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Connecting a 2" Flattener to an AT115EDT

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#1 santafe retiree

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Posted 21 February 2020 - 01:50 PM

In this thread:

 

https://www.cloudyni...-2#entry9996105

 

a discussion was started about connecting a 2" flattener (FF) to an AT 115EDT. I started this thread to widen the possible audience to get more ideas.

 

I have a TSFlat2 inserted into the 2" EP adapter, not screwed into the focuser.  On my rig, I do not have lateral "slop" but I do have tilt.

 

This adapter:

 

https://agenaastro.c...apter-m-03.html

 

is what I think is the way to thread the FF directly onto the focuser.

 

I unthreaded the 2" accessory adapter from the focuser tube and measured the male thread and got 53.87mm.  The FF has a standard 48mm female thread.  So a 54mm male to a 48mm male should do the trick.

 

Unfortunately Agena is out of stock and like so many parts coming out of China, there is no ETA due to the corona virus disruption.  I looked on Aliexpress and found what looks to be an identical unit for $13 USD.  I ordered it and have my fingers crossed.  When/if I get it I am going to douse it in acetone and set it on fire before I use it smile.gif

 

I suspect that what the poster in the other thread is experiencing is lateral slop due to the 2" compression ring not squarely sitting in the safety bevel.

 

Some folks like this flattener because of the self centering feature:

 

https://agenaastro.c...-flattener.html

 

The AT 2" 0.8x reducer/flattener for this scope has the male 54mm threads as part of the barrel so it is curious that the flattener does not have the threads.

 

Other ideas?

 

Tom


Edited by santafe retiree, 22 February 2020 - 01:09 PM.


#2 photoracer18

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Posted 21 February 2020 - 02:44 PM

Based on Stellarvue's flatteners and reducers they only do thread-on for the ones that are for larger format sensors where they need the extra width (SV uses a 63mm thread in their 2.5" focusers). If you want to lock a slip in reducer why not put a Baader click lock adapter in the focuser. That should lock it in and center it better.

Unfortunately my AT115EDT is in Albuquerque with my brother and I have never actually seen it in person.


Edited by photoracer18, 21 February 2020 - 02:45 PM.


#3 santafe retiree

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Posted 21 February 2020 - 06:40 PM

Based on Stellarvue's flatteners and reducers they only do thread-on for the ones that are for larger format sensors where they need the extra width (SV uses a 63mm thread in their 2.5" focusers). If you want to lock a slip in reducer why not put a Baader click lock adapter in the focuser. That should lock it in and center it better.

Unfortunately my AT115EDT is in Albuquerque with my brother and I have never actually seen it in person.

That's an interesting idea but how do you propose to attach the Baader Click Lock to the AT115EDT focuser drawtube?



#4 fmeschia

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Posted 22 February 2020 - 12:59 PM

Neither of the Agena links seem to work.



#5 santafe retiree

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Posted 22 February 2020 - 01:10 PM

Neither of the Agena links seem to work.

Sorry -- try it now -- Tom



#6 fmeschia

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Posted 23 February 2020 - 06:16 PM

Thanks, the links work now.

The M54-to-M48 adapter ring would work, but assuming you plan to use it with the M48 filter thread of the flattener, I wonder if that thread would be strong enough to support the weight of your camera. That said, I’ve never used it myself for that purpose, so you’ll probably want to wait for the opinion of someone who has direct experience.

Francesco



#7 santafe retiree

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Posted 23 February 2020 - 06:55 PM

Thanks, the links work now.

The M54-to-M48 adapter ring would work, but assuming you plan to use it with the M48 filter thread of the flattener, I wonder if that thread would be strong enough to support the weight of your camera. That said, I’ve never used it myself for that purpose, so you’ll probably want to wait for the opinion of someone who has direct experience.

Francesco

Thanks for your input - I had not thought about whether the filter threads would be strong enough to carry the weight of the camera/EFW -turns out the vendor on AliExpress shipped the adapter yesterday so I may have it sooner than I thought -- will update when I get it


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#8 Tbob32

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Posted 24 June 2020 - 01:00 PM

Did you ever get the adapter and did it work? Inquiring minds want to know.

 

Thanks,

Bob



#9 santafe retiree

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Posted 24 June 2020 - 02:51 PM

Yes I received the AliExpress unit and it worked as intended -- M54 male threaded into the AT115 focuser and the M48 male threaded into the TSFlat2 --

 

BUT --- the backfocus for the TSFlat2 is a whopping 91mm -- and that caused focus travel issues - I was able to attain focus but just barely --

 

SO --- I bought this instead

 

https://www.firstlig...48-adapter.html

 

and it works GREAT!!!

 

and at less than 1/2 the price of the TS unit

 

I am so thrilled that I am ordering the 0.8 reducer as well

 

Cheers,

 

Tom



#10 Tbob32

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Posted 24 June 2020 - 03:00 PM

Thanks for the update.

 

Do you have the StellaMira threaded on or is it inserted into the eyepiece holder.

 

It appears to be the same thing as the AstroTech AT2FF.

 

Thanks,

Bob 


Edited by Tbob32, 24 June 2020 - 03:00 PM.


#11 santafe retiree

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Posted 24 June 2020 - 03:07 PM

Thanks for the update.

 

Do you have the StellaMira threaded on or is it inserted into the eyepiece holder.

 

It appears to be the same thing as the AstroTech AT2FF.

 

Thanks,

Bob 

Threaded -- end to end -- AT115 focuser > threaded male M54 adapter to male M48 > StellaMira Flattener > ZWO M42 16mm extension tube > ZWO 11mm extension tube > ZWO EFW > ASI1600MM Pro -- solid as far as I can tell  - no slop




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