William Optics Ultra-Cat 131 WFID APO Petzval OTA | L-UC131 NEAF2026 the T ring sets the

the T ring sets the distance to 55mm

two of them with type-C connector

That means you can get more out of every observing session

makes the scope reassuringly rugged

Identical filter thickness to existing standards and double-sided fine polishing

William Optics Ultra-Cat 131 WFID APO Petzval OTA | L-UC131 NEAF2026 the T ring sets theThe 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,