Date   

Re: PA Error what is acceptable for 530mm FL & 2.1arc sec/pix

Ray Gralak
 

Thank you Ray. I have a permanent pier in concrete that has been set up since 2013, so I do not believe it
shifts, especially since I have constructed it with steel Rebars in concrete.
There are two types of concrete: concrete that is cracked, and concrete that hasn't yet cracked. :-)

Yes, the ground can shift in a permanent setup like yours. Just not as quickly.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Shailesh Trivedi
Sent: Tuesday, September 28, 2021 6:37 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] PA Error what is acceptable for 530mm FL & 2.1arc sec/pix

Thank you Ray. I have a permanent pier in concrete that has been set up since 2013, so I do not believe it
shifts, especially since I have constructed it with steel Rebars in concrete.

Shailesh


Re: Reflection in image

Robert Chozick <rchozick@...>
 

I think the reflection pattern and size would be different if it were one of the extension tubes. 


On Sep 27, 2021, at 3:11 PM, Martin Magnan <martin.magnan@...> wrote:

Hello

"t-thread extensions  + t-thread to 2 inch adapter + 2 inch extensions + CCDT67"

I once had a very similar setup and the internal reflection was caused by a "shiny" adapter. The problem was solved by flocking the inside of the adapter with black hockey tape.

Martin


Re: PA Error what is acceptable for 530mm FL & 2.1arc sec/pix

Shailesh Trivedi
 

Thank you Ray. I have a permanent pier in concrete that has been set up since 2013, so I do not believe it shifts, especially since I have constructed it with steel Rebars in concrete.

Shailesh


Re: PA Error what is acceptable for 530mm FL & 2.1arc sec/pix

Ray Gralak
 

Hi Shailesh,

I ran a 290 point APPM model last Friday and am having trouble centering to a target (I am off by several
degrees). Ray suggested "Plate Solve and Recal" in APPM, but I noticed something odd in looking at the
Model numbers. The polar elevation is -600 something arc seconds and the polar azimuth is -300 something,
see attached.
Provided polar alignment has not shifted, the model will compensate for polar alignment errors in both pointing and tracking.

I said "provided" because some people have noticed that settling in the ground can cause measurable changes in polar alignment.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Shailesh Trivedi
Sent: Monday, September 27, 2021 8:27 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] PA Error what is acceptable for 530mm FL & 2.1arc sec/pix

Hi,

I ran a 290 point APPM model last Friday and am having trouble centering to a target (I am off by several
degrees). Ray suggested "Plate Solve and Recal" in APPM, but I noticed something odd in looking at the
Model numbers. The polar elevation is -600 something arc seconds and the polar azimuth is -300 something,
see attached.

I know that APPM is expected to correct for PA errors, but for a 530mm FL and image scale of 2.1 arc sec
per pixel, is this error too much?

I prefer to dial it down to less than 10 arc sec, but the night I did my PA with PEMPRO, I was chasing the
seeing in suburban Sacramento.



Please shed light. thanks.

Shailesh


Re: It works! NINA, ASTAP, Model, new AP1100AE

 

Hi Linwood

nice to hear your success

>>> if you have an all sky model, should you check the DEC Arc tracking anyway?

it's an optional feature, but yes I suggest you check it. It's a "tracking improvement" feature. The worst that happens is your guiding doesn't improve, and you can disable it


Brian 



On Mon, Sep 27, 2021 at 6:06 PM ap@... <ap@...> wrote:
Ok, it's another one of those "surprise, it did what it said it would" posts, but... first really clear night since i got the mount (2 months ago). First real model where I could get the whole sky.

NINA and ASTAP used, 79 points, 79 good, none failed, 32 minutes (about 2.5 points per minute) with a C11 @ 2800mm, ASI6200MM bin 2, 3 sec exposures.  Polar aligned with NINA's new tool.

With light winds (gusting to 5mph with a big dew shield on it), PHD2 over 200 seconds shows RMS error of 0.46" -- with guiding OFF (Guiding Assistant). 

First slew across half the sky plate solved to 20" by 1" off.

Many thanks to Dale, Ray and whoever else helped with the NINA/ASTAP integration.  I can't get my camera to work reliably with APPM directly, and I really didn't want to use TSX, so this is a terrific combination, and at least to me seems quite fast.  Not sure I NEED a model but it is nice to know I can build one reasonably fast.

I'm now imaging and guiding at 0.31" RMS despite the light wind (prior mounts almost any wind with that big dew shield was a mess). All that with a non-locked mirror as well.

So I do have one question: if you have an all sky model, should you check the DEC Arc tracking anyway?  (I realize the model is not really important since I'm guiding, but trying to learn in case I want to ever image unguided. )

So anyway, thanks again for all that made the new integration work!

Linwood



--
Brian 



Brian Valente


Re: It works! NINA, ASTAP, Model, new AP1100AE

ap@CaptivePhotons.com
 

Bill Long wrote:

 

  • Definitely best to encounter a problem before paying a load of money to fix it. :) 

 

Despite vendor wishes to the contrary.  😊

 

Of course, it presumes the wisdom to notice a problem.  Something I worry about at times.

 

  • I have always assumed the numbers on one side being different than the other were due to orthogonality issues or a slight pier imbalance. Ray would know better though. 

 

I stare at the numbers and even if I know a definition, I lack the context to know if it is actionable.  E.g. is 113 Tube Flexure, for a C11 on an AP1100 grossly awful or really good or somewhere in between?   (Or maybe more to the point are any of these actionable intelligence about one’s setup; maybe the answer is problems show up elsewhere, this is not a good place to look).

 


Re: It works! NINA, ASTAP, Model, new AP1100AE

Bill Long
 

Definitely best to encounter a problem before paying a load of money to fix it. :) 

I have always assumed the numbers on one side being different than the other were due to orthogonality issues or a slight pier imbalance. Ray would know better though. 


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of ap@... <ap@...>
Sent: Monday, September 27, 2021 6:33 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] It works! NINA, ASTAP, Model, new AP1100AE
 

Bill Long wrote:

 

  • Its a little bit different of a ballgame with SCT's though. I think with an external focuser and the mirror locks engaged you can mitigate the flop issue that can cause problems.  

 

Other than a need to refocus after long slews, it really is more of a theoretical problem than one I notice.  I spent a lot of time researching external focusers (and rotators and tilt adapters) and just decided to wait until I was sure I had a problem that needed fixing.  Frankly with talk of focuser sag (I have a fairly heavy camera) on some of them, and others that eat up too much back focus, indefinite delays on others, and the price tag on some … Well, waiting for the problem to become more evident.


Though speaking of which, do the numbers here like flex or east vs west values speak to how much mirror flop occurred during all that slewing?   I won’t pretend to understand the implication of the specific numbers below.

 

 


Re: It works! NINA, ASTAP, Model, new AP1100AE

ap@CaptivePhotons.com
 

Bill Long wrote:

 

  • Its a little bit different of a ballgame with SCT's though. I think with an external focuser and the mirror locks engaged you can mitigate the flop issue that can cause problems.  

 

Other than a need to refocus after long slews, it really is more of a theoretical problem than one I notice.  I spent a lot of time researching external focusers (and rotators and tilt adapters) and just decided to wait until I was sure I had a problem that needed fixing.  Frankly with talk of focuser sag (I have a fairly heavy camera) on some of them, and others that eat up too much back focus, indefinite delays on others, and the price tag on some … Well, waiting for the problem to become more evident.


Though speaking of which, do the numbers here like flex or east vs west values speak to how much mirror flop occurred during all that slewing?   I won’t pretend to understand the implication of the specific numbers below.

 

 


Re: It works! NINA, ASTAP, Model, new AP1100AE

Bill Long
 

Its a little bit different of a ballgame with SCT's though. I think with an external focuser and the mirror locks engaged you can mitigate the flop issue that can cause problems.  


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Joseph Beyer <jcbeyer2001@...>
Sent: Monday, September 27, 2021 6:23 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] It works! NINA, ASTAP, Model, new AP1100AE
 
With the encoders and a good model your reliance on guiding will be a lot less.  The guider wont have to work as hard to keep the course.  I’ve stopped guiding at all with my Mach1 using 50 point models at short focal length (530mm). 

On Sep 27, 2021, at 6:06 PM, ap@... wrote:

Ok, it's another one of those "surprise, it did what it said it would" posts, but... first really clear night since i got the mount (2 months ago). First real model where I could get the whole sky.

NINA and ASTAP used, 79 points, 79 good, none failed, 32 minutes (about 2.5 points per minute) with a C11 @ 2800mm, ASI6200MM bin 2, 3 sec exposures.  Polar aligned with NINA's new tool.

With light winds (gusting to 5mph with a big dew shield on it), PHD2 over 200 seconds shows RMS error of 0.46" -- with guiding OFF (Guiding Assistant). 

First slew across half the sky plate solved to 20" by 1" off.

Many thanks to Dale, Ray and whoever else helped with the NINA/ASTAP integration.  I can't get my camera to work reliably with APPM directly, and I really didn't want to use TSX, so this is a terrific combination, and at least to me seems quite fast.  Not sure I NEED a model but it is nice to know I can build one reasonably fast.

I'm now imaging and guiding at 0.31" RMS despite the light wind (prior mounts almost any wind with that big dew shield was a mess). All that with a non-locked mirror as well.

So I do have one question: if you have an all sky model, should you check the DEC Arc tracking anyway?  (I realize the model is not really important since I'm guiding, but trying to learn in case I want to ever image unguided. )

So anyway, thanks again for all that made the new integration work!

Linwood


Re: It works! NINA, ASTAP, Model, new AP1100AE

Joseph Beyer
 

With the encoders and a good model your reliance on guiding will be a lot less.  The guider wont have to work as hard to keep the course.  I’ve stopped guiding at all with my Mach1 using 50 point models at short focal length (530mm). 

On Sep 27, 2021, at 6:06 PM, ap@... wrote:

Ok, it's another one of those "surprise, it did what it said it would" posts, but... first really clear night since i got the mount (2 months ago). First real model where I could get the whole sky.

NINA and ASTAP used, 79 points, 79 good, none failed, 32 minutes (about 2.5 points per minute) with a C11 @ 2800mm, ASI6200MM bin 2, 3 sec exposures.  Polar aligned with NINA's new tool.

With light winds (gusting to 5mph with a big dew shield on it), PHD2 over 200 seconds shows RMS error of 0.46" -- with guiding OFF (Guiding Assistant). 

First slew across half the sky plate solved to 20" by 1" off.

Many thanks to Dale, Ray and whoever else helped with the NINA/ASTAP integration.  I can't get my camera to work reliably with APPM directly, and I really didn't want to use TSX, so this is a terrific combination, and at least to me seems quite fast.  Not sure I NEED a model but it is nice to know I can build one reasonably fast.

I'm now imaging and guiding at 0.31" RMS despite the light wind (prior mounts almost any wind with that big dew shield was a mess). All that with a non-locked mirror as well.

So I do have one question: if you have an all sky model, should you check the DEC Arc tracking anyway?  (I realize the model is not really important since I'm guiding, but trying to learn in case I want to ever image unguided. )

So anyway, thanks again for all that made the new integration work!

Linwood


It works! NINA, ASTAP, Model, new AP1100AE

ap@CaptivePhotons.com
 

Ok, it's another one of those "surprise, it did what it said it would" posts, but... first really clear night since i got the mount (2 months ago). First real model where I could get the whole sky.

NINA and ASTAP used, 79 points, 79 good, none failed, 32 minutes (about 2.5 points per minute) with a C11 @ 2800mm, ASI6200MM bin 2, 3 sec exposures.  Polar aligned with NINA's new tool.

With light winds (gusting to 5mph with a big dew shield on it), PHD2 over 200 seconds shows RMS error of 0.46" -- with guiding OFF (Guiding Assistant). 

First slew across half the sky plate solved to 20" by 1" off.

Many thanks to Dale, Ray and whoever else helped with the NINA/ASTAP integration.  I can't get my camera to work reliably with APPM directly, and I really didn't want to use TSX, so this is a terrific combination, and at least to me seems quite fast.  Not sure I NEED a model but it is nice to know I can build one reasonably fast.

I'm now imaging and guiding at 0.31" RMS despite the light wind (prior mounts almost any wind with that big dew shield was a mess). All that with a non-locked mirror as well.

So I do have one question: if you have an all sky model, should you check the DEC Arc tracking anyway?  (I realize the model is not really important since I'm guiding, but trying to learn in case I want to ever image unguided. )

So anyway, thanks again for all that made the new integration work!

Linwood


Re: APCC Temperature readings

S Berrada
 

Hi,

Based on my limited research, it seems that temperature will have a bigger impact on refraction than barometric pressure - this is because of the magnitude and rapidity of change.

Both are important to input in APCC, but accurate temperature seems the most important.

https://en.m.wikipedia.org/wiki/Atmospheric_refraction

 

Refraction increases approximately 1% for every 0.9 kPa increase in pressure.  Similarly, refraction increases approximately 1% for every 3 °C decrease in temperature


Re: Is this tilt in the image train?

Tom Blahovici
 

Yes I have noticed this myself. Stacking the images usually reduces the abberations.
The direction of tilt shown by CCD inspector is the same as before. I wonder if the new ap mount is now more accurate now that the stars are more steady. 
Before I would have 0.7,-0.8 arc sec RMS tracking, now down to .25.
Tom


Re: Is this tilt in the image train?

Dean Jacobsen
 

On Mon, Sep 27, 2021 at 02:49 PM, Joseph Beyer wrote:
Initially I connected my filter wheel to the camera with the stock tilt adjuster sandwiched in between.  Images were terrible with elongation of stars nearly across the frame.  I removed the tilt adjuster and immediately got better stars but not great yet.
Interesting.
--
Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/


Re: Is this tilt in the image train?

Joseph Beyer
 

The individual sub images are more telling of the remaining problem.  Stacking the subs seemed to “fix” the remaining elongation more than I expected. I agree with you though, it sure looks reasonable.  I’ll post a link to one of the subs later.  Good luck! 


Joe


Re: APCC feature request - Get time from mount

Nick Iversen
 

Ray

I can get the mount's time from the site tab but then I have to manually set the computer to that time - a bit of a pain to do with any accuracy (but good enough for most purposes).

The computer is not connected to the internet so nettime is not an option (although it is installed).

Regards
Nick


Re: APCC Temperature readings

Tom Blahovici
 

Hi
Not only that, but I have an MGBox V2 and a Sensorpush high accuracy sensor for temperature and there is a three degree difference between them....


Re: Is this tilt in the image train?

Tom Blahovici
 

Joe,
That image is close to perfect.  You would never see any funny stars even with a 4 foot wide print.
So my next outing will be to tighten everything up.  That includes the adapters and the screws on the flanges for the nightcrawler.
Then I will start looking.
1) Take images at different points in the sky to see if things shift.
2) If not then attempt to adjust the tilt.
I guess I should attempt this before returning the scope.  If I do send the scope, then it will wait until March when I switch scopes to my galaxy scope.
Thanks all.


Re: APCC Temperature readings

S Berrada
 

Hi Dale and Sebastien- thank you so much, this is very helpful.

I can see how temperature is important for the APCC model, but does anyone have an idea of how important barometric pressure or RH are ?

Thanks
sam 


Re: Is this tilt in the image train?

Bill Long
 

Mine was fixed in Houston as well. AndySea on CN had to have his sent back to Japan.


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Luca Marinelli <photo@...>
Sent: Monday, September 27, 2021 2:45 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Is this tilt in the image train?
 
No, the collimation for my FSQ106 was performed in Houston. It didn’t have to go to Japan.

Luca

On Sep 27, 2021, at 5:40 PM, Tom Blahovici via groups.io <tom.va2fsq@...> wrote:

Ok, that's how it should be.  Was never like that for me, from day 1.
Did they send it to Japan?
Seems like the normal situation is 4 months without Japan!!

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