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RedCat 71 WIFD vs Ultra-Cat 76 — which one’s really better?

William Optics Redcat 71 ZWO AM3 Equipment Harmonic Mount Refractors Beginner Buying Advice Deep Sky
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Deniz Üzel avatar
Deniz Üzel avatar

Hey everyone,

I’m setting up a deep-sky rig and can’t decide between these two William Optics bundles:

🔹 RedCat 71 WIFD + ZWO AM3 Full Package

🔹 Ultra-Cat 76 + ZWO AM3 Full Package

Both are almost the same price, so I’d love to know:

– Which setup would you go for, and why?

– What are the real differences between the RedCat 71 WIFD and Ultra-Cat 76 (optics, image circle, sharpness, speed, etc)?

– Is the 76 worth it, or are they basically the same in real-world performance?

Any insights from people who’ve used either (or both) would be awesome.

Thanks in advance — clear skies!

– DÜ

ScottF avatar
ScottF avatar

I don’t have either but if it were me, I’d get the 76mm. Having a standard focuser makes adding an electronic focuser easier and avoiding belts and such.

Dunk avatar
Dunk avatar

ScottF · Nov 7, 2025 at 09:28 PM

Having a standard focuser makes adding an electronic focuser easier and avoiding belts and such

The 71 is a WIFD - no belts needed.

The 76 appears to be the better scope though - 5-element Petzval (vs 4 “Petzval-like”), better glass, larger image circle, slightly faster/longer for essentially the same price.

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ScottF avatar
ScottF avatar

Dunk · Nov 7, 2025 at 11:48 PM

ScottF · Nov 7, 2025 at 09:28 PM

Having a standard focuser makes adding an electronic focuser easier and avoiding belts and such

The 71 is a WIFD - no belts needed.

The 76 appears to be the better scope though - 5-element Petzval (vs 4 “Petzval-like”), better glass, larger image circle, slightly faster/longer for essentially the same price.

Yep. I looked at the wrong scope.

Rick Krejci avatar
Rick Krejci avatar

If you look at the spot diagrams for both, the Ultracat 76 should have far tighter stars from the center and especially the corners.

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AstroÅmazer avatar
AstroÅmazer avatar

Not RedCat 71. I had a refurbished, non WIFD version with the helical focuser, I got directly from William Optics, traded in for a new GT81IV.

I have not used the UltraCat 76 but is has comparable glass to the SQA 70 which I have now and there is no comparison. SQA 70 is super sharp and only limited by my seeing.

I like William Optics build quality. Even though my RedCat 71 developed focuser issues, their customer service was great. It was within the warranty period, and I did not want it back as I did not like the helical focuser. They gave me the option to trade up (or down… I went up 10cm) to a GT81IV bundle paying the cost difference (I think it was ~$100, GT81WIFD bundle would have been much more). If the UltraCat76 had been available then, I would have gone for that.

But comparing my RedCat 71 before the focuser issues, to the SQA 70, the glass quality, hence the picture quality is in a different ballpark. FPL55 > FPL53, especially if you plan to use small-ish sensor cameras (3.76um or less).

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Al Loan avatar
Al Loan avatar

Hey there, I have been imaging with the newer RedCat 71 WIFD with a ASI2400MC pro for ~one year. The scope has had zero issues, the removal of back focus has been a real boon. The images are excellent with tight stars right to the edges,. My only issue, if I was to have one, would be the screw that hold the rotation of the focuser barrel. It has a tendency to loosen which results in the inadvertent rotation of my camera and the ZWO filter wheel. My solution, (very high Teck) was to attach a wire to the filter wheel to fixed location on my scope to prevent any rotation.

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