{"product_id":"takahashi-fc-76dcu-76mm-f-7-5-fluorite-doublet-refractor-ota","title":"Takahashi FC-76DCU 76mm f\/7.5 Fluorite Doublet Refractor OTA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FC-76DCU is Takahashi's 76 mm fluorite doublet apochromat — a step up in aperture from the FS-60 line, in a tube with a fixed 80 mm barrel and a retractable dew shield that extends to 95 mm. At 570 mm focal length and f\/7.5 it runs 656 mm long and weighs 1.7 kg, and it ships with a working set of visual couplings and adapters rather than a bare tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you want more aperture and focal length than a 60 mm refractor offers, in a tube that still packs down for travel with its retractable dew shield. It suits visual observers who want brighter, higher-resolution views of the moon and planets than a 60 mm scope delivers, and imagers who want a mid-aperture apochromat that reduces and flattens cleanly for deep-sky framing.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir-spaced fluorite doublet:\u003c\/strong\u003e two elements in two groups, the same fluorite-crystal design language as the rest of Takahashi's FC\/FS range, scaled to 76 mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e570 mm at f\/7.5:\u003c\/strong\u003e more aperture and reach than the FS-60 line, still a compact travel-length tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e159 mm of back focus:\u003c\/strong\u003e enough room for a diagonal, filter wheel or imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRetractable dew shield:\u003c\/strong\u003e extends to 95 mm over an 80 mm tube, and collapses for transport.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e30 mm drawtube extension\u003c\/strong\u003e on a rack-and-pinion focuser.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncluded couplings:\u003c\/strong\u003e ships with a visual adapter, aux ring, eyepiece adapter and camera couplings — a working visual train out of the box.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.7 kg:\u003c\/strong\u003e light enough for mid-sized equatorial and travel mounts.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe objective is a two-element, air-spaced fluorite doublet, the same design family as the FS-60 and FS-60Q but built to a 76 mm aperture. Fluorite's anomalous partial dispersion keeps the red, green and blue focal points close enough together that the two-element design controls colour the way a more complex triplet would at this size, and hard multicoatings on the fluorite surface protect it and cut internal reflections.\u003c\/p\u003e\u003cp\u003eThe 159 mm of back focus is what makes the FC\/FS MFL 1.04x flattener and the 76D RD NC 0.85x reducer usable on this tube — both reach focus within the published spacing, turning the same objective into either a flat 590 mm f\/7.8 imaging setup or a faster 486 mm f\/6.4 wide-field configuration.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eVisual observing:\u003c\/strong\u003e lunar, planetary and double-star work at 570 mm and f\/7.5, with more resolution than a 60 mm aperture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat-field deep-sky imaging:\u003c\/strong\u003e with the FC\/FS MFL 1.04x flattener at 590 mm and f\/7.8, corrected to a 44 mm circle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field imaging:\u003c\/strong\u003e with the 76D RD NC 0.85x reducer at 486 mm and f\/6.4.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTravel and eclipse observing:\u003c\/strong\u003e the retractable dew shield keeps the packed length manageable.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FC-76DCU's system chart, plus its Extender-C2X and Extender-Q charts, are in the Downloads tab and list every adapter and distance for each configuration. Our \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e collects the same figures for the whole range.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack focus:\u003c\/strong\u003e 159 mm at prime focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField flattener:\u003c\/strong\u003e FC\/FS MFL 1.04x — 590 mm, f\/7.8, 44 mm circle, 75.0 mm back focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal reducer:\u003c\/strong\u003e 76D RD NC 0.85x — 486 mm, f\/6.4, 44 mm circle, 56.0 mm back focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncluded in the box:\u003c\/strong\u003e Visual Adapter (TKP20005), Coupling L (TKP00104), Aux Ring (TKP20001), Eyepiece Adapter (TKP00101) and Coupling DT (TKP20006B) — a visual train ready to accept a 1.25-inch diagonal and eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMount:\u003c\/strong\u003e sold as an OTA — no mount, rings or dovetail included. At 1.7 kg it suits mid-sized equatorial and travel mounts.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you are planning an imaging train and want to confirm spacing before ordering, send us your camera and filter setup and we will work it out 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\u003eThis is an optical tube assembly.\u003c\/strong\u003e Mount, tripod, rings and dovetail are sold separately, though the visual couplings needed for an eyepiece are included.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA flat field for imaging needs the flattener or reducer.\u003c\/strong\u003e At prime focus the field curves, as on any doublet refractor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe FURD 0.64x reducer is built for the longer-tube FC-76DP, not this one.\u003c\/strong\u003e The DCU uses the 76D RD NC 0.85x reducer instead.\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 ships with the visual couplings needed for a diagonal and eyepiece, and the system chart in the Downloads tab lists every part and distance for imaging configurations.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eVisual observing of the moon and planets at 76 mm aperture, and deep-sky imaging once the flattener or reducer is fitted.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the difference between the FC-76DCU and FC-76DP?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eSame 76 mm objective and 570 mm native focal length, different tube. The DCU has a shorter, retractable-dew-shield tube at 159 mm back focus; the DP is a longer fixed tube with 207.1 mm of back focus for its own dedicated FURD reducer.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it need a flattener for astrophotography?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAt prime focus, yes, for a flat field to the edge — the MFL 1.04x flattener or the 0.85x reducer each correct it.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat comes in the box besides the tube?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eA visual adapter, aux ring, eyepiece adapter and two couplings — enough to attach a 1.25-inch diagonal and eyepiece without buying additional adapters.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 76 mm fluorite doublet apochromat at 570 mm and f\/7.5, with 159 mm of back focus, a retractable dew shield, and the couplings needed for visual use included — ready to flatten or reduce for imaging when you add the matching corrector.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047053971567,"sku":"TAK-TFK07640","price":1859.0,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TFK07640_FC-76DCU_OTA_1.jpg?v=1786911918","url":"https:\/\/ontariotelescope.com\/products\/takahashi-fc-76dcu-76mm-f-7-5-fluorite-doublet-refractor-ota","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}