and PEMPro, and downloaded the curve from the mount. This is what I got:



(watch out for line wrap)

www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg



Does anyone know what happened here? I know of one other person with a recent mount who had a similar issue.



Thanks,

Daniel Perry

www.californiastars.net/



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

#25782 Sep 24, 2009

Daniel,



Assuming there was no error reading the PEC data it sure looks like bad

data.



-Ray

> -----Original Message-----

> From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]

> On Behalf Of dannysperry

> Sent: Thursday, September 24, 2009 5:14 PM

> To: ap-gto@yahoogroups.com

> Subject: [ap-gto] AP900GTO - Factory PEC Curve

>

>

>

> Have there been issues with the PEC curves that are supposed

> to be customized to the new mount... or did I do something

> wrong? I just setup the mount, computer, and PEMPro, and

> downloaded the curve from the mount. This is what I got:

>

> (watch out for line wrap)

> www.californiastars.net/images/help/AP900_PEMPro_FromMo

unt.jpg www.californiastars.net/images/help/AP900>

_PEMPro_FromMount.jpg> >

> Does anyone know what happened here? I know of one other

> person with a recent mount who had a similar issue.

>

> Thanks,

> Daniel Perry

> www.californiastars.net/ www.californiastars.net/>

>

>

>

>

>



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

#25784 Sep 25, 2009

Hi Danny,



That was me, and mine looked exactly like yours.



Dean





----- Original Message -----

From: "dannysperry" danny@...>

To: ap-gto@yahoogroups.com>

Sent: Thursday, September 24, 2009 8:14 PM

Subject: [ap-gto] AP900GTO - Factory PEC Curve





> Have there been issues with the PEC curves that are supposed to be

customized to the new mount... or did I do something wrong? I just setup the

mount, computer, and PEMPro, and downloaded the curve from the mount. This

is what I got:

>

> (watch out for line wrap)

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg

>

> Does anyone know what happened here? I know of one other person with a

recent mount who had a similar issue.

>

> Thanks,

> Daniel Perry

> www.californiastars.net/

>

>

>

>

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

>

> To UNSUBSCRIBE, or for general information on the ap-gto list

> see groups.yahoo.com/group/ap-gtoYahoo! Groups Links

>

>

>



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

#25785 Sep 25, 2009

Wanted to say, it was not a big deal to do a few runs and make my own curve.

Just was surprised it was not there.



But with the small, and smooth PE of both my 1200 and this new 900, it

really is not even necessary to run PEC when guiding anyways. I had a Mach1

for a year, which the 900 replaced, and never even bothered to check the PE

on it since it guided perfectly from day one.



Dean



----- Original Message -----

From: "Dean S" dean@...>

To: ap-gto@yahoogroups.com>

Sent: Friday, September 25, 2009 8:51 AM

Subject: Re: [ap-gto] AP900GTO - Factory PEC Curve





> Hi Danny,

>

> That was me, and mine looked exactly like yours.

>

> Dean

>

>

>

> ----- Original Message -----

> From: "dannysperry" danny@...>

> To: ap-gto@yahoogroups.com>

> Sent: Thursday, September 24, 2009 8:14 PM

> Subject: [ap-gto] AP900GTO - Factory PEC Curve

>

>

> > Have there been issues with the PEC curves that are supposed to be

> customized to the new mount... or did I do something wrong? I just setup

the

> mount, computer, and PEMPro, and downloaded the curve from the mount. This

> is what I got:

> >

> > (watch out for line wrap)

> > www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg

> >

> > Does anyone know what happened here? I know of one other person with a

> recent mount who had a similar issue.

> >

> > Thanks,

> > Daniel Perry

> > www.californiastars.net/

> >

> >

> >

> >

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

> >

> > To UNSUBSCRIBE, or for general information on the ap-gto list

> > see groups.yahoo.com/group/ap-gtoYahoo! Groups Links

> >

> >

> >

>

>

>

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

>

> To UNSUBSCRIBE, or for general information on the ap-gto list

> see groups.yahoo.com/group/ap-gtoYahoo! Groups Links

>

>

>



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

#25786 Sep 25, 2009

Hi Daniel,







Give me a call at AP to discuss. I believe that for some reason the

PEC data didn't actually get saved to the mount, even though I can't

imagine how that would happen since we run the program a second time

with PEC on to verify that the curve is loaded and correcting PE

properly. The 255 values are the default values in a blank chip.







Please have your mount serial number available when you call.







If you have everything set up anyway, you might just want to go ahead

and record a new PE curve using an actual star and more worm cycles than

we can do here. Ray usually recommends 6 or so. I ran 8 cycles on my

Mach1GTO and now measure +0.4/-0.4!







Mag. 7 skies!







Howard Hedlund



Astro-Physics, Inc.



815-282-1513



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



From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] On Behalf

Of Ray Gralak (Yahoo Groups)

Sent: Thursday, September 24, 2009 10:56 PM

To: ap-gto@yahoogroups.com

Subject: RE: [ap-gto] AP900GTO - Factory PEC Curve











Daniel,



Assuming there was no error reading the PEC data it sure looks like bad

data.



-Ray

> -----Original Message-----

> From: ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

[mailto:ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com> ] > On Behalf Of dannysperry

> Sent: Thursday, September 24, 2009 5:14 PM

> To: ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

> Subject: [ap-gto] AP900GTO - Factory PEC Curve

>

>

>

> Have there been issues with the PEC curves that are supposed

> to be customized to the new mount... or did I do something

> wrong? I just setup the mount, computer, and PEMPro, and

> downloaded the curve from the mount. This is what I got:

>

> (watch out for line wrap)

> www.californiastars.net/images/help/AP900_PEMPro_FromMo

www.californiastars.net/images/help/AP900_PEMPro_FromMo>

unt.jpg www.californiastars.net/images/help/AP900

www.californiastars.net/images/help/AP900> >

_PEMPro_FromMount.jpg> >

> Does anyone know what happened here? I know of one other

> person with a recent mount who had a similar issue.

>

> Thanks,

> Daniel Perry

> www.californiastars.net/ www.californiastars.net/>

www.californiastars.net/ www.californiastars.net/> > >

>

>

>

>











[Non-text portions of this message have been removed]







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

#25787 Sep 25, 2009

Hi Daniel,



In my AP900 the PEC curve was properly present when the maount was delivered by AP. Just as a backup measure I used PEMpro to retrieve the curve from the mount and save it to my computer. (Later I never had a problem with it so I never needed the backup) When I turned the PEC curve off I found a (for AP) surprisingly large error of +/- 5arcsec for a total oscillation of 10arcsec. The spec on their web page says 7arcsec is their limit. Maybe something went wrong in the production of mine. PEMpro fixed it to better than +/-2arcsec. The wear in the gears will make a new curve necessary over time anyway. Does anybody know how often that should be done?



Clear Skies,

Gert



--- In ap-gto@yahoogroups.com, "dannysperry" danny@...> wrote:

>

> Have there been issues with the PEC curves that are supposed to be customized to the new mount... or did I do something wrong? I just setup the mount, computer, and PEMPro, and downloaded the curve from the mount. This is what I got:

>

> (watch out for line wrap)

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg

>

> Does anyone know what happened here? I know of one other person with a recent mount who had a similar issue.

>

> Thanks,

> Daniel Perry

> www.californiastars.net/

>



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

#25788 Sep 25, 2009

Gert,



If you had +/-2 arc-secs *after* PEMPro correction I suspect the image scale

might have been set incorrectly so the measured value could have been wrong.

If you use your mount regularly I recommend you check the periodic error

every few months and redo it if measured PE with PEM enabled is more than

1.5 arc-secs peak-peak.



-Ray

> -----Original Message-----

> From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]

> On Behalf Of drgert1

> Sent: Friday, September 25, 2009 9:42 AM

> To: ap-gto@yahoogroups.com

> Subject: [ap-gto] 10arcsec oscillation: Re: AP900GTO -

> Factory PEC Curve

>

>

>

> Hi Daniel,

>

> In my AP900 the PEC curve was properly present when the

> maount was delivered by AP. Just as a backup measure I used

> PEMpro to retrieve the curve from the mount and save it to my

> computer. (Later I never had a problem with it so I never

> needed the backup) When I turned the PEC curve off I found a

> (for AP) surprisingly large error of +/- 5arcsec for a total

> oscillation of 10arcsec. The spec on their web page says

> 7arcsec is their limit. Maybe something went wrong in the

> production of mine. PEMpro fixed it to better than

> +/-2arcsec. The wear in the gears will make a new curve

> necessary over time anyway. Does anybody know how often that

> should be done?

>

> Clear Skies,

> Gert

>

> --- In ap-gto@yahoogroups.com

> mailto:ap-gto%40yahoogroups.com> , "dannysperry" danny@...> wrote:

> >

> > Have there been issues with the PEC curves that are

> supposed to be customized to the new mount... or did I do

> something wrong? I just setup the mount, computer, and

> PEMPro, and downloaded the curve from the mount. This is what I got:

> >

> > (watch out for line wrap)

> >

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg

> >

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg

> > >

> >

> > Does anyone know what happened here? I know of one other

> person with a recent mount who had a similar issue.

> >

> > Thanks,

> > Daniel Perry

> > www.californiastars.net/ www.californiastars.net/>

> >

>

>

>

>

>



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

#25789 Sep 25, 2009

In a message dated 9/25/2009 11:42:42 AM Central Daylight Time,

drgert1@... writes:



> When I turned the PEC curve off I found a (for AP) surprisingly large

> error of +/- 5arcsec for a total oscillation of 10arcsec.



You can measure the PE also by simply taking a 7 minute unguided exposure

with PEM turned off. Allow the declination to drift slowly by offsetting the

azimuth axis. You will get a sinusoidal trail on your exposure, and you can

then measure the peak to peak error in arc seconds using your pixel scale.

This can be compared to what you get in PEMPro as a backup measurement, sort

of a sanity check on your measurements.



Rolando





[Non-text portions of this message have been removed]



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

#25805 Sep 27, 2009

Hi Ray et al,



Please take a look at the uploaded PEMPro files.



Native AP900 with factory PEC off showing +4.6/-5.3arcsec of periodic error:

www.trivalleystargazers.org/gert/download/PemPro-2009-08-17-214814_AP900_initial.txt



It is somewhat concerning to me that this is above the published AP spec.



Same AP900 after applying PEC now showing +0.7/-1.0arcsec periodic error:

www.trivalleystargazers.org/gert/download/PemPro-2009-08-17-222724_AP900_withPEC.txt



The camera is an ST10 and the scope an AP130 F6.3 at 820.1mm fl (pixel scale 1.71" x 1.71")



Clear Skies,

Gert



--- In ap-gto@yahoogroups.com, "Ray Gralak \(Yahoo Groups\)" yahoo@...> wrote:

>

> Gert,

>

> If you had +/-2 arc-secs *after* PEMPro correction I suspect the image scale

> might have been set incorrectly so the measured value could have been wrong.

> If you use your mount regularly I recommend you check the periodic error

> every few months and redo it if measured PE with PEM enabled is more than

> 1.5 arc-secs peak-peak.

>

> -Ray

>

> > -----Original Message-----

> > From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]

> > On Behalf Of drgert1

> > Sent: Friday, September 25, 2009 9:42 AM

> > To: ap-gto@yahoogroups.com

> > Subject: [ap-gto] 10arcsec oscillation: Re: AP900GTO -

> > Factory PEC Curve

> >

> >

> >

> > Hi Daniel,

> >

> > In my AP900 the PEC curve was properly present when the

> > maount was delivered by AP. Just as a backup measure I used

> > PEMpro to retrieve the curve from the mount and save it to my

> > computer. (Later I never had a problem with it so I never

> > needed the backup) When I turned the PEC curve off I found a

> > (for AP) surprisingly large error of +/- 5arcsec for a total

> > oscillation of 10arcsec. The spec on their web page says

> > 7arcsec is their limit. Maybe something went wrong in the

> > production of mine. PEMpro fixed it to better than

> > +/-2arcsec. The wear in the gears will make a new curve

> > necessary over time anyway. Does anybody know how often that

> > should be done?

> >

> > Clear Skies,

> > Gert

> >

> > --- In ap-gto@yahoogroups.com

> > mailto:ap-gto%40yahoogroups.com> , "dannysperry" danny@> wrote:

> > >

> > > Have there been issues with the PEC curves that are

> > supposed to be customized to the new mount... or did I do

> > something wrong? I just setup the mount, computer, and

> > PEMPro, and downloaded the curve from the mount. This is what I got:

> > >

> > > (watch out for line wrap)

> > >

> > www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg

> > >

> > www.californiastars.net/images/help/AP900_PEMPro_FromMount.jpg

> > > >

> > >

> > > Does anyone know what happened here? I know of one other

> > person with a recent mount who had a similar issue.

> > >

> > > Thanks,

> > > Daniel Perry

> > > www.californiastars.net/ www.californiastars.net/>

> > >

> >

> >

> >

> >

> >

>







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

#25807 Sep 28, 2009

Gert,



The original data set has an irregular first cycle which may be skewing the

results. Would you mind collecting another 6 cycles on the next night you

have a chance? The frequency spectrum of the data with PEC OFF shows mostly

the worm and a 2x fundamental. After correction there is still a little of

both fundamentals present.



Also, how old is this AP900?



-Ray

> Hi Ray et al,

>

> Please take a look at the uploaded PEMPro files.

>

> Native AP900 with factory PEC off showing +4.6/-5.3arcsec of

> periodic error:

> www.trivalleystargazers.org/gert/download/PemPro-2009-0

> 8-17-214814_AP900_initial.txt

> www.trivalleystargazers.org/gert/download/PemPro-2009-

> 08-17-214814_AP900_initial.txt>

>

> It is somewhat concerning to me that this is above the

> published AP spec.

>

> Same AP900 after applying PEC now showing +0.7/-1.0arcsec

> periodic error:

> www.trivalleystargazers.org/gert/download/PemPro-2009-0

> 8-17-222724_AP900_withPEC.txt

> www.trivalleystargazers.org/gert/download/PemPro-2009-

> 08-17-222724_AP900_withPEC.txt>

>

> The camera is an ST10 and the scope an AP130 F6.3 at 820.1mm

> fl (pixel scale 1.71" x 1.71")

>

> Clear Skies,

> Gert

>

> --- In ap-gto@yahoogroups.com

> mailto:ap-gto%40yahoogroups.com> , "Ray Gralak \(Yahoo

> Groups\)" yahoo@...> wrote:

> >

> > Gert,

> >

> > If you had +/-2 arc-secs *after* PEMPro correction I

> suspect the image

> > scale might have been set incorrectly so the measured value

> could have been wrong.

> > If you use your mount regularly I recommend you check the periodic

> > error every few months and redo it if measured PE with PEM

> enabled is

> > more than

> > 1.5 arc-secs peak-peak.

> >

> > -Ray

> >

> > > -----Original Message-----

> > > From: ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

> > > [mailto:ap-gto@yahoogroups.com

> mailto:ap-gto%40yahoogroups.com> ]

> > > On Behalf Of drgert1

> > > Sent: Friday, September 25, 2009 9:42 AM

> > > To: ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

> > > Subject: [ap-gto] 10arcsec oscillation: Re: AP900GTO -

> Factory PEC

> > > Curve

> > >

> > >

> > >

> > > Hi Daniel,

> > >

> > > In my AP900 the PEC curve was properly present when the

> maount was

> > > delivered by AP. Just as a backup measure I used PEMpro

> to retrieve

> > > the curve from the mount and save it to my computer.

> (Later I never

> > > had a problem with it so I never needed the backup) When I turned

> > > the PEC curve off I found a (for AP) surprisingly large

> error of +/-

> > > 5arcsec for a total oscillation of 10arcsec. The spec on

> their web

> > > page says 7arcsec is their limit. Maybe something went

> wrong in the

> > > production of mine. PEMpro fixed it to better than

> > > +/-2arcsec. The wear in the gears will make a new curve

> > > necessary over time anyway. Does anybody know how often

> that should

> > > be done?

> > >

> > > Clear Skies,

> > > Gert

> > >

> > > --- In ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

> > > mailto:ap-gto%40yahoogroups.com> , "dannysperry" danny@> wrote:

> > > >

> > > > Have there been issues with the PEC curves that are

> > > supposed to be customized to the new mount... or did I do

> something

> > > wrong? I just setup the mount, computer, and PEMPro, and

> downloaded

> > > the curve from the mount. This is what I got:

> > > >

> > > > (watch out for line wrap)

> > > >

> > >

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.jp

> > > g

> > >

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.j

> > > pg>

> > > >

> > >

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.j

> > > pg

> > >

> www.californiastars.net/images/help/AP900_PEMPro_FromMount.j

> > > pg>

> > > > >

> > > >

> > > > Does anyone know what happened here? I know of one other

> > > person with a recent mount who had a similar issue.

> > > >

> > > > Thanks,

> > > > Daniel Perry

> > > > www.californiastars.net/

> www.californiastars.net/>

> > > > www.californiastars.net/

> www.californiastars.net/>

> > > > >

> > > >

> > >

> > >

> > >

> > >

> > >

> >

>

>

>

>

>



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

#25811 Sep 28, 2009

Hi Ray,



Hmm, why would there be an irregular cycle? There was plenty of time before the recording was started for the gears to get going.



I took delivery of this AP900 brand new from AP in Feb 2007. It has seen normal usage, since. (1-2 weekends around the new moons)



It was of the series where AP had started to include pre-programmed PEC into shipped mounts. Maybe they loosened the pre-PEC tracking specs in their productions and fix it later in the PEC.



Thanks & Clear Skies,

Gert



--- In ap-gto@yahoogroups.com, "Ray Gralak \(Yahoo Groups\)" yahoo@...> wrote:

>

> Gert,

>

> The original data set has an irregular first cycle which may be skewing the

> results. Would you mind collecting another 6 cycles on the next night you

> have a chance? The frequency spectrum of the data with PEC OFF shows mostly

> the worm and a 2x fundamental. After correction there is still a little of

> both fundamentals present.

>

> Also, how old is this AP900?

>

> -Ray

>

> > Hi Ray et al,

> >

> > Please take a look at the uploaded PEMPro files.

> >

> > Native AP900 with factory PEC off showing +4.6/-5.3arcsec of

> > periodic error:

> > www.trivalleystargazers.org/gert/download/PemPro-2009-0

> > 8-17-214814_AP900_initial.txt

> > www.trivalleystargazers.org/gert/download/PemPro-2009-

> > 08-17-214814_AP900_initial.txt>

> >

> > It is somewhat concerning to me that this is above the

> > published AP spec.

> >

> > Same AP900 after applying PEC now showing +0.7/-1.0arcsec

> > periodic error:

> > www.trivalleystargazers.org/gert/download/PemPro-2009-0

> > 8-17-222724_AP900_withPEC.txt

> > www.trivalleystargazers.org/gert/download/PemPro-2009-

> > 08-17-222724_AP900_withPEC.txt>

> >

> > The camera is an ST10 and the scope an AP130 F6.3 at 820.1mm

> > fl (pixel scale 1.71" x 1.71")

> >

> > Clear Skies,

> > Gert

> >

> > --- In ap-gto@yahoogroups.com

> > mailto:ap-gto%40yahoogroups.com> , "Ray Gralak \(Yahoo

> > Groups\)" yahoo@> wrote:

> > >

> > > Gert,

> > >

> > > If you had +/-2 arc-secs *after* PEMPro correction I

> > suspect the image

> > > scale might have been set incorrectly so the measured value

> > could have been wrong.

> > > If you use your mount regularly I recommend you check the periodic

> > > error every few months and redo it if measured PE with PEM

> > enabled is

> > > more than

> > > 1.5 arc-secs peak-peak.

> > >

> > > -Ray

> > >

> > > > -----Original Message-----

> > > > From: ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

> > > > [mailto:ap-gto@yahoogroups.com

> > mailto:ap-gto%40yahoogroups.com> ]

> > > > On Behalf Of drgert1

> > > > Sent: Friday, September 25, 2009 9:42 AM

> > > > To: ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

> > > > Subject: [ap-gto] 10arcsec oscillation: Re: AP900GTO -

> > Factory PEC

> > > > Curve

> > > >

> > > >

> > > >

> > > > Hi Daniel,

> > > >

> > > > In my AP900 the PEC curve was properly present when the

> > maount was

> > > > delivered by AP. Just as a backup measure I used PEMpro

> > to retrieve

> > > > the curve from the mount and save it to my computer.

> > (Later I never

> > > > had a problem with it so I never needed the backup) When I turned

> > > > the PEC curve off I found a (for AP) surprisingly large

> > error of +/-

> > > > 5arcsec for a total oscillation of 10arcsec. The spec on

> > their web

> > > > page says 7arcsec is their limit. Maybe something went

> > wrong in the

> > > > production of mine. PEMpro fixed it to better than

> > > > +/-2arcsec. The wear in the gears will make a new curve

> > > > necessary over time anyway. Does anybody know how often

> > that should

> > > > be done?

> > > >

> > > > Clear Skies,

> > > > Gert

> > > >

> > > > --- In ap-gto@yahoogroups.com mailto:ap-gto%40yahoogroups.com>

> > > > mailto:ap-gto%40yahoogroups.com> , "dannysperry" danny@> wrote:

> > > > >

> > > > > Have there been issues with the PEC curves that are

> > > > supposed to be customized to the new mount... or did I do

> > something

> > > > wrong? I just setup the mount, computer, and PEMPro, and

> > downloaded

> > > > the curve from the mount. This is what I got:

> > > > >

> > > > > (watch out for line wrap)

> > > > >

> > > >

> > www.californiastars.net/images/help/AP900_PEMPro_FromMount.jp

> > > > g

> > > >

> > www.californiastars.net/images/help/AP900_PEMPro_FromMount.j

> > > > pg>

> > > > >

> > > >

> > www.californiastars.net/images/help/AP900_PEMPro_FromMount.j

> > > > pg

> > > >

> > www.californiastars.net/images/help/AP900_PEMPro_FromMount.j

> > > > pg>

> > > > > >

> > > > >

> > > > > Does anyone know what happened here? I know of one other

> > > > person with a recent mount who had a similar issue.

> > > > >

> > > > > Thanks,

> > > > > Daniel Perry

> > > > > www.californiastars.net/

> > www.californiastars.net/>

> > > > > www.californiastars.net/

> > www.californiastars.net/>

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#25813 Sep 28, 2009

In a message dated 9/28/2009 12:57:43 PM Central Daylight Time,

drgert1@... writes:



> Maybe they loosened the pre-PEC tracking specs in their productions and

> fix it later in the PEC.

>



No. We never did any such thing. Pre-PEM is pre-PEM.



Rolando





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