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The Askar FRA 400 Quintuplet Astrograph

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#51 tkottary

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Posted 15 October 2020 - 08:10 PM

I received my scope yesterday and i am quite disappointed with the focuser and rotator .Focuser is not very smooth. No marking on the rotator, rotator knob really needs to be tightened so much to avoid camera rotation .I could even rock the camera with knob fully tighten.


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#52 RossW

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Posted 15 October 2020 - 08:49 PM

I received my scope yesterday and i am quite disappointed with the focuser and rotator .Focuser is not very smooth. No marking on the rotator, rotator knob really needs to be tightened so much to avoid camera rotation .I could even rock the camera with knob fully tighten.

Well that is disappointing. The focuser in my copy is truly buttery-smooth, so if yours is not, I would send it back for a replacement.

 

No marking on the rotator,

 

The images I provided in this thread show that there are no degree markings on the rotator; I agree that those would be helpful though.

 

rotator knob really needs to be tightened so much to avoid camera rotation .I could even rock the camera with knob fully tighten.

 

I see none of this with my scope, and the imaging train is reasonably heavy with the full-frame ASI6200, large 2" seven-position filter wheel, and large M68 OAG. I'd get a replacement.

 

Cheers,

 

Ross



#53 astro rocketeer

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Posted 15 October 2020 - 09:04 PM

I don’t have any of the rotating issues on mine either and I have a heavy Canon 60D with battery grip + ASI Air Pro on an L-bracket with all the cables hanging off of it. Sounds like you got a bad one. I’d return it if possible. This is a great scope!



#54 tkottary

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Posted 16 October 2020 - 12:34 AM

Yea i have asked Agena to replace the focuser and rotator if possible. I do want to keep this scope :) 



#55 desper0

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Posted 16 October 2020 - 04:48 PM

I also noticed that the coarse focus is not incredibly smooth, but the fine focuser knob is. It does not bother me, I would be bothered if the fine focuser were not smooth as I plan to fit a Sesto Senso focuser. No issues with the rotator. After reading this, I fit my heavies diagonal/eyepiece combination and it is rock solid. Haven't had the chance to check the optics as I received it yesterday and last night was used to finally getting some Mars pictures with my C9.25 after days of clouds. I plan to check it again tonight.. Beautiful little scope though..

 

IMG 20201016 145420

 


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#56 tkottary

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Posted 16 October 2020 - 06:22 PM

Here is the set up with RST 135 asi 6200 and sesto senso 2.

21BF785B-19CB-4B03-A894-6EA3496FE641.jpeg


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#57 astro rocketeer

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Posted 16 October 2020 - 06:49 PM

Here is the set up with RST 135 asi 6200 and sesto senso 2.

attachicon.gif21BF785B-19CB-4B03-A894-6EA3496FE641.jpeg

Thanks for sharing. Whats the attachment you have between the telescope focuser and the cone that connects your filter wheel? Nice set-up!



#58 tkottary

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Posted 16 October 2020 - 07:20 PM

That is a Gerd Neumann CTU to remove any tilt . The dovetail bar that came with the setup is too small. When you add all the adapters the imaging train becomes very much back heavy . I need some raisers to mount it on bigger dovetail.


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#59 desper0

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Posted 17 October 2020 - 08:22 PM

Here is the set up with RST 135 asi 6200 and sesto senso 2.

attachicon.gif21BF785B-19CB-4B03-A894-6EA3496FE641.jpeg

Nice setup. Can you install the Sesto Senso 2 into the FRA400 with the bushings that came with the SS2, or did you need a custom one?



#60 tkottary

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Posted 18 October 2020 - 12:21 AM

Used the yellow bushing that came with SS2.

#61 Gene3

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Posted 23 October 2020 - 08:52 AM

I am hoping an FRA400 owner can help me out:

 

I am trying to have an adapter (M68 to M54) made for my FRA400 (on order, not received yet). I will be attaching a QHY268C image train which has the M54 thread and takes up 37mm of backfocus. I believe the BF of the scope is 148 but I am not sure how the 60mm of focuser travel impacts the BF and thus the length of the adapter I need.

 

I am struggling to get the BF information correct. Is it actually 148mm as stated by Agena Astro? The link to the Askar drawing shows it to be 110mm. http://www.askarlens...class2/182.html

If I go with the 148 then minus my image train (37) I get 111mm of BF. Then if I subtract the mid point of focus travel (30mm) from the 111mm I get 81mm for my adapter length. Does that sound right?

 

Also, Precise Parts who is making my adapter would like a very clear picture of the M68 thread at the back of the OTA that the adapter would be attached to, I am hoping a current FRA owner can take a couple photo's of the M68 thread and send it to me so I could pass it on the Precise Parts.

 

Thank you,

Gene



#62 nicknacknock

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Posted 24 October 2020 - 12:27 AM

Can’t help with backfocus, but here’s a M68 to M54 adapter if of interest..


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#63 robonrome

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Posted 24 October 2020 - 08:25 AM

I am hoping an FRA400 owner can help me out:

I am trying to have an adapter (M68 to M54) made for my FRA400 (on order, not received yet). I will be attaching a QHY268C image train which has the M54 thread and takes up 37mm of backfocus. I believe the BF of the scope is 148 but I am not sure how the 60mm of focuser travel impacts the BF and thus the length of the adapter I need.

I am struggling to get the BF information correct. Is it actually 148mm as stated by Agena Astro? The link to the Askar drawing shows it to be 110mm. http://www.askarlens...class2/182.html
If I go with the 148 then minus my image train (37) I get 111mm of BF. Then if I subtract the mid point of focus travel (30mm) from the 111mm I get 81mm for my adapter length. Does that sound right?

Also, Precise Parts who is making my adapter would like a very clear picture of the M68 thread at the back of the OTA that the adapter would be attached to, I am hoping a current FRA owner can take a couple photo's of the M68 thread and send it to me so I could pass it on the Precise Parts.

Thank you,
Gene


Its not a backfocus requirement. The 148mm is the available amount of backfocus you have to play with. This scope is designed such that it doesn't matter precisely how far back your sensor is so long as it is within the available backfocus range. That is its party piece.

Edited by robonrome, 24 October 2020 - 08:27 AM.

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#64 Gene3

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Posted 24 October 2020 - 10:43 AM

Its not a backfocus requirement. The 148mm is the available amount of backfocus you have to play with. This scope is designed such that it doesn't matter precisely how far back your sensor is so long as it is within the available backfocus range. That is its party piece.

Ok Got it. I forgot that the flattener is in front of the focuser.


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#65 Gene3

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Posted 24 October 2020 - 11:00 AM

On the FRA400, is the male M68 thread M68x1 or M68 x0.75?

 

Thanks,

Gene



#66 RogeZ

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Posted 24 October 2020 - 03:31 PM

Gene:

New FRA400 come with M68-M54 adapters already. The older ones like mine are M68-M48.
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#67 Gene3

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Posted 24 October 2020 - 05:20 PM

Gene:

New FRA400 come with M68-M54 adapters already. The older ones like mine are M68-M48.

Wow -seriously it comes with the adapter?

That is fantastic news and a huge relief.

Thanks,

Gene



#68 pmuller

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Posted 24 October 2020 - 05:28 PM

Its not a backfocus requirement. The 148mm is the available amount of backfocus you have to play with. This scope is designed such that it doesn't matter precisely how far back your sensor is so long as it is within the available backfocus range. That is its party piece.

I believe that the backfocus has to be spot on only with the reducer. Roger can probably say better as I got his reducer but weather has not helped me to test it yet lol.gif

 

I have had the scope for almost a month, have had the chance to literally use it for about 8 hours (3 different nights) as South Florida weather has been brutal with the record breaking hurricane season. APS-C sensor delivers pinpoint stars in the whole frame.

 

Attached a 5 mins sub from a B3 site, no calibration, just stretched 

Attached Thumbnails

  • IMG_0578_s.jpg

Edited by pmuller, 24 October 2020 - 05:29 PM.

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#69 Cziffra

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Posted 25 October 2020 - 12:01 PM

Would the Askar reducer work with other refractors of similar f ratio?



#70 robonrome

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Posted 25 October 2020 - 11:44 PM

Ok Got it. I forgot that the flattener is in front of the focuser.


One point to note is that the above applies to use without the optional 0.7x reducer. If you use that then you need to set up a specific 55mm backfocus distance from reducer to sensor.


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