{"title":"Field Flatteners","description":"\u003cp\u003eField Flatteners from every brand we carry. Part of \u003ca href=\"\/collections\/flatteners-and-reducers\"\u003eFlatteners, Reducers \u0026amp; Correctors\u003c\/a\u003e.\u003c\/p\u003e","products":[{"product_id":"starfield-1-0x-field-flattener","title":"Starfield 1.0x Field Flattener","description":"\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe Starfield 1.0x Field Flattener enhances the imaging capabilities of refractors by elliminating fiel curvature in short, optically fast refractors providing a flat image for the camera sensor.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cbr style=\"clear: both;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eWhen using a DSLR and a refractor between f\/5.5 to f\/6.5 the field is flattened across the entire sensor.  When using small chips like popular 4\/3rd's or 1\" size sensors refractors up to f\/7.5 will not experience any change in focal length\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cbr style=\"clear: both;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt;\"\u003eRequiring a standard 55mm of back focus, this flattener is perfect for any DSLR imager.  No additional extension rings are required.  With 38mm of clear aperture remove the chance of vignetting and is well suited for APS-C and smaller sensors. With the optional 48mm adapter a clear aperture of 42mm is provided. A 44mm Clear aperture when the optional 48mm T-Ring adapter is used.  Your imaging sessions will benefit with a flat field while maintiaining your telescopes focal length.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt;\"\u003eA standard 10mm T-Ring is required.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eMulti-coated optics housed in a high polish, and hard anodize finished aluminum body to help reduce weight.  This all metal constructed accessory will look like jewelry for your telescope.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eIncludes standard M42 T thread for camera connection, and 48mm filter thread to add your favorite light pollution filter.    \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cbr style=\"clear: both;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eWeights 7.5oz\u003c\/span\u003e\u003c\/p\u003e","brand":"Starfield","offers":[{"title":"Default Title","offer_id":44013465501807,"sku":"SF-FF-10","price":194.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Lens-01_B__93689.jpg?v=1766553726"},{"product_id":"large-field-flattener","title":"Large Field Flattener","description":"\u003cp\u003e\u003cspan style=\"font-family: Arial;\"\u003eDon't be hampered by fields that are not flat.  Up your imaging game and get the flat field you deserve!\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan style=\"font-family: Arial;\"\u003eImprove the overall field of view and gain better sight lines.   Become the envy of that star party next month when you show up with the biggest field flattener available.\u003c\/span\u003e\u003c\/p\u003e\u003cp\u003e\u003c\/p\u003e\u003cp\u003e\u003cspan style=\"font-family: Arial;\"\u003eLimited time offer!!\u003c\/span\u003e\u003c\/p\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cp\u003eIt is a Big Toy that everyone needs in their Astronomy Tool Box\u003c\/p\u003e\n\u003cp\u003eIt comes in Yellow, its a Diesel.  \u003c\/p\u003e\n\u003cp\u003eIt serves a double duty as well!!  Turn it on at night to get everyone awake so that no one misses out on the clear night.  When its cloudy you can charge extra for kids to climb on it to help make your investment back.\u003c\/p\u003e\u003c\/span\u003e\u003cp\u003e\u003cbr\u003e\u003c\/p\u003e\u003cp\u003e\u003c\/p\u003e","brand":"Ontario Telescope and Accessories","offers":[{"title":"Default Title","offer_id":44013473103983,"sku":"LFF","price":2000000.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/maxresdefault__41014.jpg?v=1766554338"},{"product_id":"field-flattener-for-evoguide-50","title":"Field Flattener for EvoGuide 50","description":"\u003cul data-mce-fragment=\"1\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: transparent; margin-top: 1rem; margin-bottom: 1rem; padding-left: 20px; font-size: 16px; background-color: rgb(255, 255, 255);\"\u003e\n\u003cli data-mce-fragment=\"1\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: transparent;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eCorrects for field curvature, allowing the Evoguide 50ED and 50DX to be used for astrophotography\u003c\/span\u003e\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: transparent;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThread on metal caps\u003c\/span\u003e\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: transparent;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eT-thread connection or 1.25\" opening for camera mounting\u003c\/span\u003e\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: transparent;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003e28mm imaging circle\u003c\/span\u003e\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: transparent;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003e17.5mm back focus\u003c\/span\u003e\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\" style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: transparent;\"\u003e\u003cspan style=\"font-family: Arial;\"\u003e5.33 x 3.57-degree field of view when used with APS-C crop sensor \u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":44013692092527,"sku":"S20214","price":160.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/S20214_Evo50_Flat_web_1800x1800__62760.jpg?v=1766559887"},{"product_id":"starfield-adjustable-1-0x-flattener","title":"Starfield Adjustable 1.0x Flattener","description":"\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003eThe Starfield 1.0x adjustable flattener makes finding the correct back focus easy!  Fighting with adapters is a thing of the past! \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003e\u003cbr style=\"box-sizing: inherit; clear: both;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003eBy setting the adjustment required for your telescope, achieving the correct amount of back focus is simple.  If more adjustment is needed for fine tuning all that is needed is a small twist. If you are using accessories such as filter wheels and rotators you can not still get the required back focus.   Just add up the thickness of all the accessories, plus the distance to your sensor and subtract from 69.87 and then set the reducer to the number that is calculated.\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003e\u003cbr style=\"box-sizing: inherit; clear: both;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003eThe reducer attaches directly to the Starfield telescope focusers.  Using the supplied 1.5mm Allen key, loosen off the three screws a half turn and then unscrew the lock.  \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003e\u003cbr style=\"box-sizing: inherit; clear: both;\"\u003eThread the reducer onto the focuser.   \u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003e\u003cbr style=\"box-sizing: inherit; clear: both;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003eThis Flattener is designed for telescopes ranging from 80mm to 155mm\u003c\/span\u003e\u003c\/p\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cbr\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-family: Helvetica, arial, sans-serif;\"\u003e80 mm \/ focal ratio f\/6 - 81.2 mm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-family: Helvetica, arial, sans-serif;\"\u003e90mm \/ focal ratio f\/6 - 82.5mm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-family: Helvetica, arial, sans-serif;\"\u003e102 mm \/ focal ratio f\/7 - 75.3 mm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-family: Helvetica, arial, sans-serif;\"\u003e115 mm \/ focal ratio f\/7 - 73.0 mm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-family: Helvetica, arial, sans-serif;\"\u003e130 mm \/ focal ratio f\/7 - 69.7 mm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-family: Helvetica, arial, sans-serif;\"\u003e140 mm \/ focal ratio f\/6.5 - 68.0 mm\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-family: Arial;\"\u003e155 mm \/ focal ratio f\/8 - 57.0 mm\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003c\/p\u003e\u003cp style=\"box-sizing: inherit; margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit; font-family: Helvetica, arial, sans-serif;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\u003cp style=\"font-size: 16px; box-sizing: inherit; margin: 0px; font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"box-sizing: inherit;\"\u003eFilters can be added inside the reducer.\u003c\/span\u003e\u003c\/p\u003e","brand":"Starfield","offers":[{"title":"Default Title","offer_id":44013792493679,"sku":"SF-FFA1","price":274.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/SF-FFA1__07764.jpg?v=1766562906"},{"product_id":"explore-scientific-field-flattener-f-5-to-f-7","title":"Explore Scientific Field Flattener f\/5 to f\/7","description":"\u003cul style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); margin-top: 1rem; margin-bottom: 1rem; padding-left: 20px; color: rgb(29, 29, 29); font-family: \" nunito sans sans-serif rgb font-size:=\"\" background-color:=\"\"\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003eThis is a field flattener for refractor-type telescopes with a focal ratio of f\/5 to f\/7\u003c\/li\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003eCauses no change to the telescope focal length\u003c\/li\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003e2-inch barrel to easily attach to a two-inch focuser\u003c\/li\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003eFully multi-coated optics\u003c\/li\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003eT-ring thread on the device so a T-ring can be used to easily attach a DSLR camera or a dedicated astrocamera\u003c\/li\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003e38 mm of clear aperture\u003c\/li\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003eRequires 55mm (+\/-2) of back focus\/spacing between the device and the camera sensor\u003c\/li\u003e\n\u003cli style=\"box-sizing: inherit; -webkit-font-smoothing: antialiased; text-size-adjust: none; -webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"\u003ePremium high glossy anodizing finish\u003c\/li\u003e\n\u003c\/ul\u003e\u003cdiv\u003e\u003cspan style=\"font-family: \" nunito sans sans-serif color: rgb\u003e\u003cdiv\u003eFits the following Explore Scientific telescopes:\u003c\/div\u003e\n\u003cdiv\u003eDAR1020765-01\u003c\/div\u003e\n\u003cdiv\u003eDAR127065-02\u003c\/div\u003e\n\u003cdiv\u003eDAR152065-01\u003c\/div\u003e\n\u003cdiv\u003eES-ED0806-02\u003c\/div\u003e\n\u003cdiv\u003eES-ED10207-02\u003c\/div\u003e\n\u003cdiv\u003eFCD100-0806-01\u003c\/div\u003e\n\u003cdiv\u003eFCD100-10207-02\u003c\/div\u003e\u003c\/span\u003e\u003c\/div\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013865173103,"sku":"ES-FF2F5\/F7","price":193.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/ES-FF2F5_F7__85161.jpg?v=1766564971"},{"product_id":"61edph-iii-full-frame-flattener","title":"61EDPH III Full frame flattener","description":"\u003cp\u003e\u003cspan\u003eThe flattener: One end of the thread is M68 × 1, connected to the focuser; the other end of the thread is M48 × 0.75 and has a built-in 2\" filter thread. The back focus is 55mm. If it needs to be extended, the adapter can be screwed down to reveal the M54 × 0.75 male thread, and the back focus becomes 81.5mm. The flattener adopts a triplet air-spaced structure, the peripheral light reduction control is excellent, can effectively improve the curvature of the field, improve the corner image quality, and reduce aberrations, so that users can take clearer astronomical photos.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cimg src=\"https:\/\/omo-oss-image.thefastimg.com\/portal-saas\/new2022072923460240318\/cms\/image\/c4cced6a-b648-40dc-88e0-86640123b2ee.jpg\"\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Sharpstar","offers":[{"title":"Default Title","offer_id":44013898793071,"sku":"61EDPHIII-F","price":317.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/61EDPH_III_flatener_1__43589.png?v=1766565957"},{"product_id":"160apo-1x-full-frame-flattener","title":"160APO 1x Full-frame Flattener","description":"\u003cp\u003e\u003cspan\u003eThe Askar 160 APO comes with three optional premium accessories, a 1.0x flattener and a 0.8x reducer. Introduced here is the 1.0x flattener, which is optimized for the Askar 160APO, and can provide more possibilities for telescope use.\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv id=\"ie_fimg-1736818366331\" class=\"ie_fimg\"\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/omo-oss-image.thefastimg.com\/portal-saas\/pg2024111409483993253\/cms\/image\/c143bdb5-29f0-4174-ba8f-6b526dcf3732.jpg\" alt=\"长友气体\"\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv id=\"ie_line-1736818366581\" class=\"ie_line\"\u003e\n\u003cdiv\u003e \u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv id=\"ie_text-1736818366586\" class=\"reset_style\"\u003e\n\u003cdiv\u003e\n\u003cp\u003e\u003cspan\u003eThe 1.0x flattener does not change the telescope's focal ratio itself. After connecting with the Askar 160APO, it still maintained a focal ratio of 7. The flattener corrects field curvature and coma, resulting in flatter field edges and finer star points.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe 1.0x flattener adopts a triplet design and supports a 44mm full-frame image circle.  The back focus from the M48 thread is a standard 55mm. The front thread is M92*1. At the camera end, it is equipped with M68*1, M54*0.75, and M48*0.75 three sizes of adapters, which are convenient for connection. At the same time, it has a built-in M48*0.75 2-inch filter thread, which can be directly installed and used. The overall CNC machined, both end threaded metal caps prevent ash when not in use.\u003c\/span\u003e\u003c\/p\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable width=\"84.20%\" cellspacing=\"0\" align=\"center\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\"\u003e\n\u003cp\u003e\u003cstrong\u003e1x Flattener Size Diagram\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003cp\u003e\u003cimg class=\"image_resized\" src=\"https:\/\/omo-oss-image.thefastimg.com\/portal-saas\/pg2024111409483993253\/cms\/image\/d9b2c108-4323-4eef-9ba7-2fd468ea243c.jpg\" alt=\"长友气体\"\u003e\u003c\/p\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable width=\"84.20%\" cellspacing=\"0\" align=\"center\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\"\u003e\n\u003cp\u003e\u003cstrong\u003e1x Flattener Installation\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003cp\u003e\u003cimg class=\"image_resized\" src=\"https:\/\/omo-oss-image.thefastimg.com\/portal-saas\/pg2024111409483993253\/cms\/image\/6fac3c9d-95bd-414a-83dd-4ad887ac02bf.jpg\" alt=\"长友气体\"\u003e\u003c\/p\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable width=\"84.20%\" cellspacing=\"0\" align=\"center\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"3\"\u003e\n\u003cp\u003e\u003cstrong\u003eSpot Diagram\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003cp\u003e\u003cimg class=\"image_resized\" src=\"https:\/\/omo-oss-image.thefastimg.com\/portal-saas\/pg2024111409483993253\/cms\/image\/850a58d0-a499-44f1-a227-16642dce87c5.jpg\" alt=\"长友气体\"\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":44014108541039,"sku":"ASK-Flat-APO-160","price":477.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/36dcdff4-2634-48ac-baae-73f8f7cb8932__39041.png?v=1766571594"},{"product_id":"william-optics-flat-61a-field-flattener","title":"William Optics FLAT 61A Field Flattener","description":"\u003cp\u003eThe \u003cstrong\u003eWilliam Optics FLAT 61A\u003c\/strong\u003e is a 1.0x field flattener designed to improve edge-to-edge star sharpness when imaging with compatible William Optics refractors, especially the Zenithstar 61. It helps correct field curvature so astrophotographers can capture cleaner stars across APS-C and full-frame camera sensors.\u003c\/p\u003e\u003ch2\u003eWho Is This Product Best For?\u003c\/h2\u003e\u003cp\u003eThe FLAT 61A is best for astrophotographers using a Zenithstar 61 or compatible small William Optics refractor who want a flatter imaging field for deep-sky photography.\u003c\/p\u003e\u003ch2\u003eWhy Choose This Product?\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.0x correction:\u003c\/strong\u003e Flattens the field without reducing focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAPS-C and full-frame support:\u003c\/strong\u003e Designed for common astronomy and DSLR\/mirrorless camera setups.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCamera adapter support:\u003c\/strong\u003e Uses an M48 camera-side thread and supports common T-mount ecosystems.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eWide-field deep-sky astrophotography\u003c\/li\u003e\n\u003cli\u003eImproving star shape at the edge of the frame\u003c\/li\u003e\n\u003cli\u003eZenithstar 61 imaging setups\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eUse the recommended back focus spacing for your telescope and camera. Customers should confirm camera adapter, T-ring, and spacing requirements before imaging.\u003c\/p\u003e\u003ch2\u003eImportant Limitations\u003c\/h2\u003e\u003cp\u003eThis is an imaging accessory, not a visual observing accessory. Correct spacing is required for best results.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003ch3\u003eDoes the FLAT 61A reduce focal length?\u003c\/h3\u003e\u003cp\u003eNo. It is a 1.0x field flattener.\u003c\/p\u003e\u003ch3\u003eWhich telescope is it mainly for?\u003c\/h3\u003e\u003cp\u003eIt is primarily intended for Zenithstar 61 imaging systems.\u003c\/p\u003e\u003ch2\u003eOur Recommendation\u003c\/h2\u003e\u003cp\u003eChoose the FLAT 61A if you image with a Zenithstar 61 and want cleaner corner stars without changing the telescope’s focal length.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":53154238627951,"sku":"P-FLAT61A","price":384.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/william-optics-flat-61a.jpg?v=1779654739"},{"product_id":"william-optics-flat-gt-field-flattener","title":"William Optics FLAT GT Field Flattener","description":"\u003cp\u003eThe \u003cstrong\u003eWilliam Optics FLAT GT\u003c\/strong\u003e is a 1.0x field flattener for compatible Gran Turismo refractors, designed to improve edge-to-edge star sharpness without reducing focal length.\u003c\/p\u003e\u003ch2\u003eWho Is This Product Best For?\u003c\/h2\u003e\u003cp\u003eBest for astrophotographers using compatible William Optics GT refractors who want a flatter imaging field for deep-sky photography.\u003c\/p\u003e\u003ch2\u003eWhy Choose This Product?\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.0x correction:\u003c\/strong\u003e Keeps the telescope focal length unchanged.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField flattening:\u003c\/strong\u003e Improves corner star shape.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGT compatibility:\u003c\/strong\u003e Designed for compatible Gran Turismo refractor setups.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eDeep-sky astrophotography\u003c\/li\u003e\n\u003cli\u003eGT refractor imaging setups\u003c\/li\u003e\n\u003cli\u003eImproving corner stars\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eConfirm telescope compatibility, camera adapter, and required backfocus spacing before imaging.\u003c\/p\u003e\u003ch2\u003eImportant Limitations\u003c\/h2\u003e\u003cp\u003eThis is an imaging accessory and requires correct spacing for best results.\u003c\/p\u003e\u003ch2\u003eOur Recommendation\u003c\/h2\u003e\u003cp\u003eChoose the FLAT GT when your compatible GT refractor needs field correction without focal reduction.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":53154240954479,"sku":"P-FLAT-GT","price":361.2,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/william-optics-flat-gt.jpg?v=1779654768"},{"product_id":"william-optics-flat-73a-field-flattener","title":"William Optics FLAT 73A Field Flattener","description":"\u003cp\u003eThe \u003cstrong\u003eWilliam Optics FLAT 73A\u003c\/strong\u003e is a 1.0x field flattener designed for compatible William Optics refractors, especially Zenithstar 73 imaging systems. It helps correct field curvature so astrophotographers can capture sharper stars from the centre to the edge of the frame.\u003c\/p\u003e\u003ch2\u003eWho Is This Product Best For?\u003c\/h2\u003e\u003cp\u003eBest for astrophotographers using a compatible William Optics refractor who want improved corner star performance without reducing focal length.\u003c\/p\u003e\u003ch2\u003eWhy Choose This Product?\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.0x correction:\u003c\/strong\u003e Keeps the telescope focal length unchanged.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField flattening:\u003c\/strong\u003e Helps improve edge-to-edge star shape.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging accessory:\u003c\/strong\u003e Designed for camera-based deep-sky astrophotography.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eZenithstar 73 astrophotography\u003c\/li\u003e\n\u003cli\u003eWide-field deep-sky imaging\u003c\/li\u003e\n\u003cli\u003eImproving corner star sharpness\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eConfirm telescope compatibility, adapter requirements, and camera backfocus spacing before imaging.\u003c\/p\u003e\u003ch2\u003eImportant Limitations\u003c\/h2\u003e\u003cp\u003eThis is an imaging accessory and requires correct spacing for best results.\u003c\/p\u003e\u003ch2\u003eOur Recommendation\u003c\/h2\u003e\u003cp\u003eChoose the FLAT 73A if your compatible William Optics refractor needs field correction without focal reduction.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":53154242265199,"sku":"P-FLAT73A","price":384.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/william-optics-flat-73a.jpg?v=1779654781"},{"product_id":"william-optics-flat-68iii-field-flattener","title":"William Optics FLAT 68III Field Flattener","description":"\u003cp\u003eThe \u003cstrong\u003eWilliam Optics FLAT 68III\u003c\/strong\u003e is a premium 1.0x field flattener for compatible William Optics refractors and full-frame astrophotography systems. It is designed to correct field curvature and improve star shape across large camera sensors without reducing focal length.\u003c\/p\u003e\u003ch2\u003eWho Is This Product Best For?\u003c\/h2\u003e\u003cp\u003eBest for astrophotographers using compatible William Optics refractors who want full-frame field correction while keeping the telescope’s native focal length.\u003c\/p\u003e\u003ch2\u003eWhy Choose This Product?\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.0x correction:\u003c\/strong\u003e Maintains native focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull-frame imaging support:\u003c\/strong\u003e Designed for larger camera sensors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField flattening:\u003c\/strong\u003e Helps improve edge-to-edge star quality.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eFull-frame deep-sky astrophotography\u003c\/li\u003e\n\u003cli\u003eCompatible William Optics refractor imaging\u003c\/li\u003e\n\u003cli\u003eImproving corner star shape\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eConfirm your telescope model, adapter requirements, camera thread, and backfocus spacing before imaging.\u003c\/p\u003e\u003ch2\u003eImportant Limitations\u003c\/h2\u003e\u003cp\u003eThis is an imaging accessory and correct spacing is required for best results.\u003c\/p\u003e\u003ch2\u003eOur Recommendation\u003c\/h2\u003e\u003cp\u003eChoose the FLAT 68III when you need premium full-frame field correction without focal reduction.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":53154242658415,"sku":"P-FLAT68III","price":1087.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/william-optics-flat-68iii.jpg?v=1779654796"},{"product_id":"william-optics-30mm-flattener-adapter","title":"William Optics 30mm Flattener Adapter","description":"\u003cp\u003eThe \u003cstrong\u003eWilliam Optics 30mm Flattener Adapter\u003c\/strong\u003e is a mechanical spacing adapter used to configure compatible William Optics flatteners, reducers, and camera systems for astrophotography.\u003c\/p\u003e\u003ch2\u003eWho Is This Product Best For?\u003c\/h2\u003e\u003cp\u003eBest for astrophotographers who need a 30mm extension adapter to complete the correct camera spacing in a William Optics imaging train.\u003c\/p\u003e\u003ch2\u003eWhy Choose This Product?\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e30mm spacing:\u003c\/strong\u003e Helps achieve the required mechanical distance.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging train support:\u003c\/strong\u003e Useful for flattener and reducer setups.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWilliam Optics compatibility:\u003c\/strong\u003e Designed for compatible WO accessories.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eCamera spacing\u003c\/li\u003e\n\u003cli\u003eFlattener\/reducer setup\u003c\/li\u003e\n\u003cli\u003eDeep-sky astrophotography accessories\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eConfirm your telescope, reducer\/flattener, camera-side thread, and backfocus requirements before purchase.\u003c\/p\u003e\u003ch2\u003eImportant Limitations\u003c\/h2\u003e\u003cp\u003eThis is a mechanical adapter only and does not provide optical correction by itself.\u003c\/p\u003e\u003ch2\u003eOur Recommendation\u003c\/h2\u003e\u003cp\u003eChoose this adapter when your William Optics imaging setup requires a 30mm spacing adapter.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":53154250752111,"sku":"AD-M80TOM54","price":80.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/william-optics-30mm-flattener-adapter.jpg?v=1779655087"},{"product_id":"sky-watcher-esprit-100edx-field-flattener","title":"Sky-Watcher Esprit 100EDX Field Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Esprit 100EDX Flattener is Sky-Watcher's dedicated field corrector for the Esprit 100EDX super apochromatic refractor. A fast triplet objective focuses onto a gently curved surface; a camera sensor is flat. The flattener resolves that mismatch, so stars hold their shape out to the frame edges instead of drawing short radial streaks in the corners while the centre of the frame stays sharp.\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes a 44 mm corrected image circle for this corrector. That encloses the 43.3 mm diagonal of a full-frame sensor and covers APS-C with margin to spare, so framing choices are driven by focal length rather than by how much of the sensor the corrector reaches. On the Esprit 100EDX — published by Sky-Watcher as 100 mm aperture, 550 mm focal length, f\/5.5, FPL-53 triplet — that is a wide, fast field with corners that hold up.\u003c\/p\u003e\n\u003cp\u003eOne name to keep straight: this part is published for the \u003cstrong\u003eEsprit\u003c\/strong\u003e 100EDX, the super-apochromatic triplet. The \u003cstrong\u003eEvostar\u003c\/strong\u003e 100EDX doublet is served by a different corrector (S20216, which also covers the Esprit 70EDX).\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is the corrector Sky-Watcher pairs with the Esprit 100EDX, and it is the right part if you own that telescope and want flat, round stars across a large sensor at the scope's native focal length and ratio.\u003c\/p\u003e\n\u003cp\u003eIt suits deep-sky imagers working at the 100EDX's native 550 mm — large nebulae, open clusters, mid-size galaxy fields and mosaic panels — where the goal is a clean frame edge to edge rather than a shorter, faster field from a reducing corrector.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched to the Esprit 100EDX:\u003c\/strong\u003e Sky-Watcher publishes compatibility with the Esprit 100EDX specifically. The correction is computed for that objective rather than sold as a universal flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm corrected image circle:\u003c\/strong\u003e the published figure covers a full-frame sensor's 43.3 mm diagonal and leaves APS-C well inside the corrected zone.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlattening only:\u003c\/strong\u003e Sky-Watcher publishes no reduction factor for this corrector, so the telescope's native 550 mm and f\/5.5 carry through it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSingle-piece corrector:\u003c\/strong\u003e one optic in the imaging train between focuser and camera, with no separate elements to align.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat it corrects:\u003c\/strong\u003e field curvature across the imaging field of the Esprit 100EDX. The visible symptom it removes is corner stars that elongate radially, pointing away from the frame centre, while the middle of the frame focuses cleanly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrected image circle:\u003c\/strong\u003e 44 mm, as published by Sky-Watcher. Sensor coverage follows directly from that number — a full-frame sensor measures 43.3 mm corner to corner and an APS-C sensor roughly 28 mm, so both sit inside the corrected field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eResulting focal length and focal ratio:\u003c\/strong\u003e Sky-Watcher publishes no reduction factor and no altered figures, consistent with a flattener that works at native focal length. The Esprit 100EDX's published 550 mm and f\/5.5 are what you image at with this part in the train. At 550 mm across a 44 mm circle, a full-frame sensor takes in roughly three and a half degrees on the long axis, which is why this pairing suits large targets and mosaic work.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRequired backfocus and thread interface:\u003c\/strong\u003e Sky-Watcher does not publish a backfocus distance in millimetres or a thread size for this corrector on its product page, and no manual or datasheet is linked there. Those two numbers determine how the corrector spaces to your sensor, and corner star shape is what depends on getting the spacing right. Send us your camera, filter drawer or filter wheel and any adapters and we will lay the train out with you before you order.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky astrophotography at native focal length:\u003c\/strong\u003e large emission nebulae, open clusters, mid-size galaxy fields and star fields at 550 mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLarge-sensor imaging:\u003c\/strong\u003e the 44 mm circle supports full-frame and APS-C cameras, including cooled astronomical CMOS bodies in those formats.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMosaic panels:\u003c\/strong\u003e flat corners let adjacent panels blend without a ring of distorted stars at every seam.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrowband and broadband alike:\u003c\/strong\u003e field curvature is a geometric error, so the correction applies regardless of the filter in front of the sensor.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eSky-Watcher lists one compatible telescope: the Esprit 100EDX. Their EDX correctors are published tube by tube — S20216 covers the Esprit 70EDX and the Evostar 100EDX, S20218 the Esprit 120EDX, S20219 the Esprit 150EDX — and refractors from other makers pair with their own. Tell us the exact model printed on your tube and we will confirm which corrector belongs on it.\u003c\/p\u003e\n\u003cp\u003eThe vendor does not publish the thread interface or the spacing distance to the sensor, so the adapters between this corrector and your camera cannot be specified from published data. Send us your camera model, filter wheel or drawer, and any off-axis guider in the train, and we will map the imaging train and tell you exactly what sits between the two.\u003c\/p\u003e\n\u003cp\u003eNothing about this part changes the mount side of the setup: it adds a short optic and roughly a pound behind the focuser rather than changing how the telescope mounts.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus is not published.\u003c\/strong\u003e Sky-Watcher gives no spacing figure in millimetres for this corrector. Corner star shape depends on hitting the correct sensor distance, and we can work that out with you from your specific camera and adapters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread interface is not published.\u003c\/strong\u003e No thread size appears on the vendor page, so the camera-side connection is confirmed case by case rather than assumed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEsprit 100EDX, not Evostar 100EDX.\u003c\/strong\u003e The two share a 100 mm aperture and a similar name but take different correctors; the Evostar doublet is covered by S20216.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a flattener, not a reducer.\u003c\/strong\u003e No reduction factor is published, so focal length and focal ratio stay at the telescope's native values.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBox contents are not published.\u003c\/strong\u003e The vendor states no spacer, adapter or case as supplied with the corrector.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight figure is the vendor's shipping weight.\u003c\/strong\u003e Sky-Watcher lists 1.0 lb for this item and publishes no separate optic-only mass in a specification table.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVendor image note.\u003c\/strong\u003e Sky-Watcher states \"Images subject to change\" on this listing, which is normal for a recently released part.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003ePhysically it is one optic that goes into the imaging train between the focuser and the camera, and it stays there. The part that takes attention is the spacing to the sensor, which Sky-Watcher does not publish for this corrector. Send us the camera and adapters you plan to use and we will lay out the train for you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it change the focal length or focal ratio?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes no reduction factor, resulting focal length, or resulting focal ratio for this corrector. It flattens the field at the telescope's native 550 mm and f\/5.5.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it cover my full-frame camera?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe published corrected image circle is 44 mm and a full-frame sensor measures 43.3 mm across the diagonal, so the sensor sits inside the corrected field. APS-C sits well inside it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eI have an Evostar 100EDX — is this the one?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. The Evostar 100EDX doublet is published against S20216, the corrector shared with the Esprit 70EDX. This part is published for the Esprit 100EDX triplet. Send us the model printed on your tube and we will match it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it fit the earlier Esprit 100ED?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes compatibility only with the Esprit 100EDX for this part. Earlier Esprit models have their own correctors in the range. Send us the model on your tube and we will confirm which one applies.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat weight does it add to the imaging train?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher lists 1.0 lb for this item. It is a small addition behind the focuser next to the camera, filters and any guider.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eA dedicated flattener for the Esprit 100EDX with a published 44 mm corrected circle — enough to keep stars round across a full-frame sensor at the telescope's native 550 mm and f\/5.5. Sky-Watcher leaves the backfocus and thread figures unpublished, so we confirm the spacing with you against your own camera and adapters and send it out ready to drop into the train.\u003c\/p\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":53896756691055,"sku":"S20217","price":330.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/100_2.jpg?v=1785253569"},{"product_id":"sky-watcher-esprit-120edx-field-flattener","title":"Sky-Watcher Esprit 120EDX Field Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Esprit 120EDX Flattener is Sky-Watcher's dedicated field corrector for the Esprit 120EDX super apochromatic refractor. A fast triplet objective focuses onto a gently curved surface; a camera sensor is flat. The flattener resolves that mismatch so stars hold their shape out to the frame edges instead of drawing short radial streaks in the corners while the centre stays sharp.\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes a 44 mm corrected image circle for this corrector. That encloses the 43.3 mm diagonal of a full-frame sensor and covers APS-C with margin to spare, so framing choices are driven by focal length rather than by how much of the sensor the corrector reaches.\u003c\/p\u003e\n\u003cp\u003eThis is a flattener, not a reducer. Sky-Watcher publishes no reduction factor and no altered focal length or focal ratio for it, so the Esprit 120EDX images at its native figures with this part in the train. The 0.77x Reducer\/Flattener for the Esprit 120 (S20209) is a separate optic with a different prescription.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is the corrector Sky-Watcher pairs with the Esprit 120EDX, and it is the right part if you own that telescope and want flat, round stars across a large sensor at the scope's native focal length \u0026amp; ratio.\u003c\/p\u003e\n\u003cp\u003eIt suits deep-sky imagers who want the full native image scale — galaxies, globular clusters, planetary nebulae, small to mid-size emission targets — rather than the wider, faster field a reducing corrector produces. If your priority is shorter exposures and a wider frame, the 0.77x reducer\/flattener for the Esprit line is the part built for that job.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched to the Esprit 120EDX:\u003c\/strong\u003e Sky-Watcher publishes compatibility with the Esprit 120EDX specifically. The correction is computed for that objective rather than sold as a universal flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm corrected image circle:\u003c\/strong\u003e the published figure covers a full-frame sensor's 43.3 mm diagonal and leaves APS-C well inside the corrected zone.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlattening only:\u003c\/strong\u003e no published reduction factor, so the telescope's native focal length and focal ratio carry through the corrector.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSingle-piece corrector:\u003c\/strong\u003e one optic in the imaging train between focuser and camera, with no separate elements to align.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat it corrects:\u003c\/strong\u003e field curvature across the imaging field of the Esprit 120EDX. The visible symptom it removes is corner stars that elongate radially, pointing away from the frame centre, while the middle of the frame focuses cleanly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrected image circle:\u003c\/strong\u003e 44 mm, as published by Sky-Watcher. Sensor coverage follows directly from that number — a full-frame sensor measures 43.3 mm corner to corner and an APS-C sensor roughly 28 mm, so both sit inside the corrected field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eResulting focal length and focal ratio:\u003c\/strong\u003e Sky-Watcher publishes none, consistent with a flattener that works at native focal length. We publish only what they publish, so no altered figures appear here.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRequired backfocus and thread interface:\u003c\/strong\u003e Sky-Watcher does not publish a backfocus distance in millimetres or a thread size for this corrector on its product page, and no manual or datasheet is linked there. Those two numbers determine how the corrector spaces to your camera, so send us your camera, filter drawer and any adapters and we will work the train out with you before you order.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky astrophotography at native focal length:\u003c\/strong\u003e galaxies, globular clusters, planetary nebulae and compact emission regions where image scale matters more than field width.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLarge-sensor imaging:\u003c\/strong\u003e the 44 mm circle supports full-frame and APS-C cameras, including cooled astronomical CMOS bodies in those formats.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMosaic panels:\u003c\/strong\u003e flat corners let adjacent panels blend without a ring of distorted stars at every seam.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrowband and broadband alike:\u003c\/strong\u003e field curvature is a geometric error, so the correction applies regardless of the filter in front of the sensor.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eSky-Watcher lists one compatible telescope: the Esprit 120EDX. Other Esprit models — including the earlier Esprit 120ED — have their own correctors in Sky-Watcher's range, and refractors from other makers pair with their own. Tell us the exact model on your tube and we will confirm which corrector belongs on it.\u003c\/p\u003e\n\u003cp\u003eThe vendor does not publish the thread interface or the spacing distance to the sensor, so the adapters between this corrector and your camera cannot be specified from published data. Send us your camera model, filter wheel or drawer, and any off-axis guider in the train, and we will map the imaging train and tell you exactly what sits between the two.\u003c\/p\u003e\n\u003cp\u003eNothing about this part changes the mount side of the setup: it adds a short optic and roughly a pound behind the focuser rather than changing how the telescope mounts.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus is not published.\u003c\/strong\u003e Sky-Watcher gives no spacing figure in millimetres for this corrector. Corner star shape depends on hitting the correct sensor distance, and we can work that out with you from your specific camera and adapters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread interface is not published.\u003c\/strong\u003e No thread size appears on the vendor page, so the camera-side connection is confirmed case by case rather than assumed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished for the Esprit 120EDX.\u003c\/strong\u003e The 44 mm figure is stated for that telescope and is not carried across to other models.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a flattener, not a reducer.\u003c\/strong\u003e Focal length and focal ratio stay at the telescope's native values; the separate 0.77x reducer\/flattener is the part that changes them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight figure is the vendor's shipping weight.\u003c\/strong\u003e Sky-Watcher lists 1.0 lb for this item and publishes no separate optic-only mass in a specification table.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVendor image note.\u003c\/strong\u003e Sky-Watcher states \"Images subject to change\" on this listing, which is normal for a recently released part.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003ePhysically it is one optic that goes into the imaging train between the focuser and the camera, and it stays there. The part that takes attention is the spacing to the sensor, which Sky-Watcher does not publish for this corrector. Send us the camera and adapters you plan to use and we will lay out the train for you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it change the focal length or focal ratio?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes no reduction factor, resulting focal length, or resulting focal ratio for this corrector. It flattens the field at the telescope's native figures. The 0.77x Reducer\/Flattener is the part that shortens focal length and speeds the ratio.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it cover my full-frame camera?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe published corrected image circle is 44 mm and a full-frame sensor measures 43.3 mm across the diagonal, so the sensor sits inside the corrected field. APS-C sits well inside it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it fit the Esprit 120ED rather than the 120EDX?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes compatibility only with the Esprit 120EDX for this part. The Esprit 120ED has its own correctors in the range, including a 0.77x reducer\/flattener. Send us the model printed on your tube and we will match it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat weight does it add to the imaging train?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher lists 1.0 lb for this item. It is a small addition behind the focuser next to the camera, filters and any guider.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eA dedicated flattener for the Esprit 120EDX with a published 44 mm corrected circle — enough to keep stars round across a full-frame sensor at the telescope's native focal length. Sky-Watcher leaves the backfocus and thread figures unpublished, so we confirm the spacing with you against your own camera and adapters and send it out ready to drop into the train.\u003c\/p\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":53896761639023,"sku":"S20218","price":440.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/120FieldCorrector_2_5fc66d00-f553-4b84-8181-6c6d16fc7c32.jpg?v=1785253650"},{"product_id":"sky-watcher-esprit-150edx-field-flattener","title":"Sky-Watcher Esprit 150EDX Field Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Esprit 150EDX Flattener is Sky-Watcher's dedicated field corrector for the Esprit 150EDX super apochromatic refractor. The objective brings light to focus on a slightly curved surface while a camera sensor is flat, and that difference is what turns corner stars into short radial streaks while the centre of the frame is pinpoint. This corrector sits in the imaging train and flattens the focal surface onto the sensor plane.\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes a 44 mm corrected image circle for it. A full-frame sensor measures 43.3 mm across the diagonal, so the corrected field encloses full-frame and leaves an APS-C sensor comfortably inside it.\u003c\/p\u003e\n\u003cp\u003eThis part flattens; it does not reduce. Sky-Watcher publishes no reduction factor, no altered focal length and no altered focal ratio for it, so the Esprit 150EDX images at its native figures with this corrector in place. The 0.77x Reducer\/Flattener for the Esprit 150 (S20215) is a separate optic built for the opposite job.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is the corrector Sky-Watcher pairs with the Esprit 150EDX, so it is the right part if you own that telescope and want flat, round stars across a large sensor at the scope's native focal length \u0026amp; ratio.\u003c\/p\u003e\n\u003cp\u003eThe Esprit 150 is the longest tube in the line, and the reason to flatten rather than reduce is image scale: galaxy detail, globular cluster cores, planetary nebulae and small emission knots all benefit from keeping every millimetre of native focal length. If a wider, faster field is what you are after instead, the 0.77x reducer\/flattener for the Esprit 150 is the part built for that.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched to the Esprit 150EDX:\u003c\/strong\u003e Sky-Watcher publishes compatibility with the Esprit 150EDX specifically, so the correction is figured for that objective rather than sold as a universal flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm corrected image circle:\u003c\/strong\u003e covers a full-frame sensor's 43.3 mm diagonal and places APS-C well inside the corrected zone.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlattening only:\u003c\/strong\u003e with no published reduction factor, the telescope's native focal length and focal ratio carry straight through.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSingle optic in the train:\u003c\/strong\u003e one corrector between focuser and camera, with no separate elements to align against each other.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat it corrects:\u003c\/strong\u003e field curvature across the Esprit 150EDX imaging field. The symptom it removes is radial elongation of stars toward the frame corners while the centre focuses cleanly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrected image circle:\u003c\/strong\u003e 44 mm, as published by Sky-Watcher. Sensor coverage follows from that figure — full-frame spans 43.3 mm corner to corner and APS-C roughly 28 mm, so both fall inside the corrected field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eResulting focal length and focal ratio:\u003c\/strong\u003e Sky-Watcher publishes neither, which is consistent with a flattener that works at native focal length. Only published figures appear here, so no altered numbers are given.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRequired backfocus and thread interface:\u003c\/strong\u003e the vendor product page carries no backfocus distance in millimetres and no thread size, and links no manual or datasheet. Those two figures set how the corrector spaces to the sensor, so send us your camera, filter drawer or wheel and any adapters and we will work the spacing out with you.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky astrophotography at native focal length:\u003c\/strong\u003e galaxies, globular clusters, planetary nebulae and compact nebular detail, where the Esprit 150's image scale is the point.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLarge-sensor imaging:\u003c\/strong\u003e the 44 mm circle supports full-frame and APS-C cameras, including cooled astronomical CMOS bodies in those formats.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMosaics:\u003c\/strong\u003e flat corners let adjacent panels stitch without a ring of distorted stars at each seam.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrowband and broadband:\u003c\/strong\u003e field curvature is geometric, so the correction holds whatever filter is in front of the sensor.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eSky-Watcher lists one compatible telescope for this corrector: the Esprit 150EDX. The earlier Esprit 150ED and the other tubes in the range have their own correctors, and refractors from other makers pair with theirs. Send us the exact model printed on your tube and we will confirm which corrector belongs on it.\u003c\/p\u003e\n\u003cp\u003eBecause the thread interface and sensor spacing are not published, the adapter stack between this corrector and your camera cannot be specified from vendor data alone. Tell us your camera model, filter wheel or drawer, and any off-axis guider, and we will map the imaging train and tell you exactly what sits where.\u003c\/p\u003e\n\u003cp\u003eOn the mount side nothing changes: this adds a short optic and roughly a pound behind the focuser rather than altering how the telescope rides.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus is not published.\u003c\/strong\u003e Sky-Watcher gives no spacing figure in millimetres for this corrector. Corner star shape depends on hitting the correct sensor distance, and we can work that out with you from your camera and adapters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread interface is not published.\u003c\/strong\u003e No thread size appears on the vendor page, so the camera-side connection is confirmed case by case.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished for the Esprit 150EDX.\u003c\/strong\u003e The 44 mm figure is stated for that telescope and is not carried across to other models.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a flattener, not a reducer.\u003c\/strong\u003e Focal length and focal ratio stay at the telescope's native values; the separate 0.77x reducer\/flattener is the part that changes them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight figure is the vendor's shipping weight.\u003c\/strong\u003e Sky-Watcher lists 1.0 lb for this item and publishes no separate optic-only mass in a specification table.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVendor image note.\u003c\/strong\u003e Sky-Watcher states \"Images subject to change\" on this listing, which is usual for a recently released part.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt is one optic that installs between the focuser and the camera and then stays there. The element that takes attention is the spacing to the sensor, which Sky-Watcher does not publish for this corrector. Send us the camera and adapters you plan to use and we will lay the train out for you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it change the focal length or focal ratio?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes no reduction factor, resulting focal length or resulting focal ratio for it. It flattens the field at the telescope's native figures. The 0.77x Reducer\/Flattener is the part that shortens focal length and speeds the ratio.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it cover my full-frame camera?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe published corrected image circle is 44 mm and a full-frame sensor measures 43.3 mm on the diagonal, so the sensor sits inside the corrected field. APS-C sits well inside it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it fit the Esprit 150ED rather than the 150EDX?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes compatibility only with the Esprit 150EDX for this part. The Esprit 150ED has its own correctors in the range, including a 0.77x reducer\/flattener. Send us the model on your tube and we will match it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much does it add to the imaging train?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher lists 1.0 lb for this item — a small addition behind the focuser alongside the camera, filters and any guider.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe dedicated flattener for the Esprit 150EDX, with a published 44 mm corrected circle that keeps stars round across a full-frame sensor at the telescope's native focal length. Sky-Watcher leaves backfocus and thread figures unpublished, so we confirm the spacing against your own camera and adapters and send it out ready to drop into the train.\u003c\/p\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":53896765112431,"sku":"S20219","price":550.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/150_2.jpg?v=1785253731"},{"product_id":"sky-watcher-esprit-70edx-evostar-100edx-field-flattener","title":"Sky-Watcher Esprit 70EDX \/ Evostar 100EDX Field Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is Sky-Watcher's dedicated field corrector for two telescopes: the Esprit 70EDX and the Evostar 100EDX. A refractor objective brings light to focus on a gently curved surface; a camera sensor is flat. The flattener resolves that mismatch, so stars hold their shape out to the frame edges instead of drawing short radial streaks in the corners while the centre stays sharp.\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes it as a 1.0X flattener with a 44 mm corrected image circle. The 1.0X figure means it corrects without reducing: focal length and focal ratio stay at the telescope's native values. The 44 mm circle encloses the 43.3 mm diagonal of a full-frame sensor and covers APS-C with margin to spare, so framing decisions come down to focal length rather than to how much of the sensor the corrector actually reaches.\u003c\/p\u003e\n\u003cp\u003eThe dual fitment is worth reading carefully, because Sky-Watcher's naming runs close together here. This part is published for the \u003cstrong\u003eEvostar\u003c\/strong\u003e 100EDX — the ED doublet. The \u003cstrong\u003eEsprit\u003c\/strong\u003e 100EDX, the super-apochromatic triplet, has its own corrector (S20217).\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is the corrector Sky-Watcher pairs with the Esprit 70EDX and the Evostar 100EDX, and it is the right part if you own either telescope and want flat, round stars across a large sensor at the scope's native focal length and ratio.\u003c\/p\u003e\n\u003cp\u003eOn the Esprit 70EDX — published by Sky-Watcher as 70 mm aperture, 455 mm focal length, f\/6.5 — that means very wide fields with corners that hold up: large emission nebulae, star fields, comets, mosaics. On the Evostar 100EDX doublet it means a longer-focal-length field with the same corner correction across a full-frame sensor.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMatched to two telescopes:\u003c\/strong\u003e Sky-Watcher publishes compatibility with the Esprit 70EDX and the Evostar 100EDX. The correction is computed for those objectives rather than sold as a universal flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.0X flattener:\u003c\/strong\u003e no reduction. The telescope's native focal length and focal ratio carry through the corrector unchanged.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm corrected image circle:\u003c\/strong\u003e the published figure covers a full-frame sensor's 43.3 mm diagonal and leaves APS-C well inside the corrected zone.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSingle-piece corrector:\u003c\/strong\u003e one optic in the imaging train between focuser and camera, with no separate elements to align.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOne part for a triplet and a doublet:\u003c\/strong\u003e Sky-Watcher publishes the same corrector against the 70 mm Esprit triplet and the 100 mm Evostar doublet, so a two-telescope setup built from those models needs one flattener rather than two.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat it corrects:\u003c\/strong\u003e field curvature across the imaging field of the Esprit 70EDX and the Evostar 100EDX. The visible symptom it removes is corner stars that elongate radially, pointing away from the frame centre, while the middle of the frame focuses cleanly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrected image circle:\u003c\/strong\u003e 44 mm, as published by Sky-Watcher. Sensor coverage follows directly from that number — a full-frame sensor measures 43.3 mm corner to corner and an APS-C sensor roughly 28 mm, so both sit inside the corrected field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMagnification factor:\u003c\/strong\u003e 1.0X. Sky-Watcher publishes no reduction, so the Esprit 70EDX continues to image at its published 455 mm and f\/6.5 with this part in the train, and the Evostar 100EDX at its own native figures.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRequired backfocus and thread interface:\u003c\/strong\u003e Sky-Watcher does not publish a backfocus distance in millimetres or a thread size for this corrector on its product page, and no manual or datasheet is linked there. Those two numbers determine how the corrector spaces to your sensor, and corner star shape is what depends on getting the spacing right. Send us your camera, filter drawer or filter wheel and any adapters and we will lay the train out with you before you order.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field deep-sky astrophotography:\u003c\/strong\u003e on the Esprit 70EDX at 455 mm, large emission nebulae, open clusters, comets and star fields fill the frame with corners that stay clean.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLonger-focal-length imaging on the Evostar 100EDX:\u003c\/strong\u003e the same corner correction applied to the doublet's field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLarge-sensor imaging:\u003c\/strong\u003e the 44 mm circle supports full-frame and APS-C cameras, including cooled astronomical CMOS bodies in those formats.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMosaic panels:\u003c\/strong\u003e flat corners let adjacent panels blend without a ring of distorted stars at every seam.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrowband and broadband alike:\u003c\/strong\u003e field curvature is a geometric error, so the correction applies regardless of the filter in front of the sensor.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eSky-Watcher lists two compatible telescopes for this corrector: the Esprit 70EDX and the Evostar 100EDX. The name similarity across their range is the thing to watch — the Esprit 100EDX triplet takes S20217, the Esprit 120EDX takes S20218 and the Esprit 150EDX takes S20219, each published against its own tube. Tell us the exact model printed on your telescope and we will confirm which corrector belongs on it.\u003c\/p\u003e\n\u003cp\u003eThe vendor does not publish the thread interface or the spacing distance to the sensor, so the adapters between this corrector and your camera cannot be specified from published data. Send us your camera model, filter wheel or drawer, and any off-axis guider in the train, and we will map the imaging train and tell you exactly what sits between the two.\u003c\/p\u003e\n\u003cp\u003eNothing about this part changes the mount side of the setup: it adds a short optic and roughly a pound behind the focuser rather than changing how the telescope mounts.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus is not published.\u003c\/strong\u003e Sky-Watcher gives no spacing figure in millimetres for this corrector. Corner star shape depends on hitting the correct sensor distance, and we can work that out with you from your specific camera and adapters.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread interface is not published.\u003c\/strong\u003e No thread size appears on the vendor page, so the camera-side connection is confirmed case by case rather than assumed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEvostar 100EDX, not Esprit 100EDX.\u003c\/strong\u003e The 100 mm telescope named for this part is the Evostar doublet. The Esprit 100EDX triplet is served by S20217.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe 44 mm figure is published for these two telescopes.\u003c\/strong\u003e Other refractors pair with their own correctors, and the figure is not carried across to them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt is a flattener, not a reducer.\u003c\/strong\u003e Sky-Watcher publishes 1.0X, so focal length and focal ratio stay at each telescope's native values.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBox contents are not published.\u003c\/strong\u003e The vendor states no spacer, adapter or case as supplied with the corrector.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight figure is the vendor's shipping weight.\u003c\/strong\u003e Sky-Watcher lists 1.0 lb for this item and publishes no separate optic-only mass in a specification table.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003ePhysically it is one optic that goes into the imaging train between the focuser and the camera, and it stays there. The part that takes attention is the spacing to the sensor, which Sky-Watcher does not publish for this corrector. Send us the camera and adapters you plan to use and we will lay out the train for you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it fit both telescopes, or do I need two?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes this one corrector against both the Esprit 70EDX and the Evostar 100EDX. If you own both, this is the single part for the pair.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it change the focal length or focal ratio?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. It is published as a 1.0X flattener, so the Esprit 70EDX images at its native 455 mm and f\/6.5 and the Evostar 100EDX at its own native figures.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it cover my full-frame camera?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe published corrected image circle is 44 mm and a full-frame sensor measures 43.3 mm across the diagonal, so the sensor sits inside the corrected field. APS-C sits well inside it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eI have an Esprit 100EDX — is this the one?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 100 mm telescope Sky-Watcher names here is the Evostar 100EDX doublet. For the Esprit 100EDX triplet the published corrector is S20217. Send us the model printed on your tube and we will match it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat weight does it add to the imaging train?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher lists 1.0 lb for this item. It is a small addition behind the focuser next to the camera, filters and any guider.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eA dedicated 1.0X flattener published for both the Esprit 70EDX and the Evostar 100EDX, with a 44 mm corrected circle — enough to keep stars round across a full-frame sensor at each telescope's native focal length. Sky-Watcher leaves the backfocus and thread figures unpublished, so we confirm the spacing with you against your own camera and adapters and send it out ready to drop into the train.\u003c\/p\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":53896786083951,"sku":"S20216","price":310.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/100_2_c036ec1b-e071-4037-9437-5adb55294a87.jpg?v=1785253987"},{"product_id":"askar-1x-full-frame-flattener-for-103apo","title":"Askar 1x Full-frame Flattener for 103APO","description":"\u003cp\u003e\u003cspan\u003eThe 1x flattener does not change the telescope's focal ratio itself. After connecting with the Askar 103APO, it still maintained a focal length of 6.8. The flattener corrects field curvature and coma, resulting in flatter field edges and finer star points.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe 1.0x flattener adopts a triplet design and supports a 44mm full-frame image circle. The overall weight is 0.58kg. The back focus from the M48 thread is a standard 55mm. The front thread is M84*1. At the camera end, it is equipped with M54*0.75 and M48*0.75 two sizes of adapters, which are convenient for connection. At the same time, it has a built-in M48*0.75 2-inch filter thread, which can be directly installed and used. The overall CNC machined, both end threaded metal caps prevent ash when not in use.\u003c\/span\u003e\u003c\/p\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":54035100794991,"sku":null,"price":300.0,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/IMG-6936.webp?v=1786728372"},{"product_id":"takahashi-fc-fs-multi-flattener-1-04x-field-flattener","title":"Takahashi FC\/FS Multi-Flattener 1.04x Field Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FC\/FS Multi-Flattener 1.04x is Takahashi's universal field flattener for the FC and FS doublet refractor families. It replaces the separate model-specific flatteners Takahashi previously sold: one optic now covers the whole range, with a telescope-specific CA ring setting the correct spacing for each tube.\u003c\/p\u003e\u003cp\u003eTwo elements in one group, 40 mm long, 60 mm across and 110 g. It threads M56 x 0.75 female on the telescope side and presents M52 x 0.75 male to your camera adapter, with 40 mm of backfocus behind it. The 1.04x factor means focal length moves only slightly — a 355 mm FS-60CB becomes 370 mm — so this is a corrector, not a focal-length changer.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you image with an FC or FS doublet and your stars go elongated toward the corners of the frame. At prime focus these telescopes have a curved field; the flattener corrects it and gives a 44 mm flat circle on the shorter tubes — enough to cover APS-C completely and most of full frame.\u003c\/p\u003e\u003cp\u003eIf you observe visually with an eyepiece, this has no application in that train. It corrects a photographic field for a sensor.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo elements in one group:\u003c\/strong\u003e a cemented pair that corrects field curvature without adding measurable chromatic error of its own.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.04x magnification factor:\u003c\/strong\u003e focal length and focal ratio shift only marginally — the point is the flat field, not a speed change.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm corrected image circle\u003c\/strong\u003e on FS-60CB, FC-76D, FC-100D, FC-50, FC-65, FC-76 and FS-78; \u003cstrong\u003e40 mm\u003c\/strong\u003e on FC-100DL, FC-60, FC-100, FC-125, FS-102, FS-128 and FS-152.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM56 x 0.75 female in, M52 x 0.75 male out:\u003c\/strong\u003e standard Takahashi interfaces on both faces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e40 mm backfocus:\u003c\/strong\u003e the distance from the rear thread to the sensor, which your camera adapter stack must total.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e110 g and 40 mm long:\u003c\/strong\u003e adds almost nothing to focuser load or train length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOne optic, whole family:\u003c\/strong\u003e replaces the older per-telescope flatteners; the CA ring does the model-specific work.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA doublet refractor focuses a curved surface, not a plane. Stars at the centre of the frame come to focus in front of the stars at the corners, so a flat sensor cannot record both sharply at once — which is why uncorrected short refractors show round stars in the middle and elongated ones at the edges.\u003c\/p\u003e\u003cp\u003eThe MFL 1.04x introduces the opposite curvature. Two elements in a single group bend the focal surface flat across the working circle while adding only 4% to the focal length. Because it is a corrector rather than a reducer, it does not compress the image or brighten the field — an FS-60CB goes from 355 mm at f\/5.9 to 370 mm at f\/6.2, and the corners come into line with the centre.\u003c\/p\u003e\u003cp\u003eWhat makes it universal is that the optical correction is common to the FC and FS doublets while only the required spacing differs. Takahashi puts that difference in the CA ring rather than in the glass, so a single flattener covers telescopes from 50 mm to 152 mm of aperture.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/takahashi-fc-fs-mfl-104x-flattener-dimensional-diagram.png?v=1786907633\" alt=\"Dimensional diagram of the Takahashi FC\/FS MFL 1.04x field flattener showing M56x0.75 input thread, M52x0.75 output thread, 40 mm backfocus and 40 mm overall length\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep-sky imaging with a DSLR, mirrorless or cooled astro camera\u003c\/strong\u003e on any current FC or FS doublet.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAPS-C and full-frame coverage:\u003c\/strong\u003e the 44 mm circle covers APS-C entirely and reaches most of a full-frame corner.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplacing an older model-specific flattener\u003c\/strong\u003e when you own more than one FC or FS tube and want one corrector for both.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field mosaics\u003c\/strong\u003e where edge star shape has to match between panels.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe flattener and the CA ring are bought together — the ring is what sets the metal back distance for your particular telescope. Takahashi publishes the pairing:\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eTakahashi part\u003c\/th\u003e\n\u003cth\u003eCA ring\u003c\/th\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eMetal back distance\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTKA20203\u003c\/td\u003e\n\u003ctd\u003eCA-60C\u003c\/td\u003e\n\u003ctd\u003eFS-60CB\u003c\/td\u003e\n\u003ctd\u003e87.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTKA18203\u003c\/td\u003e\n\u003ctd\u003eCA-76\u003c\/td\u003e\n\u003ctd\u003eFC-76D, FC-76, FS-78\u003c\/td\u003e\n\u003ctd\u003e75.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTKA19203\u003c\/td\u003e\n\u003ctd\u003eCA-100\u003c\/td\u003e\n\u003ctd\u003eFC-100D, FC-100\u003c\/td\u003e\n\u003ctd\u003e71.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTKA01203\u003c\/td\u003e\n\u003ctd\u003eCA-50\u003c\/td\u003e\n\u003ctd\u003eFC-50\u003c\/td\u003e\n\u003ctd\u003e84.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTKA03203\u003c\/td\u003e\n\u003ctd\u003eCA-65\u003c\/td\u003e\n\u003ctd\u003eFC-60, FC-65\u003c\/td\u003e\n\u003ctd\u003e78.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTKA07203\u003c\/td\u003e\n\u003ctd\u003eCA-125\u003c\/td\u003e\n\u003ctd\u003eFC-100DL, FS-102, FC-125\u003c\/td\u003e\n\u003ctd\u003e69.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTKA24203\u003c\/td\u003e\n\u003ctd\u003eCA-128\u003c\/td\u003e\n\u003ctd\u003eFS-128, FS-152\u003c\/td\u003e\n\u003ctd\u003e66.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCamera side:\u003c\/strong\u003e M52 x 0.75 male, with 40 mm of backfocus to the sensor. Your camera adapter, filter drawer and spacers together need to total that 40 mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters count:\u003c\/strong\u003e a filter in the light path adds roughly one third of its thickness to the optical path. A 2 mm filter shifts focus by about 0.7 mm, which comes out of the spacer stack.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNot compatible with the FOA-60 or SKY90.\u003c\/strong\u003e Both use different optical designs. The FOA-60 has its own 0.93x flattener; ask us and we will point you to the right part.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you tell us your telescope, camera and any filters you use, we will work out the spacer stack with you and confirm the CA ring before you order.\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\u003eThe CA ring is a separate purchase.\u003c\/strong\u003e The flattener does not include one, and it will not reach correct spacing without the ring matched to your telescope. The table above names it; we stock the range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is a photographic corrector.\u003c\/strong\u003e It has no application in a visual train with an eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus is 40 mm from the rear thread.\u003c\/strong\u003e The corner star shape follows how closely your adapter stack hits that figure, and the diagram above gives you the reference distances to measure against.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe corrected circle depends on the telescope.\u003c\/strong\u003e 44 mm on the shorter tubes, 40 mm on the longer ones — the list above tells you which applies. A full-frame sensor has a 43.3 mm diagonal, so full-frame corners are covered on the 44 mm group and just short on the 40 mm group.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt does not fit the FOA-60 or SKY90.\u003c\/strong\u003e Those telescopes take their own correctors.\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\u003eIt threads on directly — the CA ring goes on the telescope, the flattener onto the ring, and your camera adapter behind it. The work is in getting the 40 mm backfocus right on the camera side, and that is arithmetic rather than trial and error: add up your adapter, filter drawer and spacers to 40 mm. Send us your camera and filter setup and we will do the sum with you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it change my focal length?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eSlightly. The 1.04x factor takes a 355 mm FS-60CB to 370 mm and f\/5.9 to f\/6.2. It is a flattener, not a reducer.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhich CA ring do I need?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe table above pairs every FC and FS telescope with its ring and metal back distance. For an FS-60CB it is the CA-60C, Takahashi part TKA20203.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it cover a full-frame sensor?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eOn the 44 mm group — FS-60CB, FC-76D, FC-100D, FC-50, FC-65, FC-76, FS-78 — yes, a full-frame diagonal of 43.3 mm sits inside the corrected circle. On the 40 mm group the extreme corners fall outside it.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it with a filter in the train?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes. Allow for the focus shift a filter introduces — about a third of its thickness — when you build the spacer stack to 40 mm.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the difference between this and the older flatteners?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eTakahashi previously sold a flattener per telescope. This one optic covers the whole FC and FS doublet range, with the CA ring handling the model-specific spacing.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work on my FOA-60?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — the FOA-60 and SKY90 use different optical designs. The FOA-60 takes the dedicated 0.93x flattener.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: one 110 g corrector that flattens the field across the whole FC and FS doublet range, giving a 44 mm circle on the shorter tubes and 40 mm on the longer ones, at 40 mm of backfocus. Pair it with the CA ring for your telescope and it does its job — and we will confirm which ring and what spacing before you order.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54046965858415,"sku":"TAK-TKA00582","price":299.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA00582_1.jpg?v=1786907709"},{"product_id":"takahashi-ca-76-multi-flattener-ca-ring","title":"Takahashi CA-76 Multi-Flattener CA Ring","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe CA-76 is the spacer ring that sets correct back focus for the \u003ca href=\"\/products\/takahashi-fc-fs-multi-flattener-1-04x-field-flattener\"\u003eTakahashi FC\/FS Multi-Flattener 1.04x\u003c\/a\u003e on the FC-76D, FC-76 and FS-78. The flattener is a common optic across the FC and FS doublet line; the CA ring is what makes the spacing correct for your specific tube. Fitted with the CA-76, the pair sets a 75.0 mm metal back distance, the figure Takahashi publishes for this telescope group.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you own an FC-76D, FC-76 or FS-78 and are fitting the FC\/FS Multi-Flattener 1.04x for imaging. It has no function on its own — it is bought alongside the flattener, not instead of it.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTelescope-specific spacing:\u003c\/strong\u003e sets the 75.0 mm metal back distance Takahashi publishes for the FC-76D, FC-76 and FS-78 with this flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreads directly onto the Multi-Flattener:\u003c\/strong\u003e the ring's accessory side mates with the flattener's M56 x 0.75 telescope-side thread.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact and light:\u003c\/strong\u003e a single machined ring, adding minimal length ahead of the flattener.\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\u003eImaging setup on the FC-76D, FC-76 or FS-78:\u003c\/strong\u003e fitted between telescope and flattener whenever this model group is used for astrophotography.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSwitching the Multi-Flattener between tubes:\u003c\/strong\u003e if you own more than one FC or FS telescope, the CA ring is what changes when you move the flattener across them.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe CA-76 is one of seven CA rings Takahashi publishes for the Multi-Flattener 1.04x, each matched to a different telescope group:\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eCA ring\u003c\/th\u003e\n\u003cth\u003eTakahashi part\u003c\/th\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eMetal back distance\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-50\u003c\/td\u003e\n\u003ctd\u003eTKA01203\u003c\/td\u003e\n\u003ctd\u003eFC-50\u003c\/td\u003e\n\u003ctd\u003e84.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-60C\u003c\/td\u003e\n\u003ctd\u003eTKA20203\u003c\/td\u003e\n\u003ctd\u003eFS-60CB\u003c\/td\u003e\n\u003ctd\u003e87.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-65\u003c\/td\u003e\n\u003ctd\u003eTKA03203\u003c\/td\u003e\n\u003ctd\u003eFC-60, FC-65\u003c\/td\u003e\n\u003ctd\u003e78.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-76\u003c\/td\u003e\n\u003ctd\u003eTKA18203\u003c\/td\u003e\n\u003ctd\u003eFC-76D, FC-76, FS-78\u003c\/td\u003e\n\u003ctd\u003e75.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-100\u003c\/td\u003e\n\u003ctd\u003eTKA19203\u003c\/td\u003e\n\u003ctd\u003eFC-100D, FC-100\u003c\/td\u003e\n\u003ctd\u003e71.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-125\u003c\/td\u003e\n\u003ctd\u003eTKA07203\u003c\/td\u003e\n\u003ctd\u003eFC-100DL, FS-102, FC-125\u003c\/td\u003e\n\u003ctd\u003e69.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-128\u003c\/td\u003e\n\u003ctd\u003eTKA24203\u003c\/td\u003e\n\u003ctd\u003eFS-128, FS-152\u003c\/td\u003e\n\u003ctd\u003e66.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eFull spacing figures for the FC and FS line are in the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e.\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 does not work alone.\u003c\/strong\u003e The CA-76 only sets spacing for the Multi-Flattener 1.04x — the flattener itself is a separate purchase.\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 between the telescope and the flattener, setting the 75.0 mm back focus without any adjustment on your part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need this if I already own the Multi-Flattener?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes, if your telescope is an FC-76D, FC-76 or FS-78. The flattener ships without a ring; the ring is what makes it fit your tube.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the CA-76 fit a different FC or FS model?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — each CA ring is matched to a specific telescope group and back focus figure. Send us your model and we will confirm the right ring.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: the spacer ring that fits the FC\/FS Multi-Flattener 1.04x to the FC-76D, FC-76 and FS-78, setting the 75.0 mm back focus Takahashi publishes for this group.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047104073839,"sku":"TAK-TKA18203","price":48.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tka18203_1.jpg?v=1786913769"},{"product_id":"takahashi-ca-100-multi-flattener-ca-ring","title":"Takahashi CA-100 Multi-Flattener CA Ring","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe CA-100 is the spacer ring that sets correct back focus for the \u003ca href=\"\/products\/takahashi-fc-fs-multi-flattener-1-04x-field-flattener\"\u003eTakahashi FC\/FS Multi-Flattener 1.04x\u003c\/a\u003e on the FC-100D and FC-100. The flattener is a common optic across the FC and FS doublet line; the CA ring is what makes the spacing correct for your specific tube. Fitted with the CA-100, the pair sets a 71.2 mm metal back distance, the figure Takahashi publishes for this telescope group.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you own an FC-100D or FC-100 and are fitting the FC\/FS Multi-Flattener 1.04x for imaging. It has no function on its own — it is bought alongside the flattener, not instead of it.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTelescope-specific spacing:\u003c\/strong\u003e sets the 71.2 mm metal back distance Takahashi publishes for the FC-100D and FC-100 with this flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreads directly onto the Multi-Flattener:\u003c\/strong\u003e the ring's accessory side mates with the flattener's M56 x 0.75 telescope-side thread.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact and light:\u003c\/strong\u003e a single machined ring, adding minimal length ahead of the flattener.\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\u003eImaging setup on the FC-100D or FC-100:\u003c\/strong\u003e fitted between telescope and flattener whenever this model group is used for astrophotography.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSwitching the Multi-Flattener between tubes:\u003c\/strong\u003e if you own more than one FC or FS telescope, the CA ring is what changes when you move the flattener across them.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe CA-100 is one of seven CA rings Takahashi publishes for the Multi-Flattener 1.04x, each matched to a different telescope group:\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eCA ring\u003c\/th\u003e\n\u003cth\u003eTakahashi part\u003c\/th\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eMetal back distance\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-50\u003c\/td\u003e\n\u003ctd\u003eTKA01203\u003c\/td\u003e\n\u003ctd\u003eFC-50\u003c\/td\u003e\n\u003ctd\u003e84.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-60C\u003c\/td\u003e\n\u003ctd\u003eTKA20203\u003c\/td\u003e\n\u003ctd\u003eFS-60CB\u003c\/td\u003e\n\u003ctd\u003e87.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-65\u003c\/td\u003e\n\u003ctd\u003eTKA03203\u003c\/td\u003e\n\u003ctd\u003eFC-60, FC-65\u003c\/td\u003e\n\u003ctd\u003e78.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-76\u003c\/td\u003e\n\u003ctd\u003eTKA18203\u003c\/td\u003e\n\u003ctd\u003eFC-76D, FC-76, FS-78\u003c\/td\u003e\n\u003ctd\u003e75.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-100\u003c\/td\u003e\n\u003ctd\u003eTKA19203\u003c\/td\u003e\n\u003ctd\u003eFC-100D, FC-100\u003c\/td\u003e\n\u003ctd\u003e71.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-125\u003c\/td\u003e\n\u003ctd\u003eTKA07203\u003c\/td\u003e\n\u003ctd\u003eFC-100DL, FS-102, FC-125\u003c\/td\u003e\n\u003ctd\u003e69.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-128\u003c\/td\u003e\n\u003ctd\u003eTKA24203\u003c\/td\u003e\n\u003ctd\u003eFS-128, FS-152\u003c\/td\u003e\n\u003ctd\u003e66.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eFull spacing figures for the FC and FS line are in the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e.\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 does not work alone.\u003c\/strong\u003e The CA-100 only sets spacing for the Multi-Flattener 1.04x — the flattener itself is a separate purchase.\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 between the telescope and the flattener, setting the 71.2 mm back focus without any adjustment on your part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need this if I already own the Multi-Flattener?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes, if your telescope is an FC-100D or FC-100. The flattener ships without a ring; the ring is what makes it fit your tube.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the CA-100 fit a different FC or FS model?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — each CA ring is matched to a specific telescope group and back focus figure. Send us your model and we will confirm the right ring.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: the spacer ring that fits the FC\/FS Multi-Flattener 1.04x to the FC-100D and FC-100, setting the 71.2 mm back focus Takahashi publishes for this group.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047104106607,"sku":"TAK-TKA19203","price":48.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/screenshot_2026-08-26_at_2.43.08_pm.png?v=1787929184"},{"product_id":"takahashi-ca-60c-multi-flattener-ca-ring","title":"Takahashi CA-60C Multi-Flattener CA Ring","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe CA-60C is the spacer ring that sets correct back focus for the \u003ca href=\"\/products\/takahashi-fc-fs-multi-flattener-1-04x-field-flattener\"\u003eTakahashi FC\/FS Multi-Flattener 1.04x\u003c\/a\u003e on the FS-60CB. The flattener is a common optic across the FC and FS doublet line; the CA ring is what makes the spacing correct for your specific tube. Fitted with the CA-60C, the pair sets an 87.5 mm metal back distance, the figure Takahashi publishes for the FS-60CB.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you own an FS-60CB and are fitting the FC\/FS Multi-Flattener 1.04x for imaging. It has no function on its own — it is bought alongside the flattener, not instead of it.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTelescope-specific spacing:\u003c\/strong\u003e sets the 87.5 mm metal back distance Takahashi publishes for the FS-60CB with this flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreads directly onto the Multi-Flattener:\u003c\/strong\u003e the ring's accessory side mates with the flattener's M56 x 0.75 telescope-side thread.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact and light:\u003c\/strong\u003e a single machined ring, adding minimal length ahead of the flattener.\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\u003eImaging setup on the FS-60CB:\u003c\/strong\u003e fitted between telescope and flattener whenever this compact doublet is used for astrophotography.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSwitching the Multi-Flattener between tubes:\u003c\/strong\u003e if you own more than one FC or FS telescope, the CA ring is what changes when you move the flattener across them.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe CA-60C is one of seven CA rings Takahashi publishes for the Multi-Flattener 1.04x, each matched to a different telescope group:\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eCA ring\u003c\/th\u003e\n\u003cth\u003eTakahashi part\u003c\/th\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eMetal back distance\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-50\u003c\/td\u003e\n\u003ctd\u003eTKA01203\u003c\/td\u003e\n\u003ctd\u003eFC-50\u003c\/td\u003e\n\u003ctd\u003e84.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-60C\u003c\/td\u003e\n\u003ctd\u003eTKA20203\u003c\/td\u003e\n\u003ctd\u003eFS-60CB\u003c\/td\u003e\n\u003ctd\u003e87.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-65\u003c\/td\u003e\n\u003ctd\u003eTKA03203\u003c\/td\u003e\n\u003ctd\u003eFC-60, FC-65\u003c\/td\u003e\n\u003ctd\u003e78.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-76\u003c\/td\u003e\n\u003ctd\u003eTKA18203\u003c\/td\u003e\n\u003ctd\u003eFC-76D, FC-76, FS-78\u003c\/td\u003e\n\u003ctd\u003e75.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-100\u003c\/td\u003e\n\u003ctd\u003eTKA19203\u003c\/td\u003e\n\u003ctd\u003eFC-100D, FC-100\u003c\/td\u003e\n\u003ctd\u003e71.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-125\u003c\/td\u003e\n\u003ctd\u003eTKA07203\u003c\/td\u003e\n\u003ctd\u003eFC-100DL, FS-102, FC-125\u003c\/td\u003e\n\u003ctd\u003e69.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCA-128\u003c\/td\u003e\n\u003ctd\u003eTKA24203\u003c\/td\u003e\n\u003ctd\u003eFS-128, FS-152\u003c\/td\u003e\n\u003ctd\u003e66.2 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eFull spacing figures for the FC and FS line are in the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e.\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 does not work alone.\u003c\/strong\u003e The CA-60C only sets spacing for the Multi-Flattener 1.04x — the flattener itself is a separate purchase.\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 between the telescope and the flattener, setting the 87.5 mm back focus without any adjustment on your part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need this if I already own the Multi-Flattener?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes, if your telescope is an FS-60CB. The flattener ships without a ring; the ring is what makes it fit your tube.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the CA-60C fit a different FC or FS model?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — each CA ring is matched to a specific telescope group and back focus figure. Send us your model and we will confirm the right ring.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: the spacer ring that fits the FC\/FS Multi-Flattener 1.04x to the FS-60CB, setting the 87.5 mm back focus Takahashi publishes for this telescope.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047104204911,"sku":"TAK-TKA20203","price":48.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/screenshot_2026-08-26_at_2.46.18_pm.png?v=1787944630"},{"product_id":"takahashi-sd-ring-for-fs-60c-multi-flattener","title":"Takahashi SD Ring for FS-60C Multi-Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe SD Ring is the spacing adapter Takahashi publishes for fitting the \u003ca href=\"\/products\/takahashi-fc-fs-multi-flattener-1-04x-field-flattener\"\u003eFC\/FS Multi-Flattener 1.04x\u003c\/a\u003e to the FS-60C. It threads M55.9 x 0.75 and adds a 17.5 mm light path — the figures Takahashi lists in its accessory ring table for this part.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you own an FS-60C and are setting up the FC\/FS Multi-Flattener 1.04x for imaging. It is a spacing part, not a standalone accessory.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eM55.9 x 0.75 thread:\u003c\/strong\u003e the interface Takahashi publishes for this ring.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e17.5 mm light path:\u003c\/strong\u003e the length it adds to the imaging train ahead of the flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurpose-built for the FS-60C:\u003c\/strong\u003e distinct from the CA-60C ring used on the FS-60CB.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e\n\u003cstrong\u003eImaging setup on the FS-60C\u003c\/strong\u003e with the FC\/FS Multi-Flattener 1.04x.\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi's own accessory ring table notes that the SD Ring cannot be threaded onto the female port of the Camera Angle Adjuster S — the same restriction applies to the M55.9 Extension Tube L30. If your train includes the Camera Angle Adjuster S, check the fit with us before ordering. Full spacing figures for the FC and FS line are in the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e.\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 does not work alone.\u003c\/strong\u003e The SD Ring only sets spacing for the Multi-Flattener 1.04x on the FS-60C — the flattener itself is a separate purchase.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNot for use with the Camera Angle Adjuster S\u003c\/strong\u003e — Takahashi's own documentation flags this combination as incompatible. If that is part of your train, send us the details and we will confirm an alternative.\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 directly into the imaging train ahead of the flattener at the published M55.9 x 0.75 interface.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this the same as the CA-60C ring?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. The CA-60C is matched to the FS-60CB; the SD Ring is the part Takahashi publishes for the FS-60C.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it with the Camera Angle Adjuster S?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eTakahashi's documentation says no — the thread will not engage the Camera Angle Adjuster S's female port. Send us your setup and we will work out the right combination.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: an M55.9 x 0.75, 17.5 mm spacing ring that sets up the FC\/FS Multi-Flattener 1.04x correctly on the FS-60C.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047107547247,"sku":"TAK-TKA20583","price":54.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tka20583-1.jpg?v=1786913864"},{"product_id":"takahashi-toa-130-25mm-spacer-ring-for-67-flattener","title":"Takahashi TOA-130 25mm Spacer Ring for 67 Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis 25 mm ring — Takahashi's \"Ring #82\" — is the TOA-130NFB-specific output adapter for the 67FL Flattener system. The 67FL Flattener corrects a 90 mm image circle at an optimal 106.2 mm back focus, and this ring is what sets that spacing correctly on the TOA-130NFB.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you own a TOA-130NFB and are fitting the 67FL Flattener for large-format imaging. It is a spacing part, not a standalone corrector.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e25 mm output length:\u003c\/strong\u003e the figure published for the TOA-130NFB fitting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM92 x 1.0 interface:\u003c\/strong\u003e matches the 67FL Flattener's own thread family.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTelescope-specific:\u003c\/strong\u003e the TOA-150 uses a different ring in the same system, at 17 mm output.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e\n\u003cstrong\u003eLarge-format imaging on the TOA-130NFB\u003c\/strong\u003e with the 67FL Flattener, covering the system's 90 mm corrected circle.\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe 67FL Flattener kit uses different output rings depending on the host telescope: 25 mm for the TOA-130NFB (this ring, TKA31584) and 17 mm for the TOA-150 (TKA26583). Confirm which telescope you're fitting before ordering — the rings are not interchangeable between the two. Full spacing figures are in the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e.\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 does not work alone.\u003c\/strong\u003e This ring only sets spacing for the 67FL Flattener on the TOA-130NFB — the flattener itself is a separate purchase.\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 67FL Flattener at the published M92 x 1.0 interface and sets the 25 mm spacing without adjustment.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this fit my TOA-150?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — the TOA-150 uses its own 17 mm ring (TKA26583) in the same 67FL Flattener system. This 25 mm ring is specific to the TOA-130NFB.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need the 67FL Flattener as well?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — this ring only sets the spacing; the flattener carries the optics.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: the 25 mm output ring that fits the 67FL Flattener to the TOA-130NFB at the M92 x 1.0 interface, setting up the system's 90 mm corrected image circle.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047108071535,"sku":"TAK-TKA31584","price":126.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA31584_1.jpg?v=1786913882"},{"product_id":"takahashi-toa-150b-0-99x-toa-645-field-flattener","title":"Takahashi TOA-150B 0.99x TOA-645 Field Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe TOA-645 Field Flattener 150 Set is Takahashi's dedicated flattener kit for the TOA-150B refractor, built for high-resolution medium-format imaging. It holds the telescope's own 1100mm f\/7.3 essentially unchanged — 1085mm at f\/7.2 — while flattening the field across a Φ60mm image circle, large enough for today's full-frame and medium-format sensors.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis flattener suits TOA-150B owners shooting with large-format cameras — full-frame CMOS or medium-format backs — who need corner-to-corner sharpness across a wide sensor rather than a reduced focal length. Takahashi's own figures put the RMS spot diameter at 1 micron on-axis and 5 microns at the full 60mm diameter.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo-element flattener:\u003c\/strong\u003e two fully multi-coated elements in two groups, purpose-built for digital sensors rather than adapted from a film-era design.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eΦ60mm corrected image circle:\u003c\/strong\u003e covers full-frame and medium-format sensors with minimal fall-off.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear-native focal length:\u003c\/strong\u003e 1085mm at f\/7.2 keeps the TOA-150B's own field of view essentially intact.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBundled CA35 (50.8) ring:\u003c\/strong\u003e included in this kit, matched to the TOA-150B's mount so the flattener installs as a complete system.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe flattener threads to the TOA-150B's 50.8 Adapter on an M72x1 male-to-female interface and outputs to the included CA35 ring on an M54x0.75 female thread. Total kit weight is 330g. The corrected back focus is 56.2mm measured from the CA35 ring — the figure to build the rest of your imaging train from. See the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e for the full spacing chain.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eHigh-resolution deep-sky imaging with full-frame or medium-format cameras on the TOA-150B; wide-field mosaicless framing of large nebulae and galaxy fields where the full Φ60mm circle is put to use; observatory and long-exposure narrowband work where field flatness across the whole sensor matters.\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\u003eTOA-150B (this kit, TKA32587S)\u003c\/td\u003e\n\u003ctd\u003e1085mm\u003c\/td\u003e\n\u003ctd\u003ef\/7.2\u003c\/td\u003e\n\u003ctd\u003eΦ60mm\u003c\/td\u003e\n\u003ctd\u003e56.2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTOA-130NS \/ TOA-130NFB\u003c\/td\u003e\n\u003ctd\u003e990mm\u003c\/td\u003e\n\u003ctd\u003ef\/7.6\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\u003eTOA-130NS and TOA-130NFB owners use the sibling kit, the TOA-645 Flattener 130 Set (TKA31587S), which bundles the same flattener with a CA Ring 130 sized for that telescope's mount instead of this kit's CA35 ring — we stock this listing for the TOA-150B specifically. The optical element itself is common to both kits.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eSold as a complete kit:\u003c\/strong\u003e the CA35 ring is bundled with this flattener, so there's nothing separate to source to reach the 56.2mm back focus figure.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eBuilt for the TOA-150B:\u003c\/strong\u003e if you own a TOA-130NS or TOA-130NFB instead, the matching kit is the TOA-645 Flattener 130 Set — get in touch and we'll point you to the right one.\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 TOA-150B's 50.8 Adapter and outputs directly to the included CA35 ring, which sets the 56.2mm back focus for you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eHigh-resolution astrophotography on the TOA-150B with full-frame or medium-format sensors, where a flat Φ60mm image circle matters more than a shorter focal length.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it reduce the focal length?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eBarely — at 0.99x it holds the TOA-150B close to its native 1100mm f\/7.3, landing at 1085mm f\/7.2. It flattens the field rather than speeding up the system.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat's the difference between this and the TOA-35 Reducer?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThis flattener keeps the focal length essentially native while widening the corrected circle to Φ60mm. The TOA-35 Reducer instead cuts the focal length to f\/5.2 for a faster, narrower-circle system — the two serve different imaging goals on the same telescope.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA complete TOA-150B flattener kit that holds the telescope near its native 1100mm focal length at f\/7.2 while flattening a Φ60mm image circle for full-frame and medium-format imaging, with the matched CA35 ring included.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047109415023,"sku":"TAK-TKA32587S","price":1100.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tka32587s-1_3.jpg?v=1786913942"},{"product_id":"takahashi-toa130fn-flattener-wide-t-mount","title":"Takahashi TOA130FN Flattener Wide T-Mount","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe TOA130FN combines a field flattener with a T-mount adapter in one part, built for DSLR and 35mm film photography on the TOA-130. It attaches your camera directly to the telescope through a T-Ring (sold separately), or through the Extender TOA when you need additional focal length.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you own a TOA-130 and want to shoot with a DSLR or 35mm film body directly on the telescope, with the field corrected for a flat frame.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eCombining the flattener and T-mount interface into a single part removes one connection point from the imaging train compared with fitting a separate flattener and T-ring adapter — fewer joints to seat correctly, and one less place for the stack to drift out of square. The flattener element corrects the field curvature the TOA-130's triplet objective otherwise produces at prime focus.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDSLR and 35mm film astrophotography on the TOA-130\u003c\/strong\u003e at prime focus, corrected for field curvature.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtending the setup\u003c\/strong\u003e with the Extender TOA when a longer focal length is wanted for the same camera.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA camera-specific T-Ring is required and sold separately — the TOA130FN provides the T-mount interface, not the camera-side bayonet. It is also compatible with the Extender TOA for extended focal length work. See the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e for TOA-130 back focus figures, and send us your camera body if you want the T-Ring confirmed before you order.\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\u003eA T-Ring is not included.\u003c\/strong\u003e It is sold separately and is specific to your camera mount — tell us your camera and we will confirm the right one.\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 TOA-130 and takes a T-Ring on the camera side, combining the flattener and mount into one connection.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need a separate flattener as well?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — the flattener is built into this part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it with the Extender TOA?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — it's compatible with the Extender TOA for extended focal length imaging.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a combined field flattener and T-mount adapter for DSLR and 35mm imaging on the TOA-130, taking a camera-specific T-Ring on the back.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047111643247,"sku":"TAK-TKA31201","price":228.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tca1050_3_6.jpg?v=1786913992"},{"product_id":"takahashi-flattener-1-01x-for-fsq-85edx","title":"Takahashi Flattener 1.01x for FSQ-85EDX","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis flattener extends the FSQ-85EDX's corrected field to a 44 mm image circle — enough to cover a full-frame sensor's 43.3 mm diagonal completely. At 1.01x it changes focal length only fractionally, from 450 mm (f\/5.3) to 455 mm (f\/5.4), so this is a corrector rather than a focal-length changer.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is what you need if you image with an FSQ-85EDX on a full-frame sensor and want flat, round stars into the corners of the frame, not just the APS-C centre.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FSQ-85EDX's petzval design is already well corrected across a smaller field; this flattener extends that correction out to a 44 mm circle by adding the last small amount of field curvature correction the native optical path doesn't reach on its own. The 1.01x factor is nearly unity — the flattener is doing geometry, not speed — which is why the focal length shift is so small: 450 mm becomes 455 mm, f\/5.3 becomes f\/5.4. Backfocus behind the flattener is 36 mm, with a 56.2 mm metal back distance from the telescope's own reference point, and the front face takes M58 filters directly.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull-frame deep-sky imaging on the FSQ-85EDX\u003c\/strong\u003e where the native field falls short of covering the sensor's corners.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field mosaics\u003c\/strong\u003e where consistent corner star shape across panels matters.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe flattener threads M72 x 1.0 male into the telescope side and presents M54 x 0.75 female to your camera adapter, with 36 mm of backfocus to the sensor. The front face's female thread accepts M58 filters directly, ahead of the flattener glass. If you're building out a full imaging train and want the spacer stack confirmed to the 36 mm figure, send us your camera and filter setup and we will work it out with you. See the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e for the FSQ-85EDX's full published figures.\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\u003eThis is a photographic corrector.\u003c\/strong\u003e It has no application in a visual train with an eyepiece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus is 36 mm from the rear thread.\u003c\/strong\u003e Corner star shape follows how closely your adapter stack hits that figure — send us your setup and we will confirm the spacer stack before you order.\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\u003eIt threads directly onto the FSQ-85EDX at M72 x 1.0. The work is in hitting the 36 mm backfocus on the camera side, which is arithmetic — add up your adapter, filter drawer and spacers, and send us the numbers if you want them checked.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it change my focal length?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eOnly slightly — 450 mm at f\/5.3 becomes 455 mm at f\/5.4. It's a flattener, not a reducer.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it cover a full-frame sensor?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — the 44 mm corrected circle covers a full-frame diagonal of 43.3 mm.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I fit filters directly to it?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — the front face takes M58 filters ahead of the flattener glass.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 200 g, 1.01x flattener that gives the FSQ-85EDX a 44 mm corrected circle for full-frame sensors, at 36 mm of backfocus — send us your camera and filter setup and we'll confirm the spacer stack with you.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047112626287,"sku":"TAK-TKA37582","price":347.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA37582_1.jpg?v=1786914068"},{"product_id":"takahashi-foa-60-0-93x-flattener","title":"Takahashi FOA-60 0.93x Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60 0.93x Flattener is the field corrector built specifically for Takahashi's FOA-60 Ortho Apochromat. Threaded to the FOA-60's 2-inch drawtube and finishing in an M52 x 0.75 female output, it brings the focal length from 530 mm down to 495 mm at f\/8.2 while flattening the field to within 10 microns across a 44 mm image circle. It weighs 205 g and adds 67 mm of length ahead of the sensor.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you already own the FOA-60 and want a flat, coma-free field for imaging — small-sensor deep-sky work, lunar mosaics, or solar eclipse photography where the corner stars matter as much as the center.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurpose-built for the FOA-60:\u003c\/strong\u003e not a universal flattener — matched specifically to this 60mm ortho-apochromat's native curvature.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44mm corrected image circle:\u003c\/strong\u003e covers full-frame sensors with the field flattened to within roughly 10 microns.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e495mm f\/8.2 result:\u003c\/strong\u003e a modest 0.93x reduction that trims the native 530mm f\/8.8 slightly while correcting the field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact in-line design:\u003c\/strong\u003e 56mm diameter, 67mm long, 205g, threading directly between the 2-inch drawtube and an M52 x 0.75 camera train.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe corrector uses two lens elements in two groups to cancel the FOA-60's residual field curvature, the tradeoff Takahashi's ortho-apochromat design makes for its high on-axis Strehl ratio. The output back focus works out to 56.0 mm from the flattener, so spacing to the sensor is a fixed rather than adjustable figure once the M52 x 0.75 thread is engaged.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eDeep-sky imaging where corner star shape matters, lunar mosaic photography, and solar eclipse imaging with a full-frame or APS-C sensor.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis flattener is matched to the FOA-60 only — the table below is Takahashi's published figure for that pairing.\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eNative\u003c\/th\u003e\n\u003cth\u003eWith FL 0.93x\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\u003eFOA-60\u003c\/td\u003e\n\u003ctd\u003e530mm f\/8.8\u003c\/td\u003e\n\u003ctd\u003e495mm f\/8.2\u003c\/td\u003e\n\u003ctd\u003eΦ44mm\u003c\/td\u003e\n\u003ctd\u003e56.0mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA28582_FOA-60_FL093x_schema.png?v=1786913972\" alt=\"Dimensional diagram of the Takahashi FOA-60 0.93x Flattener\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003cp\u003eBackfocus and thread spacing for the whole FOA-60 imaging train are covered in the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eNot combined with the FOA-60Q 1.7x extender:\u003c\/strong\u003e the flattener and the EX 1.7xR extender serve different configurations of the same tube and are not used together.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eBuilt for imaging, not eyepiece use:\u003c\/strong\u003e the flattened field has no benefit for visual observing, where the FOA-60's native curvature is not a 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 threads onto the FOA-60's 2-inch drawtube on one side and presents an M52 x 0.75 female thread on the camera side, so the spacing is fixed by the part itself rather than something to measure out.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eFlat-field imaging on the FOA-60 — deep-sky, lunar, and solar eclipse photography.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it work on other Takahashi refractors?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — it is matched to the FOA-60's specific curvature. Other Takahashi models use their own matched flatteners; if you are unsure which one applies to your scope, send us your setup and we will confirm it.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it change the FOA-60 into the FOA-60Q?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — that conversion uses the separate EX 1.7xR extender, which is not used together with this flattener.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60 0.93x Flattener is the matched corrector for Takahashi's FOA-60, turning it into a 495mm f\/8.2 system with a flat 44mm image circle for imaging, at 205 g and a fixed 56.0mm back focus.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047112724591,"sku":"TAK-TKA28582","price":470.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA28582_FOA-60_flattener_1.jpg?v=1786914111"},{"product_id":"takahashi-2-7-flattener-for-takahashi-toa-130s","title":"Takahashi TOA-35FL 2.7\" Flattener for TSA-120\/TOA-130\/TOA-150B","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe TOA-35FL is Takahashi's 2.7-inch field flattener for the TSA-120 and TOA-130\/150 triplet apochromats. It threads onto a 2-inch drawtube and presents a 2-inch female output, correcting the field to a 40mm image circle with essentially no edge distortion, at a published weight of 200 g.\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 TSA-120, TOA-130NS\/NFB, or TOA-150B and are imaging with a CCD or CMOS sensor up to full-frame, where corner star shape needs correcting that the native triplet design does not fully address on its own.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eShared across three telescopes:\u003c\/strong\u003e the same part flattens the field on the TSA-120, TOA-130NS\/NFB, and TOA-150B, each with its own resulting focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e40mm corrected image circle:\u003c\/strong\u003e covers virtually all common CCD and CMOS sensor sizes without edge-of-field distortion.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e117.5mm back focus\u003c\/strong\u003e held constant across all three host telescopes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact 2-inch in-line design:\u003c\/strong\u003e 60mm diameter, 74mm long, 200g.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe TOA and TSA triplet apochromats are corrected for a flat visual field but benefit from a dedicated flattener when imaging across a full sensor. The TOA-35FL sits between the 2-inch drawtube and the camera train, trimming the focal length by a small, telescope-specific amount while holding the 40mm image circle and 117.5mm back focus fixed regardless of which of the three host telescopes it is mounted on.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA31582_TOA-35FL_schema.png?v=1786913972\" alt=\"Dimensional diagram of the Takahashi TOA-35FL 2.7 inch Flattener\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eFull-frame and APS-C deep-sky imaging on the TSA-120, TOA-130NS\/NFB, or TOA-150B where flat corner stars are required across the sensor.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi publishes this flattener for three telescopes.\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eNative\u003c\/th\u003e\n\u003cth\u003eWith TOA-35FL\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\u003eTSA-120\u003c\/td\u003e\n\u003ctd\u003e900mm f\/7.5\u003c\/td\u003e\n\u003ctd\u003e880mm f\/7.3\u003c\/td\u003e\n\u003ctd\u003eΦ40mm\u003c\/td\u003e\n\u003ctd\u003e117.5mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTOA-130NS \/ TOA-130NFB\u003c\/td\u003e\n\u003ctd\u003e1000mm f\/7.7\u003c\/td\u003e\n\u003ctd\u003e980mm f\/7.5\u003c\/td\u003e\n\u003ctd\u003eΦ40mm\u003c\/td\u003e\n\u003ctd\u003e117.5mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTOA-150B\u003c\/td\u003e\n\u003ctd\u003e1100mm f\/7.3\u003c\/td\u003e\n\u003ctd\u003e1080mm f\/7.2\u003c\/td\u003e\n\u003ctd\u003eΦ40mm\u003c\/td\u003e\n\u003ctd\u003e117.5mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eFor sensors larger than 40mm, Takahashi's TOA-645 flattener line covers TOA-130 and TOA-150B with a 60mm image circle instead — see the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e for the full spacing picture.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003e40mm image circle, not full-format:\u003c\/strong\u003e larger sensors needing a 60mm circle should look to the TOA-645 flattener line instead of this part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eBuilt for imaging:\u003c\/strong\u003e the flattened field has no benefit for eyepiece observing, where the native triplet field is already flat enough.\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 2-inch drawtube and presents a fixed 117.5mm back focus on the camera side, so there is no spacing to calculate.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eFlat-field deep-sky imaging on the TSA-120, TOA-130NS\/NFB, or TOA-150B.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it fit sensors larger than APS-C?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIts 40mm image circle covers most full-frame sensors; for larger formats, Takahashi's TOA-645 flattener (60mm circle) is the better match — send us your sensor size and we will confirm which one you need.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the same part used on all three telescopes?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — one flattener, with a slightly different resulting focal length on each host telescope.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe TOA-35FL is a single 2.7-inch flattener that corrects the field to a 40mm image circle at a fixed 117.5mm back focus across the TSA-120, TOA-130NS\/NFB, and TOA-150B.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047117836399,"sku":"TAK-TKA31582","price":651.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA31582_1.jpg?v=1786914243"},{"product_id":"takahashi-toa-645-flattener-0-99x-for-toa-130ns-nfb","title":"Takahashi TOA-645 Flattener 0.99x for TOA-130NS\/NFB","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe TOA-645 Flattener is Takahashi's large-format field corrector for the TOA-130NS and TOA-130NFB, holding the focal length essentially unchanged at 990mm f\/7.6 while opening the corrected image circle to 60mm — large enough for today's bigger CMOS sensors. Two lens elements in two groups thread between M72 x 1 male and female interfaces, in a compact 78mm diameter, 42mm long, 265 g housing.\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 TOA-130NS or TOA-130NFB and are imaging with a large-format CMOS sensor where the older 67-series flatteners and the 40mm-circle TOA-35FL fall short of full corner coverage.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e60mm corrected image circle:\u003c\/strong\u003e built for large modern CMOS sensors rather than the 40mm circle of the TOA-35FL.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear-unity focal ratio change:\u003c\/strong\u003e 1000mm f\/7.7 native becomes 990mm f\/7.6 — correction with almost no reach traded away.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTight spot diagrams:\u003c\/strong\u003e Takahashi publishes 1 micron RMS on-axis, rising to 5 microns at the full 60mm diameter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM72 x 1 threads on both sides,\u003c\/strong\u003e in a compact 78mm x 42mm housing at 265 g.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eWhere the TOA-35FL corrects the TOA-130NS\/NFB to a 40mm circle, the TOA-645 uses two lens elements in two groups to hold correction out to 60mm, addressing the larger sensor formats that have become common since the earlier 67-series flatteners were designed. Takahashi states the newer design performs nearly aberration-free with today's smaller pixel pitches, where the older flatteners show their age.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eFull-frame and medium-format CMOS deep-sky imaging on the TOA-130NS or TOA-130NFB, where corner correction across a 60mm circle is required.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi publishes this flattener for the TOA-130NS\/NFB.\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eNative\u003c\/th\u003e\n\u003cth\u003eWith TOA-645FL\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\u003eTOA-130NS \/ TOA-130NFB\u003c\/td\u003e\n\u003ctd\u003e1000mm f\/7.7\u003c\/td\u003e\n\u003ctd\u003e990mm f\/7.6\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\u003eThe TOA-150B takes the same optical design in a separate kit, part TKA32587S, which Ontario Telescope lists separately — the two are not interchangeable at the mechanical level despite sharing the optical formula. For smaller-sensor use, the 40mm-circle TOA-35FL is also available. Full spacing detail is in the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eNot interchangeable with the TOA-150B kit:\u003c\/strong\u003e that telescope uses its own TOA-645 flattener kit (TKA32587S) rather than this TOA-130-specific part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eBuilt for imaging:\u003c\/strong\u003e the corrected field has no benefit for eyepiece observing.\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 between M72 x 1 interfaces with a fixed 56.2mm back focus, so there is no spacing to calculate.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eFull-frame and large-format CMOS deep-sky imaging on the TOA-130NS or TOA-130NFB.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow is this different from the TOA-35FL?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe TOA-35FL corrects a 40mm image circle; the TOA-645 corrects out to 60mm for larger sensors, at nearly the same resulting focal length.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes this fit my TOA-150B?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe TOA-150B uses its own TOA-645 flattener kit rather than this part; send us your telescope model and sensor size and we will confirm which flattener you need.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe TOA-645 Flattener corrects the TOA-130NS\/NFB to a 60mm image circle at essentially its native 990mm f\/7.6, built for the large CMOS sensors that have outgrown the older 40mm-circle flatteners.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047124750447,"sku":"TAK-TKA31587S","price":945.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tka31587s-1_3.jpg?v=1786914538"}],"url":"https:\/\/ontariotelescope.com\/collections\/fr-field-flatteners.oembed?page=2","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}