{"product_id":"svbony-sv188-90-zenith-mirror-diagonal-125in","title":"SVBONY SV188 90° Zenith Mirror Diagonal - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eProvides a comfortable 90-degree viewing angle\u003c\/li\u003e\n\u003cli\u003eStandard 1.25\" barrel fits most refractor and SCT focusers\u003c\/li\u003e\n\u003cli\u003eFeatures a 90% reflectivity mirror for bright images\u003c\/li\u003e\n\u003cli\u003eDurable all-metal housing maintains optical alignment\u003c\/li\u003e\n\u003cli\u003eSingle-screw clamp secures 1.25\" eyepieces\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 SV188 Zenith Mirror Diagonal 1.25inch 90 Degree\u003c\/h2\u003e\n\u003cp\u003eThe SVBONY SV188 Zenith Mirror Diagonal redirects the light path of your refractor telescope by 90 degrees, placing the eyepiece in a much more comfortable position for astronomical viewing. Its standard 1.25-inch barrel ensures compatibility with a vast range of telescopes and eyepieces, while the internal mirror's 90% reflectivity preserves the brightness and clarity of the image delivered by your objective lens.\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% Reflectivity Mirror for Brighter, Clearer Views\u003c\/h3\u003e\n\u003cp\u003eThe core of the SV188 is its mirror, which features a reflective coating that transmits 90% of the incoming light to your eyepiece. This level of reflectivity is crucial for preserving image brightness, especially when observing faint deep-sky objects like the Orion Nebula (M42) or distant galaxies. Unlike some entry-level prisms, a mirror diagonal introduces no chromatic aberration, ensuring that bright objects like Jupiter and Sirius remain free of false color.\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\u003eDurable Metal Housing \u0026amp; 1.25\" Refractor Compatibility\u003c\/h3\u003e\n\u003cp\u003eBuilt with a metal housing, the SVBONY SV188 is designed for durability and to hold the mirror in precise alignment, night after night. The 1.25-inch nosepiece and eyepiece holder are standard sizes, ensuring a secure fit in the focusers of most refractors, Schmidt-Cassegrains, and Maksutov-Cassegrains. A single locking screw provides a firm grip on your eyepieces.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRefractor-Specific Design:\u003c\/strong\u003e This diagonal is optimized for telescopes where you view from the back of the tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNewtonian Limitation:\u003c\/strong\u003e The SV188 is not suitable for Newtonian reflectors. Its light path is too long, which prevents the telescope from reaching focus.\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\u003eSV188 Mirror vs. Prism Diagonal: A 90° Difference\u003c\/h3\u003e\n\u003cp\u003eWhile both mirror and prism diagonals provide a 90-degree viewing angle, they achieve it differently. The SV188's mirror reflects the light, which generally provides better color fidelity and light throughput compared to standard, uncoated prism diagonals. While high-end prisms can offer excellent views, a quality mirror diagonal like the SV188 is often a significant upgrade over the basic prism included with many beginner telescopes, yielding sharper and brighter images.\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 should I use the SVBONY SV188 diagonal with my refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary reason is comfort. Without a diagonal, viewing objects high in the sky through a refractor requires you to crouch or kneel in an awkward position. The SV188's \u003cstrong\u003e90-degree\u003c\/strong\u003e angle lets you observe comfortably while seated, leading to steadier views and longer, more enjoyable sessions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the SVBONY SV188 work with my Newtonian telescope?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the SV188 is \u003cstrong\u003enot suitable for Newtonian reflectors\u003c\/strong\u003e. Newtonian telescopes have a very specific focal plane and require a secondary mirror, not a diagonal, to direct light to the side-mounted focuser. Adding this diagonal would prevent the telescope from achieving focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the SV188 diagonal affect views of the Moon in my 80mm refractor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV188 will provide bright, sharp views of the Moon. Its \u003cstrong\u003e90% reflectivity\u003c\/strong\u003e ensures minimal light loss, keeping lunar features like crater walls and rilles high in contrast. Because it's a mirror diagonal, it won't introduce any chromatic aberration (color fringing), preserving the true color and fine detail along the terminator.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the SVBONY SV188 provide a \"correct\" image for terrestrial viewing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. Like all standard astronomical mirror diagonals, the SV188 provides an image that is correct up-and-down but is reversed left-to-right. This is perfectly acceptable for astronomy, but for terrestrial viewing (like bird watching), you would need a 45-degree correct-image erecting prism.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the SVBONY SV188 on a Maksutov-Cassegrain like a Celestron NexStar 4SE?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. Maksutov-Cassegrain and Schmidt-Cassegrain telescopes function like refractors in that they have a rear-mounted focuser. The SV188 is perfectly compatible and is a common accessory for these types of telescopes to achieve a more comfortable viewing position.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of the SV188 mirror diagonal over a basic prism diagonal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV188's main advantages are typically better light transmission and color fidelity. Its \u003cstrong\u003e90% reflectivity\u003c\/strong\u003e mirror surface avoids the potential light absorption and scattering of a lower-quality prism and does not introduce the slight chromatic aberration that can occur as light passes through the glass of a prism.\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\u003eEyepiece Connection\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTelescope Connection\u003c\/td\u003e\n\u003ctd\u003e1.25\" (or 2\" with optional adapter)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyepiece Clamp\u003c\/td\u003e\n\u003ctd\u003eSingle screw\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReflectivity\u003c\/td\u003e\n\u003ctd\u003e90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHousing Material\u003c\/td\u003e\n\u003ctd\u003eMetal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Telescope Types\u003c\/td\u003e\n\u003ctd\u003eRefractors, Schmidt-Cassegrains, Maksutov-Cassegrains\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIncompatible Telescope Types\u003c\/td\u003e\n\u003ctd\u003eNewtonian Reflectors\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\"\u003eSV188 1.25\" Zenith 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\"\u003eDust Cap (Eyepiece Side)\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 (Telescope Side)\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":52861237461277,"sku":"SV-F9171A","price":34.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV188-Zenith-Mirror-Diagonal-1-25inch-90-Degree-For-Refractors-1_e283a9c2-ef17-4efb-bee3-fc97ff1c0caf.jpg?v=1788883436","url":"https:\/\/davidastro.com\/products\/svbony-sv188-90-zenith-mirror-diagonal-125in","provider":"David Astro","version":"1.0","type":"link"}