{"product_id":"svbony-sv221-90-brass-mirror-diagonal-125in","title":"SVBONY SV221 90° Brass Mirror Diagonal - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e90° Deflection Angle for Comfortable Viewing\u003c\/li\u003e\n\u003cli\u003eAluminum-Coated Mirror with \u0026gt;92% Reflectivity\u003c\/li\u003e\n\u003cli\u003eStandard 1.25\" Barrel and Eyepiece Clamp\u003c\/li\u003e\n\u003cli\u003eAccepts 1.25\" Filters via M28.5x0.6 Threads\u003c\/li\u003e\n\u003cli\u003eBrass Compression Ring Prevents Eyepiece Scratches\u003c\/li\u003e\n\u003cli\u003eLightweight 90.5g Construction\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\u003eSVBONY SV221 1.25\" 90° Brass Diagonal for Refractor Telescope\u003c\/h2\u003e\n\u003cp\u003eThe SVBONY SV221 1.25\" 90° Brass Diagonal redirects the light path of your refractor, providing a comfortable viewing angle for objects high in the sky. Its aluminum-coated mirror has a reflectivity greater than 92% across a 29.5mm clear aperture, ensuring bright images with minimal light loss. The integrated M28.5x0.6 thread allows for the use of standard 1.25\" filters, and at just 90.5g, it adds minimal weight to your optical train.\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\u003e90° Viewing Angle with \u0026gt;92% Reflectivity\u003c\/h3\u003e\n\u003cp\u003eA 90° diagonal is an essential accessory for any refractor or Schmidt-Cassegrain telescope, eliminating neck strain when observing targets near the zenith. The SVBONY SV221 uses an aluminum-coated mirror with a reflectivity of over 92% to deliver bright, high-contrast views. The 29.5mm clear aperture is large enough to prevent vignetting with standard 1.25\" Plössl eyepieces, preserving the brightness of your telescope's optics. Note that as a mirror diagonal, it provides an image that is vertically correct but horizontally reversed (Erect Image, Mirror Inverted), which is normal for astronomical viewing but not ideal for terrestrial use where correct image orientation is required.\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\u003eBrass Ring Clamp and M28.5x0.6 Filter Threads\u003c\/h3\u003e\n\u003cp\u003eThe SV221 is engineered to protect your equipment while enhancing its capabilities. Unlike basic diagonals that use a single screw to hold the eyepiece, this model features a brass compression ring that provides a secure, non-marring grip on your eyepiece barrels, preventing scratches and gouges. The nosepiece is threaded for standard M28.5x0.6 filters, allowing you to easily add a moon filter or light pollution filter to your setup without needing to thread it onto each individual eyepiece.\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 main purpose of the SVBONY SV221 diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SVBONY SV221 is a \u003cstrong\u003e90° mirror diagonal\u003c\/strong\u003e designed for refractor and Schmidt-Cassegrain telescopes. Its primary purpose is to bend the light path at a right angle, allowing you to observe comfortably, especially when the telescope is pointing towards the zenith (straight up).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the brass pressure ring on the SV221 protect my eyepieces?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe brass compression ring provides a significant advantage over simple set-screw designs. When you tighten the clamp, the soft brass ring gently and evenly squeezes the eyepiece barrel. This holds it securely in place without the screw tip digging into the barrel, which prevents the scratches and gouges common with lower-quality diagonals.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use 1.25\" filters with the SVBONY SV221?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The 1.25\" nosepiece of the SVBONY SV221 has standard \u003cstrong\u003eM28.5x0.6 threads\u003c\/strong\u003e. This allows you to screw any standard 1.25\" filter, such as a moon filter or a nebula filter, directly onto the diagonal itself.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the SVBONY SV221 suitable for observing Jupiter with my 80mm refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The SVBONY SV221 is an excellent choice for planetary viewing with an 80mm refractor. Its \u003cstrong\u003e\u0026gt;92% reflectivity\u003c\/strong\u003e ensures that the bright image of Jupiter (and its moons) reaches your eyepiece with minimal light loss, preserving contrast and detail in the planet's cloud bands. The 90° angle will make observing much more comfortable as Jupiter climbs higher in the sky.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"Erect Image, Mirror Inverted\" mean for the view through the SV221?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis describes the image orientation. \"Erect Image\" means the view is right-side up, but \"Mirror Inverted\" means it is flipped left-to-right. For astronomy, this is perfectly acceptable as there is no \"up\" or \"down\" in space. However, it means that text or terrestrial objects would appear backward, making it less suitable for daytime terrestrial viewing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI find it difficult to look through my refractor when it's pointed at the zenith. Will the SVBONY SV221 diagonal help?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, this is exactly what the SVBONY SV221 is designed for. By redirecting the light path by \u003cstrong\u003e90°\u003c\/strong\u003e, it allows you to look down into the eyepiece from a comfortable standing or seated position, even when the telescope is aimed directly overhead. This completely solves the issue of having to crouch or kneel to use your refractor.\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\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eSVBONY\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize\u003c\/td\u003e\n\u003ctd\u003e1.25 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eMirror Diagonal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDeflection 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\u003e\u0026gt;92%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReflection Surface\u003c\/td\u003e\n\u003ctd\u003eAluminum Coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e29.5mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Orientation\u003c\/td\u003e\n\u003ctd\u003eErect Image, Mirror Inverted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLens-Sided Connection\u003c\/td\u003e\n\u003ctd\u003e1.25\" Barrel with M28.5x0.6 Filter Thread\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyepiece-Sided Connection\u003c\/td\u003e\n\u003ctd\u003e1.25\" Clamp\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClamping System\u003c\/td\u003e\n\u003ctd\u003eBrass Compression Ring with Screw Clamps\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Length\u003c\/td\u003e\n\u003ctd\u003eapprox. 73mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003ePlastic \u0026amp; Metal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet Weight\u003c\/td\u003e\n\u003ctd\u003e90.5g \/ 3.19oz\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\"\u003eSV221 1.25\" 90 Degree Mirror 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\"\u003eM3 Screws\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 3\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\"\u003eDust Plug\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\/svbony-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eSVBONY 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SVBONY","offers":[{"title":"Default Title","offer_id":52861237559581,"sku":"SV-W9178A","price":21.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV221-1-25-90-Brass-Diagonal-for-Refractor-Telescope-1_8b7ba08c-cdce-47b8-adc1-807d5a4a713f.jpg?v=1788883600","url":"https:\/\/davidastro.com\/fr\/products\/svbony-sv221-90-brass-mirror-diagonal-125in","provider":"David Astro","version":"1.0","type":"link"}