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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
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$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