{"title":"William Optics Dura Bright Dielectric Diagonals","description":"\u003cp\u003eWilliam Optics Dura Bright diagonals use a 99% reflective dielectric mirror to send light at 90° to the eyepiece, giving a brighter image and a more comfortable viewing angle with refractors and SCTs.\u003c\/p\u003e\u003cp\u003eThe line includes a 1.25\" diagonal for smaller eyepieces, a 2\" diagonal for wide-field eyepieces, and a 2\" version with a threaded connection for SCT telescopes. They suit visual observers who want a durable, high-reflectivity diagonal.\u003c\/p\u003e","products":[{"product_id":"william-optics-99-dielectric-dura-bright-diagonal-1-25","title":"William Optics 99% Dielectric Dura Bright Diagonal - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e1.25\" Barrel Diameter\u003c\/li\u003e\n\u003cli\u003e99% Dielectric Coated Mirror\u003c\/li\u003e\n\u003cli\u003e1\/12λ Mirror Surface Accuracy\u003c\/li\u003e\n\u003cli\u003e12mm Thick Mirror Substrate\u003c\/li\u003e\n\u003cli\u003e100% Real Carbon Fiber Side Plates\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eWilliam Optics 99% Dielectric Dura Bright Diagonal - 1.25\"\u003c\/h2\u003e\n      \u003cp\u003eThe William Optics 1.25\" Dura-Bright Diagonal delivers maximum image brightness and contrast through its 99% reflective dielectric coatings and a precision 1\/12λ mirror. Built on a thermally stable 12mm thick substrate and housed in a patented, permanently aligned chassis with 100% real carbon fiber plates, this diagonal ensures your telescope's optical path remains perfect from the first day of use.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eThe 1\/12λ Mirror: 99% Reflectivity for Maximum Contrast\u003c\/h3\u003e\n      \u003cp\u003eA star diagonal is a critical element in the optical chain, and the Dura-Bright is built around a laboratory-grade mirror. The 12mm thick substrate provides exceptional thermal and mechanical stability, while the surface is polished to a 1\/12λ wave accuracy, preserving the sharpness produced by your telescope's objective. Dielectric coatings provide 99% reflectivity, noticeably brightening the image and increasing contrast on faint deep-sky targets and subtle planetary details like the cloud bands of Jupiter.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003ePatented Design: 100% Carbon Fiber and Permanent Alignment\u003c\/h3\u003e\n      \u003cp\u003eWilliam Optics rejects the idea that a diagonal should ever need user adjustment. Where competing designs use collimation screws—an admission of potential mechanical flexure—the Dura-Bright employs a patented, fixed housing that guarantees perfect alignment for life. The 100% real carbon fiber side plates provide extreme rigidity and a touch of class, while internal baffles eliminate stray light for blacker backgrounds.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eCompression Rings:\u003c\/strong\u003e Both the 1.25\" eyepiece holder and adapter use brass compression rings to securely grip your eyepieces without marring their barrels.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eGlove-Friendly Screws:\u003c\/strong\u003e Large, knurled thumbscrews are easy to operate even on cold nights while wearing gloves.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eInternal Safety Stop:\u003c\/strong\u003e A machined stop prevents long 1.25\" eyepiece barrels from ever making contact with the diagonal's mirror surface.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n    \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eDura-Bright vs. Standard Diagonals: A 5% Gain in Reflectivity\u003c\/h3\u003e\n      \u003cp\u003eCompared to standard aluminum or silver diagonals that typically offer 90-94% reflectivity, the Dura-Bright's 99% dielectric mirror transmits significantly more light to your eye. This 5% or greater increase in light throughput makes a visible difference when observing at the limits of your telescope, rendering faint galaxies brighter and globular clusters more resolved. The dielectric coatings are also far more durable than standard coatings, ensuring this brightness advantage does not degrade over years of use and cleaning.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of the William Optics Dura-Bright Diagonal's 99% reflectivity?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \u003cstrong\u003e99% reflectivity\u003c\/strong\u003e from the dielectric coatings ensures the maximum amount of light from your telescope reaches the eyepiece. This results in brighter images and higher contrast compared to standard diagonals (which are often 90-94% reflective), making faint objects easier to see and planetary details more distinct.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the 1.25\" Dura-Bright Diagonal improve my views of Jupiter and Saturn?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes. The combination of high reflectivity and the \u003cstrong\u003e1\/12λ mirror surface\u003c\/strong\u003e preserves the finest details your telescope can resolve. This allows for sharper views of Jupiter’s Great Red Spot, subtle cloud bands, and the Cassini Division in Saturn’s rings, especially when compared to a lower-quality stock diagonal.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy doesn't the William Optics Dura-Bright Diagonal have collimation screws?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWilliam Optics considers adjustable alignment systems a sign of poor mechanical design. The Dura-Bright uses a \u003cstrong\u003epatented, rigid, non-adjustable housing\u003c\/strong\u003e to guarantee perfect alignment from the factory that will not shift over time. This ensures consistent, optimal performance without the need for user adjustment.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the carbon fiber on the Dura-Bright Diagonal just for aesthetics?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile the \u003cstrong\u003e100% real carbon fiber\u003c\/strong\u003e side plates are visually striking, their primary purpose is structural. Carbon fiber is exceptionally strong, rigid, and lightweight, contributing to the diagonal's robust, permanently aligned construction.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use filters with the William Optics 1.25\" Dura-Bright Diagonal?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYou attach standard \u003cstrong\u003e1.25\" threaded filters\u003c\/strong\u003e directly to the barrel of your 1.25\" eyepieces before inserting them into the diagonal. The diagonal itself does not have filter threads.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Dura-Bright Diagonal perform for splitting double stars like Albireo in my 80mm refractor?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor a task like splitting the colorful components of Albireo (Beta Cygni), the Dura-Bright excels. Its high-precision \u003cstrong\u003e1\/12λ mirror\u003c\/strong\u003e prevents any degradation of the star's Airy disk, ensuring the tightest possible stars. The high light transmission also helps maintain the brightness and rich color contrast of the binary pair in a smaller 80mm aperture.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eDiagonal Size\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eViewing Angle\u003c\/td\u003e\n\u003ctd\u003e90°\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eReflectivity\u003c\/td\u003e\n\u003ctd\u003e99%\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMirror Coatings\u003c\/td\u003e\n\u003ctd\u003eDielectric\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMirror Surface Accuracy\u003c\/td\u003e\n\u003ctd\u003e1\/12λ\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMirror Thickness\u003c\/td\u003e\n\u003ctd\u003e12mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSide Plate Material\u003c\/td\u003e\n\u003ctd\u003e100% Real Carbon Fiber\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAlignment\u003c\/td\u003e\n\u003ctd\u003ePatented Non-Adjustable Design\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eEyepiece Holder\u003c\/td\u003e\n\u003ctd\u003eBrass Compression Ring\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eBaffling\u003c\/td\u003e\n\u003ctd\u003eInternal Anti-Reflection Baffling\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSafety Feature\u003c\/td\u003e\n\u003ctd\u003eInternal Stop for Eyepiece Barrels\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003e1.25\" Dura Bright Dielectric Diagonal\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eDust Caps\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 2\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/william-optics-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eWilliam Optics 2-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":44967224181021,"sku":"WO-D-125D-C-DB","price":190.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/William-Optics-Dura-Bright-Dielectric-Diagonal-1-25-inch-D-125D-C-DB-1__99095.1596133245.1280.1280.jpg?v=1684339363"},{"product_id":"william-optics-99-dielectric-dura-bright-diagonal-2","title":"William Optics 99% Dielectric Dura Bright Diagonal - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e2\" Barrel with 90° Viewing Angle\u003c\/li\u003e\n\u003cli\u003e99% Reflectivity Dielectric Coatings\u003c\/li\u003e\n\u003cli\u003e1\/12th Wave Precision Polished Mirror\u003c\/li\u003e\n\u003cli\u003e12mm Thick Mirror Substrate for Thermal Stability\u003c\/li\u003e\n\u003cli\u003e100% Real Carbon Fiber Side Plates\u003c\/li\u003e\n\u003cli\u003eIncludes 2\" to 1.25\" Adapter with Compression Ring\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eWilliam Optics 99% Dielectric Dura Bright Diagonal - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe William Optics 2\" Dura-Bright Diagonal is built around a 12mm thick, 1\/12th wave mirror substrate with 99% reflective dielectric coatings, delivering maximum light transmission for critical observations. Its 90° mirror design is housed in a precision-machined body featuring 100% real carbon fiber side plates, and it includes a 2\" to 1.25\" adapter to accommodate your entire eyepiece collection.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e99% Reflectivity from a 1\/12th Wave Dielectric Mirror\u003c\/h3\u003e\n\u003cp\u003eAt the heart of the Dura-Bright is a mirror polished to a 1\/12th wave accuracy, ensuring that the image remains free of optical errors. This precision flat is supported by a 12mm thick substrate for excellent thermal stability, preventing image shift during temperature changes. The mirror's dielectric coatings achieve 99% reflectivity, providing noticeably brighter images and higher contrast when observing fine details on Jupiter's cloud bands or splitting close binary stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fiber Build with Non-Marring Compression Rings\u003c\/h3\u003e\n\u003cp\u003eThe diagonal's body is distinguished by 100% real carbon fiber side plates, reducing weight and adding structural rigidity. Both the 2\" diagonal barrel and the included 1.25\" adapter use brass compression rings, which secure your eyepieces firmly without scratching or marring their barrels. Internally, anti-reflection baffling eliminates stray light, while a safety stop prevents 2\" eyepiece barrels from ever contacting the mirror surface.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003ePatented Design: Permanently Aligned for Life\u003c\/h3\u003e\n\u003cp\u003eUnlike diagonals that require periodic adjustment, the William Optics Dura-Bright is engineered to hold its collimation permanently. A non-adjustable design is a testament to its mechanical integrity; the diagonal is CNC-machined from a solid block of aluminum to guarantee its optical axis remains perfectly aligned from the first day of use. This robust construction ensures your telescope's optical train remains precise, session after session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of the William Optics Dura-Bright's 99% dielectric coating?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e99% dielectric coating\u003c\/strong\u003e ensures that virtually all light gathered by your telescope reaches your eyepiece. This results in brighter, higher-contrast images compared to standard aluminum or silver coatings, which is especially critical for observing faint planetary details, deep-sky objects, and the subtle color differences in stars.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy doesn't the William Optics Dura-Bright diagonal have collimation screws?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe absence of collimation screws is a design feature, not a limitation. William Optics builds the Dura-Bright diagonal with such high mechanical precision that it is guaranteed to hold its alignment permanently. Diagonals that offer adjustments often do so because their construction is less robust and can shift over time; the Dura-Bright's patented, solid design eliminates this possibility.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Dura-Bright diagonal scratch my eyepiece barrels?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. Both the main 2\" holder and the included 1.25\" adapter use \u003cstrong\u003ebrass compression rings\u003c\/strong\u003e. Unlike simple lock screws that dig into the eyepiece barrel, a compression ring provides a secure, even grip around the entire barrel, preventing any cosmetic damage or marring.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the 12mm thick mirror in the Dura-Bright help when observing Jupiter with my FLT-132?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e12mm thick mirror substrate\u003c\/strong\u003e provides superior thermal stability. When observing an object like Jupiter for an extended period, especially as your telescope adjusts to ambient temperature, a thinner mirror could slightly deform and soften the image. The Dura-Bright's thick mirror resists these changes, ensuring your view of the Great Red Spot and its cloud bands remains sharp and stable all night.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use 1.25\" eyepieces with the 2\" William Optics Dura-Bright diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The diagonal comes with a high-quality \u003cstrong\u003e2\" to 1.25\" adapter\u003c\/strong\u003e. This adapter also features a compression ring, so your 1.25\" eyepieces are held just as securely and safely as your 2\" eyepieces.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Dura-Bright a good choice for splitting close double stars like Epsilon Lyrae with a GT102?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it's an excellent choice. Splitting tight doubles like the \"Double Double\" Epsilon Lyrae requires maximum image contrast and sharpness. The Dura-Bright's \u003cstrong\u003e1\/12th wave mirror\u003c\/strong\u003e and \u003cstrong\u003e99% reflectivity coatings\u003c\/strong\u003e preserve the delicate Airy disk and diffraction rings of the stars, making it easier to achieve a clean separation at high magnification with a high-end refractor like the GT102.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eViewing Angle\u003c\/td\u003e\n\u003ctd\u003e90°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Type\u003c\/td\u003e\n\u003ctd\u003eDura-Bright Dielectric\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReflectivity\u003c\/td\u003e\n\u003ctd\u003e99%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Substrate Thickness\u003c\/td\u003e\n\u003ctd\u003e12mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Flatness\u003c\/td\u003e\n\u003ctd\u003e1\/12th wave\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSide Plate Material\u003c\/td\u003e\n\u003ctd\u003e100% Real Carbon Fiber\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClamping Mechanism\u003c\/td\u003e\n\u003ctd\u003eBrass Compression Rings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBaffling\u003c\/td\u003e\n\u003ctd\u003eInternal Anti-Reflection Baffling\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSafety Feature\u003c\/td\u003e\n\u003ctd\u003eInternal Barrel Stop\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdapter Included\u003c\/td\u003e\n\u003ctd\u003e2\" to 1.25\" with Compression Ring\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eWilliam Optics 2\" 99% Dielectric Dura Bright Diagonal\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e2\" to 1.25\" Eyepiece Adapter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/william-optics-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eWilliam Optics 2-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":44967224213789,"sku":"WO-D-DIG2D-C-DB","price":228.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/William-Optics-2-inch-Durabright-CF-Plate-D-DIG2D-C-DB-T-1__49229.1642255347.1280.1280.jpg?v=1684339370"},{"product_id":"william-optics-d-dig2d-c-db-sct","title":"William Optics 2\" 90° Dura Bright Dielectric Diagonal for SCT threaded Scope","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eEnables use of 2-inch eyepieces for wide-field views\u003c\/li\u003e\n\u003cli\u003e90° viewing angle for comfortable observing at the zenith\u003c\/li\u003e\n\u003cli\u003eDura-Bright dielectric coatings for superior light transmission and durability\u003c\/li\u003e\n\u003cli\u003eThreads directly to the rear cell of SCT-threaded telescopes\u003c\/li\u003e\n\u003cli\u003eReduces mechanical flexure compared to standard slip-fit diagonals\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003e2\" 90° Dura Bright Dielectric Diagonal for SCT threaded Scope\u003c\/h2\u003e\n      \u003cp\u003eThis 2\" 90° Dura Bright Dielectric Diagonal is an essential upgrade for any Schmidt-Cassegrain telescope owner looking to maximize both optical throughput and mechanical stability. By threading directly onto your SCT's rear cell, it creates a solid, flex-free connection ideal for heavy 2-inch eyepieces and imaging equipment. The highly reflective and durable dielectric coatings ensure that the maximum amount of light from your telescope's optics reaches your eye, delivering brighter images and improved contrast on faint deep-sky objects.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eThe Stability of a Direct SCT Thread-On Connection\u003c\/h3\u003e\n      \u003cp\u003eUnlike standard diagonals that require a visual back and use a slip-fit compression ring, this model threads directly onto the rear port of most Schmidt-Cassegrain telescopes. This single, solid connection eliminates a common source of mechanical sag and potential misalignment, which is critical when using heavy, wide-field 2-inch eyepieces or a camera. Your optical train remains perfectly collinear, preserving the sharp focus your SCT is designed to deliver.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eDura-Bright Dielectric Coatings for Maximum Reflectivity\u003c\/h3\u003e\n      \u003cp\u003eThe \"Dura-Bright\" mirror features advanced dielectric coatings, which offer two key advantages over standard aluminum or silver coatings. First, they provide extremely high reflectivity across the visual spectrum, transmitting more light to the eyepiece for visibly brighter images. Second, these multi-layer coatings are far more durable and resistant to environmental degradation, ensuring your diagonal maintains its peak optical clarity for years of use without tarnishing.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n    \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eUnlocking Wide-Field Views with the 2-Inch Format\u003c\/h3\u003e\n      \u003cp\u003eThe primary reason to upgrade to a 2-inch diagonal is to gain access to the widest possible true fields of view your telescope can produce. By accommodating 2-inch eyepieces, this diagonal transforms your SCT into a capable instrument for sweeping the Milky Way and framing large celestial objects like the Andromeda Galaxy (M31) or the North American Nebula (NGC 7000) in a single view.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eSCT Thread-On vs. Slip-Fit Diagonals: Why Rigidity Matters\u003c\/h3\u003e\n      \u003cp\u003eFor an SCT owner, the choice between a thread-on and a slip-fit diagonal comes down to stability. While a slip-fit diagonal offers rotational convenience, it can also introduce tilt or sag, especially under the load of a heavy eyepiece like a Tele Vue Nagler or Ethos.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eThread-On Advantage:\u003c\/strong\u003e By becoming a rigid extension of the optical tube, a thread-on diagonal like this Dura Bright model maintains perfect alignment. This prevents focus shift and ensures that stars at the edge of the field remain as sharp as your telescope's optics will allow.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eSlip-Fit Limitation:\u003c\/strong\u003e The small amount of play in a slip-fit connection can be enough to slightly degrade image sharpness, an issue that becomes more apparent during high-magnification planetary viewing or astrophotography.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy should I upgrade to this 2\" Dura Bright SCT Diagonal from my stock 1.25\" diagonal?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eUpgrading to this 2\" diagonal offers three major improvements. You gain access to \u003cstrong\u003ewide-field 2-inch eyepieces\u003c\/strong\u003e, your views will be noticeably \u003cstrong\u003ebrighter due to the dielectric coatings\u003c\/strong\u003e, and the \u003cstrong\u003edirect SCT thread connection provides a more rigid and stable\u003c\/strong\u003e optical path than the standard visual back and slip-fit diagonal combination.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of a \"dielectric\" diagonal?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eA dielectric diagonal uses dozens of micro-thin layers of optical coatings to achieve extremely high reflectivity. This means more light is sent to your eyepiece, making faint objects easier to see. These coatings are also incredibly durable and resistant to aging, so the mirror will not tarnish or lose reflectivity over time like a standard aluminum mirror can.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill this 2\" Dura Bright diagonal help me see faint objects like the Veil Nebula (NGC 6960) with my 8\" SCT?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes. The combination of using a 2-inch, low-power eyepiece and the high-reflectivity dielectric coatings is ideal for observing large, faint objects like the Veil Nebula. The wider field of view helps you frame the nebula, and the increased light transmission makes it appear brighter against the background sky, especially when paired with a UHC or O-III filter.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does this Dura Bright diagonal improve views of open clusters like the Pleiades (M45) in my Celestron 11\" SCT?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eA large SCT like an 11\" has a long focal length, making it difficult to fit large open clusters like the Pleiades into a single field of view with 1.25\" eyepieces. This 2\" diagonal allows you to use long focal length 2\" eyepieces, reducing the magnification and expanding your true field of view to frame the entire cluster beautifully.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the direct-thread connection of this SCT diagonal prevent my eyepiece from rotating?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, the diagonal body itself is fixed in place once threaded onto the telescope. However, the eyepiece holder on the diagonal typically uses a non-marring compression ring that allows you to rotate the eyepiece to the most comfortable viewing orientation without loosening the diagonal itself.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use this Dura Bright SCT Diagonal on my refractor or Newtonian telescope?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, not directly. This diagonal is designed specifically with SCT threads to attach to the rear cell of a Schmidt-Cassegrain or Maksutov-Cassegrain telescope. It does not have a 2\" nosepiece for use in a standard refractor or Newtonian focuser.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSpecifications\u003c\/td\u003e\n\u003ctd\u003eNo specifications available for this product.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eBox Contents\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003eBox contents have not been specified by the manufacturer.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\n\u003cli\u003e\n\u003cp\u003eWarranty information is not available for this product.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":52853691613469,"sku":"WO-D-DIG2D-C-DB-SCT","price":286.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/WilliamOptics-2-90-Dura-Bright-Dielectric-Diagonal-for-SCT-threaded-Scope-1_8816c6a4-d15b-4d84-afc9-ba6a23f3ec08.jpg?v=1788457875"}],"url":"https:\/\/davidastro.com\/en-us\/collections\/william-optics-dura-bright-dielectric-diagonals.oembed","provider":"David Astro","version":"1.0","type":"link"}