William Optics Apochromatic refractor AP 56/269 UltraCat 56 WIFD

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.

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.

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

The William Optics Internal Focus Design (WIFD) is an innovative and revolutionary design that combines a precise (patented) internal focusing mechanism with the highest quality optics available, offering the ultimate apochromatic refractor for astrophotography. Designed from the ground up to handle even the largest, heaviest, cooled cameras, this optics is uncompromising in its quality. The focuser movement is integrated into the main tube, so no adjustments are visible from the outside.

The user can enjoy the benefits of a conventional focuser with two fine focus controls without having to worry about the limitations normally found with conventional rear-mounted focusers (vignetting). The integrated position indicator window on the focuser allows instant verification of the graduated numerical display.

The focus is compatible with ZWO's EAF.

Specification