Available for Pre-Order. Expected near the end of Q1 as per William Optics.
The William Optics UltraCat108 is a cutting-edge 108mm apochromatic refractor designed for astrophotographers who demand top-tier performance. Featuring a 5-element advanced Petzval optical design and a fast f/4.8 focal ratio, it delivers breathtaking edge-to-edge clarity and vivid detail, making it perfect for capturing expansive celestial views. Its robust build, exceptional optics, and innovative features redefine the standard for astrophotography.
Key Features:
Advanced 5-Element Petzval Design
Eliminates field curvature, providing sharp, flat-field images without requiring additional flatteners.
60mm Superior Image Circle
Fully supports full-frame and medium-format cameras for wide-field and detailed astrophotography, outperforming standard 106mm telescopes.
F/4.8 Fast Optics
Offers exceptional light-gathering capability for vibrant deep-sky photography.
WIFD (William’s Internal Focuser Design)
Patented internal focuser ensures precise, stable, and hassle-free imaging, avoiding balance issues and eliminating vignetting.
Anti-Shrink Lens Cell Technology
Minimizes thermal expansion and contraction, maintaining perfect optical alignment in any environment.
Sensor Tilt Corrector
Integrated and patented design eliminates distortion, optimizing sharpness and detail for professional-level results.
Built-In Patented Bahtinov Mask
Simplifies focusing for pinpoint precision, a feature that sets it apart from competitors.
Patented Handle Bar Design
Combines ergonomic usability with enhanced portability.
Specifications
| Lens Type | 5-Element Advanced Petzval |
| Lens Elements | Super ED Glass x2 ED Glass x1 Lanthanum Glass x1 X-Element x1 |
| Focal Length | 518 mm |
| Diameter | 108 mm |
| Focal Ratio | f/4.8 |
| Image circle | 60 mm |
| Focuser | WIFD R&P Focuser Compatible with EAF |
| Adapter Included | Sensor Tilt Corrector Rotator M68, M54, M48 Camera Adapters |
| Optional Flattener | No Flattener Required |
| T-Mount Supported | Canon EF, RF Nikon F, Z Sony E Pentax K MFT (M4/3) FUJI X |
| Camera Format | Medium Format Full Frame APS-C M4/3 |
| Tube Length | 510.5 mm - 588.5 mm |
| OTA Weight | 7.95 kg / 17.53 lbs |