The William Optics UltraCat108 is a color-free refractor with a 108 mm aperture, designed for astrophotographers demanding top performance. It features an advanced Petzval optical design with 5 elements and a fast focal ratio of f/4.8, providing sharpness from edge to edge and vivid detail, making it ideal for capturing extensive celestial landscapes. Its robust construction and exceptional optical components redefine standards for astrophotography.

• Petzval 5-element design: Eliminates field curvature, delivering crisp, flat-field images without additional flattening elements.
• 60 mm image circle: Supports full-frame and medium-format cameras for wide-field astrophotography.
• Fast focal ratio f/4.8: Offers excellent light-gathering capability for live deep-sky imaging.
• William's Internal Focuser Design (WIFD): Ensures precise and stable imaging, avoiding balance issues.
• Lens cell technology: Minimizes thermal expansion and maintains perfect optical alignment.
Gradient correction with sensor: Eliminates distortion for improved clarity.
• Built-in Bahtinov mask: Simplifies focusing for absolute accuracy.
• Patented handle design: Combines ergonomic usability with enhanced portability.