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Polar Alignment with Asiair Pro

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12 replies to this topic

#1 Horst Ziegler

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Posted 08 August 2020 - 10:16 AM

Hi,
yesterday I wanted to start a session with my new Asiair Pro. First I did a polar alignment using my polarscope and then a 1star alignment. Alignment was ok. Goto IC1805 and images without guiding were ok.
Then I tried polar alignment with Asiair pro after slewing back to home. After several iterations moving RA knobs as required alignment error still was greater than 30 arcsecs.
Any idea what i do wrong? Also Goto IC1805 and Platesolve never came to an end
Hardware used:

CGEM2

ASIair Pro

ASI533MC Pro Main Camera on Esprit 80/400

ASI120mini Guidecam on Skywatcher 9x50

Thanks Horst


Edited by Horst Ziegler, 08 August 2020 - 10:24 AM.


#2 Guest7564635

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Posted 09 August 2020 - 12:34 PM

Hello Horst,

since you mention "my new Asiair Pro" did you also update the APP to the newest ASIAIR version ?? if not, then please do that.

 

Then, did you also enter the correct FOCAL LENGHT of your scope (if you use a reducer, then considering the reducer Focal Lenght also) ?

 

I also have a ASIAIR PRO, and actually there is not really muich to insert, than the LOCATION + FOCAL LENGHT of GUIDER SCOPE and MAIN SCOPE, the ASI CAMERAS are automatiocally recognized and under settings also the mount you have or use..

 

But please check, if your ASIAIR PRO has the latest software version, the most actual ASIAIR version is, Version    1.4.4 Updated   Jun. 17, 2020

 

Regards and good luck for the moment with plate solving issue..

Martin


Edited by artem2, 09 August 2020 - 12:46 PM.


#3 Horst Ziegler

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Posted 10 August 2020 - 01:00 AM

Good morning Martin,

thank you for your response.

yes, everything what you mentioned is as described.

Yesterday my next trial was the following:
 

- Polaralignment with a polarscope, with help of the APP PS Align Pro

- Power on CGEM, all data entered in CGEM HC
- Power on ASIAir, Connected, all data correct
- 1Star Alignment with HC

- Slew to IC1805, no guiding
- Image of 10 seconds without any drift, Stars are dots

- Slew back to home position
 

- image 2 secods with ASIAir

- Platesolve ok

- PA with some corrections

- Firewirk with only 2“ error

- Slew to IC1805, no guiding

- Image of 10 seconds 
- Platesolve stopped after 15 iterations

- another image taken

- stars are bananas

- Tried to start guiding, calibration failed

 

So what is wrong. Of course the main camera is not aligned on the optical axis with the polarscope.
Is it therefor really necessary, at the beginning of the session to do every time a 3 Star alignment with my mobile Setup?

If Yes, why do I need ASIAir. I can stay with MaximDl to do the rest

 

Best Horst


Edited by Horst Ziegler, 10 August 2020 - 01:04 AM.


#4 Guest7564635

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Posted 10 August 2020 - 10:12 AM

Hello Horst,

 

I personally, never do any star aligning, and according to ASIAIR MANUAL, you do not need to perfrom any star aligning at all, the plate solving with ASIAIR will perfrom that for you..

 

Here is my process, it is also stated in ASIAIR MANUAL " Most of the equatorial mount's sync function is equivalent to a one-star calibration, so in general, you don't need to perform one or more star calibrations in advance"

 

1) Connect Mount + CCD+GUIDER to ASIAIR and insert all relevant data into ASIAIR..

2) Perfrom the FOCUS action.. and once FOCUS is also fine and done, then

3) PLATE SOLVE + then SYNC MOUNT and that should perfrom for you the so called star aligning, and your mount should be SYNCHRONIZED with ASIAIR..

 

Then you can also move over to perfrom polar aligning..

 

In case you have problem to plate solve, then there must be something wrong with your setup data in ASIAIR, but I do read in your answer, that you were able to plate solve with AASIAIR..

 

Regards

 

Martin



#5 Horst Ziegler

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Posted 10 August 2020 - 10:58 AM

Hello Martin,  

thank you very much for your helpful comments.

I normally start with my mobile setup at a prepared place and check the polar alignment with my polarscope in the home position. Maximum small changes are necessary. Then I do a plate solve around polaris with asiair, that is ok. A sync to the mount is not possible because to near at Polaris.

I thought, PA with Asiair would now help, but this results in a different alignment and next goto and plate solve are not successful.

Tonight I try to slew to IC1805 like yesterday, but without a second PA after the first one with the polarscope.

Then hopefully plate solve and sync mount is ok.

 

But why then another  PA with Asiair? Is that necessary at all with my prealigned mount?

My question is, how can Asiair perform a successful PA with the imaging camera, which is normally not perfect aligned on the optical axis with the polar scope? 
 

I did PA first with the polarscope and the stars were round for a while without guiding

Then I did a second PA with Asiair (successful with firework) and the stars were stripes, so wrong alignment

 

 Tonight I will try your approach, but without PA, because the mount is already aligned.

 

Thanks Horst



#6 Guest7564635

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Posted 10 August 2020 - 12:50 PM

Hello Horst,

 

On a short way told, you claim that when you perform polar alignment with my polarscope then you get rounder stars, and when you perfrom polar alignment and adjust AZ/RA in accordance to the PA results goven by ASIAIR, then the stars are stripes ? and you are asking why ??

 

To be honest, I really can't explain that..

 

I would suggest that you ask the question to the experts at ZWO, they have a forum for Technical questions..

https://bbs.astronom...ing-camera.com/

 

With my experence, I can say, polar alignment with a SOFTWARE DRIVEN ALigning and Plate Solving is by far more accurate than with a polarscope, and also back pain free like-button.jpg

 

 

 

Regards

 

Martin


Edited by artem2, 10 August 2020 - 12:51 PM.


#7 Horst Ziegler

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Posted 10 August 2020 - 04:16 PM

Hij Martin,

i had  chance tonight to start a new session. 
I checked the polar alignment from yesterday which i solved with the polarscope. Was very exact, took only 1 minute to adjust the time difference. Slew to target, plate solve and sync to mount with ASIAir worked now perfect and i could start guiding and imaging. I don‘t know why PA with ASIAir yesterday failed, but obviously i don‘t need it because my alignment is already good and i use always the same location for my mobile setup.

 

Thank you very much for your comments and help. My workflow is now clear and ASIAir Is really excellent

 

Horst


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#8 Guest7564635

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Posted 11 August 2020 - 01:31 AM

Thank you Horst, Happy that ASIAIR works for you now.. 

 

Good luck and all the best

 

Martin



#9 Horst Ziegler

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Posted 05 February 2021 - 10:47 AM

Thank you Horst, Happy that ASIAIR works for you now..

Good luck and all the best

Martin



#10 Horst Ziegler

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Posted 05 February 2021 - 11:10 AM

SkyGuider.jpg
 

 

SkyGuider4.jpg
 

Hi Martin,

I test my ASIAIR Pro now also with my new ultra light setup

CS Horst


Edited by Horst Ziegler, 05 February 2021 - 11:24 AM.

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#11 Horst Ziegler

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Posted 10 June 2021 - 12:48 PM

Hello again,

i have now a complete different setup with my image train on a GEM28 mount.

Before starting again a polar alignment with this equipment I have again a question of understanding.

One method of PA would be, to use the built-in iPolar with Software on my windows laptop but which I don‘t like  in the field.

The second method would be to use my ASI120mini on the ASI guidescope with PA on ASIAIR Pro.

But how can this be an exact PA, when the guidescope is not 100% aligned with the optical RA axis?

I am a bit confused because in the past I always used an optical polar scope.

Thanks for your help for clarification.

Horst


Edited by Horst Ziegler, 10 June 2021 - 12:51 PM.


#12 davidparks

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Posted 10 June 2021 - 01:37 PM

The imaging camera (you can use a main camera, guide camera, etc), does not need to be aligned with the axis when using a "rotate the axis" type routine for polar alignment.  This would include ASIAIR, Sharpcap, and even iPolar (as well as other products).  Even iPolar, although in 'normal' usage doesn't rotate, is based upon a previously saved calibration which included rotation .

 

Platesolveing both before and after RA Axis Rotation is a very accurate way of calculating your exact RA Axis position, and Polar Alignment adjustment guidance is thereby given based on the RA Axis (not the center of your camera).



#13 Horst Ziegler

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Posted 10 June 2021 - 03:52 PM

Hi David, 

ah, thanks a lot. It is clear now, i forgot the rotation of the RA axis which I used some years ago with my EQ8

Regards, Horst




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