Cat 91 WIFD (Pre-order, ships in one week)
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.
Highlights:
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Petzval Design, No Backfocus Hassles: The 5-element Petzval design eliminates the need for backfocus adjustments, providing sharp, edge-to-edge images with pinpoint stars—ideal for wide-field and detailed astrophotography alike.
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Full-Frame & Medium-Format Ready, No Extra Flattener Needed: With a large 50mm image circle, the RedCat 91 is perfect for both full-frame and medium-format cameras. Its advanced optics achieve flat-field images without requiring an additional flattener, giving astrophotographers the freedom to capture expansive views with unparalleled clarity.
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Fast f/4.9 Focal Ratio: The RedCat 91's fast f/4.9 focal ratio is designed for bright, vivid captures of galaxies, nebulae, and beyond, ensuring excellent light-gathering power and sharp detail even on faint celestial objects.
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Seamless WIFD Focusing: Equipped with William Optics' WIFD focuser, the RedCat 91 provides precise, stable focusing without additional adjustments, enhancing the ease of use for both seasoned astrophotographers and beginners.
The RedCat 91 blends the trusted RedCat heritage with William Optics’ innovative design, making it the ultimate choice for those ready to elevate their night-sky explorations.
First 30 sets gets Free Uniguide
UniGuide 32mm f/3.75
Enhance your astrophotography setup with the William Optics UniGuide 32mm f/3.75, a compact and versatile guide scope designed for precision and ease of use. This lightweight guide scope weighs only 240g and features a high-quality, fully multi-coated 32mm objective lens, ensuring bright, clear guiding stars.
The UniGuide 32mm offers a fast f/3.75 focal ratio and a 120mm focal length, ideal for accurately tracking celestial objects. It comes equipped with a slide-base Vixen/Synta-style rail for easy attachment directly to compatible William Optics telescopes, streamlining your setup and eliminating the need for conventional guidescope rings.
This guide scope is compatible with a variety of guide cameras, including popular models like the ZWO ASI120 Mini and Starlight Xpress Lodestars, thanks to its 1.25" adaptor and M42 thread. Available in four stylish colors—red, gold, space grey, and blue—the UniGuide 32mm not only performs superbly but also adds a touch of elegance to your astronomical equipment.
Whether you are a novice astrophotographer or a seasoned veteran, the William Optics UniGuide 32mm guide scope is an excellent addition to your astronomical toolkit, helping you achieve perfect tracking for flawless long-exposure images.
Pairs well with
- Lens Type
- 5-Element Advanced Petzval
- Lens Elements
- Super ED Glass x2
- ED Glass x1
- Lanthanum Glass x1
- X-Element x1
- Focal Length
- 448 mm
- Diameter
- 91 mm
- Focal Ratio
- f/4.9
- Image circle
- 55 mm
- Focuser
- WIFD R&P Focuser
- Compatible with EAF
- Focus travel
- 0-36mm (Ruler to 40mm)
- Adapter Included
- Tilt Adjuster
- Rotator
- M63 → M54 Adapter
- M63 → M48 Adapter
- 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 ( needs additional adapter )
- Full Frame
- APS-C
- M4/3
- Tube Length
- 556 mm
- OTA Weight
- 4.72 kg / 10.41 lbs
- Total Weight
- 6.3 kg / 13.89 lbs
Choose options
What's in the box
Main Tube
Bahtinov Cap
M48 & M54 adapter
Mounting Plate
Mounting Ring Handle bar
Soft Carry Case
Allen Key Set
The cat with medium-format soul
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
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
Compatible with Electronic Motorized Devices
Hassle Free Installation
( No Mounting Bracket Kit required )
Leading the market
Wo patented design
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.
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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.
Learn More
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.
comprehensive configuration
Precision Imaging Adjustment
Tilt Adjuster
The built-in tilt adjuster makes it easy to correct camera sensor tilt issues.
Camera Angle Rotator
Correct any angular discrepancies, and get the perfect angle on your images.
▲ M45 (Full-Frame)
Cat 91 + ZWO ASI 6200MC Pro
Courtesy of Dear Bear
- Stacked ( After Process )
- Original Single Shot Corner Grid