William Optics Ultra-Cat 76 – Limited 30th Anniversary Edition with UniGuide 32mm

LIMITED EDITION

A Milestone Worth Celebrating

The Cat series has always marked significant turning points in William Optics’ journey. In 2019, William Optics introduced the RedCat 51, revolutionizing the refractor market with its lightweight, portable, and high-quality design. It quickly became a favorite among amateur astronomers worldwide. To this day, the RedCat 51 remains William Optics’ best-selling refractor, with countless astrophotographers proudly calling it their first serious telescope.

In 2024, William Optics unveiled the WIFD focuser system, a structural innovation that opened a new chapter for the brand. The following year, in 2025, the company advanced optical design even further with the release of a 5-element Petzval, launching the Ultra-Cat series. With unmatched pinpoint star performance, the Ultra-Cat refractors quickly became some of the most discussed instruments in global astronomy communities. The larger 91mm and 108mm models set a new standard for wide-field astrophotography and achieved remarkable sales success.

Now, in celebration of its 30th Anniversary, William Optics proudly introduces the Ultra-Cat 76 as the commemorative edition. With its moderate size, balanced portability, and accessible pricing, the 76 is poised to become the most popular member of the Ultra-Cat family, just as the RedCat 51 once did for the original Cat line.

Anniversary Highlights

• Limited to 100 Units – Each telescope is individually numbered, affirming its rarity as a commemorative edition.

• Symbolic Laser Engraving – A special design featuring a cat embracing the number “30,” honoring the legacy of the Cat series.

• Commemorative Certificate – Every unit is accompanied by an official 30th Anniversary certificate.

• Exclusive Accessory – Includes a complimentary UniGuide 32mm guide scope to complete your anniversary edition set.

• Legacy & Future – Celebrates 30 years of William Optics, linking the success of the Cat series to a new era of Ultra-Cat innovation.

Optical & Mechanical Excellence

• 76mm Aperture, f/4.8 Advanced Petzval – Delivers a flat, wide image circle with pinpoint stars across full-frame sensors.

• Compact Yet Powerful – A perfect balance between portability and professional-grade performance.

• Signature WO Craftsmanship – Precision-machined WIFD focuser, retractable dew shield, and unmatched mechanical finish.

A Tribute to 30 Years

From a homemade telescope in 1979 to becoming a global leader in apochromatic refractors, William Optics has always stood for artistry, innovation, and accessibility. The Ultra-Cat 76 · 30th Anniversary Edition is not only a high-performance imaging instrument, but also a symbol of our history—celebrating three decades of passion for the night sky, and looking forward to the future of astrophotography.

Description

The Ultra-Cat 76 is a high-performance 76mm apochromatic refractor, designed for astrophotographers who demand exceptional clarity and true color accuracy.

With a 5-element advanced Petzval optical design, including super ED and lanthanum glass, and a fast f/4.8 focal ratio, this telescope delivers stunningly sharp, flat-field images across its 50mm image circle. Optimized for Full Frame, APS-C, and M4/3 sensors, it also offers compatibility with Medium Format cameras for outstanding wide-field astrophotography.

Key Features:

Advanced 5-Element Petzval Optics
Eliminates field curvature, ensuring sharp, edge-to-edge stars without additional flatteners.

50mm Large Image Circle
Fully supports Full Frame cameras, APS-C and M4/3 sensors for optimal performance. Compatible with Medium Format.

Fast f/4.8 Optics
Superior light-gathering capability, enabling deep-sky imaging with shorter exposure times.

WIFD (William’s Internal Focuser Design)
Patented internal rack-and-pinion focuser ensures stable and precise focusing.
No vignetting or balance issues — ideal for astrophotography.
Compatible with EAF (Electronic Automatic Focuser) for precision focus control.

Sensor Tilt Xterminator (STX) & Rotator
Integrated tilt adjuster eliminates sensor misalignment, ensuring uniform image sharpness.

No Flattener Required
The optical design naturally corrects field curvature, simplifying setup.

Anti-Shrink Lens Cell Technology
Reduces thermal expansion effects, maintaining perfect optical alignment in any climate.

Patented Bahtinov Mask for Focusing
Built-in focusing aid ensures pinpoint star sharpness with ease.

Premium Build & Ergonomic Design
Lightweight yet robust (4.31 kg / 9.5 lbs) construction with a sleek anodized finish.
Patented handle bar design for enhanced portability and ease of use.

Versatile Camera Compatibility
Supports Canon EF, RF, Nikon F,Z, Sony E, Pentax K, MFT, and FUJI X mounts.

Technical Specifications

In the Box

Red William Optics UniGuide 32mm Scope Included 

Warranty

William Optics 2-Year Warranty