Date   

Re: Tracking and guiding with and without encoders - Part2

Bill Long
 

If it's a waste, why bother bringing it up? 


From: ap-gto@... on behalf of badgerz49@... [ap-gto]
Sent: Tuesday, September 17, 2019 9:15 PM
To: ap-gto@...
Subject: RE: [ap-gto] Re: Tracking and guiding with and without encoders - Part2
 
 

Ray,


The RA drift you're talking about didn't seem to affect my guiding.  I'm pretty sure I was getting .4" or lower Total RMS on both mounts for much of that night.

I don't care to waste any more time discussing this.  I think skepticism is good and in short supply in this hobby.  I haven't seen evidence encoders improve guided imaging and I'll leave it at that.  It's possible they make a big difference, I don't know.  Maybe it'll be hashed out someday.  Regarding PEC, my tests have all been anecdotal and I haven't concluded anything about how it affects guiding.  I'm happy with my mounts and hope others are too.

Chad


Re: Tracking and guiding with and without encoders - Part2

Chad A
 

Ray,

The RA drift you're talking about didn't seem to affect my guiding.  I'm pretty sure I was getting .4" or lower Total RMS on both mounts for much of that night.

I don't care to waste any more time discussing this.  I think skepticism is good and in short supply in this hobby.  I haven't seen evidence encoders improve guided imaging and I'll leave it at that.  It's possible they make a big difference, I don't know.  Maybe it'll be hashed out someday.  Regarding PEC, my tests have all been anecdotal and I haven't concluded anything about how it affects guiding.  I'm happy with my mounts and hope others are too.

Chad


Re: Tracking and guiding with and without encoders - Part2

Bill Long
 

I dont get why you feel the need, Chad, to continue along this path of trying to determine if Encoders provide better performance. I am pretty sure the image shared by Roland, put that to bed. 

I also dont get why you are persisting to attack Ray. The dude is trying to help.


From: ap-gto@...
Sent: Tuesday, September 17, 2019 7:51 PM
To: ap-gto@...
Subject: RE: [ap-gto] Re: Tracking and guiding with and without encoders - Part2
 
 

Hi Chad,

> You showed images of a mount with "40 arc seconds PE." Assuming you ran a valid test it only demonstrates that
> PEC improves guiding if your mount has 40" PE. I fully expect it would. That doesn't begin to address whether
> PEC improves guiding on an AP mount with less than +/- 3" P-P smooth native PE.

As I said previously I have run many tests, including many at 5 arc-sec Peak-Peak that showed up to 10% improvement in FWHM.

> These logs will be very difficult to draw any conclusions from since I had zero intention of making them clear and
> intelligible. What I can tell you is:
>
> PEM was enabled near the end of the night on one of the two mounts. I believe it was enabled on the file that ends
> in 201308 but I don't remember for sure. Total RMS stayed right around Total RMS for the other mount which had
> PEM disabled. I also didn't notice a change from when PEM was off vs. on.

As I suspected the RA data is dominated by drift and mostly overshadows the periodic error. It's no wonder that you didn't notice much difference.

Are you using APCC Pro? If you are I think there is something wrong with the data model you are using. You should have little residual drift in RA and Dec.

> I will try and do a proper test tonight. If there's improvement, that's what I'll report. I hope there is.

If your mount still has that a lot of RA drift then any improvement will be diminished. Also, you must do the tests on the same mount because each mount may have different levels of drift. Drift will affect the RMS error, sometimes more so than periodic error.

So, please do your tests with the same mount. I will be able to isolate and analyze the drift and periodic error in the logs to determine exactly what is contributing to your RMS error.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

> -----Original Message-----
> From: ap-gto@... [mailto:ap-gto@...]
> Sent: Tuesday, September 17, 2019 3:10 PM
> To: ap-gto@...
> Subject: RE: [ap-gto] Re: Tracking and guiding with and without encoders - Part2
>
>
>
> Ray,
> You showed images of a mount with "40 arc seconds PE." Assuming you ran a valid test it only demonstrates that
> PEC improves guiding if your mount has 40" PE. I fully expect it would. That doesn't begin to address whether
> PEC improves guiding on an AP mount with less than +/- 3" P-P smooth native PE.
>
> Regarding guide logs... here's a copy of the email I just sent you - with guide logs from both mounts on Sep. 4
> attached. I can't imagine they'll be helpful - it's just one of the times I've enabled PEM and noticed no difference. I
> can also provide you PEMPro logs from that same evening if such a thing exists. I plan to do a proper and much
> longer test when the weather cooperates - possibly tonight.
>
> --Email below---
>
> Ray,
> There was a lot going on this particular evening ... creating new PEC curves in PEMPro, running guiding assistant,
> testing various PHD2 settings, testing PEM on/off, etc.
>
> These logs will be very difficult to draw any conclusions from since I had zero intention of making them clear and
> intelligible. What I can tell you is:
>
> PEM was enabled near the end of the night on one of the two mounts. I believe it was enabled on the file that ends
> in 201308 but I don't remember for sure. Total RMS stayed right around Total RMS for the other mount which had
> PEM disabled. I also didn't notice a change from when PEM was off vs. on.
>
> I will try and do a proper test tonight. If there's improvement, that's what I'll report. I hope there is.
>
> Chad
>
>
>


Re: Tracking and guiding with and without encoders - Part2

Ray Gralak
 

Hi Chad,

You showed images of a mount with "40 arc seconds PE." Assuming you ran a valid test it only demonstrates that
PEC improves guiding if your mount has 40" PE. I fully expect it would. That doesn't begin to address whether
PEC improves guiding on an AP mount with less than +/- 3" P-P smooth native PE.
As I said previously I have run many tests, including many at 5 arc-sec Peak-Peak that showed up to 10% improvement in FWHM.

These logs will be very difficult to draw any conclusions from since I had zero intention of making them clear and
intelligible. What I can tell you is:

PEM was enabled near the end of the night on one of the two mounts. I believe it was enabled on the file that ends
in 201308 but I don't remember for sure. Total RMS stayed right around Total RMS for the other mount which had
PEM disabled. I also didn't notice a change from when PEM was off vs. on.
As I suspected the RA data is dominated by drift and mostly overshadows the periodic error. It's no wonder that you didn't notice much difference.

Are you using APCC Pro? If you are I think there is something wrong with the data model you are using. You should have little residual drift in RA and Dec.

I will try and do a proper test tonight. If there's improvement, that's what I'll report. I hope there is.
If your mount still has that a lot of RA drift then any improvement will be diminished. Also, you must do the tests on the same mount because each mount may have different levels of drift. Drift will affect the RMS error, sometimes more so than periodic error.

So, please do your tests with the same mount. I will be able to isolate and analyze the drift and periodic error in the logs to determine exactly what is contributing to your RMS error.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Tuesday, September 17, 2019 3:10 PM
To: ap-gto@yahoogroups.com
Subject: RE: [ap-gto] Re: Tracking and guiding with and without encoders - Part2



Ray,
You showed images of a mount with "40 arc seconds PE." Assuming you ran a valid test it only demonstrates that
PEC improves guiding if your mount has 40" PE. I fully expect it would. That doesn't begin to address whether
PEC improves guiding on an AP mount with less than +/- 3" P-P smooth native PE.

Regarding guide logs... here's a copy of the email I just sent you - with guide logs from both mounts on Sep. 4
attached. I can't imagine they'll be helpful - it's just one of the times I've enabled PEM and noticed no difference. I
can also provide you PEMPro logs from that same evening if such a thing exists. I plan to do a proper and much
longer test when the weather cooperates - possibly tonight.

--Email below---

Ray,
There was a lot going on this particular evening ... creating new PEC curves in PEMPro, running guiding assistant,
testing various PHD2 settings, testing PEM on/off, etc.

These logs will be very difficult to draw any conclusions from since I had zero intention of making them clear and
intelligible. What I can tell you is:

PEM was enabled near the end of the night on one of the two mounts. I believe it was enabled on the file that ends
in 201308 but I don't remember for sure. Total RMS stayed right around Total RMS for the other mount which had
PEM disabled. I also didn't notice a change from when PEM was off vs. on.

I will try and do a proper test tonight. If there's improvement, that's what I'll report. I hope there is.

Chad



Re: SGP/APCC meridian limits vs. Homing/limits

rob
 

well the problem is you've got 2 programs, each with potentially their own idea of when the meridian flip should happen. so Ray put in this feature that lets APCC tell SGP what the meridian delay should be. that way, APCC can be configured with some complex meridian limit surface and it can tell SGP how many minutes before that limit is reached that it should attempt a meridian flip.

if you don't want to use that feature (and in truth it's probably not necessary in a configuration like mine where i have the same limit for all declinations) you can just do something like set SGP to a 0 minute delay and set the meridian limit surface in APCC for 10 minutes past the true meridian at all declinations. i think perhaps that's not enough time though depending on what your subexposure length is.

so - how far past the meridian do you have your limits set in SGP? how far past the meridian can your mount track in the worst case before the camera hits the pier/tripod? what is your subexposure length?

rob


Re: Tracking and guiding with and without encoders - Part2

Michael Fulbright <mike.fulbright@...>
 

I haven't given it much thought but if you assume a Gaussian profile for your stars and the guide errors are normally distributed I would think the final FWHM of the star broadened by guide errors would add in quadrature.

sigma_F = sqrt( (sigma_*)^2 + (sigma_g)^2)

where sigma_F is the final sigma of the Gaussian star profile, sigma_* is the unbroadened star profile, and sigma_g is the error guiding.

If you have seeing like me and most stars are around sigma_*=2 arcsec and sigma_g=0.4 arcsec I get sigma_F = 2.04 arc sec.

I'm sure there is work on this in professional journals if someone really wanted to know the answer.

Just a quick search I  found this:

http://articles.adsabs.harvard.edu/full/1996ESOC...54..275J

Seems to consider many sources that must be controlled to give the best image resolution including atmospheric and guiding effects.

You could do a test and take a < 5 second exposure of a bright star cluster then take a 300s exposure of a fainter star field and compare FWHM.  Presumably the short exposure is roughly measuring your optics and short term turbulence while the longer would incorporate guiding errors as well.

Michael Fulbright


On 9/17/19 5:14 PM, badgerz49@... [ap-gto] wrote:
 

Ray, 

You showed images of a mount with "40 arc seconds PE."  Assuming you ran a valid test it only demonstrates that PEC improves guiding if your mount has 40" PE.  I fully expect it would.  That doesn't begin to address whether it improves guiding on an AP mount with less than +/- 3" P-P smooth native PE.

This is bizarre why someone can't run simple tests to hash out how much improvement in guiding encoders offer.  Nothing is stopping AP from testing it, or better yet, enlisting an unbiased source to do the testing.

Regarding guide logs... here's a copy of the email I just sent you - with guide logs from Sep. 4 attached.  I can't imagine they'll be helpful.  I can also provide you PEMPro logs from that same evening if such a thing exists.

--Email below---

Ray,
There was a lot going on this particular evening ... creating new PEC curves in PEM Pro, running guiding assistant, testing various PHD2 settings, testing PEM on/off, etc.

These logs will be very difficult to draw any conclusions from since I had zero intention of making them clear and intelligible.  What I can tell you is:

PEM was enabled near the end of the night on one of the two mounts.  I believe it was enabled on the file that ends in 201308 but I don't remember for sure.  Total RMS stayed right around Total RMS for the other mount which had guiding disabled.  I did not notice any improvement from when PEC had been disabled either.

I will try and do a proper test tonight.  If there's improvement, that's what I'll report.  I hope there is.

Chad

-- End Email --




Re: Tracking and guiding with and without encoders - Part2

Chad A
 

Ray, 
You showed images of a mount with "40 arc seconds PE."  Assuming you ran a valid test it only demonstrates that PEC improves guiding if your mount has 40" PE.  I fully expect it would.  That doesn't begin to address whether PEC improves guiding on an AP mount with less than +/- 3" P-P smooth native PE.

Regarding guide logs... here's a copy of the email I just sent you - with guide logs from both mounts on Sep. 4 attached.  I can't imagine they'll be helpful - it's just one of the times I've enabled PEM and noticed no difference.  I can also provide you PEMPro logs from that same evening if such a thing exists.  I plan to do a proper and much longer test when the weather cooperates - possibly tonight.

--Email below---

Ray,
There was a lot going on this particular evening ... creating new PEC curves in PEMPro, running guiding assistant, testing various PHD2 settings, testing PEM on/off, etc.

These logs will be very difficult to draw any conclusions from since I had zero intention of making them clear and intelligible.  What I can tell you is:

PEM was enabled near the end of the night on one of the two mounts.  I believe it was enabled on the file that ends in 201308 but I don't remember for sure.  Total RMS stayed right around Total RMS for the other mount which had PEM disabled.  I also didn't notice a change from when PEM was off vs. on.

I will try and do a proper test tonight.  If there's improvement, that's what I'll report.  I hope there is.

Chad


Re: SGP/APCC meridian limits vs. Homing/limits

Rodolphe G.
 

Hi Rob,
Thanks for taking the time to answer.
To be frank, I'm even more confused :(

SGP seems to compute the time at which the meridian flip would theoretically occur. I let SGP manage the flip by itself. I don't want to interfere with this - just want to ensure that the current frame is finished before the flip. I thus changed the setting in SGP to wait for 10 more minutes,

But what should I do in APCC? Leave everything empty in APCC and the AP ASCOM driver? I noticed that setting values there to what I believed were correct for what I wanted to achieve, ruined my session last night: the mount has stopped in a weird position.

I wish a recommended approach / clear directions were documented somewhere.

Thanks

Rodolphe


Re: Tracking and guiding with and without encoders - Part2

Ray Gralak
 

The logs should be from the same setup, not two different setups.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Tuesday, September 17, 2019 10:36 AM
To: ap-gto@yahoogroups.com
Subject: RE: [ap-gto] Re: Tracking and guiding with and without encoders - Part2



I forgot I sold my duplicate ASI1600 last week, so the two rigs are identical except for the cameras. One will use
an ASI1600 and the other an ASI183.


Re: Tracking and guiding with and without encoders - Part2

Roland Christen
 

You will notice improvement with long focal lengths in good seeing. Otherwise you are limited by pixel resolution and atmospheric seeing.

Using the 180F9 refractor I was getting 1.2 to 1.3 arc sec FWHM all night during good seeing. The mount was guiding in both axes at 0.1 to 0.13 rms. I don't think that this would be possible with the non-encoder version of this mount - the Mach1. In our Chile observatory (1600 encoder mount) at LasCampanas we measured FWHM of 0.9 arc sec with the 305F8 Mak-Cass astrograph when we were setting it up.

As I indicated before, the Mach2 doesn't really work without the axis shaft encoders, just like your mount doesn't really work without the motor shaft encoders. Every decent mount has to have encoders somewhere, either on the motor shaft or on the axis shaft. The feedback from these encoders provides loop control and steady tracking rates. If the encoder is on the motor shaft then it does not account for errors in the geartrain. If it's on the output shaft then all errors are accounted for except for the encoder itself. Since we are opting to use high accuracy encoders on the output shaft, the errors are very very small, almost 5 times smaller than the best you can do with worm and spur gear reduction, even accounting for the use of PEM. You are then only limited by the atmosphere and your scope/camera resolution.

The encoders also provide a number of other benefits that people have wanted all along, so we are advancing the technology and raising the bar. The Mach2 is a very effective mount for high performing scopes and can handle larger loads better than its predecessor.

Rolando



-----Original Message-----
From: badgerz49@... [ap-gto]
To: ap-gto
Sent: Tue, Sep 17, 2019 11:34 am
Subject: Re: [ap-gto] Re: Tracking and guiding with and without encoders - Part2



Roland - so you are saying Total RMS will improve with encoders.  Back to the original question; how much improvement is there in Total RMS for guided imaging with typical 2-3 second guide intervals?

In limited testing I haven't noticed any improvement in Total RMS with PEC on vs. off, which is why I have doubts encoders will improve Total RMS much, if any.  That's with an excellent PEC curve that almost eliminated PE.  Seeing seems to be the limiting factor.  Fast oscillations, backlash, and PE are negligible.

Chad



Re: Tracking and guiding with and without encoders - Part2

Ray Gralak
 

Chad,

I ask because my experience has not been the same as you claim. I provided you with test results showing visible and measurable differences in FWHM and stellar eccentricity. The very least you can do is to provide guide logs that show no measurable difference in RMS when pec is enabled versus disabled. Please feel free to provide the logs alone. If they are phd2 logs my log viewer app can detect the moves and reconstruct periodic error to confirm pec was disabled in one of the logs (and thus a proper comparison).

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Tuesday, September 17, 2019 10:25 AM
To: ap-gto@yahoogroups.com
Subject: RE: [ap-gto] Re: Tracking and guiding with and without encoders - Part2



Ray, I have guide logs but the AP ASCOM driver Logs folders are empty. I don't recall unchecking the "Enable
Debug Log" option, so maybe it's unchecked by default. It wasn't checked on either of the laptops for my AP
mounts.

I shouldn't have to do it, but I'm happy to run a complete test of guided Total RMS with PEC enabled vs. disabled
and share the results. I have identical AP1100 and identical OTA/Imaging trains which get total RMS almost
exactly in sync with each other. This acts as a control against variations in seeing being the cause of (non)
differences with PEC on/off. I will also show in PEMPro that my PEC curve almost completely eliminates PE. I'll
do it tonight if it's clear.

Chad



Re: Tracking and guiding with and without encoders - Part2

Chad A
 

I forgot I sold my duplicate ASI1600 last week, so the two rigs are identical except for the cameras.  One will use an ASI1600 and the other an ASI183.


Re: Tracking and guiding with and without encoders - Part2

Chad A
 

Ray, I have guide logs but the AP ASCOM driver Logs folders are empty.  I don't recall unchecking the "Enable Debug Log" option, so maybe it's unchecked by default.  It wasn't checked on either of the laptops for my AP mounts.

I shouldn't have to do it, but I'm happy to run a complete test of guided Total RMS with PEC enabled vs. disabled and share the results.  I have identical AP1100 and identical OTA/Imaging trains which get total RMS almost exactly in sync with each other.  This acts as a control against variations in seeing being the cause of (non) differences with PEC on/off.  I will also show in PEMPro that my PEC curve almost completely eliminates PE.  I'll do it tonight if it's clear.

Chad


Re: Tracking and guiding with and without encoders - Part2

Ray Gralak
 

Hi Chad,

Would you post some guide logs with pec enabled and not? Also include your ap v2 ascom driver logs.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Tuesday, September 17, 2019 8:54 AM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] Re: Tracking and guiding with and without encoders - Part2



Roland - so you are saying Total RMS will improve with encoders. Back to the original question; how much
improvement is there in Total RMS for guided imaging with typical 2-3 second guide intervals?


In limited testing I haven't noticed any improvement in Total RMS with PEC on vs. off, which is why I have doubts
encoders will improve Total RMS much, if any. That's with an excellent PEC curve that almost eliminated PE.
Seeing seems to be the limiting factor. Fast oscillations, backlash, and PE are negligible.


Chad


Re: SGP/APCC meridian limits vs. Homing/limits

rob
 

the way i have this configured is that i have a linear 'surface' defined in the meridian limit window which puts the meridian 45 minutes past the real meridian. originally i had the action set to "stop tracking" but i found that sometimes PHD2 might send a command to the mount after the limit was reached, resulting in the mount trying to start tracking again. so for a while i had it set to "park mount" but eventually i decided that if i set it to "flip mount" that perhaps SGP could recover from reaching the meridian limit. but ever since ray implemented the flip offset, this has never happened.

anyway, in the "fip offset" box i have entered 40 mins. i think what this does is tell SGP that its flip point should be 5 minutes past the real meridian (45-5), which gives 40 minutes for SGP to finish the current exposure and peform the flip. since i use 30 min exposures at maximum, this seems to work fine.

i'm not sure what would happen if i had a more complex meridian surface - say for instance if there were some areas that defined a 35 minute meridian delay. in theory that would ask SGP to flip 5 minutes before the meridian, but my understanding is that SGP won't support an early flip point on an AP mount because there are some missing methods in the ASCOM driver that they want to see. not sure what SGP does in this case; maybe it just clamps the meridian delay to 0. but then the effective offset is reduced.

rob


Re: Tracking and guiding with and without encoders - Part2

Chad A
 

Roland - so you are saying Total RMS will improve with encoders.  Back to the original question; how much improvement is there in Total RMS for guided imaging with typical 2-3 second guide intervals?

In limited testing I haven't noticed any improvement in Total RMS with PEC on vs. off, which is why I have doubts encoders will improve Total RMS much, if any.  That's with an excellent PEC curve that almost eliminated PE.  Seeing seems to be the limiting factor.  Fast oscillations, backlash, and PE are negligible.

Chad


Re: Tracking and guiding with and without encoders - Part2

Roland Christen
 


It seems you're not claiming guiding results, particularly Total RMS, will be improved with encoders. 
Yes, for sure guiding results will improve with the encoders. Dec response is instant, zero backlash. RA periodic error goes away, so no PE curve is required. Makes long term adjustment, tweaking, maintenance negligible, especially for remote mounts. RA guiding becomes relatively easy since you don't have to guide at rapid rates. You can take longer guide exposures without having the guide star wander due to short term tracking errors. The Mach2 tracks measurably better than the Mach1 for sure. By a factor of 2 on good nights. And even on poor nights there is less wander especially in the Dec axis.

Rolando


-----Original Message-----
From: badgerz49@... [ap-gto]
To: ap-gto
Sent: Tue, Sep 17, 2019 9:11 am
Subject: Re: [ap-gto] Re: Tracking and guiding with and without encoders - Part2



Roland,

It seems you're not claiming guiding results, particularly Total RMS, will be improved with encoders.  That's what I wanted to know.

It's never been in doubt whether encoders remove fast oscillations.  The oscillations in your graph are very small over a typical 2-3 second guide interval.  Whether they're detectable in guided images is a different topic.  I don't know what the seeing threshold is to notice them but I image it's beyond what most/all of us will ever have.

Chad



Re: Tracking and guiding with and without encoders - Part2

Chad A
 

Ray,

Yes, comparing FWHM seems like a good way to quantify the difference.  Rapid changes in seeing might make it difficult to test properly.  Any difference in results should be statistically confirmed over many samples and repeatable.  The test would be:

Guided encoder off FWHM vs. 1 second FWHM

against

Guided encoder on for same duration vs. 1 second FWHM

Chad







Re: Tracking and guiding with and without encoders - Part2

Ray Gralak
 

Hi Chad,

RMS guide error is the wrong measurement because it depends on the sampling of autoguider moves.

What you want to compare is average stellar FWHM and eccentricity of non-saturated stars in images. The image integrates light over the entire duration of an image and is the way to best determine guide quality. You want to compare the guided image's FWHM and eccentricity to those values in a very short duration image (e.g. 1 second duration).

-Ray Gralak
Author of APCC (Astro-Physics Command Center): http://www.astro-physics.com/index.htm?products/accessories/software/apcc/apcc
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com]
Sent: Tuesday, September 17, 2019 7:00 AM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] Re: Tracking and guiding with and without encoders - Part2



Roland,


It seems you're not claiming guiding results, particularly Total RMS, will be improved with encoders. That's what I
wanted to know.

It's never been in doubt whether encoders remove fast oscillations. The oscillations in your graph are very small
over a typical 2-3 second guide interval. Whether they're detectable in guided images is a different topic. I don't
know what the seeing threshold is to notice them but I image it's beyond what most/all of us will ever have.


Chad


Re: Tracking and guiding with and without encoders - Part2

Chad A
 

Roland,

It seems you're not claiming guiding results, particularly Total RMS, will be improved with encoders.  That's what I wanted to know.

It's never been in doubt whether encoders remove fast oscillations.  The oscillations in your graph are very small over a typical 2-3 second guide interval.  Whether they're detectable in guided images is a different topic.  I don't know what the seeing threshold is to notice them but I image it's beyond what most/all of us will ever have.

Chad

17521 - 17540 of 84163