Date   

APCC Tracking Corrections Not Working #APCC

dnakic@...
 

I did a 25 point Point Model Solve as I just purchased software (just got the software and doing a small model first).  I was able to get Pointing to work effectively but the tracking is not working.  When I turn on Tracking Correction, I see the stars streak.  My AP1600GTO polar alignment and PEC was just completed recently with Pempro and tracks less than 1.5 arcsec of drift in 5min.  I have the latest software for APCC, 1.8.1.1, ASCOM and drivers, MaximDL Pro, and TheSkyX Pro.  Appreciate help on this matter.


Some screen captures:







5sec image without guiding with Point Correction On and Tracking Correction Off



5sec image without guiding with Point Correction On and Tracking Correction On

 

 


Re: PHD 2 Guiding "Good Enough"

Charles Thompson
 

Thanks Roland, I was able to record a curve for the 1100 and Mach1 Saturday night. I should be able to test them with PhD2 the next time we get another clear night. They are rare in Tennessee this time of year. 



Thanks,
Charles

Sent from mobile device.


-------- Original message --------
From: "uncarollo2 <chris1011@...> via groups.io" <chris1011@...>
Date: 5/4/20 9:31 AM (GMT-06:00)
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"


Can you run PEC while guiding with PhD2?
With the AP mounts, yes absolutely you can run PEM while guiding. There is no conflict whatsoever and it will make guiding better.

Rolando


-----Original Message-----
From: Charles Thompson via groups.io <cthomp97@...>
To: main@ap-gto.groups.io
Sent: Sat, May 2, 2020 2:19 pm
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

I would be happy with your current guiding RMS but I image from the city. My RMS is usually around .5-.8 and that had been fine for any imaging I do.

Can you run PEC while guiding with PhD2? I've read conflicting information on this subject and never really asked. I've always left it turned off since my stars are good. 



Thanks,
Charles

Sent from mobile device.


-------- Original message --------
From: Dean Jacobsen <deanjacobsen@...>
Date: 5/2/20 12:47 PM (GMT-06:00)
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

Yes, one can certainly get sucked down the guiding perfection black hole.  As Brian has said, how do your stars look?  Are you happy with the stacked images?

However, as Roland noted, there is some room for improvement that really doesn't take a lot of time.  Use PEM Pro to evaluate your native periodic error and then have the software create a new solution.  You will be amazed at the difference when you run the PE analysis again in PemPro with the new PE solution running.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: PHD 2 Guiding "Good Enough"

Roland Christen
 


Can you run PEC while guiding with PhD2?
With the AP mounts, yes absolutely you can run PEM while guiding. There is no conflict whatsoever and it will make guiding better.

Rolando


-----Original Message-----
From: Charles Thompson via groups.io <cthomp97@...>
To: main@ap-gto.groups.io
Sent: Sat, May 2, 2020 2:19 pm
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

I would be happy with your current guiding RMS but I image from the city. My RMS is usually around .5-.8 and that had been fine for any imaging I do.

Can you run PEC while guiding with PhD2? I've read conflicting information on this subject and never really asked. I've always left it turned off since my stars are good. 



Thanks,
Charles

Sent from mobile device.


-------- Original message --------
From: Dean Jacobsen <deanjacobsen@...>
Date: 5/2/20 12:47 PM (GMT-06:00)
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

Yes, one can certainly get sucked down the guiding perfection black hole.  As Brian has said, how do your stars look?  Are you happy with the stacked images?

However, as Roland noted, there is some room for improvement that really doesn't take a lot of time.  Use PEM Pro to evaluate your native periodic error and then have the software create a new solution.  You will be amazed at the difference when you run the PE analysis again in PemPro with the new PE solution running.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: PHD 2 Guiding "Good Enough"

Dean Jacobsen
 

OK, after pulling the imaging computer out and looking at the PHD2 settings I see that under the Algorithms/Mount Guide Algorithms/Right Ascension settings I am not using Predictive PEC.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: PHD 2 Guiding "Good Enough"

Dean Jacobsen
 

I’m confused now.  What are you guys talking about?  I guide my mount with PHD2 and with the mount’s on board PEC/PEM turned on.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: PHD 2 Guiding "Good Enough"

Ray Gralak
 

Bryan,

You wrote:
Did you mean PPEC algorithm? There is no PHD2 algorithm in PHD2.
Yes, the PPEC algorithm is in PHD2, so I consider it a "PHD2 algorithm".

My intent was not to 'hype' PPEC, but to answer the OP's original question about PEC and guiding. I extracted
info from the PHD2 Help that discusses that question and it happens to fall in the PPEC portion of the manual.
Understood! I was just pointing out that using that PHD2 algorithm should not provide any benefit over using AP's PEC (aka PEM). In fact, if it falsely identified frequencies it may be detrimental.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Worsel via groups.io
Sent: Sunday, May 3, 2020 2:18 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

Ray

You wrote
"I would not rely on the PHD2 algorithm for most AP mounts. It will not be able to accurately predict any residual
periodic error that could already be taken out by AP's PEC mechanism. It may be useful if there is periodic error
not correctable by PEC because it doesn't repeat in phase every worm cycle, but there are very few cases where
that might happen. "

Did you mean PPEC algorithm? There is no PHD2 algorithm in PHD2.

My intent was not to 'hype' PPEC, but to answer the OP's original question about PEC and guiding. I extracted
info from the PHD2 Help that discusses that question and it happens to fall in the PPEC portion of the manual.

Bryan


Re: PHD 2 Guiding "Good Enough"

Worsel
 

Ray

You wrote
"I would not rely on the PHD2 algorithm for most AP mounts. It will not be able to accurately predict any residual periodic error that could already be taken out by AP's PEC mechanism. It may be useful if there is periodic error not correctable by PEC because it doesn't repeat in phase every worm cycle, but there are very few cases where that might happen. "

Did you mean PPEC algorithm?  There is no PHD2 algorithm in PHD2.

My intent was not to 'hype' PPEC, but to answer the OP's original question about PEC and guiding.  I extracted info from the PHD2 Help that discusses that question and it happens to fall in the PPEC portion of the manual.

Bryan


Re: PHD 2 Guiding "Good Enough"

Ray Gralak
 

Hi Bryan,

That said, PEC in the mount is never perfect, and you will often see residual repetitive errors even when PEC is
active. These often arise when the tracking errors occur with a frequency that is not a harmonic (integer fraction)
of the mount’s worm period – most PEC implementations can’t deal with those. You can also get residual
periodic errors if they are dependent on the mechanical loading of the mount or if the mount’s behavior has
changed since the PEC was programmed..
I would not rely on the PHD2 algorithm for most AP mounts. It will not be able to accurately predict any residual periodic error that could already be taken out by AP's PEC mechanism. It may be useful if there is periodic error not correctable by PEC because it doesn't repeat in phase every worm cycle, but there are very few cases where that might happen.

Even then, It may not be very effective unless the residual error is truly periodic and you can wait for multiple periods for the phase and amplitude to be determined to reasonable accuracy. For example, the result may inaccurate because portions of continuous timeline tracking data may be missing while image downloading or dithering operations. Just check your PE every few months and update it if necessary. This will provide better overall results. (And a more advanced solution is coming. :-)

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Worsel via groups.io
Sent: Sunday, May 3, 2020 11:59 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

Charles

See Slide 14 in Best Practices for PHD2 <https://openphdguiding.org/PHD2_BestPractices_2019-12.pdf>

Also. from the Help file discussing the PPEC algorithm in PHD2 (note that PPEC guiding algorithm is NOT the
same as PEC in the mount)

·Short-term: for high-frequency errors such as those caused by gear roughness or seeing

·Medium-term: for residual periodic errors, typically occurring at intervals less than or equal to the worm period

·Longer-term: for steady drift and for lower frequency (longer time interval) harmonics that can be caused by the
interaction of multiple gears in the drive train

The short-term behavior is used to identify the unpredictable noise in the system, which is essentially filtered out
in order to identify components that are predictable. For most mounts, the medium-term component is likely to
be the most important. If you’re following best practices, you will have programmed periodic error correction in
your mount (assuming that feature is available to you). Doing this reduces the amount of work that needs to be
done by PHD2, and the PEC correction in the mount is normally saved permanently. This approach is preferable
to having to measure and infer the periodic error behavior every time you set up your equipment.

That said, PEC in the mount is never perfect, and you will often see residual repetitive errors even when PEC is
active. These often arise when the tracking errors occur with a frequency that is not a harmonic (integer fraction)
of the mount’s worm period – most PEC implementations can’t deal with those. You can also get residual
periodic errors if they are dependent on the mechanical loading of the mount or if the mount’s behavior has
changed since the PEC was programmed..

Bryan


Re: PHD 2 Guiding "Good Enough"

Worsel
 

Charles

See Slide 14 in Best Practices for PHD2

Also. from the Help file discussing the PPEC algorithm in PHD2 (note that PPEC guiding algorithm is NOT the same as PEC in the mount)

·Short-term: for high-frequency errors such as those caused by gear roughness or seeing

·Medium-term: for residual periodic errors, typically occurring at intervals less than or equal to the worm period

·Longer-term: for steady drift and for lower frequency (longer time interval) harmonics that can be caused by the interaction of multiple gears in the drive train

The short-term behavior is used to identify the unpredictable noise in the system, which is essentially filtered out in order to identify components that are predictable.  For most mounts, the medium-term component is likely to be the most important.  If you’re following best practices, you will have programmed periodic error correction in your mount (assuming that feature is available to you).  Doing this reduces the amount of work that needs to be done by PHD2, and the PEC correction in the mount is normally saved permanently.  This approach is preferable to having to measure and infer the periodic error behavior every time you set up your equipment. 

That said, PEC in the mount is never perfect, and you will often see residual repetitive errors even when PEC is active.  These often arise when the tracking errors occur with a frequency that is not a harmonic (integer fraction) of the mount’s worm period – most PEC implementations can’t deal with those.  You can also get residual periodic errors if they are dependent on the mechanical loading of the mount or if the mount’s behavior has changed since the PEC was programmed..

Bryan


Re: PHD 2 Guiding "Good Enough"

John Thompson <jbtgolfer@...>
 

Thanks Mike.....

Good advice on the re-mesh of the gears. Thanks for all your comments. I will be at my remote site ( about 120 miles away in the Bradshaw Mountains ) in 2 weeks. I will give you an update .

Clear Sky's


Re: PHD 2 Guiding "Good Enough"

Mike Shade
 

Prior to a PEC curve, you might want to remesh the gears...then run your curve.

 

Mike J. Shade

Mike J. Shade Photography:

mshadephotography.com

 

In War: Resolution

In Defeat: Defiance

In Victory: Magnanimity

In Peace: Goodwill

Sir Winston Churchill

Already, in the gathering dusk, a few of the stars are turning on their lights.

Vega, the brightest one, is now dropping towards the west.  Can it be half

a year since I watched her April rising in the east?  Low in the southwest

Antares blinks a sad farwell to fall...

Leslie Peltier, Starlight Nights

 

International Dark Sky Association: www.darksky.org

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of John Thompson via groups.io
Sent: Saturday, May 02, 2020 5:05 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

 

Thank you for the responses to my "Guiding-Good enough" post. Yes. I have run PEMPro, loaded the "model" to the CP4 controller and Enabled PEC on the mount. However, it has been a while (>1 yr) so a new run at it would probably be beneficial. I will make that my first priority. I would like to reduce the RA error.

I have two AP mounts in the observatory , an AP 1100 and an AP 1600. The AP 1100 has encoders. I plan to add encoders to the AP 1600 this summer. I agree that it is easy to get drawn into "perfection" on this topic. However, when you ( all of us) make a big investment in the best equipment ( Astro Physics) you like to get full value. That's my excuse and I am sticking to it.


Re: PHD 2 Guiding "Good Enough"

John Thompson <jbtgolfer@...>
 

Thank you for the responses to my "Guiding-Good enough" post. Yes. I have run PEMPro, loaded the "model" to the CP4 controller and Enabled PEC on the mount. However, it has been a while (>1 yr) so a new run at it would probably be beneficial. I will make that my first priority. I would like to reduce the RA error.

I have two AP mounts in the observatory , an AP 1100 and an AP 1600. The AP 1100 has encoders. I plan to add encoders to the AP 1600 this summer. I agree that it is easy to get drawn into "perfection" on this topic. However, when you ( all of us) make a big investment in the best equipment ( Astro Physics) you like to get full value. That's my excuse and I am sticking to it.


Re: PHD 2 Guiding "Good Enough"

Charles Thompson
 

Well I guess I know what I'm going tonight. Thanks Dean!





Thanks,
Charles

Sent from mobile device.


-------- Original message --------
From: Dean Jacobsen <deanjacobsen@...>
Date: 5/2/20 2:25 PM (GMT-06:00)
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

On Sat, May 2, 2020 at 12:19 PM, Charles Thompson wrote:
Can you run PEC while guiding with PhD2?
Yes.
 
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: PHD 2 Guiding "Good Enough"

Dean Jacobsen
 

On Sat, May 2, 2020 at 12:19 PM, Charles Thompson wrote:
Can you run PEC while guiding with PhD2?
Yes.
 
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: PHD 2 Guiding "Good Enough"

Charles Thompson
 

I would be happy with your current guiding RMS but I image from the city. My RMS is usually around .5-.8 and that had been fine for any imaging I do.

Can you run PEC while guiding with PhD2? I've read conflicting information on this subject and never really asked. I've always left it turned off since my stars are good. 



Thanks,
Charles

Sent from mobile device.


-------- Original message --------
From: Dean Jacobsen <deanjacobsen@...>
Date: 5/2/20 12:47 PM (GMT-06:00)
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PHD 2 Guiding "Good Enough"

Yes, one can certainly get sucked down the guiding perfection black hole.  As Brian has said, how do your stars look?  Are you happy with the stacked images?

However, as Roland noted, there is some room for improvement that really doesn't take a lot of time.  Use PEM Pro to evaluate your native periodic error and then have the software create a new solution.  You will be amazed at the difference when you run the PE analysis again in PemPro with the new PE solution running.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: PHD 2 Guiding "Good Enough"

Dean Jacobsen
 

Yes, one can certainly get sucked down the guiding perfection black hole.  As Brian has said, how do your stars look?  Are you happy with the stacked images?

However, as Roland noted, there is some room for improvement that really doesn't take a lot of time.  Use PEM Pro to evaluate your native periodic error and then have the software create a new solution.  You will be amazed at the difference when you run the PE analysis again in PemPro with the new PE solution running.
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: Mach2 Status Update

Karen Christen
 

Hello Sebastien,

 

Since we have exhausted the old Mach1 list from late 2018/early 2019, the second run of Mach2s will be offered beginning with folks who signed up in April 2019.  With the Illinois stay-at-home order recently extended we do not anticipate having our production staff back until the end of May at the earliest.  This makes it very difficult to estimate delivery dates for these mounts, which is why we have not yet notified anyone on the list.  We are hopeful to begin notification late this month with delivery starting in late Summer 2020.  However, this may all change based on Illinois law.  Thank you all for your patience. 

 

Karen

AP

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Seb@stro
Sent: Friday, May 1, 2020 9:46 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach2 Status Update

 

Hello Karen,

Is the second run you're in the middle of for those who signed up in April 2019 ?  I did sign up back  then but I have not been notified yet. Have you started notifying people on that list ? The website seems a bit outdated as it says we will be notified in mid-march...

Thank you and be safe.

Sébastien


--
Karen Christen
Astro-Physics


Re: PHD 2 Guiding "Good Enough"

Roland Christen
 

It looks like you have a fair amount of PE error which is contributing to that last remaining .5 arc sec of RA back and forth movement. You can determine the periodic error a number of ways, and of course you can use PEMPro to eliminate 90% of it. Have you ever run a simple PE curve to see where you are?

Rolando



-----Original Message-----
From: John Thompson via groups.io <jbtgolfer@...>
To: main@ap-gto.groups.io
Sent: Sat, May 2, 2020 10:30 am
Subject: [ap-gto] PHD 2 Guiding "Good Enough"

I know this is not a PHD 2 forum but I want to set reasonable expectations of my mount when guiding. Guiding can become an obsession and I want to know when to stop. I have a AP 1600 (no encoders) with a TEC 140 f/7 combined with a STF8300 main camera and an off-axis STi guide camera. I plan to install encoders this summer. I attached a screen shot that shows most of the relevant guiding info from PHD 2. My question is should I be happy with a .23 RMS and a +- .5 arc sec oscillation of the RA. The Dec looks stable and below .5 arc sec. The RA oscillation bothers me a little but perhaps it is "seeing" driven however this is a permanent observatory in a fairly dark site ( 21.6 SQM). I am getting reasonably round stars at 1200 second exposures. I have worked the polar alignment and drift pretty hard. Would appreciate hearing your thoughts or suggestions. I am also posting this to a PHD 2 forum.


Re: PHD 2 Guiding "Good Enough"

 

Hi John

cancel that - i calculated it at 1.14 arcsec/px

there's a lot of ways to look at this

your guiding right now is pretty exceptional, and the error results in maybe 1/5th of a pixel of error on your images according to your image scale. if you work really hard on improving it, and you get it down by 50% so it averages .15" rms. now the error is 1/7th of a pixel. would you really see that?

If your stars are tight and round (i assume they are) and you are happy with your images, i'm not sure there's much to b gained for you by obsessing on this particular aspect.



On Sat, May 2, 2020 at 8:30 AM John Thompson via groups.io <jbtgolfer=yahoo.com@groups.io> wrote:
I know this is not a PHD 2 forum but I want to set reasonable expectations of my mount when guiding. Guiding can become an obsession and I want to know when to stop. I have a AP 1600 (no encoders) with a TEC 140 f/7 combined with a STF8300 main camera and an off-axis STi guide camera. I plan to install encoders this summer. I attached a screen shot that shows most of the relevant guiding info from PHD 2. My question is should I be happy with a .23 RMS and a +- .5 arc sec oscillation of the RA. The Dec looks stable and below .5 arc sec. The RA oscillation bothers me a little but perhaps it is "seeing" driven however this is a permanent observatory in a fairly dark site ( 21.6 SQM). I am getting reasonably round stars at 1200 second exposures. I have worked the polar alignment and drift pretty hard. Would appreciate hearing your thoughts or suggestions. I am also posting this to a PHD 2 forum.



--
Brian 



Brian Valente


Re: PHD 2 Guiding "Good Enough"

 

What is your imaging resolution?

On Sat, May 2, 2020 at 8:30 AM John Thompson via groups.io <jbtgolfer=yahoo.com@groups.io> wrote:
I know this is not a PHD 2 forum but I want to set reasonable expectations of my mount when guiding. Guiding can become an obsession and I want to know when to stop. I have a AP 1600 (no encoders) with a TEC 140 f/7 combined with a STF8300 main camera and an off-axis STi guide camera. I plan to install encoders this summer. I attached a screen shot that shows most of the relevant guiding info from PHD 2. My question is should I be happy with a .23 RMS and a +- .5 arc sec oscillation of the RA. The Dec looks stable and below .5 arc sec. The RA oscillation bothers me a little but perhaps it is "seeing" driven however this is a permanent observatory in a fairly dark site ( 21.6 SQM). I am getting reasonably round stars at 1200 second exposures. I have worked the polar alignment and drift pretty hard. Would appreciate hearing your thoughts or suggestions. I am also posting this to a PHD 2 forum.

--
Brian 



Brian Valente

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