William Optics WIFD Ultra-Cat 108 APO Refractor

If you’re looking for top-tier imaging performance, the William Optics Ultra-Cat 108 is the telescope for you.

You can expect astrophotography with exceptional sharpness and perfect correction! Additionally, its large 108mm (4.25”) aperture captures a significant amount of light, delivering remarkable contrast and outstanding detail resolution.

As a Petzval refractor, there is no need to add a field flattener or perform backfocus distance calculations, making camera connection incredibly simple.

Stars will remain sharp across the entire field of view, even with medium format and full-frame cameras! Thanks to William Optics' innovation, the Ultra-Cat 108 APO refractor is designed to take your astrophotography to new heights.

With a 108mm aperture and a 518mm focal length, it boasts a fast f/4.8 focal ratio, making it an excellent system for deep-sky imaging. Featuring an impressive 60mm image circle, the William Optics Ultra-Cat 108 is compatible with both medium format and full-frame cameras, delivering stunning wide-field images.

In addition to its high-quality optics, this APO telescope is equipped with William Optics' internal focusing system (WIFD), ensuring smooth and stable focusing. You can even attach an optional electronic autofocus system for fully automated focusing. With these advanced features, the William Optics Ultra-Cat 108 is the ultimate tool for astrophotographers looking to capture breathtaking images of the universe.

Internal Focusing System for Maximum Stability

Instead of shifting your imaging train back and forth to achieve focus, the William Optics Ultra-Cat 108 refractor utilizes an internal focusing system, moving the optical elements to adjust focus. By keeping your imaging train stable, it reduces the risk of focuser tube flex, especially with heavier equipment. This also helps minimize vignetting and the risk of tilt, further enhancing image quality. If you wish to automate focusing, this system is also compatible with an electronic autofocuser (EAF)!

Unparalleled Performance with 5 Internal Lenses

The William Optics Ultra-Cat 108 is built with quality in mind, housing a total of five lens elements, including one ED and two Super ED glass elements. These lenses work together to eliminate coma, field curvature, and other aberrations, providing exceptional color correction and clarity. Supporting both medium-format and full-frame cameras, you can expect edge-to-edge sharpness across the entire 60 mm image circle. With these outstanding optics, you can easily resolve stunning structures within galaxies, exquisite detail within nebulae, and sharp definitions of star clusters!

Offering a wide range of imaging possibilities, the William Optics Ultra-Cat 108 is a must-have for those looking to capture outstanding astronomical images. With a 518mm focal length, it is perfect for framing celestial objects such as the Pleiades open cluster, the Orion Nebula, the Andromeda Galaxy, and many more. Thanks to its large 108mm aperture, your images will be bright, and the fast f/4.8 focal ratio will allow you to collect a significant amount of light in a short time.

This package includes three adapters—M68, M54, and M48—ensuring seamless connection to your imaging setup, so you can head under the stars without delay.