William Optics Ultra-Cat 131 f/4.9 WIFD Petzval Refractor Telescope

Ultra-Cat 131 Refractor Telescope

The William Optics Ultra-Cat 131 is the flagship of the Ultra-Cat series, representing the pinnacle of wide-field astrophotography performance. Built around a large-aperture 131mm apochromatic optical system and an advanced 5-element Petzval design, it delivers extraordinary light-gathering power, exceptional color correction, and razor-sharp stars across an expansive, flat image circle.

Designed for serious astrophotographers and observatories alike, the Ultra-Cat 131 combines a fast focal ratio with uncompromising optical precision, enabling stunning deep-sky detail, rich contrast, and immersive wide-field compositions. Its premium mechanical construction, thermal stability, and flagship-level engineering set a new benchmark for large-format astrophotography systems.

At Starhunter, we support astrophotographers with professional astronomy knowledge, practical experience, and reliable after-sales support to help you get the most from your imaging equipment.