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GT71 1x Flattener/Reducer

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3 replies to this topic

#1 Wow!

Wow!

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Posted 06 December 2021 - 12:03 AM

Hi all

 

I'm looking at getting a travel scope setup, and the front runner is the ASKAR FRA400. However stock is difficult and it could only arrive "sometime next year", so the William Optics GT71 is my next option.

 

With the paired flattener, they are the same price locally in Australia, but I don't really want to go below 400mm focal length.

 

Does anyone know of a flattener that can be used with this WO scope that is 1x and keeps the focal length as is?

 

Thanks!



#2 900SL

900SL

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Posted 07 December 2021 - 02:34 AM

Bookmarked as I've asked this before.

 

There is a Hotech SCA 1.0 that reportedly fits, however I've not been able to find much in the way of detail (image circle, field flatness, coma etc) 

 

There is also an Altair astro 1.0 that MAY fit, looks pretty cheap and no idea how this performs 

 

TS Flat 72 perhaps, although not sure about spacing 

 

also possibly an AT2FF Astro Tech may work..


Edited by 900SL, 07 December 2021 - 06:59 AM.


#3 iantaylor2uk

iantaylor2uk

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Posted 07 December 2021 - 07:12 AM

Bookmarked as I've asked this before.

 

There is a Hotech SCA 1.0 that reportedly fits, however I've not been able to find much in the way of detail (image circle, field flatness, coma etc) 

 

There is also an Altair astro 1.0 that MAY fit, looks pretty cheap and no idea how this performs 

 

TS Flat 72 perhaps, although not sure about spacing 

 

also possibly an AT2FF Astro Tech may work..

I have the Hotech SCA flattener, and it works well on my WO GT 81 IV with a camera which has an APS-C sensor. Certainly a massive improvement on not having any flattener! One plus for the Hotech flattener is that it should work for any telescope in the range f/5 to f/8, so I also use it on a Tak TSA 102 which I have, and it seems good on that scope too. 


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#4 900SL

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Posted 07 December 2021 - 07:36 AM

Thanks Ian useful feedback




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