{"product_id":"takahashi-coupling-tw-22-5mm-wide-mount-adapter","title":"Takahashi Coupling (TW) 22.5mm Wide Mount Adapter","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi's Coupling (TW), part TKP31003, is the ring that carries a telescope-side accessory train across to the Wide Mount T-ring camera system. Takahashi publishes a 22.5 mm light path for it — the length it contributes to your optical train, not the length you would measure across the part on a bench. On the system charts it is no. 8, a step away from the Wide T-mount entry it feeds.\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 through a Takahashi refractor and want your camera hanging off the Wide Mount T-ring system rather than the narrower standard T-thread.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoupling (TW) — Takahashi part TKP31003:\u003c\/strong\u003e no. 8 in Takahashi's system charts, where it links the telescope-side accessory chain to the Wide T-mount.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e22.5 mm light path:\u003c\/strong\u003e Takahashi's published figure for what this coupling contributes to the optical train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide Mount camera side:\u003c\/strong\u003e it opens onto the DX-WR Wide Mount T-ring family, so the camera body attaches through the wider of Takahashi's two ring systems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurely mechanical:\u003c\/strong\u003e no optical element, and no change to focal length or focal ratio.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrime-focus imaging\u003c\/strong\u003e with a Wide Mount T-ring on a Takahashi refractor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRebuilding a camera train\u003c\/strong\u003e around the Wide Mount system after a change of camera body.\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\u003e22.5 mm of the budget.\u003c\/strong\u003e Every flattener and reducer has a back focus target, and this coupling spends 22.5 mm of it, which is worth working out before the rest of the train is fixed. The \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e lists the figure alongside the back focus target for each Takahashi telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide Mount T-rings are the other half.\u003c\/strong\u003e The DX-WR rings for Canon EOS and Nikon carry the camera-side connection and are sold separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThere is a second version for the CCA-250.\u003c\/strong\u003e Takahashi lists that one as no. 8A, part TKP86003, at 34.2 mm — a different length for a different accessory family, so the two are not interchangeable.\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 threads between two accessory families that were designed to meet here, and there is nothing to align or adjust once it is seated.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat does it add to my optical train?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e22.5 mm, per Takahashi's published light path figure.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow is it different from the CCA-250 coupling?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThat one is TKP86003, chart no. 8A, and it runs 34.2 mm. It belongs to the 98 mm CCA-250 accessory family rather than this one.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it include any optics?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo, it is a mechanical coupling only.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi's no. 8 coupling: 22.5 mm of light path between a telescope-side accessory train and a Wide Mount T-ring. With the Wide Mount ring for your camera body, the connection is complete — and if you would like a second pair of eyes on the spacing, send us the rest of your train and we will work it out with you.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54054832373871,"sku":"TAK-TKP31003","price":140.14,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKP31003_1.jpg?v=1787024985","url":"https:\/\/ontariotelescope.com\/products\/takahashi-coupling-tw-22-5mm-wide-mount-adapter","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}