{"product_id":"takahashi-newtonian-collimating-tube-crosshair","title":"Takahashi Newtonian Collimating Tube with Crosshair","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Newtonian Collimating Tube with Crosshair is a machined alignment tool built for centering the secondary mirror on Takahashi's Epsilon-series Newtonian astrographs. A wire crosshair is stretched across the objective end of the tube, giving you a fixed reference point to center against the reflection of the primary mirror. It threads via M36.4 x 1 to the \u003ca href=\"\/products\/takahashi-collimating-eyepiece-newtonians-cassegrains\"\u003eCollimating Eyepiece\u003c\/a\u003e (TKA00441, sold separately), and together the two function as a Cheshire eyepiece. At 39.5 mm in diameter, 80 mm long and 50 g, it fits in a case with the rest of your collimation kit.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you run a Takahashi Epsilon astrograph and check secondary mirror centering as part of your regular collimation routine.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFixed wire crosshair:\u003c\/strong\u003e stretched across the objective end, giving a stable reference point for centering the primary mirror's reflection.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM36.4 x 1 male thread:\u003c\/strong\u003e mates directly to the Collimating Eyepiece for a combined Cheshire-eyepiece assembly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMachined construction:\u003c\/strong\u003e holds the crosshair's position precisely, session after session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurpose-built for Epsilon optics:\u003c\/strong\u003e matched to the secondary mirror geometry of Takahashi's hyperbolic Newtonian astrographs.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThreaded to the Collimating Eyepiece, the assembly works as a Cheshire eyepiece: you sight through the eyepiece's peephole, and the crosshair in this tube gives you a fixed target to center the secondary mirror's shadow against. The crosshair wire is taped across a notch at the tube end and can be replaced if it's ever damaged.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA00442-schema.png?v=1786912644\" alt=\"Takahashi Newtonian collimating tube TKA00442 half-section dimensional schematic\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eSecondary mirror collimation on Takahashi Epsilon 130D, Epsilon 160ED and Epsilon 180ED astrographs; paired use with the Collimating Eyepiece for a full Cheshire-style alignment check before an imaging session.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThreads via M36.4 x 1 to the \u003ca href=\"\/products\/takahashi-collimating-eyepiece-newtonians-cassegrains\"\u003eCollimating Eyepiece\u003c\/a\u003e (TKA00441), which is sold separately and required to complete the Cheshire-eyepiece assembly.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIt ships without the Collimating Eyepiece.\u003c\/strong\u003e The two parts are sold separately and thread together to form the full Cheshire-eyepiece assembly.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eTakahashi matches it to its own Epsilon astrographs.\u003c\/strong\u003e If you're aligning a different Newtonian, send us the model and we can help you work out the right collimation tool for it.\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 onto the Collimating Eyepiece by hand, and the crosshair is already fitted at the factory.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eCentering the secondary mirror on a Takahashi Epsilon astrograph as part of routine collimation.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need any other accessories?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — the Collimating Eyepiece (TKA00441) threads onto this tube to complete the Cheshire-eyepiece assembly.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work on non-Takahashi Newtonians?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eTakahashi designs it around its own Epsilon-series secondary mirror geometry.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA crosshair-equipped alignment tube matched to Takahashi's Epsilon astrographs, threading to the Collimating Eyepiece for a complete Cheshire-style secondary mirror check.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047078645871,"sku":"TAK-TKA00442","price":91.52,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tce0030_2_2.jpg?v=1786912929","url":"https:\/\/ontariotelescope.com\/products\/takahashi-newtonian-collimating-tube-crosshair","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}