{"product_id":"takahashi-2-extension-tube-l","title":"Takahashi 2\" Extension Tube (L)","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi's Extension Tube (L) (50.8), part TKP31112, is a 2-inch sleeve that lengthens a Takahashi imaging or visual train. Takahashi publishes a light path length of 73.5 mm for it — not its physical size, but what it adds once it's in the train — and it's the longer of Takahashi's two 50.8 mm extension tubes; the shorter Extension Tube (50.8) (TKP27112) adds 62 mm instead.\u003c\/p\u003e\u003cp\u003eAt 73.5 mm it's a substantial step, useful when a shorter extension leaves you short of focus or short of a flattener's specified backfocus.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if your setup needs roughly 73.5 mm of additional 2-inch spacing to reach focus or hit a flattener's specified backfocus — on a TOA-130 imaging train, for instance, where Takahashi lists it as a compatible accessory.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e50.8 mm sleeve:\u003c\/strong\u003e accepts standard 2-inch fittings on both ends.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e73.5 mm light path length:\u003c\/strong\u003e Takahashi's published figure for the spacing this tube adds.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBlack anodized finish:\u003c\/strong\u003e non-reflective inside the light path.\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\u003eReaching focus\u003c\/strong\u003e in trains with a long inward-travel requirement.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHitting a flattener or reducer's specified backfocus,\u003c\/strong\u003e where the shorter extension tube falls short.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtending a TOA-130 imaging or visual train,\u003c\/strong\u003e where Takahashi lists it as a compatible part.\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\u003e50.8 mm sleeve fitting\u003c\/strong\u003e on both ends, compatible with Takahashi's 2-inch accessory system.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdds 73.5 mm to the optical path\u003c\/strong\u003e — worth working into a full train calculation before you order. Our \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e lists it alongside the back focus figures for each telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurely mechanical\u003c\/strong\u003e — no optical element, no change to focal length or focal ratio.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt's the longer of two similar Takahashi extension tubes.\u003c\/strong\u003e The shorter Extension Tube (50.8) adds 62 mm rather than 73.5 mm — tell us your target spacing and we'll confirm which one you need.\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's a straight sleeve that fits between two 2-inch fittings, with nothing to align.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does it add to my optical train?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e73.5 mm — send us your full train if you'd like it checked against a flattener's backfocus spec before you order.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs there a shorter version?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — Takahashi's Extension Tube (50.8) adds 62 mm instead, sold as a separate part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it include any optics?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. It's a mechanical adapter only.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: Takahashi's 2-inch Extension Tube (L) — a 50.8 mm sleeve adding 73.5 mm of light path, for trains that need the longer of Takahashi's two standard extension steps.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047927173231,"sku":"TAK-TKP31112","price":247.39,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tet0002l_2_6.jpg?v=1786936711","url":"https:\/\/ontariotelescope.com\/products\/takahashi-2-extension-tube-l","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}