The Telescope Built Like a Camera Lens: WO GT81 WIFD Review

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Hope you enjoyed this review of the WO GT81 WIFD, a very interesting and innovative refractor telescope. This thing's main selling point is the internal focusing mechanism, which eliminates focuser sag. This means it is very well suited for full-frame imaging.
If you want to see my full size finished images you can find them here on my astrobin: www.astrobin.com/uaxtrq/
If you want to learn how I edit my photos, and get some of my high quality data, you can visit my website here: astrofalls.com/

[@astrocarone9671]

Not surprised by WO at all. They always kill it. Both my Refractors are WO. Love them.

[@pessorrusso]

Great review, direct to the point. Thank you! WO gear is one of the best, their quality is great.

[@woody5109]

Finally, great review.

[@derekbaker3279]

Great review Bray! A lot of excellent points! Love the Rho Oph image too! (..my fav area of the sky..)👍👍 Note: All owners of harmonic mounts can skip the first two minutes re balance issues...😉 LOL. (..just kidding..) Any rumours of WO repeating the same concept with their 91mm FLT? (I have heard talk of a RedCat 91, but....)🤔 Also, I can vouch for the fact that setting up autofocusing on the RedCat 51 & 71 is pretty straight-forward & works well.👍

[@dinosworkshop6870]

Great video with a lot of good ideas!

[@skye7690]

I love this business end vs party end!

[@actudoran]

great ideea ! good review mate! looks like a real good choice for an 80 apo ! I don't have all the filter wheel and oag milakee on my scope and wit a standard DSLR there's no sag on my scope ... no visible tilting and stuff ... but then again... 2.5" focuser and field flattener... beefier than most std equipment for my TS 115/800 ... I am really chuffed with my choice 😅 but I suppose once you up the ante with ear oag and filter wheel and an ASI 6200 .... things might look different. My budget isn't there for the moment... 😢 concentrating on getting my C11 up to speed for galaxy fun 😊 weather has me frustrated 🥴 ... one day ...

[@deep_space_dave]

Thanks for the review! Imagine if they made a Petzval version of this! Like the Takahashi FSQ-85 but with this design, this thing would be killer!

[@xMemn0nx]

It definitely would help with balance on these lightweight scopes. I have a Sesto Senso on my WO Z73 and, while not very heavy, its enough to make it difficult to balance the rig since all its weight is on one side and quite far from the center of gravity. Having the autofocuser closer to the center of gravity would 100% make my life easier.

[@DeepSkyDad]

Great review! Would be interesting to motorize the built in rotator in order to help center oriented balancing (less weight at the back than with dedicated field rotator). Also, i can see a customized EAF plate with asiair mount on the opposite side of the motor would be nice.

[@englishfires6728]

Good work Falls, good work! Thank you for the review. Much appreciated. How do you find it optically compared to FSQ-85ED?

[@astrofalls]

Hard to say since I didn't get to use the GT81 unreduced, only at 0.8x. What I can say is that the FSQ85 with the QE0.73x is WAY worse than the GT81 with the 0.8x. When unreduced, I think they both would be comparable optically

[@capturethephotons2078]

The WILLIAM OPTICS GT81 is my main/only telescope on an EQ6-R pro besides my DSLR skywatcherstaradventurer and lenses

[@ctortolini]

Thank you for the review. Quick question... Did you do any tests without the reducer? If so, how were the stars at the corners?

[@DSOImager]

Reminds me of a rifle scope with a side focus. Will be interesting to see if this design takes off.

[@paulvlachos7492]

Fantastic review! What guide camera are you using ?

[@skye7690]

I think for the AM5 too (i.e., you don't balance it), this kind of scope really makes a lot of sense.

[@Matt_10203]

Same idea as the Redcat, which itself is a nice scope - though the helical focuser is my biggest gripe with it. Doesn’t easily play with most EAFs and essentially requires an additional pulley and bracket.

[@hael8680]

I use a Rigel N-Step focuser on my Redcat with no issues at all and virtually no backlash. Those ZWO EAFs are low quality in my opinion. Too much backlash and they crap out in the cold.

[@3_Gold_Coins]

I have this scope. I had to add risers to help the focuser be able to not hit the mount. I installed the ZWO EAF. It all sits on the AM5 mount. My main camera is ZWO 2600mc pro. Guide camera is ZWO asi 220 mini. I set my back space. Focused my main camera on a mountain peak. My problem is I can’t get my guide camera to work

[@RJ-vc2ju]

Stumbled on your channel while researching refractors. Gotta say you do a great job on your videos! How's the imaging going in Namibia (spent age 5-16 there, what a blessing of a country to grow up in, extraordinary southern skies and, together with Botswana, probably the last remaining mostly undisturbed African nature settings). That aside, I'm looking for a single refractor to go with my Edge HD 8" as I grow into the DSO AP side of the hobby. Would you recommend this scope? I was also looking at the GT71 as something smaller and more portable. I want to keep the cost for the OTA below $3K so that I can pair it with a good harmonic mount (AM5) and have funds for the full frame camera and other gear. Cheers!

[@iskandarthegreat8365]

Well done for this the first review of this APO available. Between the FSQ85 and the GT81 WIFD, which one would you keep, if price was not a criteria ?

[@astrofalls]

Probably the FSQ since it’s faster at native FL. But the GT81 is better reduced than the FSQ

[@efx245precor3]

Nice video. 2:34. Crayford or Rack and Pinion?

[@luboinchina3013]

Let's see how long time it will take for ZWO to copy the design😊

[@JLCubing]

5 seconds

[@rogermachler2303]

Super cooles Video, dass mir sehr geholfen hat mich in meiner Entscheidung zu stärken, vielen Dank. cu roger

[@rickbria8420]

You say the corners of the images look good on a full frame. But as you panned your RHO image , it seemed you stopped panning when I started to notice coma like distorted star images to the right side of the picture. Is it because you didn’t use the field flattener on that image? Do you have to have the field flattener for round stars in the corners?

[@TheNarrowbandChannel]

Ok camera lenses are usually gunk optically compared to telescopes. Virtually all of them require you to stop them down. Maybe the mechanics might be lens like but I hope not the optics.

[@astrofalls]

I don’t think there’s any worries on that front, it’s identical optically to their other 81mm AFAIK

[@cryhavoc38]

how can we install the ZWO EAF on this?

[@michaeloppenheimer2582]

it should elluminate the need for a coma corrector !!!😊

[@derekbaker3279]

All refractors have curvature of the field, so you need either a 1.0x Flattener, or a combination Flattener/Reducer. The only exceptions are refractors that are Petzval systems (e.g. Takahashi FSQ85 & Tak FSQ106, or the TeleVue NP101 & NP127), which have two widely-space ED doublets (...in a sense, they have the flattener already in the tube).

[@markmorel1721]

Is that the dovetail that came with your scope?

[@astrofalls]

No it came with a vixen! I swapped for a primaluce dovetail for my mount

[@markmorel1721]

Thanks. Any chance you have access to a ZWO AM5 mount? If so I was wondering if the scope, dovetail, and mount play well together? My scope came and I discovered with the vixen dovetail and AM5 the focuser ring doesn’t clear the mount properly.

[@3_Gold_Coins]

I hope that Mark was able to get around the clearance problem.

[@user-dn8os3hp4y]

@@markmorel1721 You are right - I have had to deal with the same issue - the focus wheel binds with the vixen bar on the AM5 and other mounts - surprised Bray you didn't mention that. You must additionally purchase risers or a losmandy plate to use it.

[@sonicsound84]

:23 well, they could develop that ancient usb B port into a USB C to conform with the modern era. lol

[@grandmasteryoda9893]

looks good, but very expensive

[@samuelandrew4500]

Jury still out on the focuser, this review lacks evidence! if the focuser isn't up to the job, you've got no option to upgrade unlike a regular telescope. I'm happy with the 3.3" on the FLT scopes.

[@astrofalls]

Very true, like I said I don’t own an autofocuser that can be used on such a telescope, but I don’t have any doubts it would function fine given the focuser is under almost zero mechanical load

[@SkyWKing]

The only problem I see is the price. At $2000 it's in 90mm APO territory and much more expensive than the regular GT81.

[@grandmasteryoda9893]

or worse a 8 inch qattro with a moonlit focuser on top.