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Field Flattener for a 2.5" Focuser

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#1 BillD17

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Posted 13 March 2018 - 04:24 PM

I have the Astro-Tech 130mm f/7 EDT refractor and want to use it with a full-frame sensor.  The scope has a very nice 2.5" focuser, but the Astro-Tech field flattener slides into a 2 inch tube which will at the very least cause lots of vignetting - and at the worst will chop off the corners of the image.  Does anyone know of a field flattener with a larger optical path?  



#2 fmeschia

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Posted 13 March 2018 - 05:22 PM

TS has a 3" FF/FR. Their 2.5" unit is almost exactly the same (exactly same optical formula, just different camera spacing required) that Astro-Tech sells for the AT130EDT.


Edited by fmeschia, 13 March 2018 - 05:24 PM.


#3 BillD17

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Posted 13 March 2018 - 10:42 PM

Do you mean ES?  Explore Scientific?  Their 3" unit is also an 0.7 focal reducer, and I'd prefer a straight flattener.  Also, its not clear that their adapters will mate with the threads on the 2.5" focuser.



#4 fmeschia

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Posted 13 March 2018 - 11:30 PM

Sorry – I was indeed cryptic. I mean TS, Teleskop-Service. They have this 3" FF/FR:

 

https://www.teleskop...-Teleskope.html

 

and also the Riccardi reducer/flattener, which claims to have a 42 mm image circle:

 

https://www.teleskop...en-und-RCs.html



#5 CounterWeight

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Posted 14 March 2018 - 07:49 PM

This is one of the things it's best to sort out before buying a scope.  You might ask in one of the imaging forums and see if there is a best fit out there.




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