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Asiair Pro: Plate Solving can't "solve" the observed piece of sky

Meade Beginner Equipment Mount
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#1 dellavolpe

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Posted 20 September 2021 - 09:50 PM

Hi everyone: a thousand apologies for the long post, but I don't know what else to do. I'm having a hard time configuring my Asiair Pro with my mount and cameras:
Telescope: Meade LX200 GPS 10" (f10)
Cameras: ASI120MC-S (Guidescope QHYCCD 130mm f4.3) and main ASI 462MC
(Although I have an equatorial wedge, I'm first trying to learn how to use the Alt/Az features; later I'm going to the polar alignment challenge for longer exposures).
Steps: 1) I made the alignment with two stars; 2) then connect Asiair Pro and cameras (Before connecting main camera to Asiair, I connect to SharpCap first to adjust focus); 3) everything connects normally (including the assembly, the GoTo function works fine).
That's where the problem occurs: Plate Solving can't "solve" the observed piece of sky, even with a good number of stars. The program detects them, but reports a problem related to FOV. I've tried everything: I've tried using only autofocus and diagonal, I've tried using an f6.3 focal reducer, then with an f3.3, I've tried connecting the camera directly to a Meade T-CCD adapter. In all cases, the same error: stars are detected but not "resolved".
Where am I going wrong? Thank you very much for your attention.


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#2 steveincolo

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Posted 20 September 2021 - 09:56 PM

Hi everyone: a thousand apologies for the long post, but I don't know what else to do. I'm having a hard time configuring my Asiair Pro with my mount and cameras:
Telescope: Meade LX200 GPS 10" (f10)
Cameras: ASI120MC-S (Guidescope QHYCCD 130mm f4.3) and main ASI 462MC
(Although I have an equatorial wedge, I'm first trying to learn how to use the Alt/Az features; later I'm going to the polar alignment challenge for longer exposures).
Steps: 1) I made the alignment with two stars; 2) then connect Asiair Pro and cameras (Before connecting main camera to Asiair, I connect to SharpCap first to adjust focus); 3) everything connects normally (including the assembly, the GoTo function works fine).
That's where the problem occurs: Plate Solving can't "solve" the observed piece of sky, even with a good number of stars. The program detects them, but reports a problem related to FOV. I've tried everything: I've tried using only autofocus and diagonal, I've tried using an f6.3 focal reducer, then with an f3.3, I've tried connecting the camera directly to a Meade T-CCD adapter. In all cases, the same error: stars are detected but not "resolved".
Where am I going wrong? Thank you very much for your attention.

Have you tried entering 0 for focal length?  That forces the plate solver to compute the focal length. Don’t assume that the specs for focal length, with/without reducer, are accurate.  


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#3 DJL

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Posted 20 September 2021 - 10:12 PM

I have the same ASI 462MC and a 6" SCT. I had the same issue. Plate solving works by recognizing stars in the field of view, but it has a limit. With too small a field of view, it doesn't see enough to recognize the stars and plate solve. Here is what I did that worked for me.

 

I am using an equatorial goto mount, the HEQ5.

During daytime, I pointed the scope at a distant object and compared the views with the guide camera and main camera. Since I can't align my guide camera (it's in a shoe rather than rings) I used a RACI and made sure the center of the 462 field of view was centered with the RACI using the ASIAIR pro bullseye overlay and the cross hairs in the RACI. If your guide scope is in rings, align that. If you have something other than a RACI, like a Telrad or red dot finder, use that.

At night, in the ASIAIR Pro, I set the guide camera as main camera, and set the guide focal length to the guide scope focal length.

I polar align using the ASIAIR Pro and guide camera.

I goto my target using the ASIAIR Pro and guide camera.

Once on the target, I look through the RACI and make sure the target is in the crosshairs.

Now on the ASIAIR Pro, switch the main camera to the 462.

At this point, there's some chance the target is in the field of view, maybe at the edge. Assuming it's Jupiter, if it's not in the field of view, defocus a little and look for a bright area at the edge of the frame.

Use the nudge arrows on the ASIAIR Pro preview to move towards the bright area. Refocus when it's in the frame.

Long press and touch the green goto circle will not work in this case, as it relies on plate solve. However the nudge arrows still work.

 

Hope this helps.


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#4 DJL

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Posted 20 September 2021 - 11:26 PM

One more question: if the goto works, why do you need to platesolve?


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#5 Jim Waters

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Posted 20 September 2021 - 11:36 PM

Goto usually doesn't put stuff dead center.


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#6 AhBok

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Posted 21 September 2021 - 08:31 AM

Your FOV is almost certainly too small, even with the .63 reducer. The .33 reducer gives you a faster scope, but vignettes the field so I would not expect it to work either. The current ASIAIR rev will solve down to .2 degrees. You will need at least that field in both dimensions of your FOV. Go to https://astronomy.to.../field_of_view/  and I believe you will see your setup doesn’t meet this criteria.


Edited by AhBok, 21 September 2021 - 08:33 AM.

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#7 dellavolpe

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Posted 21 September 2021 - 11:05 AM

Hi everyone: a thousand apologies for the long post, but I don't know what else to do. I'm having a hard time configuring my Asiair Pro with my mount and cameras:
Telescope: Meade LX200 GPS 10" (f10)
Cameras: ASI120MC-S (Guidescope QHYCCD 130mm f4.3) and main ASI 462MC
(Although I have an equatorial wedge, I'm first trying to learn how to use the Alt/Az features; later I'm going to the polar alignment challenge for longer exposures).
Steps: 1) I made the alignment with two stars; 2) then connect Asiair Pro and cameras (Before connecting main camera to Asiair, I connect to SharpCap first to adjust focus); 3) everything connects normally (including the assembly, the GoTo function works fine).
That's where the problem occurs: Plate Solving can't "solve" the observed piece of sky, even with a good number of stars. The program detects them, but reports a problem related to FOV. I've tried everything: I've tried using only autofocus and diagonal, I've tried using an f6.3 focal reducer, then with an f3.3, I've tried connecting the camera directly to a Meade T-CCD adapter. In all cases, the same error: stars are detected but not "resolved".
Where am I going wrong? Thank you very much for your attention.

It was the first change I made: even without using the focal reducer I changed from 2500mm to 0, but it still didn't work



#8 dellavolpe

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Posted 21 September 2021 - 11:06 AM

Goto usually doesn't put stuff dead center.

 

One more question: if the goto works, why do you need to platesolve?

Exactly for this reason I would like to use this function, due to the limitations of the GoTo



#9 dellavolpe

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Posted 21 September 2021 - 11:10 AM

I have the same ASI 462MC and a 6" SCT. I had the same issue. Plate solving works by recognizing stars in the field of view, but it has a limit. With too small a field of view, it doesn't see enough to recognize the stars and plate solve. Here is what I did that worked for me.

 

I am using an equatorial goto mount, the HEQ5.

During daytime, I pointed the scope at a distant object and compared the views with the guide camera and main camera. Since I can't align my guide camera (it's in a shoe rather than rings) I used a RACI and made sure the center of the 462 field of view was centered with the RACI using the ASIAIR pro bullseye overlay and the cross hairs in the RACI. If your guide scope is in rings, align that. If you have something other than a RACI, like a Telrad or red dot finder, use that.

At night, in the ASIAIR Pro, I set the guide camera as main camera, and set the guide focal length to the guide scope focal length.

I polar align using the ASIAIR Pro and guide camera.

I goto my target using the ASIAIR Pro and guide camera.

Once on the target, I look through the RACI and make sure the target is in the crosshairs.

Now on the ASIAIR Pro, switch the main camera to the 462.

At this point, there's some chance the target is in the field of view, maybe at the edge. Assuming it's Jupiter, if it's not in the field of view, defocus a little and look for a bright area at the edge of the frame.

Use the nudge arrows on the ASIAIR Pro preview to move towards the bright area. Refocus when it's in the frame.

Long press and touch the green goto circle will not work in this case, as it relies on plate solve. However the nudge arrows still work.

 

Hope this helps.

Good idea to keep the guide and main telescope well aligned. I can ask a "silly" question (due to my inexperience): is there any relationship between the guidescope, the main telescope and this problem to solve?


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#10 bmcclana

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Posted 21 September 2021 - 06:08 PM

Take an image and run it through astrometry.net. Use that result as a baseline for the focal length in the AAP.

I use sharpcap and ASTAP and I have just changed the focal length in the correct range until I got a hit. There is usually some margin for error and still succeed. Within 10-15% usually works. So if you think you are around 1200 I would try increments of 100-150mm until something worked.

#11 DJL

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Posted 22 September 2021 - 06:48 AM

Good idea to keep the guide and main telescope well aligned. I can ask a "silly" question (due to my inexperience): is there any relationship between the guidescope, the main telescope and this problem to solve?

Actually I don't understand your question, and it would help to know what you are trying to photograph. Given that you are using a planetary camera, I assume it's the currently visible gas giants - Jupiter and Saturn.

 

Plate solving with a planetary camera + a reflector + ASIAIR Pro is apparently impossible. The FoV is too small.

 

What is the goal of plate solving? It identifies what is in the field of view, with the goal of precisely aligning on the target. If that's impossible with the first choice of equipment, how can we improvise? I described how I achieved that with the equipment available to me.

 

My guide camera has the same sensor size as my planetary camera, but being mounted on a guide scope rather than a reflector gives it enough FoV to goto. Plate solve is automated by the AAP to refine the goto, but given the misalignment of guide scope and main scope in my case, it's only a first step and the rest are manual.


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