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Baader Allen Gee 11 Telecompressor with refractors?

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#1 De Lorme

De Lorme

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Posted 04 November 2019 - 03:51 PM

Hello,

 

 

I've read that the Allen Gee 11 telecompressor would work with my Baader/Celestron binos but would it work in conjunction with my 5" F/7.5 apo?

 

Does anybody here know if it can be used on refactors?

 

The reason I'm leaning towards this is that the B/C binos only have 17mm prisms and I haven't seen any low power eyepieces{24mm} that have a field stop smaller than 17mm.

 

I'm now waiting for Meade to call me back and tell me the field stop of my Meade zooms. Hoping this will work.

 

Thanks for the help.

 

Clear Skies, 

 

De Lorme



#2 Eddgie

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Posted 04 November 2019 - 04:44 PM

I have not tried it, but my bet is that it will absolutely not work because it is almost impossible to get reduction with binoviewers in any kind of scope other than SCTs and MCTs due to the amount of inward focuser travel that would be required. 

 

The vast majority of refractors out there won't even reach focus at native focal length with binoviewers and even the ones that do reach focus using a T2 diagonal usually will not have more than a few millimeters of travel left.

 

The only reason you can do this with SCTs is because most of then essentially have the same range of focus as a 200mm long focuser tube would have on a refractor. (Most have more than this, but aperture loss will generally start between 170mm and 200mm of focal plane displacement).

 

I am not always right though and I have not tried it, but I have never seen a refractor configuration that would support using any kind of reducer over native focal length and still reach focus It just takes far to much focuser travel. 



#3 De Lorme

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Posted 04 November 2019 - 04:57 PM

Thanks Eddgie for telling ,me.  I didn't think it would have enough in focus even without needing to use a diagonal to reach focus.  I wanted this to happen so I asked the question knowing that  it probably would not work.

 

Thanks for answering my question though. 

 

BTW, the  Baader 2" T2 nosepiece opened up the view of my Meade zooms.  

 

Clear Skies,

 

De Lorme




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