William Optics, a well-regarded name in the astrophotography community, has once again set a new benchmark with its latest offering, the Ultra-Cat 76. This innovative refractor telescope is meticulously designed to cater to the needs of both novice and seasoned astrophotographers alike. With its compact form and impressive capabilities, the Ultra-Cat 76 promises a combination of premium optics, state-of-the-art features, and practical design, making it an incredibly versatile tool for capturing the wonders of the universe.

Advanced Optical Design

At the core of the Ultra-Cat 76 lies a sophisticated 5-element Petzval optical system. This intricate design incorporates two Super ED glass elements, one ED glass element, one Lanthanum glass element, and an X-Element. Together, these components work harmoniously to produce an exceptionally flat field with a 50mm image circle, effectively mitigating chromatic aberrations that can plague lesser telescopes. With a 76mm aperture and a focal length of 365mm (f/4.8), the Ultra-Cat 76 is specifically engineered for wide-field astrophotography, allowing users to capture breathtaking detail in deep-sky objects.

William Optics Ultra-Cat 76

WIFD Focuser System

A standout feature of this telescope is its William Optics Internal Focus Design (WIFD), which employs a patented rack and pinion focuser. In this design, internal lens elements shift to achieve focus, eliminating the need for a protruding drawtube. This innovative approach enhances stability and minimizes image shift, making it ideal for high-precision imaging sessions. Additionally, the Ultra-Cat 76 is compatible with electronic autofocus systems, a significant advantage for astrophotographers who wish to automate their setup for lengthy sessions or remote operations.

Sensor Tilt Xterminator (STX)

One of the most formidable challenges faced by astrophotographers is correcting sensor tilt. The Ultra-Cat 76 addresses this issue with its Sensor Tilt Xterminator (STX), which enables precise sensor alignment without the need to disassemble the imaging train. Featuring push-out and locking screws, this innovative component facilitates straightforward and accurate tilt adjustments directly on the rotator. This design choice not only saves valuable time but also simplifies the overall imaging workflow, ensuring that users can achieve perfect star shapes across the entire frame.

User-Friendly Add-Ons

In keeping with William Optics' reputation for thoughtful engineering, the Ultra-Cat 76 is equipped with a variety of user-friendly features. This includes an integrated Bahtinov mask for quick and precise focusing, a rotator for convenient image framing, and a selection of camera adapters that include M48 and M54 options. The telescope is designed to support both full-frame and medium format sensors, and it is compatible with numerous camera mounts, including Canon EF/RF, Nikon F/Z, Sony E, Pentax K, MFT, and Fuji X, with optional adapters available for each.

Technical Specifications

  • Aperture: 76mm
  • Focal Length: 365mm
  • Focal Ratio: f/4.8
  • Image Circle: 50mm
  • Optical Design: 5-element Petzval (including Super ED, ED, Lanthanum, X-Element)
  • Focuser: WIFD internal rack & pinion (compatible with electronic autofocus)
  • Tilt Adjuster: Sensor Tilt Xterminator (STX)
  • Tube Length: 363.3 mm (retracted) to 408.8 mm (extended)
  • Weight: 4.31 kg (9.5 lbs)

As anticipation builds within the community, the Ultra-Cat 76 will be available for pre-order at a price point of $1,888, with shipments expected to commence in July or August of 2025. Enthusiasts and professionals alike are eager to see how this telescope will enhance their astrophotography experiences.

Clear skies ahead!