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William Optics WIFD

Equipment Refractors Focuser
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Brian avatar
Brian avatar
Hello,

I'm considering pre-ordering a Redcat 91.
The specs look good, and the telescope is cheaper than the new SQA85 from Askar. Worst case, I can always return it.

However, I’d like to focus on the WIFD focuser from William Optics rather than the optics themselves.

What are your experiences with it, especially compared to a traditional focuser? Since this kind of system is quite uncommon,
I’m a bit worried it may not work as good as a "normal" focuser.

Greetings
Brian
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Stacey Baczkowski avatar
Stacey Baczkowski avatar
Hi Brian.  I have the WO GT81 WiFD and like the internal focuser.  It is sturdy and does not slip.  I've found that I do not need an EAF as the focus does not change through the night - even when there are large temperature changes (around 20-30 degree change overnight)  or in the cold. Where I live, cold is 30s and sometimes 20s, so I don't know how the focuser will work in colder temps.  I've used it through the winter and had no focus shift issues.  I have another telescope with an external focuser (a Stellarvue) and need an EAF with it as I get focus shift with temperature changes.  If you want to use a flattener/reducer you will need to use the WO brand or similar.  The Starizona is not compatible because it fits within the focuser and there isn't room for it with the internal design.
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Tom Boyd avatar
Tom Boyd avatar
I have it on a Redcat51 - works great.
Paul Puntin avatar
Paul Puntin avatar
Hi Brian, I also have the WO GT81 WiFD and I don't find any real difference in operation between it and a more traditional focuser. I have an EAF on mine as I like a fully automated system and it works great. One of the main advantages of the internal focuser design is you don't have any focuser sag no matter what weight your imaging gear is as the gear is screwed to the actual telescope tube. The only niggle I have is that the focuser knobs are in just the wrong place for the lever on my HEM27. So I wouldn't have any concerns regarding the WIFD focuser not working as well as more traditional focuser.
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Christian Bennich avatar
Christian Bennich avatar
I have the Redcat 51 WIFD and the focuser is rock solid. Once set, it keeps the focus all night. 

I am strongly considering that my next scope will also be a WO WIFD.
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Tony Gondola avatar
Tony Gondola avatar
Keep in mid that traditional camera lenses are internal focusing. That's a long proven way to focus a lens and works well. I wouldn't have any concerns.
Brian avatar
Brian avatar
Thank you for your answers.

I just preorderd the Redcat 91. Here in Germany the scope is cheaper then the new SQA85. Strange

I think the WIFD is a nice thing.
No tilt from the focuser because of a heavy cam setup. Also the scope allways has the same length.



Tony Gondola:
Keep in mid that traditional camera lenses are internal focusing. That's a long proven way to focus a lens and works well. I wouldn't have any concerns.

Also the older Redcats (51 and 71) had a helical focuser with internal movement of the lenses and they worked good.
So I think there will be only advantages with the WIFD. Also you need no belt
Ben Kerlik avatar
Ben Kerlik avatar
Brian, 

Hello - I can only speak to the Redcat 51 WIFD but I do like the focuser. I have an EAF on it but have not noticed any slipping over long periods of time or temp changes. 

Having the focuser in the middle of the scope also helps with balance issues. There is slightly less weight on the bottom end. 

I've previously used WO products in the Zenithstar line and each were high quality. The Redcat 51 I own now is visually gorgeous, and the images are great too. Also, I thought with the Petzval design you did not need an approximate backfocus number/focal reducer to work with. 

I hope this helps.
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Bill McLaughlin avatar
Bill McLaughlin avatar
RedCat 71 WIFD here and so far it is great.
Fabiano R. Maioli avatar
Fabiano R. Maioli avatar
Hi, does anyone have experience with Redcat WIFD and the Sesto Senso 2 focuser? I have this autofocuser and was thinking to acquire a RedCat 51 WIFD, but I can't find information if Sesto Senso is compatible with it, as the installation mechanism is different than EAF.
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