{"product_id":"svbony-sv188-1-25-mirror-diagonal","title":"SVBONY SV188 1.25″ 90° Mirror Diagonal for Refractors","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/6371934719254349607262056.jpg?v=1791669914\" alt=\"SVBONY SV188 1.25 inch 90 degree mirror diagonal key visual\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe SVBONY SV188 is a 1.25″ 90° mirror star diagonal for refractors. It turns the light path through a right angle so the eyepiece sits at a comfortable position when you observe high in the sky. The mirror has a published reflectivity of 90%, the housing is metal, and a single thumbscrew holds 1.25″ eyepieces. The nosepiece fits 1.25″ focusers directly and 2″ focusers with an adapter.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you observe visually with a refractor that takes 1.25″ eyepieces and want an upright-angle viewing position for the Moon, planets and deep-sky objects, or if you need a replacement for a lost or damaged diagonal.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e90° mirror diagonal:\u003c\/strong\u003e places the eyepiece at a right angle to the tube for comfortable viewing near the zenith.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e90% reflectivity:\u003c\/strong\u003e the published reflectance of the mirror coating.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision-machined alignment:\u003c\/strong\u003e SVBONY machines the mirror seat to hold optical alignment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBlackened internal threads:\u003c\/strong\u003e threaded baffling inside the barrel reduces glare and stray reflections.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMetal housing\u003c\/strong\u003e with a single-screw 1.25″ eyepiece clamp.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/6371934719246909342776934.jpg?v=1791669913\" alt=\"SVBONY SV188 mirror diagonal precision-aligned mirror detail\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/6371934717356889712318365.jpg?v=1791669913\" alt=\"SVBONY SV188 mirror diagonal blackened internal threads detail\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar and planetary observing\u003c\/strong\u003e with a 1.25″ eyepiece set on a refractor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky viewing near the zenith\u003c\/strong\u003e, where a straight-through view is awkward.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplacement diagonal\u003c\/strong\u003e for entry-level and travel refractors.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/6373085363400990158429545.jpg?v=1791669914\" alt=\"SVBONY SV188 mirror diagonal on a refractor\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyepiece side:\u003c\/strong\u003e 1.25″, one clamping screw.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTelescope side:\u003c\/strong\u003e 1.25″ nosepiece; 2″ focusers need a 2″-to-1.25″ adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTelescope type:\u003c\/strong\u003e designed for refractors. SVBONY names refractors such as Celestron EQ and Meade Infinity models as examples.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNot for Newtonians:\u003c\/strong\u003e a Newtonian's focal plane sits too close to the focuser for a diagonal to reach focus.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/6373085365203498263994258.jpg?v=1791669914\" alt=\"SVBONY SV188 mirror diagonal eyepiece clamp and nosepiece\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMirror-reversed image:\u003c\/strong\u003e like all 90° mirror diagonals, it shows an upright image that is reversed left to right. For a fully correct image, an erecting prism diagonal is the alternative.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRefractors (and similar) only:\u003c\/strong\u003e it is not suitable for Newtonian reflectors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e SVBONY does not publish a weight for this diagonal.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. It slides into the 1.25″ focuser and the eyepiece slides into the diagonal, each held by a thumbscrew.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it work in my 2″ focuser?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes, with a 2″-to-1.25″ adapter in the focuser.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it on a Newtonian?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. SVBONY lists it as not suitable for Newtonians.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the image orientation?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eUpright but mirror-reversed left to right, as with any single-mirror diagonal.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 1.25″ 90° metal-bodied mirror diagonal with 90% reflectivity and blackened internal threads, for comfortable visual observing with a refractor.\u003c\/p\u003e","brand":"SvBony","offers":[{"title":"Default Title","offer_id":67722222076015,"sku":"F9171A","price":34.19,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f9171a---9-_20250806105250_4152_20260810154813_1315.webp?v=1791670090","url":"https:\/\/ontariotelescope.com\/products\/svbony-sv188-1-25-mirror-diagonal","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}