{"product_id":"takahashi-extender-q-2-inch-adapter","title":"Takahashi Extender-Q 2\" Adapter","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA 2-inch adapter that fits the visual section of the Takahashi Extender-Q, opening the train up from Takahashi's M42 x 0.75 fitting to a standard 50.8 mm barrel. With it in place the Extender-Q accepts 2-inch star diagonals and 2-inch eyepieces — the wide-field oculars that will not fit a 1.25-inch train at all.\u003c\/p\u003e\u003cp\u003eTakahashi lists it as the 50.8 Adapter (EX-Q), part TKA00596, with a published light path length of 39.5 mm. It is machined from black-anodized aluminium and retains the accessory with two thumbscrews rather than one, which is what keeps a heavy diagonal square rather than letting it tilt on a single contact point.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is the part you need if you use the Extender-Q visually and own 2-inch eyepieces or a 2-inch diagonal. The Extender-Q's own visual section does not take them directly; this adapter is what bridges it.\u003c\/p\u003e\u003cp\u003eIt has no application in an imaging train — a camera connects to the Extender-Q through the photographic path, not through a 2-inch visual barrel.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eM42 x 0.75 female telescope side:\u003c\/strong\u003e threads directly onto the Extender-Q's visual section.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch (50.8 mm) accessory side:\u003c\/strong\u003e takes standard 2-inch diagonals and eyepieces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e39.5 mm light path length:\u003c\/strong\u003e Takahashi's published figure for what this adapter contributes to the optical train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDual thumbscrews:\u003c\/strong\u003e two contact points hold a heavy diagonal square instead of letting it pivot on one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBlack-anodized aluminium:\u003c\/strong\u003e non-reflective inside the light path and light enough not to shift focuser balance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo-play fit:\u003c\/strong\u003e machined to Takahashi's mechanical tolerance, so a loaded diagonal does not rock in the seat.\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\u003eUsing 2-inch wide-field eyepieces\u003c\/strong\u003e behind an Extender-Q on a Takahashi refractor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitting a 2-inch star diagonal\u003c\/strong\u003e where the extra optical path and larger clear aperture are wanted.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUpgrading an existing Extender-Q setup\u003c\/strong\u003e from a 1.25-inch to a 2-inch visual train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHolding heavier oculars securely\u003c\/strong\u003e where a single-screw fitting would allow tilt.\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\u003eFits the Takahashi Extender-Q visual section\u003c\/strong\u003e via M42 x 0.75 female thread. It is designed for that fitting specifically and is not a universal 2-inch adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccessory side:\u003c\/strong\u003e 2-inch (50.8 mm), holding 2-inch diagonals and eyepieces with two thumbscrews.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLight path length is 39.5 mm.\u003c\/strong\u003e That is the figure to add when you are checking a train against your focus travel. Our \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e lists the light path length of every Takahashi adapter alongside the back focus figures for each telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMechanical only.\u003c\/strong\u003e There is no optical element in it — it does not correct, magnify or reduce.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you are not sure whether your eyepieces will still reach focus with this in the train, send us your telescope, Extender-Q configuration and eyepiece list 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\u003eIt requires an Extender-Q.\u003c\/strong\u003e The adapter threads onto that product's visual section and is not a standalone telescope accessory. If you do not own one, tell us what you are trying to connect and we will find the right part.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a mechanical adapter.\u003c\/strong\u003e No glass, no correction, no change to focal length or focal ratio.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVisual use only.\u003c\/strong\u003e Imaging trains take the photographic path through the Extender-Q instead.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt adds 39.5 mm to the optical path.\u003c\/strong\u003e On tubes with limited inward travel that figure is worth checking against the back focus guide before ordering — and we will check a specific combination for you.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2-inch accessories are heavier.\u003c\/strong\u003e The dual thumbscrews are there for that reason, and the fit is machined without play, so a loaded diagonal sits square.\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 onto the Extender-Q visual section, and the diagonal or eyepiece slides in and is held by the two thumbscrews. There is nothing to align.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need an Extender-Q to use it?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes. It is made for that product's M42 x 0.75 visual section. Tell us what you are connecting and we will confirm the right adapter if you do not have one.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it change magnification or focal length?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. It is a mechanical adapter with no optical element. The Extender-Q itself supplies the 1.6x factor.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does it add to my optical train?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e39.5 mm, per Takahashi's published figure. The back focus guide on this site lists it alongside every other Takahashi adapter so you can add up a train.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it with 1.25-inch eyepieces?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eWith a 2-inch to 1.25-inch reducing adapter, yes. We stock those.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it made of?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eBlack-anodized aluminium, machined to Takahashi's standard tolerance so the seat holds a loaded diagonal without play.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: Takahashi's 50.8 Adapter for the Extender-Q — M42 x 0.75 in, 2-inch out, 39.5 mm of light path, held on two thumbscrews so a heavy ocular sits square. Purely mechanical, and it is what lets a 2-inch diagonal onto an Extender-Q train.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54046972280943,"sku":"TAK-TKA00596","price":111.54,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tka00596_1_2400x2400_1708d20a-66db-4de6-8917-07971fcc80a8.jpg?v=1786907918","url":"https:\/\/ontariotelescope.com\/products\/takahashi-extender-q-2-inch-adapter","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}