William Optics Cat 91 WIFD

Step up your astrophotography game with the William Optics RedCat 91, an advanced apochromatic refractor tailored for full-frame and medium-format cameras. This latest addition to the RedCat series combines portability with superior optical performance, making it a versatile tool for capturing breathtaking detail in deep-sky objects.
An advanced apochromatic refractor tailored for full-frame and medium-format cameras. This latest addition to the RedCat series combines portability with superior optical performance, making it a versatile tool for capturing breathtaking detail in deep-sky objects.

Advanced Petzval

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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

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Needs no flattener

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The Petzval design inherently flattens the field, eliminating the need for an external field flattener.

Never easier to capture deep sky objects

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Compatible with Electronic Motorized Devices

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Hassle Free Installation ( No Mounting Bracket Kit required )

Wo patented design

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The Cat 91 holds three unique patents, ensuring easy and perfect focusing along with precise coaxial image quality, preventing draw tube tilt issues caused by optical misalignment.

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.

CAT Handle Bar

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Crafts for enhanced portability and versatility.
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.

Integrated Bahtinov mask

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Laser engraved on high-definition and stable optical PMMA. Enhances astrophotography experience with quick and accurate adjustments.