William Optics has once again raised the bar in the world of astrophotography with the introduction of the Ultra-Cat 76. This compact yet powerful refractor telescope is designed for both amateur and professional astrophotographers. It offers a blend of premium optics, cutting-edge features, and practical design that makes it incredibly versatile.
Advanced Optical Design
At the heart of the Ultra-Cat 76 is its 5-element advanced Petzval optical system. It includes two Super ED glass elements, one ED glass element, one Lanthanum glass element, and an X-Element. Together, they deliver an exceptionally flat field with a 50mm image circle, while virtually eliminating chromatic aberrations. With a 76mm aperture and a 365mm focal length (f/4.8), this scope is purpose-built for wide-field astrophotography, capturing detailed deep-sky objects with stunning clarity.
WIFD Focuser System
The telescope features the William Optics Internal Focus Design (WIFD)—a patented rack and pinion focuser where internal lens elements move to achieve focus. This means there’s no drawtube sticking out, improving stability and reducing image shift. It’s also compatible with electronic autofocus systems, which is a huge bonus for imagers looking to automate their setup for long sessions or remote operation.
Sensor Tilt Xterminator (STX)
A major challenge in astrophotography is tilt correction. The Ultra-Cat 76 tackles this with the Sensor Tilt Xterminator (STX), which allows for sensor alignment without disassembling the imaging train. With push-out and locking screws, it offers easy and precise tilt adjustments directly on the rotator. This saves time, simplifies the imaging workflow, and helps achieve perfect star shapes across the entire frame.
User-Friendly Add-Ons
True to William Optics’ tradition, this scope is packed with thoughtful features. It includes an integrated Bahtinov mask for quick and accurate focusing, a rotator for convenient image framing, and both M48 and M54 camera adapters to cover a wide range of imaging setups. It supports full-frame and medium format sensors, and is compatible with major camera mounts like Canon EF/RF, Nikon F/Z, Sony E, Pentax K, MFT, and Fuji X with optional adapters.
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 (electronic autofocus compatible)
- Tilt Adjuster: Sensor Tilt Xterminator (STX)
- Tube Length: 363.3 mm (retracted) to 408.8 mm (extended)
- Weight: 4.31 kg (9.5 lbs)
The Ultra-cat 76 scope is available to pre-order for $1,888, and it is supposed to begin shipping in July/August 2025.
Clear skies!
