{"product_id":"svbony-sv193-0-8x-reducer-flattener-sv503-102ed","title":"SVBONY SV193 2″ 0.8x Reducer\/Flattener for SV503 102ED","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9152d-0_20251231154749_0802.webp?v=1791670394\" alt=\"SVBONY SV193 2 inch 0.8x reducer flattener for SV503 102ED\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe SVBONY SV193 is a 2″, 0.8x reducer and field flattener made for the SV503 102ED f\/7 refractor. It shortens the focal length by 20%, widening the field and speeding up the focal ratio, while flattening the field curvature that is normal for refractors so stars stay round towards the edge of the frame. The optics are 3 elements in 2 groups, fully multi-coated with blackened lens edges, in a hard-anodised aluminium body with a standard M48×0.75 thread and 55 mm backfocus. It weighs 177 g.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you image deep-sky targets with an SV503 102ED and want a wider, faster field than the native f\/7 with flat stars across a DSLR, mirrorless or astronomy camera sensor.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e0.8x reduction:\u003c\/strong\u003e shorter focal length and a faster focal ratio for shorter exposures at the same signal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField flattening\u003c\/strong\u003e for round stars toward the corners.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e3-element \/ 2-group FMC optics\u003c\/strong\u003e with blackened edges.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003e2″ barrel and M48×0.75 thread.\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e55 mm backfocus\u003c\/strong\u003e from the M48 thread to the sensor.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eHard-anodised aluminium body.\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe three-element corrector sits in the converging light cone ahead of the focal plane. It reduces focal length by 0.8x and corrects the curved focal surface of the objective. Correction depends on placing the sensor 55 mm behind the M48 thread, which is the figure to build your spacing around. SVBONY states that it can also thread onto other f\/6–f\/7 refractors with 2″ focusers, with limited performance on those.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9152d-2_20250806182410_4086.jpg?v=1791670393\" alt=\"SVBONY SV193 reducer flattener M48 thread and 2 inch barrel\" 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\u003eDeep-sky imaging\u003c\/strong\u003e of larger nebulae, galaxies and clusters with the SV503 102ED.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFaster sessions:\u003c\/strong\u003e the reduced focal ratio improves signal-to-noise at a given exposure time.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDesigned for:\u003c\/strong\u003e SVBONY SV503 102ED f\/7. SVBONY makes a separate SV193 version (W9152B) for the SV503 80ED f\/7.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCamera side:\u003c\/strong\u003e M48×0.75; a filter wheel, off-axis guider or astronomy camera can follow it, as long as the total spacing reaches 55 mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRotation:\u003c\/strong\u003e SVBONY offers a 360° field rotator, sold separately, for changing framing without turning the lens.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you would like help working out spacers for your camera, filter wheel or OAG, send us your train and we will add it up with you.\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\u003eSpacing:\u003c\/strong\u003e the sensor needs to sit 55 mm behind the M48 thread; the corners are where the spacing shows.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched to the SV503 102ED:\u003c\/strong\u003e other refractors fit mechanically, with the limited performance SVBONY notes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImage circle:\u003c\/strong\u003e SVBONY does not publish an image-circle figure for the SV193.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging only:\u003c\/strong\u003e it has no application in a visual train.\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\u003eIt slides into the 2″ focuser like an eyepiece, and the camera threads on the M48 side. The one figure to set is 55 mm from the M48 thread to the sensor, made up with the T-ring or camera spacers.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it fit the SV503 80ED?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eSVBONY makes a separate SV193 version for the 80ED; this listing is the 102ED version.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use 2″ filters?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eFilters go in the camera-side train, for example in a filter drawer or wheel within the 55 mm spacing.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 2″ 0.8x reducer\/flattener for the SV503 102ED, with 3-element FMC optics and an M48 output at 55 mm backfocus, for a wider, faster and flatter deep-sky field.\u003c\/p\u003e","brand":"SvBony","offers":[{"title":"Default Title","offer_id":67722286563439,"sku":"W9152D","price":119.12,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/w9152d-0_20251231154749_0802.webp?v=1791670394","url":"https:\/\/ontariotelescope.com\/products\/svbony-sv193-0-8x-reducer-flattener-sv503-102ed","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}