{"product_id":"svbony-sv222-90-erect-image-prism-diagonal-125in","title":"SVBONY SV222 90° Erect Image Prism Diagonal - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eProduces a 90° erect, non-reversed image\u003c\/li\u003e\n\u003cli\u003eStandard 1.25-inch barrel size\u003c\/li\u003e\n\u003cli\u003eBK7 prism with anti-reflection coatings\u003c\/li\u003e\n\u003cli\u003e19mm clear aperture\u003c\/li\u003e\n\u003cli\u003eCNC machined aluminum body\u003c\/li\u003e\n\u003cli\u003eThreaded for M28.5x0.6 filters\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 SV222 1.25\" 90° Erect Prism Diagonal\u003c\/h2\u003e\n\u003cp\u003eThe Svbony SV222 1.25\" 90° Erect Prism Diagonal corrects the view in your refractor or Cassegrain telescope, delivering an upright and non-reversed image essential for terrestrial observation. Its BK7 prism provides a 19mm clear aperture, and the entire CNC-machined aluminum unit adds only 153.8g to your optical train. The optical path length is approximately 65.6mm, and the barrel is threaded to accept standard M28.5x0.6 filters.\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° BK7 Prism: Correct Orientation for Land and Sky\u003c\/h3\u003e\n\u003cp\u003eThe core of the SV222 is a BK7 glass prism that deflects light 90°, providing a comfortable viewing angle while producing an \"erect image, non-reversed\" orientation. This is critical for daytime use like birdwatching or landscape viewing, where a standard astronomy diagonal's mirror-reversed image is disorienting. For astronomy, it makes navigating with star charts more intuitive, as the view in the eyepiece matches the chart exactly.\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\u003eCNC Machined Body with a 19mm Clear Aperture\u003c\/h3\u003e\n\u003cp\u003eConstructed from CNC-machined aluminum, the SV222 body is built for durability and precise alignment. The interior is blackened and baffled around the 19mm clear aperture to absorb stray light, preventing internal reflections from reducing image contrast. This ensures a darker background sky and sharper details on both celestial and terrestrial targets.\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\u003eSecure Clamping and M28.5x0.6 Filter-Ready Design\u003c\/h3\u003e\n\u003cp\u003eThe SV222 uses a screw clamp system to securely hold your 1.25\" eyepieces, preventing wobble and maintaining optical alignment. This mechanism provides a firm grip without marring the eyepiece barrel. The 1.25\" nosepiece is threaded for M28.5x0.6 filters, allowing you to easily add a moon filter, light pollution filter, or planetary color filters to enhance your view.\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\u003eSV222 Erecting Prism vs. Standard Mirror Diagonal\u003c\/h3\u003e\n\u003cp\u003eChoosing between an erecting prism and a mirror diagonal depends entirely on your primary use case. Both provide a comfortable 90° viewing angle, but the image orientation is fundamentally different.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSV222 Erecting Prism:\u003c\/strong\u003e Delivers a fully correct image (upright and not reversed left-to-right). This is non-negotiable for terrestrial viewing and highly convenient for beginners learning to navigate the sky with charts.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard Mirror Diagonal:\u003c\/strong\u003e Produces an image that is upright but reversed left-to-right. For purely astronomical deep-sky observing, a high-quality dielectric mirror diagonal may offer slightly higher light transmission, though the SV222's anti-reflection coatings deliver bright, high-contrast images suitable for all-around use.\u003c\/li\u003e\n\u003c\/ul\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\"\u003eWhy do I need an erect image diagonal like the SVBONY SV222 for my refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA refractor or SCT naturally produces an image that is upside-down and reversed. A standard star diagonal corrects the up-down orientation but leaves it mirror-reversed. The \u003cstrong\u003eSVBONY SV222\u003c\/strong\u003e is an erecting prism that corrects both, delivering a view that is upright and correctly oriented left-to-right, just as you see with your naked eye. This is essential for daytime terrestrial viewing and makes astronomical navigation with star charts much more intuitive.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the SVBONY SV222 for observing planets like Jupiter in my 8\" SCT?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The SV222 is a great choice for planetary viewing in a Schmidt-Cassegrain or refractor. Its anti-reflection coated BK7 prism provides sharp, high-contrast images, allowing you to resolve details like Jupiter's cloud bands or Saturn's rings. The correct image orientation can also make it easier to track the planet's movement across the sky.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the SV222 a good choice for birdwatching with an 80mm refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV222 is an ideal choice for this application. Its primary function is to provide a correctly oriented image, which is exactly what you need for terrestrial use like birdwatching. The 90° angle is comfortable for viewing subjects at various elevations, and the all-metal construction ensures it can handle field use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the difference between this SV222 prism diagonal and a mirror diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe main difference is the image orientation. The \u003cstrong\u003eSV222 prism diagonal\u003c\/strong\u003e provides a fully corrected, non-reversed image. A \u003cstrong\u003emirror diagonal\u003c\/strong\u003e provides an image that is right-side-up but reversed left-to-right. For terrestrial viewing, the prism is necessary. For astronomy, it's a matter of preference; some purists prefer high-end mirror diagonals for maximum light transmission on faint deep-sky objects, while many find the prism's correct view more convenient.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the SVBONY SV222 accept 1.25\" astronomy filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The 1.25\" nosepiece that inserts into your telescope's focuser is threaded with a standard \u003cstrong\u003eM28.5x0.6 thread\u003c\/strong\u003e. This allows you to attach any standard 1.25\" filter, such as a moon filter, a light pollution filter, or colored planetary filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the SV222 correct the image in a Newtonian telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. This diagonal is designed for refractors, Maksutov-Cassegrains, and Schmidt-Cassegrains. Newtonian reflectors have a different optical design and typically do not have enough focus travel to accommodate a prism diagonal. You would not be able to reach focus with the SV222 in a standard Newtonian.\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\u003eModel\u003c\/td\u003e\n\u003ctd\u003eSV222\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\u003e90° Prism Diagonal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrism Material\u003c\/td\u003e\n\u003ctd\u003eBK7\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Orientation\u003c\/td\u003e\n\u003ctd\u003eErect image, non-reversed\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\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e19mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating\u003c\/td\u003e\n\u003ctd\u003eAnti-reflection coating\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBody Material\u003c\/td\u003e\n\u003ctd\u003eCNC Metal Aluminum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClamping System\u003c\/td\u003e\n\u003ctd\u003eScrew clamps\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyepiece Side Connection\u003c\/td\u003e\n\u003ctd\u003e1.25\" Clamp\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTelescope Side Connection\u003c\/td\u003e\n\u003ctd\u003e1.25\" Barrel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Thread\u003c\/td\u003e\n\u003ctd\u003eM28.5x0.6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Length\u003c\/td\u003e\n\u003ctd\u003eappr. 65.6mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet Weight\u003c\/td\u003e\n\u003ctd\u003e153.8g \/ 5.43oz\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\"\u003eSV222 1.25\" 90° Metal Correct Image Prism 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\"\u003eM4 Screws\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\"\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":52861237756189,"sku":"SV-W9179B","price":91.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV222-1-25-90-Erect-Prism-Diagonal-AR-Coating-Metal-Mount-1_987b12dc-40aa-494c-9004-844259ce7c79.jpg?v=1788883625","url":"https:\/\/davidastro.com\/fr\/products\/svbony-sv222-90-erect-image-prism-diagonal-125in","provider":"David Astro","version":"1.0","type":"link"}