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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.

William Optics Cat Series Telescopes

The William Optics Cat series is a family of compact Petzval refractors built for wide-field astrophotography, with a flat field that works without a separate flattener. Most models use the WIFD internal focusing design.

The line runs from the MiniCat 51 at f/3.5 and the RedCat 51, 61 and 71 to the Cat 91 and the UltraCat 56, 76 and 108 at f/4.8, up to the UltraCat 131. Cat mounting rings and a saddle handle bar are also available.

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$60.00 - $60.00
$60.00
$60.00 - $60.00
$60.00

William Optics Cat Series Saddle Handle Bar

Options available
3 variants in stock

Length: 107 mm Integrated Mini-Vixen Style Saddle Weight: 0.12 kg / 0.26 lbs Designed for William Optics Cat Series Telescopes Adds a carrying han...

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$60.00 - $60.00
$60.00
$60.00 - $60.00
$60.00
$888.00 - $888.00
$888.00
$888.00 - $888.00
$888.00

William Optics Redcat 51 WIFD

WO-L-RC51RDIII
2 in stock

Compact Apochromatic Refractor Petzval-like Optical Design for Flat Fields William Optics Internal Focus Design (WIFD) CNC-Machined Aluminum Body ...

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$888.00 - $888.00
$888.00
$888.00 - $888.00
$888.00
$988.00 - $988.00
$988.00
$988.00 - $988.00
$988.00

William Optics MiniCat 51 WIFD f/3.5

WO-T-C-MINI-RD
3 in stock

51mm Aperture Diameter 178mm Focal Length f/3.5 Focal Ratio 6-Element Petzval Optical Design 43.2mm Full-Frame Image Circle WIFD Rack & Pinion...

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$988.00 - $988.00
$988.00
$988.00 - $988.00
$988.00
$1,398.00 - $1,398.00
$1,398.00
$1,398.00 - $1,398.00
$1,398.00

William Optics Redcat 71 WIFD

WO-T-C-71RDII

Apochromatic Petzval-like Optical Design WIFD (William Optics Internal Focuser Design) Integrated Bahtinov Mask in Dust Cap Included M48 Camera Ad...

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$1,398.00 - $1,398.00
$1,398.00
$1,398.00 - $1,398.00
$1,398.00
$1,098.00 - $1,098.00
$1,098.00
$1,098.00 - $1,098.00
$1,098.00

William Optics RedCat 61 WIFD

WO-T-C-61RD
1 in stock

61mm Aperture Petzval-like Astrograph Fast f/4.9 Focal Ratio WIFD (William Optics Internal Focus Design) Focuser Requires No Backfocus Calculation...

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$1,098.00 - $1,098.00
$1,098.00
$1,098.00 - $1,098.00
$1,098.00
$50.00 - $50.00
$50.00
$50.00 - $50.00
$50.00

William Optics Cat Mounting Ring

WO-M-MR50RC-BL

50mm Inner Diameter Solid Aluminum Construction Anodized Blue Finish 1/4"-20 Threaded Mounting Holes Weight: 4.9 oz (140 g) Description FAQ Spe...

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$50.00 - $50.00
$50.00
$50.00 - $50.00
$50.00
$3,998.00 - $3,998.00
$3,998.00
$3,998.00 - $3,998.00
$3,998.00

William Optics UltraCat 108 f/4.8 WIFD

WO-T-C-108BR
1 in stock

108mm Aperture, 5-Element Advanced Petzval Optical Design Fast f/4.8 Focal Ratio with 518mm Focal Length Massive 60mm Flat-Field Image Circle Pate...

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$3,998.00 - $3,998.00
$3,998.00
$3,998.00 - $3,998.00
$3,998.00
$1,398.00 - $1,398.00
$1,398.00
$1,398.00 - $1,398.00
$1,398.00

William Optics UltraCat 56 f/4.8 WIFD

WO-T-C-56BR
6 in stock

56mm Aperture, 269mm Focal Length (f/4.8) 5-Element Advanced Petzval Optical Design 50mm Image Circle for Full-Frame Sensors William Optics Intern...

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$1,398.00 - $1,398.00
$1,398.00
$1,398.00 - $1,398.00
$1,398.00
$2,598.00 - $2,998.00
$2,598.00 - $2,998.00
$2,598.00 - $2,998.00
$2,598.00

William Optics Cat 91 WIFD

Options available
1 variants in stock

91mm Aperture, 448mm Focal Length (f/4.9) 5-Element Advanced Petzval Optical Design 55mm Corrected Image Circle WIFD Rack & Pinion Internal Fo...

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$2,598.00 - $2,998.00
$2,598.00 - $2,998.00
$2,598.00 - $2,998.00
$2,598.00
William Optics Ultra-Cat 131 f/4.9 Petzval Astrograph
$5,398.00 - $5,398.00
$5,398.00
$5,398.00 - $5,398.00
$5,398.00

William Optics Ultra-Cat 131 f/4.9 Petzval Astrograph

WO-T-C-131BR

131mm Aperture 648mm Focal Length (f/4.9) 5-Element Advanced Petzval Optical Design 60mm Flat-Field Image Circle Patented WIFD Internal Focuser 13...

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$5,398.00 - $5,398.00
$5,398.00
$5,398.00 - $5,398.00
$5,398.00
$2,198.00 - $2,198.00
$2,198.00
$2,198.00 - $2,198.00
$2,198.00

William Optics UltraCat 76 f/4.8 WIFD

WO-T-C-76BR
2 in stock

76 mm Aperture, 365 mm Focal Length (f/4.8) 5-Element Advanced Petzval Optical Design 50 mm Corrected Image Circle William Optics Internal Focusin...

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$2,198.00 - $2,198.00
$2,198.00
$2,198.00 - $2,198.00
$2,198.00