{"product_id":"takahashi-cca-250-0-72x-645-reducer-ca","title":"Takahashi CCA-250 0.72x 645 Reducer-CA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe 645 Reducer-CA 0.72x is Takahashi's dedicated focal reducer for the CCA-250 Cassegrain astrograph, cutting its focal length by 0.72x to reach 890mm at f\/3.6. The reducer delivers a Φ60mm image circle, sized for medium-format and large full-frame sensors.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis reducer suits CCA-250 owners who want a materially faster imaging system for deep-sky work with a larger-format camera. Increasing the speed of a Cassegrain design this way shortens integration time on faint targets without sacrificing the large-aperture light grasp the CCA-250 is built around.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e0.72x reduction:\u003c\/strong\u003e speeds up the CCA-250's optical system to f\/3.6 at 890mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eΦ60mm image circle:\u003c\/strong\u003e sized for larger imaging sensors, medium format included.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDedicated CCA-250 fit:\u003c\/strong\u003e engineered specifically for this telescope's Cassegrain optical path rather than adapted from a refractor reducer.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eBack focus with the reducer installed is 56.2mm on the CCA-250. See the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e for the full spacing chain when planning your camera train.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eFast deep-sky imaging on the CCA-250 with medium-format or large full-frame cameras; galaxy and nebula imaging where a faster focal ratio meaningfully shortens total exposure time on a large-aperture Cassegrain.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eResulting focal length\u003c\/th\u003e\n\u003cth\u003eResulting focal ratio\u003c\/th\u003e\n\u003cth\u003eImage circle\u003c\/th\u003e\n\u003cth\u003eBack focus\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCCA-250\u003c\/td\u003e\n\u003ctd\u003e890mm\u003c\/td\u003e\n\u003ctd\u003ef\/3.6\u003c\/td\u003e\n\u003ctd\u003eΦ60mm\u003c\/td\u003e\n\u003ctd\u003e56.2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eThis reducer is specific to the CCA-250 — the related 645RD QE 0.72x reducer serves the FSQ-106EDX4 instead, and the two aren't interchangeable between telescopes despite the similar naming and reduction factor.\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 installs into the CCA-250's optical path as a dedicated fit, and the 56.2mm back focus figure is fixed once it's in place.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eFast deep-sky astrophotography on the CCA-250 with medium-format or large full-frame sensors.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work for visual observing?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — it's built to deliver a flat photographic image circle rather than a visual eyepiece path.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat else do I need with it?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYour camera's own adapter to complete the connection at the 56.2mm back focus figure.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA dedicated 0.72x reducer for the CCA-250 that reaches 890mm at f\/3.6 across a Φ60mm image circle for medium-format astrophotography, at a 56.2mm back focus.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047117443183,"sku":"TAK-TKA86580L","price":2988.7,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tka86580l_3.jpg?v=1786914180","url":"https:\/\/ontariotelescope.com\/products\/takahashi-cca-250-0-72x-645-reducer-ca","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}