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CAT Series

Light as a cat, sharp as its eyes.
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Highlights

Precision Petzval Optics

Innovative Petzval optics in the William Optics Redcat series provide sharp, high-contrast images with minimal chromatic aberration.

Ultra-Portable Design

Redcat series offers ultra-portable solutions for astrophotography with compact, lightweight designs for easy transportation and setup.

Effortless Camera Integration

The Petzval design of the Redcat series simplifies astrophotography by eliminating backfocus adjustments, ensuring cameras can be easily attached for a user-friendly experience.

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.

Cat 91 WIFD

Advanced Petzval

5 elements Petzval design, contains 3 super ED glasses. Achieves a flawless spot diagram across a medium-format image circle.

MiniCat 51

UltraFast Petzval

6 elements Petzval design, contains 2 super ED glasses. Features a cutting-edge optical system doubles the efficiency of traditional Cat telescopes. Its 14-degree field of view is perfect for capturing wide-field deep-sky images, making it an ideal choice for astrophotographers looking to maximize playability and reduce time spent on mosaicking.

Sharp And Quick Aperture

MiniCat Cat 51
f/3.5 f/4.9
Cat 61/71 Cat 91
f/4.9 f/4.9

Center Balance

The new WO Internal Focus Design - WIFD

The William Optics Internal Focus Design (WIFD) features a patented internal focusing mechanism (Patent number: US 11,693,225 B2), revolutionizing astrophotography.

Relocating the focuser to the center of the telescope, the WIFD system addresses the issue of tube tilt caused by the weight of accessories and cameras.

Its balanced structure and superior rigidity eliminate weight limits for photographic equipment. The precise internal sliding of fixed optics prevents image shift, ensuring stable and clear observations. Additionally, the dust-free environment also makes the focuser easier to maintain.

Smooth and Precise Focusing

The rack and pinion mechanism in the William Optics WIFD series essential for achieving critical focus in astrophotography. This reliable system ensures fine control and stability, allowing for effortless and accurate focusing, even with heavy imaging equipment attached.

Dual Speed, Easy Piecey

The 1:10 fine focuser in WIFD series enhances the focusing process by enabling meticulous fine-tuning. This high-ratio mechanism allows for smooth, incremental adjustments, ensuring optimal clarity and sharpness in your celestial images.

Keep track of temp information

A temperature gauge is included in the WIFD focuser knob, allowing astrophotographers to quickly access weather information and adjust equipment settings.

The knob is also removable, allowing for easy attachment of electronic motorized devices like the EAF (Electronic Automatic Focuser).

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.

Just For Astrophotography

Tilt Adjuster

The built-in tilt adjuster makes it easy to correct camera sensor tilt problem.

Camera Angle Rotator

Correct any angular discrepancies, and get the perfect angle on your images.

T-mount Compatible

Ended with M48 thread, suitable for all camera adapters.

View All T-Mounts

Mini Cat

  • APS-C

Cat 51

  • Full-Frame
  • APS-C

Cat 61

  • Full-Frame
  • APS-C

Cat 71

  • Full-Frame
  • APS-C

Cat 91

  • Medium-Format
  • Full-Frame
  • APS-C

Compatible with Electronic Motorized Devices

Hassle Free Installation
( No Mounting Bracket Kit required )

Innovative Design

William Optics Mounting Solutions

William Optics' patented telescope carry handle bar (Patent number D905776) crafts for enhanced portability and comfort.

Complemented by lightweight mounting rings, this setup offers secure attachment and effortless handling of your telescope, perfect for astronomers seeking convenience and reliability.

Side Mounting Threads allow you to attach accessories to your telescope.

  • ASI Air
  • Guider Scope
  • Other Devices

Precision-crafted

Mounting Plates

RedCat 61 / 71

Vixen-style & Arca Swiss type
Dual side Dovetail Plate

Unmatched compatibility with various mounts, ensuring flexibility in configuring your astronomical equipment.

Mini / RedCat 51

Vixen-style & Arca Swiss type
Dual side Dovetail Plate
- Light Weight Edition

Offers enhanced compatibility with various mounts and mounting rings.

Which Cat is right for you?

 
MiniCat 51 WIFD

MiniCat 51

$898.00

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Cat 51 WIFD

Cat 51

$898.00

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Cat 61 WIFD

Cat 61

$1,398.00

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Lens Type 6-Element Petzval 4-Element Petzval 4-Element Petzval
Focal Length 178 mm 250 mm 300 mm
Diameter 51 mm 51 mm 61 mm
Aperture f/3.5 f/4.9 f/4.9
Image circle 43.2 mm 48 mm 46 mm
Focuser WIFD R&P Focuser
Compatible with EAF
WIFD R&P Focuser
Compatible with EAF
WIFD R&P Focuser
Compatible with EAF
 
Cat 71 WIFD

Cat 71

$1,798.00

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Cat 91 WIFD

Cat 91

$2,598.00

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Ultra-Cat 108 WIFD

Ultra-Cat 108

$3,598.00

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Lens Type 4-Element Petzval 5-Element Advanced Petzval 5-Element Advanced Petzval
Focal Length 350 mm 448 mm 518 mm
Diameter 71 mm 91 mm 108 mm
Aperture f/4.9 f/4.9 f/4.8
Image circle 48 mm 55 mm 60 mm
Focuser WIFD R&P Focuser
Compatible with EAF
WIFD R&P Focuser
Compatible with EAF
WIFD R&P Focuser
Compatible with EAF