Ultra-Cat 108
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.
Personalized Laser Engraving
Free customization for direct purchases, adding a personal touch to your telescope.
- 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
- Focus travel
- 0-30mm (Ruler to 31mm)
- Adapter Included
- Sensor Tilt Xterminator Rotator M68, M54, M48 Camera Adapters
- Optional Flattener
- No Flattener Required
- T-Mount Support
- 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
- 512.9 mm - 617.9 mm
- OTA Weight
- 7.82 kg / 17.24 lbs
Choose options
What's in the box
Main Tube
Bahtinov Cap
M48, M54, M68 adapter
Vixen-style Mounting Plate
Mounting Ring Handle bar
Soft Carry Case
Allen Key Set
Let the quality speaks
The UltraCat 108 embodies the pinnacle of optical engineering, merging a revolutionary 5-element Petzval design with cutting-edge features tailored for astrophotographers. Every detail—from its expansive image circle to its internal focuser and integrated tilt corrector—is crafted to deliver unmatched clarity, precision, and performance across the celestial canvas.
Advanced Petzval
Researched and developed by WO, the innovative 5-element Petzval design redefines telescope optics. This advanced system achieves a flawless spot diagram across a medium-format image circle.
Extra-low Dispersion (ED) glasses
Contains 2 Super ED, 1 ED glasses and lanthanum lenses with advanced fully multi-coated, delivering sharp, vibrant images with true-to-life colors, significantly reducing chromatic aberration.
Needs NO Flattener
The Petzval design inherently flattens the field, eliminating the need for an external field flattener.
Never easier to capture deep sky objects
comprehensive configuration
Precision Imaging Adjustment
Sensor Tilt Xterminator (STX)
The built-in STX allows quick side-access tilt adjustments without removing the camera.
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Camera Angle Rotator
Correct any angular discrepancies, and get the perfect angle on your images.
Compatible with Electronic Motorized Devices
Hassle Free Installation
( No Mounting Bracket Kit required )
The new K-ASTEC mounting bracket (optional) is now avalible to make the EAF more streamline with the OTA.
Leading the market
Wo patented design
The Ultra-Cat 108 holds three unique patents, ensuring easy and perfect focusing along with precise coaxial image quality, preventing draw tube tilt issues caused by optical misalignment.
:
Internal Focuser
The WIFD focusing Design relocates the focuser to the center of the telescope, addresses the issue of tube tilt caused by the weight of accessories and cameras.
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Integrated Bahtinov mask
Laser engraved on high-definition and stable optical PMMA. Enhances astrophotography experience with quick and accurate adjustments.
CAT Handle Bar
Crafts for enhanced portability and versatility.
Mounting Ring
Designed for seamless functionality without compromising on stability. Engineered with wide surface contacts, this innovative ring ensures a secure fit while enabling fast, easy detachment.
