{"product_id":"svbony-sv188p-90-dielectric-mirror-diagonal-2in","title":"SVBONY SV188P 90° Dielectric Mirror Diagonal - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n  \u003cli\u003e99% Reflectivity Dielectric Coatings\u003c\/li\u003e\n  \u003cli\u003e90-Degree Viewing Angle\u003c\/li\u003e\n  \u003cli\u003e11mm Thick Mirror Substrate\u003c\/li\u003e\n  \u003cli\u003eDurable Aluminum Alloy Body\u003c\/li\u003e\n  \u003cli\u003eBrass Compression Ring Eyepiece Holder\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 SV188P 99% Reflectivity 90-Degree Dielectric Mirror Diagonal\u003c\/h2\u003e\n          \u003cp\u003eThe SVBONY SV188P 90-Degree Dielectric Mirror Diagonal maximizes image brightness by delivering 99% reflectivity from its precision 11mm thick mirror. This design ensures that the absolute minimum amount of light is lost in the optical path, providing brighter, higher-contrast views through refractors and Cassegrain 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\u003e99% Dielectric Mirror: Maximizing Light Throughput\u003c\/h3\u003e\n          \u003cp\u003eAt the core of the SV188P is a mirror with advanced dielectric coatings that achieve 99% reflectivity. Unlike standard aluminum or silver coatings that can degrade over time, these multi-layer coatings are highly durable and deliver consistent light transmission across the visible spectrum. The mirror itself is 11mm thick, providing excellent thermal stability to maintain a precise figure during temperature changes.\u003c\/p\u003e\n          \u003cul\u003e\n            \u003cli\u003e\n\u003cstrong\u003e99% Reflectivity:\u003c\/strong\u003e Transmits nearly all collected light to your eyepiece, resulting in visibly brighter images compared to diagonals with lower-grade coatings.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003eDielectric Coatings:\u003c\/strong\u003e Offer superior durability and resistance to aging, ensuring the diagonal maintains its peak optical clarity for years of use.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003e11mm Thick Mirror:\u003c\/strong\u003e Provides a stable optical surface that resists warping from temperature fluctuations, preserving image sharpness.\u003c\/li\u003e\n          \u003c\/ul\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-Degree Ergonomics and Eyepiece Protection\u003c\/h3\u003e\n          \u003cp\u003eDesigned for comfortable observing, the 90-degree angle of the SV188P places the eyepiece in a natural position for viewing objects high in the sky, reducing neck strain during long sessions. The robust aluminum alloy body houses a non-marring brass compression ring, which secures your eyepieces firmly without scratching their barrels—a significant upgrade over simple set screw designs.\u003c\/p\u003e\n          \u003cul\u003e\n            \u003cli\u003e\n\u003cstrong\u003eComfortable Viewing Angle:\u003c\/strong\u003e The 90-degree bend is ideal for use with refractor and Cassegrain-style telescopes where the eyepiece would otherwise be at an awkward angle.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003eBrass Compression Ring:\u003c\/strong\u003e Grips the eyepiece barrel uniformly, preventing scratches and ensuring a secure, centered fit.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003eAluminum Alloy Construction:\u003c\/strong\u003e Provides a rigid, durable frame for the optical components, ensuring reliable alignment.\u003c\/li\u003e\n          \u003c\/ul\u003e\n        \u003c\/div\u003e\n      \u003c\/div\u003e\n      \u003cdiv class=\"DAV-bg-light\"\u003e\n        \u003cdiv class=\"DAV-section\"\u003e\n          \u003ch3\u003eSV188P's 99% Reflectivity vs. Standard Silver Diagonals\u003c\/h3\u003e\n          \u003cp\u003eWhile a standard silver-coated diagonal typically offers 95-97% reflectivity, the SVBONY SV188P's 99% dielectric coatings provide a measurable increase in image brightness. This difference is most apparent when observing faint deep-sky objects or resolving low-contrast details on planets at high magnification.\u003c\/p\u003e\n          \u003cul\u003e\n            \u003cli\u003e\n\u003cstrong\u003eBrighter Images:\u003c\/strong\u003e The 2-4% increase in light transmission can be the difference between spotting a faint galaxy arm or seeing only the core.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003eEnhanced Durability:\u003c\/strong\u003e Dielectric coatings do not tarnish or oxidize like silver, offering a longer operational life with consistent optical clarity.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003eTrade-off:\u003c\/strong\u003e The SV188P produces an image that is upright but mirror-reversed (left-to-right), making it perfect for astronomy but unsuitable for terrestrial viewing where correct image orientation is required.\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 is a 99% dielectric diagonal like the SVBONY SV188P better than a standard one?\u003c\/h3\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion-A\"\u003e\n      \u003cp\u003eA 99% dielectric diagonal like the \u003cstrong\u003eSVBONY SV188P\u003c\/strong\u003e transmits more of the light gathered by your telescope to the eyepiece. Standard diagonals can lose 5% or more of the light, but the SV188P loses only 1%. This results in brighter, higher-contrast images, which is especially critical for observing faint deep-sky objects like nebulae and galaxies.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n      \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the image orientation through the SVBONY SV188P diagonal?\u003c\/h3\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion-A\"\u003e\n      \u003cp\u003eThe SVBONY SV188P provides an image that is \u003cstrong\u003eupright but mirror-inverted\u003c\/strong\u003e (left and right are reversed). This is standard for astronomical mirror diagonals and is perfectly fine for observing celestial objects, as there is no \"up\" or \"down\" in space. However, it is not suitable for terrestrial viewing.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n      \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the SVBONY SV188P's brass compression ring protect my eyepieces?\u003c\/h3\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion-A\"\u003e\n      \u003cp\u003eInstead of a single set screw digging into your eyepiece barrel, the SVBONY SV188P uses a \u003cstrong\u003esoft brass compression ring\u003c\/strong\u003e that tightens evenly around the barrel. This provides a secure grip without leaving scratches or gouges, preserving the condition of your valuable eyepieces.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n      \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the SVBONY SV188P work with my refractor or SCT?\u003c\/h3\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion-A\"\u003e\n      \u003cp\u003eYes, the SV188P is designed specifically for telescopes that focus straight through the back, such as \u003cstrong\u003erefractors, Schmidt-Cassegrains (SCTs), and Maksutov-Cassegrains\u003c\/strong\u003e. The 90-degree angle provides a much more comfortable viewing position than looking straight through.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n      \u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the SV188P's 99% reflectivity help when observing faint details on Jupiter with my 8\" SCT?\u003c\/h3\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion-A\"\u003e\n      \u003cp\u003eWhen observing planets like Jupiter, maximizing light throughput is key to seeing subtle, low-contrast features. The SVBONY SV188P's \u003cstrong\u003e99% reflectivity\u003c\/strong\u003e ensures that the faintest details in Jupiter's cloud bands and the Great Red Spot are delivered to your eye with maximum brightness and contrast, making them easier to resolve at high magnification.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n      \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the SVBONY SV188P diagonal suitable for terrestrial viewing, like bird watching?\u003c\/h3\u003e\n    \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion-A\"\u003e\n      \u003cp\u003eNo, the SVBONY SV188P is not recommended for terrestrial use. It produces a \u003cstrong\u003emirror-reversed image\u003c\/strong\u003e, meaning text would appear backwards. For correct image orientation for daytime viewing, you would need a 45-degree or 90-degree correct-image 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\u003eBrand\u003c\/td\u003e\n          \u003ctd\u003eSVBONY\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMaterial\u003c\/td\u003e\n          \u003ctd\u003eAluminum Alloy\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eCoatings\u003c\/td\u003e\n          \u003ctd\u003eDielectric\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\u003eReflection Surface\u003c\/td\u003e\n          \u003ctd\u003eDielectrically Coated\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMirror Thickness\u003c\/td\u003e\n          \u003ctd\u003e11mm\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\u003eSet Screws\u003c\/td\u003e\n          \u003ctd\u003eM4\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\"\u003eSVBONY SV188P 2\" 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\/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":52861237526813,"sku":"SV-F9171D","price":88.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV188P-99-Reflectivity-90-Degree-Dielectric-Mirror-Diagonal-1-F9171D_86aad769-0b9e-4e84-b1cd-45a2397de09e.jpg?v=1788883456","url":"https:\/\/davidastro.com\/products\/svbony-sv188p-90-dielectric-mirror-diagonal-2in","provider":"David Astro","version":"1.0","type":"link"}