{"product_id":"tele-vue-90-degree-everbrite-diagonal-1-25-inch","title":"Tele Vue 90º Everbrite Diagonal - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eReflectivity: 99% Dielectric Coating\u003c\/li\u003e\n\u003cli\u003eSubstrate Material: Pyrex\u003c\/li\u003e\n\u003cli\u003eBarrel Size: 1.25\"\u003c\/li\u003e\n\u003cli\u003eOptical Angle: 90°\u003c\/li\u003e\n\u003cli\u003eEyepiece Holder: Non-marring Brass Clamp Ring\u003c\/li\u003e\n\u003cli\u003eFilter Threads: Yes (1.25\")\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\u003eDownloads\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\u003eThe Final Stop for Light: The Tele Vue 90º Everbrite Diagonal\u003c\/h2\u003e\n\u003cp\u003eThe Tele Vue 90º Everbrite Diagonal - 1.25\" is an essential optical component engineered to transmit the maximum amount of light from your telescope to your eyepiece without compromise. For observers who have invested in high-quality optics, this diagonal ensures that the final reflection in the optical path maintains the brightness, contrast, and resolution your telescope is capable of delivering. It is the definitive upgrade over standard aluminum or silver diagonals, offering a quantifiable improvement in image quality and a lifetime of consistent performance.\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\u003eThe Everbrite Dielectric Coating Advantage\u003c\/h3\u003e\n\u003cp\u003eAt the heart of the Everbrite is a mirror with a sophisticated dielectric coating. Unlike aluminum coatings that tarnish and lose reflectivity over time, the Everbrite's 50-layer coating provides 99% reflectivity across the visible spectrum and is impervious to aging. This translates directly to a brighter image at the eyepiece, allowing you to detect fainter stars and more subtle details in nebulae and galaxies.\u003c\/p\u003e\n\u003cp\u003eThe coating's durability means you can clean the mirror without fear of scratching or degrading its performance. This ensures your view will be just as bright and crisp in a decade as it is on the first night. The result is a consistent, high-fidelity image that honors the light-gathering power of your telescope.\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\u003eThermally Stable Pyrex Mirror Substrate\u003c\/h3\u003e\n\u003cp\u003eA mirror's coating is only as good as the surface it is deposited on. Tele Vue uses a low-expansion Pyrex substrate for the Everbrite mirror, which is ground and polished to a 1\/10th wave flatness. The key benefit of Pyrex is its thermal stability; it does not change shape as temperatures drop during an observing session.\u003c\/p\u003e\n\u003cp\u003eThis stability prevents the introduction of optical errors like astigmatism, which can soften fine planetary detail. When you are pushing the magnification on Jupiter's cloud belts or trying to split a tight double star, the Everbrite's thermal integrity ensures the image remains sharp and free of distortion caused by cooling optics.\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\u003eA Foundation of Mechanical Precision\u003c\/h3\u003e\n\u003cp\u003eThe Everbrite's body is machined from a single, solid block of aluminum. This unibody construction guarantees that the mirror is permanently aligned with the eyepiece and telescope barrels, eliminating concerns about collimation drift. The rigid structure ensures your eyepieces are held perfectly on-axis, which is critical for maintaining sharpness, especially in faster focal ratio telescopes.\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\u003eProtecting Your Eyepiece Investment\u003c\/h3\u003e\n\u003cp\u003eStandard diagonals use a simple set screw that digs into the eyepiece barrel, causing scratches and potential alignment issues. The Tele Vue Everbrite diagonal features a non-marring brass clamp ring. When you tighten the lock screw, this soft metal ring gently and evenly compresses around the eyepiece barrel, securing it firmly without leaving a mark and ensuring perfect centering in the optical path.\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\u003eMaximizing Contrast with Stray Light Control\u003c\/h3\u003e\n\u003cp\u003eImage contrast is just as important as brightness. The interior of the Everbrite diagonal is machined with fine anti-reflection threads and blackened to a matte finish. This design traps any stray light that enters the diagonal, preventing it from reflecting off internal surfaces and washing out the image. The practical effect is a darker background sky, which makes faint objects stand out more clearly against the blackness of space.\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\u003eDesigned for Secure, Real-World Use\u003c\/h3\u003e\n\u003cp\u003eThe 1.25\" barrel that inserts into your telescope's focuser is tapered with a safety groove. This small but critical feature prevents the diagonal from accidentally slipping out of the focuser if the lock screw becomes loose. The barrel is also threaded to accept standard 1.25\" filters, allowing you to easily add a moon filter or nebula filter to your observing chain without having to attach it to every individual eyepiece.\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\u003eThe Everbrite in Practice: Observing the Orion Nebula\u003c\/h3\u003e\n\u003cp\u003eThe benefit of 99% reflectivity becomes immediately apparent on a target like the Trapezium region within the Orion Nebula (M42). With a standard aluminum diagonal, the faint, wispy outer loops of the nebula can be lost in the noise. Through the Everbrite, these structures appear with more definition. The four primary stars of the Trapezium are rendered as sharp, distinct points of light, and with good seeing, the fainter E and F stars become more accessible due to the improved brightness and contrast.\u003c\/p\u003e\n\u003cp\u003eWhile a premium diagonal cannot increase your telescope's aperture, it ensures that every photon collected by your main optic reaches your eye. This is the Everbrite's primary function: to be a transparent link in the optical chain. Its limitation is simply that it cannot correct for poor seeing or a poorly collimated telescope, but it will reveal the true performance ceiling of your instrument.\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\"\u003eIs the Everbrite diagonal worth the cost over a standard diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIf you use premium eyepieces and observe faint deep-sky objects or fine planetary detail, yes. The 99% dielectric coating provides a noticeably brighter and higher-contrast image compared to standard aluminum diagonals, which typically offer 88-92% reflectivity and degrade over time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill this diagonal work with my Schmidt-Cassegrain telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the Tele Vue 90º Everbrite Diagonal will work perfectly with any telescope that has a standard 1.25\" visual back or focuser, including Schmidt-Cassegrains, refractors, and Maksutov-Cassegrains.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat's the difference between a mirror diagonal and a prism diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eMirror diagonals, like the Everbrite, tend to have higher light transmission and introduce no chromatic aberration, making them ideal for all-around and high-magnification use. Prism diagonals can sometimes offer slightly better contrast but may introduce a small amount of color error in very fast (sub f\/5) telescopes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I clean the mirror on the Everbrite diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe dielectric coating is very durable. Use a bulb blower to remove loose dust first. For fingerprints or residue, use a high-quality optical cleaning fluid and microfiber cloth, applying gentle, circular motions. The coating is as tough as the glass itself.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Everbrite diagonal correct an upside-down image?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, it provides a right-side-up but mirror-reversed (left-to-right) image, which is standard for astronomical diagonals. For a fully corrected image for terrestrial viewing, you would need an erecting prism diagonal.\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\u003eModel\u003c\/td\u003e\n\u003ctd\u003eDPC-1250\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eMirror Star Diagonal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Substrate\u003c\/td\u003e\n\u003ctd\u003ePyrex\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Flatness\u003c\/td\u003e\n\u003ctd\u003e1\/10 wave\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating\u003c\/td\u003e\n\u003ctd\u003eEverbrite Dielectric (99% reflectivity)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyepiece Holder\u003c\/td\u003e\n\u003ctd\u003eBrass Clamp Ring\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBody Material\u003c\/td\u003e\n\u003ctd\u003eMachined Aluminum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Compatibility\u003c\/td\u003e\n\u003ctd\u003eAccepts 1.25\" filters\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e7.2 oz (204 g)\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\"\u003eTele Vue 90º Everbrite 1.25\" 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 Cap\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\"\u003eBarrel Dust Cap\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\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Tele_Vue_Diagonal_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/tele-vue-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eTele Vue 5-Year Limited Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"TeleVue","offers":[{"title":"Default Title","offer_id":51223880663325,"sku":"TV-DPC-1250","price":325.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Tele_Vue_90deg_Everbrite_Diagonal_1.25in_1.jpg?v=1777515019","url":"https:\/\/davidastro.com\/en-eu\/products\/tele-vue-90-degree-everbrite-diagonal-1-25-inch","provider":"David Astro","version":"1.0","type":"link"}