{"product_id":"takahashi-multi-reducer-0-85x-m-medium","title":"Takahashi Multi-Reducer 0.85x-M for FCT-65D \/ FC-50","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe M version of Takahashi's 0.85x Multi-Reducer, matched to the \u003cstrong\u003eFCT-65D and FC-50\u003c\/strong\u003e. On the FCT-65D it gives \u003cstrong\u003e340 mm at f\/5.2\u003c\/strong\u003e; on the FC-50, 340 mm at f\/6.8. The image circle is Ø44 mm, which covers a full-frame sensor.\u003c\/p\u003e\u003cp\u003eThe Multi-Reducer comes in three versions, and the letter is not a size preference — it identifies which telescope family the reducer is computed for. M is the FCT-65D and FC-50; S is the FS-60 series; L is the FC-76 and FC-60\/65 series.\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 with an FCT-65D and want the matched reducer — the one Takahashi computed for that tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e340 mm at f\/5.2 on the FCT-65D:\u003c\/strong\u003e the configuration this version is built around.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eØ44 mm image circle:\u003c\/strong\u003e covers a full-frame sensor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFour elements in three groups:\u003c\/strong\u003e reduces and flattens together.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eM55.9 (P=0.75) telescope side, M52 (P=0.75) camera side.\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eØ60 × 54.7 mm, approx. 215 g.\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA 0.85x reduction takes 15% off the focal length and speeds the focal ratio to match — modest next to a 0.6x or 0.7x reducer, and one that keeps image scale usable rather than collapsing it. The four-element, three-group design is what holds the Ø44 mm circle: it corrects field curvature across a full-frame sensor while reducing, which a simpler design would not manage at this speed.\u003c\/p\u003e\u003cp\u003eOn the FCT-65D specifically, this takes a 65 mm fluorite triplet from f\/6.2 to f\/5.2 while keeping full-frame coverage — a meaningful gain in exposure time on an already well-corrected tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eWide-field deep-sky imaging on the FCT-65D: large nebulae, extended objects, and framing that benefits from field rather than magnification.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi computes this version for the \u003cstrong\u003eFCT-65D and FC-50\u003c\/strong\u003e. The threads are M55.9 (P=0.75) on the telescope side and M52 (P=0.75) on the camera side.\u003c\/p\u003e\u003cp\u003eNote that the FCT-65D also has a dedicated \u003cstrong\u003e65D FU Reducer 0.65x\u003c\/strong\u003e, which is a different and stronger corrector. The 0.85x-M is the gentler option; the FU reducer takes the focal length down further. We stock both — tell us what you are framing and we will talk through which suits.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eThe letter identifies the telescope, not the length:\u003c\/strong\u003e S, M and L all reduce by 0.85x. Ordering by telescope model is the way to get the right one.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eTwo reducers exist for the FCT-65D:\u003c\/strong\u003e this 0.85x and the dedicated 0.65x FU reducer. They give different focal lengths and suit different targets.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eAn imaging corrector:\u003c\/strong\u003e designed for a camera at the focal plane rather than an eyepiece.\u003c\/p\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 threads into the train on M55.9 at the telescope and M52 at the camera.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat will my FCT-65D become?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e340 mm at f\/5.2.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it cover a full-frame camera?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — Ø44 mm image circle.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow is this different from the 65D FU Reducer?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe FU reducer is 0.65x and takes the focal length down considerably further. This one is the gentler 0.85x. Both are matched to the FCT-65D.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FCT-65D version of Takahashi's 0.85x Multi-Reducer — 340 mm at f\/5.2 over a full-frame field.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54086045007983,"sku":"TAK-TKA00580M","price":676.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tka00580m.jpg?v=1787328935","url":"https:\/\/ontariotelescope.com\/products\/takahashi-multi-reducer-0-85x-m-medium","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}