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SKU: T-C-91-RD-30A

Cat 91 WIFD · 30th Anniversary Limited Edition

Sale price$2,698.00 USD Tax excluded.
⛟ Free Shipping Free shipping on orders over $498. Import charges not included.
Description
Description

The Cat 91 WIFD · 30th Anniversary Edition is a commemorative refractor celebrating three decades of William Optics craftsmanship and innovation. Built upon the acclaimed five-element advanced Petzval optical design, this limited edition of 30 units worldwide combines uncompromising astrophotography performance with a symbolic anniversary finish.

Featuring a unique laser-engraved emblem of a cat embracing “30” and accompanied by a 30th Anniversary Certificate, the Cat 91 WIFD is not only a professional imaging instrument but also a collector’s piece that honors the Cat series legacy.

Highlights:

Petzval Design, No Backfocus Hassles
The 5-element Petzval design eliminates the need for backfocus adjustments, providing sharp, edge-to-edge images with pinpoint stars—ideal for wide-field and detailed astrophotography alike.

Full-Frame & Medium-Format Ready, No Extra Flattener Needed
With a large 55mm image circle, the Cat 91 is perfect for both full-frame and medium-format cameras. Its advanced optics achieve flat-field images without requiring an additional flattener, giving astrophotographers the freedom to capture expansive views with unparalleled clarity.

Fast f/4.9 Focal Ratio
The Cat 91's fast f/4.9 focal ratio is designed for bright, vivid captures of galaxies, nebulae, and beyond, ensuring excellent light-gathering power and sharp detail even on faint celestial objects.

Seamless WIFD Focusing
Equipped with William Optics' WIFD focuser, the Cat 91 provides precise, stable focusing without additional adjustments, enhancing the ease of use for both seasoned astrophotographers and beginners.

Notice
Notice

Astrophotography Only
This telescope is specifically designed for astrophotography, and its optical design does not support visual observation.

Color:Red
Cat 91 WIFD · 30th Anniversary Limited Edition
Cat 91 WIFD · 30th Anniversary Limited Edition Sale price$2,698.00 USD Tax excluded.
UC91 - California - Peter Zelinka

California Nebula

Peter Zelinka

UC91 - Clamshell - Jonathan

Sh2 119 - The Clamshell Nebula

Jonathan

UC91 - Corona - Daemon de Chaeney

Corona Australia Molecular Cloud & NGC 6723

Daemon de Chaeney

UC91 - HorseHead - Mehmet Ergün

M20 & M8 Wide Field

Mehmet Ergün

UC91 - Jellyfish - Peter Zelinka

Jellyfish Nebula

Peter Zelinka

UC91 - NGC2237 - Reynold Edwards

NGC 2237 Rosette

Reynold Edwards

UC91 - NGC224 - Reynold Edwards

Andromeda

Reynold Edwards

UC91 - Omega - Jakub Korbel

Omega Centauri

Jakub Korbel

UC91 - Ophiuchi - Jakub Korbel

Rho Ophiuchi Region

Jakub Korbel

UC91 - Sadr - Peter Zelinka

Sadr Region

Peter Zelinka

UC91 - Soul - Peter Zelinka

Soul Nebula

Peter Zelinka

Expert Review

William Optics RedCat 91 Review

I recently tested the William Optics RedCat 91 APO refractor. This is the fourth RedCat I’ve used in the RedCat series—five if you count the two versions of the RedCat 51 (version 1 and version 3).
With a healthy aperture, fast optics, and a super flat Peztval design, the William Optics RedCat 91 has a lot going for it. It includes several thoughtful features, such as a tilt adjuster, a camera angle rotator, and a robust WIFD focuser.
This telescope has two color options: the classic red and a new black version. William Optics sent me the black one and explained that it’s one of the best telescopes he’s ever produced.