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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 Visual Accessories

William Optics visual accessories make observing with a refractor more comfortable and versatile. Dura Bright 99% dielectric diagonals come in 1.25", 2" and a 2" SCT-threaded version for bright, comfortable viewing angles.

Erecting prisms, including 90° and 45° 1.25" models and versions for the RedCat WIFD and Cat 61, give a correct, upright image for daytime and terrestrial use. The Binoviewer Complete Package and its 2x Barlow nosepiece let you observe with both eyes.

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$158.00 - $158.00
$158.00
$158.00 - $158.00
$158.00

William Optics 99% Dielectric Dura Bright Diagonal - 2"

WO-D-DIG2D-C-DB
3 in stock

2" Barrel with 90° Viewing Angle 99% Reflectivity Dielectric Coatings 1/12th Wave Precision Polished Mirror 12mm Thick Mirror Substrate for Therma...

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$158.00 - $158.00
$158.00
$158.00 - $158.00
$158.00
$369.00 - $369.00
$369.00
$369.00 - $369.00
$369.00

William Optics Binoviewer Complete Package

WO-E-BINO-P
7 in stock

Includes two 20mm 66° wide-angle eyepieces High-quality BaK4 prisms with full multi-coatings Large 20mm clear prism aperture prevents vignetting I...

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$369.00 - $369.00
$369.00
$369.00 - $369.00
$369.00
$138.00 - $138.00
$138.00
$138.00 - $138.00
$138.00

William Optics 99% Dielectric Dura Bright Diagonal - 1.25"

WO-D-125D-C-DB
1 in stock

1.25" Barrel Diameter 99% Dielectric Coated Mirror 1/12λ Mirror Surface Accuracy 12mm Thick Mirror Substrate 100% Real Carbon Fiber Side Plates ...

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$138.00 - $138.00
$138.00
$138.00 - $138.00
$138.00
$116.00 - $116.00
$116.00
$116.00 - $116.00
$116.00

William Optics 90° Erect Prism - 1.25"

WO-D-EP90-125II
5 in stock

Provides a fully corrected, upright, and non-reversed image Designed for 1.25" focusers and eyepieces 90° viewing angle for comfortable observing ...

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$116.00 - $116.00
$116.00
$116.00 - $116.00
$116.00
$59.00 - $59.00
$59.00
$59.00 - $59.00
$59.00

William Optics 2x Barlow Nosepiece for Binoviewer

WO-E-BINO-B2
6 in stock

Provides 2x magnification Enables binoviewers to reach focus in most telescopes Standard 1.25" nosepiece format Threads directly onto the binoview...

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$59.00 - $59.00
$59.00
$59.00 - $59.00
$59.00
$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00

William Optics RedCat WIFD Erecting Prism - 1.25"

WO-D-EP90-125-RC51III
1 in stock

Converts Astronomical Telescopes for Terrestrial Viewing 90-Degree Viewing Angle Accepts Standard 1.25" Eyepieces Anti-Reflection Coated BAK7 Pris...

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$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00
$110.00 - $110.00
$110.00
$110.00 - $110.00
$110.00

William Optics 45° Erecting Prism - 1.25"

WO-D-EP125
6 in stock

Provides a fully corrected image (upright and left-right correct) Comfortable 45° viewing angle for terrestrial observation Fits standard 1.25" fo...

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$110.00 - $110.00
$110.00
$110.00 - $110.00
$110.00
William Optics 1.25" 90° Erect Prism for Cat 61 WIFD
$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00

William Optics 1.25" 90° Erect Prism for Cat 61 WIFD

WO-D-EP90-125-RC61
1 in stock

Provides a fully corrected, erect image for terrestrial viewing Comfortable 90° viewing angle Standard 1.25" barrel accepts most astronomical eyep...

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$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00
William Optics 2" 90° Dura Bright Dielectric Diagonal for SCT threaded Scope
$207.00 - $207.00
$207.00
$207.00 - $207.00
$207.00

William Optics 2" 90° Dura Bright Dielectric Diagonal for SCT threaded Scope

WO-D-DIG2D-C-DB-SCT
1 in stock

Enables use of 2-inch eyepieces for wide-field views 90° viewing angle for comfortable observing at the zenith Dura-Bright dielectric coatings for...

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$207.00 - $207.00
$207.00
$207.00 - $207.00
$207.00