{"product_id":"svbony-sv222-45-correct-image-prism-diagonal-fmc-125in","title":"SVBONY SV222 45° Correct Image Prism Diagonal FMC - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eProduces an erect, non-reversed image for terrestrial and astronomical viewing\u003c\/li\u003e\n\u003cli\u003e45° deflection angle provides a comfortable viewing position\u003c\/li\u003e\n\u003cli\u003ePhase-coated BK7 prism for enhanced image contrast and brightness\u003c\/li\u003e\n\u003cli\u003eFits standard 1.25-inch focusers and eyepieces\u003c\/li\u003e\n\u003cli\u003eCNC machined aluminum body weighs only 167g\u003c\/li\u003e\n\u003cli\u003eFeatures a 16mm clear aperture and accepts 1.25\" filters (M28.5x0.6)\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\" 45° Correct Image Diagonal FMC Phase Coating\u003c\/h2\u003e\n\u003cp\u003eThe Svbony SV222 1.25\" Correct Image Diagonal uses a 45° BK7 prism to deliver a correctly oriented, non-reversed image suitable for both daytime terrestrial viewing and astronomical observation. Its phase-coated and fully multi-coated optics pass through a 16mm clear aperture, providing high-contrast views with an optical path length of approximately 93mm. The entire CNC-machined aluminum body weighs a mere 167g, adding minimal weight to your refractor or catadioptric telescope setup.\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 45° Erect, Non-Reversed View for Terrestrial and Astro Use\u003c\/h3\u003e\n\u003cp\u003eUnlike a standard 90° star diagonal that produces a mirror-reversed image, the SV222's prism design corrects the view completely. This means left is left and right is right, just as you see with your naked eye. This intuitive orientation is essential for terrestrial applications like birdwatching or landscape viewing, transforming your astronomical telescope into a high-power spotting scope. The 45° viewing angle is more natural for daytime use than a 90° angle, reducing neck strain during extended sessions.\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\u003ePhase-Coated BK7 Prism: Maximizing Contrast with a 16mm Aperture\u003c\/h3\u003e\n\u003cp\u003eThe heart of the SV222 is its BK7 prism, which features both full multi-coatings and advanced phase coatings. Phase correction is a critical treatment that eliminates destructive interference within the prism, resulting in a measurable increase in image contrast and resolution. This allows you to resolve finer details on planets and see fainter stars against a darker sky background. The interior of the diagonal is blackened and baffled to absorb stray light, further enhancing contrast. The 16mm clear aperture is sufficient for most planetary and lunar eyepieces, though it may cause slight vignetting with very long focal length 1.25\" eyepieces that have wide field stops.\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 Aluminum Build with a 1.25\" Non-Marring Brass Clamp\u003c\/h3\u003e\n\u003cp\u003eThe SV222 is built from a single piece of CNC-machined aluminum with a durable anodized finish, ensuring precise optical alignment and longevity. The 1.25\" eyepiece holder uses a brass compression ring instead of a simple screw, which clamps your eyepieces securely without scratching or marring their barrels. The 1.25\" nosepiece is threaded to accept standard M28.5x0.6 filters, allowing you to easily add a moon filter or light pollution filter to your observing chain.\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\"\u003eWhy choose the Svbony SV222 45° diagonal over a standard 90° star diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eChoose the \u003cstrong\u003eSvbony SV222\u003c\/strong\u003e when you need a correctly oriented, non-reversed image. This is essential for daytime terrestrial viewing (birdwatching, nature) where a mirror-image from a standard diagonal would be disorienting. The 45° angle is also often more comfortable for daytime use. For purely astronomical viewing, a 90° diagonal is typically preferred for its more comfortable angle when observing objects high in the sky.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does \"phase coating\" do on the SV222's prism?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003ePhase coatings\u003c\/strong\u003e correct for a phenomenon called \"phase shift\" that occurs when light is reflected within a prism. This correction prevents destructive light wave interference, resulting in significantly improved image contrast, resolution, and brightness compared to an uncoated prism. It's a premium feature that helps the SV222 deliver sharper views.\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 with my Newtonian reflector telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003e\u003cstrong\u003eNo.\u003c\/strong\u003e The Svbony SV222 has an optical path length of approximately 93mm, which is too long for a standard Newtonian reflector. You will not be able to rack the focuser in far enough to reach focus. This diagonal is designed specifically for refracting and catadioptric (SCT, Maksutov) telescopes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the SV222's 16mm clear aperture cause vignetting with my eyepieces?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e16mm clear aperture\u003c\/strong\u003e is generally well-matched for most 1.25\" eyepieces used for planetary, lunar, and double star observing. However, you may experience some vignetting (darkening at the edge of the field) if you use a 1.25\" eyepiece with a very long focal length (like a 32mm or 40mm Plössl) that has a field stop larger than 16mm.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the Svbony SV222 perform for birdwatching with a small 80mm f\/7 refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003eSvbony SV222\u003c\/strong\u003e is an excellent match for this scenario. It will provide a correctly oriented, high-contrast image, making it easy to follow birds in motion. The 45° angle is comfortable for viewing subjects at or near the horizon, and the phase-coated optics will help resolve fine feather details and subtle color variations.\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 viewing the Moon and planets with a Maksutov-Cassegrain?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it is a very capable choice. While the 45° angle might be less comfortable than a 90° for objects directly overhead, the phase-coated optics of the \u003cstrong\u003eSvbony SV222\u003c\/strong\u003e will deliver sharp, high-contrast views of lunar craters, Jupiter's cloud bands, and Saturn's rings. The correct-image orientation can also make it easier to navigate the lunar surface using a map.\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\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003ePrism 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\u003eDeflection Angle\u003c\/td\u003e\n\u003ctd\u003e45°\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\u003eBarrel Size\u003c\/td\u003e\n\u003ctd\u003e1.25 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClear Aperture\u003c\/td\u003e\n\u003ctd\u003e16mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eFully Multi-Coated + Phase Coatings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Length\u003c\/td\u003e\n\u003ctd\u003eapprox. 93mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Threads\u003c\/td\u003e\n\u003ctd\u003eM28.5x0.6 (Lens Sided)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyepiece 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\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\u003eNet Weight\u003c\/td\u003e\n\u003ctd\u003e167g \/ 5.87oz\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\" 45° 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 Warranty Policy\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SVBONY","offers":[{"title":"Default Title","offer_id":52861237657885,"sku":"SV-W9179A","price":56.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV222-1-25-45-Correct-Image-Diagonal-FMC-Phase-Coating-1_2cd5b71e-12ee-4d0e-8e90-43f927cbc48a.jpg?v=1788883612","url":"https:\/\/davidastro.com\/fr\/products\/svbony-sv222-45-correct-image-prism-diagonal-fmc-125in","provider":"David Astro","version":"1.0","type":"link"}