Ultra Cat Series

The Glorious Cat, Engineered Beyond.

Highlights

Ultra-Sharp 5-Element Petzval Optics

Redefines optical performance with a refined 5-element Petzval design, ensuring crisp, high-contrast views with outstanding color correction across the entire field.

Ultra-Wide Imaging Compatibility

Provides seamless compatibility with full-frame/medium format sensors, delivering expansive, high-quality astrophotography with exceptional detail.

Ultra-Friendly Exclusive Design

Equipped with the WIFD focuser and STX mechanism, offering smooth focusing and simplified sensor alignment, making astrophotography more efficient and user-friendly.

5 Elements

Advanced Petzval
APO Design

Extra-low Dispersion (ED) glasses

Deliver 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.

High-precision polishing

Our lenses undergo high-precision polishing, setting a standard of excellence that surpasses industry norms, ensuring optimal performance in all conditions.

Sharp And Quick Aperture

Ultra-Cat 56	Ultra-Cat 76
f/4.8	f/4.8
Cat 91	Ultra-Cat 108
f/4.9	f/4.8

Innovation debuts

Sensor Tilt Xterminator

The UltraCats are equipped with the Sensor Tilt Xterminator (STX), allowing quick side-access tilt adjustments without removing the camera. The simplified mechanism requires adjusting only 4 knobs, operating like a seesaw, ensures easy, accurate alignment.
(STX not included in Cat-91.)

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WIFD Focuser

The William Optics Internal Focus Design (WIFD) places the focusing mechanism at the center of the telescope to achieve optimal structural balance, which directly leads to the following benefits:

Eliminates Tube Tilt
By centering the focusing system, WIFD eliminates tube tilt caused by the weight of cameras and accessories.
Unobstructed Optical Path
Without a traditional rear drawtube, WIFD prevents optical path obstruction and maintains consistent light throughput.
Cleaner, Low-Maintenance Focusing System
The sealed internal focusing mechanism minimizes dust exposure, making the system easier to maintain and reliable over long-term use.

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Compatible with Electronic Motorized Devices

Hassle Free Installation
( No Mounting Bracket Kit required )

Fast and accurate focusing

Integrated Bahtinov mask in dew shield cap (Patent number: US 10,564,409 B2) ensures precise focusing. Made of high-definition and stable optical PMMA. Enhances astrophotography experience with quick and accurate adjustments.

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