{"product_id":"takahashi-collimating-telescope-refractors-cassegrains-ritchey-chretiens","title":"Takahashi Collimating Telescope for Refractors, Cassegrains \u0026 Ritchey-Chretiens","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Takahashi Collimating Telescope is a 6x18mm sighting scope built for aligning refractor, Ritchey-Chrétien and classical Cassegrain optics, including Takahashi's own Mewlon-250CRS, Mewlon-300CRS and CCA-250. It threads directly into the focuser on an M36.4 x 1 male thread and uses a 45-degree angled eyepiece for a comfortable viewing position while sighting down the optical axis. At 210 mm long, 40 mm in diameter and 235 g, it comes with a four-page instruction manual.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you own a Takahashi Mewlon Dall-Kirkham telescope, a CCA-250, or a refractor with a focal length of 820 mm or longer, and you check collimation as part of your setup routine.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e6x18mm sighting optics:\u003c\/strong\u003e a magnified, focused view down the optical axis for precise alignment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e45-degree angled eyepiece:\u003c\/strong\u003e keeps the viewing position comfortable regardless of where the focuser points.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM36.4 x 1 male thread:\u003c\/strong\u003e threads directly into the focuser drawtube, the same interface as the Collimating Eyepiece and Collimating Tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManual focus:\u003c\/strong\u003e extend or retract the eyepiece to bring the sighting image into focus.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eUnlike the Collimating Eyepiece, this is a true 6x18mm achromatic sighting telescope rather than a bare peephole. You focus it by extending and retracting the eyepiece tube by hand, and the 45-degree mirror redirects the view for a comfortable angle regardless of where the telescope is pointed. The magnified image makes fine centering errors easier to see than a direct sighting tool would.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA00443-schema.png?v=1786912644\" alt=\"Takahashi TKA00443 collimating telescope dimensional schematic\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eCollimating Mewlon-180C, Mewlon-210, Mewlon-250CRS and Mewlon-300CRS Dall-Kirkham telescopes; centering the secondary mirror on the CCA-250; checking objective alignment on refractors of 820 mm focal length or longer.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThreads via M36.4 x 1 male into any focuser accepting that thread, matching the interface used by Takahashi's Collimating Eyepiece and Collimating Tube. Also compatible with GSO, PlaneWave and RCOS Cassegrain and Ritchey-Chrétien tubes that have a marked secondary mirror for collimation reference.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIt isn't built for relay-lens Cassegrains.\u003c\/strong\u003e Takahashi doesn't recommend it on Cassegrain designs that use a relay lens as part of the optical path.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eThird-party RCs need a marked secondary to use it.\u003c\/strong\u003e On GSO, PlaneWave and RCOS tubes that means a secondary mirror with a collimation mark; if you're not sure your tube has one, send us the model and we'll help you check.\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 into the focuser exactly like an eyepiece, and focus is a simple extend-and-retract adjustment.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAligning the optical axis on Takahashi Mewlon Dall-Kirkham telescopes, the CCA-250, and refractors of 820 mm focal length or longer.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work on Cassegrains generally?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eOn classical Cassegrain and Ritchey-Chrétien designs with a marked secondary, yes; not on designs that use a relay lens.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat comes in the box?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe collimating telescope and a four-page instruction manual.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA 6x18mm sighting scope for aligning Takahashi Mewlon, CCA-250 and long-focal-length refractor optics, threading directly into the focuser and focusing by hand.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047079366767,"sku":"TAK-TKA00443","price":357.5,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/takahashi_collimating_scope_2_2.jpg?v=1786912971","url":"https:\/\/ontariotelescope.com\/products\/takahashi-collimating-telescope-refractors-cassegrains-ritchey-chretiens","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}