{"title":"Reducer-Flatteners","description":"\u003cp\u003eReducer-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":"3-field-flattener-7x-focal-reducer","title":"3\" FIELD FLATTENER .7X FOCAL REDUCER","description":"\u003cp\u003eExplore Scientific’s 3-inch Field Flattener\/0.7x Focal Reducer is a multi-faceted accessory designed to enhance your astrophotography experiences. As a field flattener, this piece addresses the edge-of-field aberrations caused by curved focal planes to ensure your night at the eyepiece will result in crisp, true images.\u003c\/p\u003e\n\u003cp\u003eAs a focal reducer, this device will reduce your f-ratio by 0.7, which results in a wider field of view, brighter images and less exposure time. Recommended for our 127mm and 152mm refracting telescopes (excluding our doublet refractors), this field flattener\/focal reducer boasts fully multi-coated optics.\u003cbr\u003e\u003cbr\u003eThis item comes with a threaded adapter that threads onto the Explore Scientific 2-inch rack-and-pinion focuser. Threaded attachment to a 2.5-hex focuser, which comes stock on our 127mm APO telescopes, requires purchase of an additional adapter. \u003c\/p\u003e\n\u003cp\u003eThe field flattener\/focal reducer offers 55 mm of back focus from the rear face of the device. The M42x0.75 adapter adds 3 mm, so the sensor needs to be 52 mm from the face of the adapter.\u003cbr\u003e\u003cbr\u003eTo connect to the 2.5 hex focuser, purchase item number\u003cspan\u003e \u003c\/span\u003e\u003ca href=\"https:\/\/ontariotelescope.com\/products\/explore-scientific-adapter-for-fffr507x-00-to-2-5-hex-focuser\" target=\"_blank\" title=\"FFFR adapter\" rel=\"noopener\"\u003e510366\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003eWhile technically this was designed for the f\/8 system, through user experiences and our subsequent testing we have concluded that our 3-inch field flattener\/reducer performs very well with our f\/7.5 refractors.\u003c\/p\u003e\n\u003ch2 style=\"margin: 0px 0px 2em; font-family: Arial, Helvetica, sans-serif; font-weight: normal; line-height: 20px; color: rgb(34, 34, 34); text-rendering: optimizeLegibility; font-size: 14px; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(236, 229, 227); text-transform: uppercase; background-color: rgb(255, 255, 255);\"\u003e\n\u003cbr\u003e\u003cbr\u003e\n\u003c\/h2\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013211680879,"sku":"FFFR507X-00","price":553.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/f1_1024x1024__16033.jpg?v=1766548832"},{"product_id":"celestron-f-6-3-reducer-corrector","title":"Celestron f\/6.3 reducer\/corrector","description":"\u003cp class=\"MsoSubtitle\"\u003e\u003cspan style=\"font-size:12.0pt;mso-bidi-font-size:13.5pt; font-family:\" arial\u003eThis combination focal reducer and field corrector lens accessory works with all Celestron 5\", 6\", 8\", 9 1\/4\", 11\" and 14\" Schmidt-Cassegrain telescopes. This clever accessory makes it possible to have a dual focal ratio instrument, without sacrificing image quality. The Reducer\/Corrector is f\/6.3 for C5, C6, C8, C9¼ and C11 telescopes and f\/7 for the C14 telescope.\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e  \u003cp class=\"MsoSubtitle\" style=\"box-sizing: border-box\"\u003e\u003cspan style=\"font-size: 12.0pt;mso-bidi-font-size:13.5pt;font-family:\" arial\u003eIf offers wide fields of view with any Schmidt-Cassegrain telescope. Used for astrophotography, it reduces exposure time by a factor of 3.\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e  \u003cp class=\"MsoSubtitle\" style=\"box-sizing: border-box\"\u003e\u003cspan style=\"font-size: 12.0pt;mso-bidi-font-size:13.5pt;font-family:\" arial\u003eCelestron doesn t offer a f\/6.3 Schmidt-Cassegrain telescope, because the design is impractical, with a large central obstruction, and resulting loss in contrast. This, added to the inability to utilize longer focal ratios for certain objects, led Celestron to design the four-element, fully multicoated f\/6.3 Reducer\/Corrector. Results are amazing both visually and photographically.\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e  \u003cp class=\"MsoSubtitle\" style=\"box-sizing: border-box\"\u003e\u003cstrong style=\"box-sizing: border-box\"\u003e\u003cspan style=\"font-size: 12pt; font-family: Arial, sans-serif; color: windowtext; text-transform: uppercase; font-weight: bold;\"\u003eTHE #94175 REDUCER\/CORRECTOR LENS IS NOT COMPATIBLE WITH CELESTRON EDGEHD OPTICAL SYSTEMS.\u003c\/span\u003e\u003c\/strong\u003e\u003cspan style=\"font-size:12.0pt;mso-bidi-font-size:13.5pt;font-family:\" arial color:windowtext\u003e\u003co:p\u003e\u003c\/o:p\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Celestron","offers":[{"title":"Default Title","offer_id":44013369000047,"sku":"94175","price":277.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/94175_reducer_corrector_01__43927.jpg?v=1766551540"},{"product_id":"starfield-0-8x-reducer-and-field-flattener","title":"Starfield - 0.8x Reducer and Field Flattener","description":"\u003cp style=\"margin: 0px; background-color: rgb(255, 255, 255);\"\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe Starfield 0.8x Reducer doubles as a field flattener.   The unique optical accessory is a must for anyone that is imaging with a DSLR or dedicated astronomy camera.  What makes this reducer different over all the others?   The M42 connection is removable and can be replaced with an optional M48 threaded adapter for Full Frame camera's. \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;\"\u003eProviding pin point stars across the field of view, the Starfield 0.8x reducer\/flattener decrease the focal length of your imaging refractor.   Designed to be used with any refractor, f\/5.5 and longer, with a 2\" focuser, and requires 55mm of back focus.  Perfect for any DSLR imager.  No additional extension rings are required.  With 38mm's of clear aperture the chance of vignetting is removed, and is well suited for APS-C sized and smaller sensors.  A 42mm clear aperture when the optional 48mm T-Ring adapter is used.  Your imaging sessions will benefit with shorter exposure times and a larger field of view.  A 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;\"\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;\"\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","brand":"Starfield","offers":[{"title":"Default Title","offer_id":44013398687855,"sku":"SF-FFR08","price":199.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/starfield1__44679.jpg?v=1766552965"},{"product_id":"skywatcher-reducer-corrector-85x-for-proed-evostar-80","title":"Skywatcher Reducer\/Corrector (.85x) for ProED \/ Evostar 80","description":"\u003cspan style=\"color: rgb(76, 81, 84); font-family: \" open sans sans-serif rgb font-size:=\"\" background-color:=\"\"\u003e0.85x Focal Reducer\/Corrector for Sky-Watcher PRO 80 ED APO is designed for serious Astro-Imagers. Optimized for the Sky-Watcher PRO 80 ED APO, this superb quality accessory effectively reduces the telescope’s focal length by a factor of 0.85x and provides much improved field-edge correction. Features:\u003c\/span\u003e\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(76, 81, 84); font-family: \" open 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);\"\u003e55mm back focus\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);\"\u003eM48 threads (not standard T-thread)\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);\"\u003eDrops ProED 80 from f\/7.5 to f\/6.3\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":44013473366127,"sku":"S20200","price":510.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/sky_watcher_s20200_focal_reducer_field_flattner_for_1060554_1800x1800__98122.jpg?v=1766554349"},{"product_id":"skywatcher-reducer-corrector-85x-for-proed-evostar-120","title":"Skywatcher Reducer\/Corrector (.85x) for ProED \/ Evostar 120","description":"\u003cspan style=\"color: rgb(76, 81, 84); font-family: \" open sans sans-serif rgb font-size:=\"\" background-color:=\"\"\u003e0.85x Focal Reducer\/Corrector for Sky-Watcher PRO 120 ED APO is designed for serious Astro-Imagers. Optimized for the Sky-Watcher PRO 120 ED APO, this superb quality accessory effectively reduces the telescope’s focal length by a factor of 0.85x and provides much improved field-edge correction. Features:\u003c\/span\u003e\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(76, 81, 84); font-family: \" open 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);\"\u003e55mm back focus\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);\"\u003eM48 threads (not standard T-thread)\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);\"\u003eDrops ProED 120 from f\/7.5 to f\/6.3\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":44013473398895,"sku":"S20202","price":550.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/reducercorrecto_large_120_1800x1800__67513.jpg?v=1766554356"},{"product_id":"skywatcher-reducer-corrector-85x-for-proed-evostar-100","title":"Skywatcher Reducer\/Corrector (.85x) for ProED \/ Evostar 100","description":"\u003cspan style=\"font-family: \" open sans sans-serif rgb font-size:=\"\" background-color:=\"\"\u003e0.85x Focal Reducer\/Corrector for Sky-Watcher PRO 100 ED APO is designed for serious Astro-Imagers. Optimized for the Sky-Watcher PRO 100 ED APO, this superb quality accessory effectively reduces the telescope’s focal length by a factor of 0.85x and provides much improved field-edge correction. Features:\u003c\/span\u003e\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; font-family: \" open 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);\"\u003e55mm back focus\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);\"\u003eM48 threads (not standard T-thread)\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);\"\u003eDrops ProED 100 from f\/9 to f\/7.56\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":44013473431663,"sku":"S20201","price":530.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/reducercorrecto_large_100_1800x1800__11765.jpg?v=1766554362"},{"product_id":"explore-scientific-2-adapter-for-fffr507x-00","title":"Explore Scientific 2-inch Adapter for FFFR507X-00 Field Flattener Focal Reducer","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is the Explore Scientific 2-inch adapter, item number 510364, which connects Explore Scientific's 3-inch 0.7X Field Flattener Focal Reducer (FFFR507X-00) to a telescope fitted with a 2-inch focuser. It also works in the other direction of the same problem: it allows a 3-inch diagonal to be mounted on a 2-inch focuser drawtube.\u003c\/p\u003e\n\u003cp\u003eExplore Scientific gives its dimensions in the product description rather than in a specification table: 76mm in diameter, 36mm in height, and a weight of .15lb (.08kg). It is a purely mechanical part — there is no glass in it — and its function is to let a 3-inch accessory work on a telescope that was never built with a 3-inch focuser.\u003c\/p\u003e\n\u003cp\u003eThe value of a piece like this is that it changes what an existing telescope can carry without changing the telescope. A 0.7X reducer and flattener is a substantial upgrade to a refractor's imaging performance, and this adapter is what puts one on a tube whose focuser is 2 inches.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of the FFFR507X-00 3-inch 0.7X field flattener focal reducer\u003c\/strong\u003e whose telescope has a 2-inch focuser rather than a 3-inch one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImagers upgrading an existing refractor\u003c\/strong\u003e who would rather add a reducer and flattener than replace the focuser or the tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of a 3-inch diagonal\u003c\/strong\u003e looking to use it on a telescope with a 2-inch focuser drawtube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone building an imaging train across two Explore Scientific size standards\u003c\/strong\u003e and needing the mechanical link between them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eObservers who have moved a flattener or diagonal between telescopes\u003c\/strong\u003e and now need the fitting for the second tube.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnects 3-inch accessories to a 2-inch focuser:\u003c\/strong\u003e the specific job it exists to do, and the reason a 3-inch flattener is not limited to 3-inch focusers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMade for the FFFR507X-00 0.7X field flattener focal reducer,\u003c\/strong\u003e which is the accessory Explore Scientific names for it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAlso takes a 3-inch diagonal onto a 2-inch focuser drawtube,\u003c\/strong\u003e so the same part covers a visual as well as an imaging case.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e76mm diameter, 36mm height:\u003c\/strong\u003e a compact connector that adds as little as possible to the optical train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e.15lb (.08kg) published weight:\u003c\/strong\u003e negligible next to the flattener or diagonal it carries, so it does not change the balance of a setup.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo optical elements:\u003c\/strong\u003e nothing in the light path to add reflections, scatter or aberration — it is a mechanical coupling only.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFitting the Explore Scientific 3-inch 0.7X field flattener focal reducer to a refractor with a 2-inch focuser.\u003c\/li\u003e\n\u003cli\u003eMounting a 3-inch diagonal on a 2-inch focuser drawtube for visual observing.\u003c\/li\u003e\n\u003cli\u003eBuilding an imaging train that spans Explore Scientific's 2-inch and 3-inch fittings.\u003c\/li\u003e\n\u003cli\u003eMoving a 3-inch flattener between a 3-inch-focuser telescope and a 2-inch-focuser telescope as your setup changes.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNamed accessory:\u003c\/strong\u003e Explore Scientific specifies this adapter for the FFFR507X-00 3-inch 0.7X Field Flattener Focal Reducer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocuser side:\u003c\/strong\u003e it is made for a 2-inch focuser, which covers the majority of refractors above about 80mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDiagonal use:\u003c\/strong\u003e Explore Scientific also lists it for mounting a 3-inch diagonal to a 2-inch focuser drawtube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeight in the train:\u003c\/strong\u003e the published height is 36mm. Every component in an imaging train consumes part of the available backfocus, so 36mm is the figure to work with when you are adding up the distance from the focuser to the sensor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread and fitting specification:\u003c\/strong\u003e Explore Scientific does not publish the thread sizes or the clamping method for this adapter. If you are matching it to something outside the two applications they name, send us the parts involved and we will confirm the fit with our Explore Scientific representative before you order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpacing:\u003c\/strong\u003e the reducer's optimum sensor spacing is a property of the reducer rather than of this adapter, and Explore Scientific does not state how the adapter's 36mm figures into it. Send us the camera and any spacers you have and we will work the numbers through with you.\u003c\/li\u003e\n\u003c\/ul\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\u003eThis is an adapter only.\u003c\/strong\u003e The FFFR507X-00 field flattener focal reducer, the diagonal and any camera-side spacers are separate items. We stock the flattener and can quote the pair together.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt contains no optics,\u003c\/strong\u003e so it does not change magnification, field or image quality on its own. It changes what mechanically fits, which is a different and equally necessary thing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt adds 36mm of length to the optical path.\u003c\/strong\u003e On a visual setup that is rarely an issue; in an imaging train, backfocus is a budget and 36mm is part of it. If you are close to the limit of your focuser travel, that is worth checking first.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific publishes no thread specification, material or finish detail\u003c\/strong\u003e for this part, so those rows read as not published in the table below rather than being estimated. Anything you need confirmed, we can ask them directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIts published weight is .15lb (.08kg),\u003c\/strong\u003e which is the part itself. That figure is worth having when you are totalling up an imaging train, and it is small enough not to affect balance.\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\u003eNo. It is a mechanical connector that goes between the 2-inch focuser and the 3-inch accessory, and it takes seconds to fit. Where care is worthwhile is in the imaging train as a whole, because the 36mm of height it adds is part of the total spacing between the reducer and the camera sensor — and we are glad to work that sum out with you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat exactly does it connect?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eExplore Scientific lists two applications: the 3-inch 0.7X Field Flattener Focal Reducer (FFFR507X-00) onto a telescope with a 2-inch focuser, and a 3-inch diagonal onto a 2-inch focuser drawtube.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it include the field flattener?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. This listing is the adapter alone. The FFFR507X-00 is a separate item, and we can put the two together on one order if that is easier.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it change the image?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNot by itself — it has no glass in it. The reducer does the optical work; this part is what lets the reducer attach.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much room does it take up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e76mm across and 36mm tall, at .15lb (.08kg). The 36mm is the number that matters when you are counting backfocus.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit my telescope?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIf your telescope has a 2-inch focuser, that is the side this adapter is made for. For anything unusual, send us the make and model of the telescope and the accessory you want to attach and we will confirm it before you order.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 76mm by 36mm, .15lb mechanical adapter that puts Explore Scientific's 3-inch 0.7X field flattener focal reducer — or a 3-inch diagonal — onto a telescope with a 2-inch focuser. If you tell us the telescope, the camera and the accessories you are joining up, we will check the spacing and the fit with you before anything ships.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013539491951,"sku":"510364","price":138.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/0510364_1_1800x1800__63738.jpg?v=1766555641"},{"product_id":"william-optics-flat73r-reducer-flattener-with-rotator","title":"William Optics Flat73R Reducer Flattener with Rotator","description":"\u003cspan style=\"font-family: Arial;\"\u003eIncrease your filed of view on the Zenith Star 73 with the William Optics 0.8x Reducer with built in rotator.  \u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial;\"\u003eThe adjustment ring allows for precise adjustment to get the correct spacing.  For DSLR's adjust the space ring to 1.8mm to get the required 55mm of back space when using a standard T-Ring.\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\n\u003cp style=\"margin: 0px 0px 1rem; padding: 0px; color: rgb(51, 51, 51); font-family: \" open sans arial neue helvetica sans-serif font-size: background-color: rgb\u003e\u003cimg src=\"https:\/\/williamoptics.com\/pub\/media\/wysiwyg\/Product\/P-FLAT73R\/Flat%2073%20R%203.jpg\" alt=\"\" style=\"margin: 0px; padding: 0px; border: 0px; height: auto; max-width: 100%; vertical-align: top;\"\u003e\u003c\/p\u003e\n\u003cp style=\"margin: 0px 0px 1rem; padding: 0px; color: rgb(51, 51, 51); font-family: \" open sans arial neue helvetica sans-serif font-size: background-color: rgb\u003e\u003cimg src=\"https:\/\/williamoptics.com\/pub\/media\/wysiwyg\/Product\/P-FLAT73R\/Flat%2073%20R%204.jpg\" alt=\"\" style=\"margin: 0px; padding: 0px; border: 0px; height: auto; max-width: 100%; vertical-align: top;\"\u003e\u003c\/p\u003e\n\u003cp style=\"margin: 0px 0px 1rem; padding: 0px; color: rgb(51, 51, 51); font-family: \" open sans arial neue helvetica sans-serif font-size: background-color: rgb\u003e\u003cimg src=\"https:\/\/williamoptics.com\/pub\/media\/wysiwyg\/Product\/P-FLAT73R\/Flat%2073%20R%205.jpg\" alt=\"\" style=\"margin: 0px; padding: 0px; border: 0px; height: auto; max-width: 100%; vertical-align: top;\"\u003e\u003c\/p\u003e\n\u003cp style=\"margin: 0px 0px 1rem; padding: 0px; color: rgb(51, 51, 51); font-family: \" open sans arial neue helvetica sans-serif font-size: background-color: rgb\u003e\u003cimg src=\"https:\/\/williamoptics.com\/media\/wysiwyg\/Product\/P-FLAT61R\/Flat%2061%20R%204%201.jpg\" alt=\"\" style=\"margin: 0px; padding: 0px; max-width: 100%; height: auto; border: 0px; vertical-align: top;\"\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":44013579173999,"sku":"P-FLAT73R","price":369.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/img_5404__54471.png?v=1766556837"},{"product_id":"x0-8-reducer-flattener-7a","title":"x0.8 Reducer Flattener 7A","description":"\u003cp style=\"box-sizing: border-box; padding: 0px; margin: 0px 0px 16px; font-family: Lato, sans-serif; line-height: 1.5; font-size: 16px; transition: none 0s ease 0s;\"\u003eThis William Optics Adjustable 0.8x Reducer\/Flattener is a great tool for those looking to increase their image quality. Made with Ohara optical glass, William Optics has designed the reducer\/flattener to be full frame ready! It has been designed to work with several different full frame camera types, whether they are CMOS or CCD. The flattener is known to work with the following:\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eM4\/3\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eNikon\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eCanon\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eSony a\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003ePentax\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eFUJI\u003c\/li\u003e\u003c\/ul\u003e\u003cp style=\"box-sizing: border-box; padding: 0px; margin: 0px 0px 16px; font-family: Lato, sans-serif; line-height: 1.5; font-size: 16px; transition: none 0s ease 0s;\"\u003e\u003cspan style=\"box-sizing: border-box; font-weight: bolder;\"\u003eThreads\u003c\/span\u003e\u003cbr style=\"box-sizing: border-box;\"\u003eOn the focuser side of the reducer\/flattener there is an M92 thread for the focuser. It can also connect to M48 T-Mounts and M48 threaded filters.\u003c\/p\u003e\u003cp style=\"box-sizing: border-box; padding: 0px; margin: 0px 0px 16px; font-family: Lato, sans-serif; line-height: 1.5; font-size: 16px; transition: none 0s ease 0s;\"\u003e\u003cspan style=\"box-sizing: border-box; font-weight: bolder;\"\u003eAdjustment Distanance for DSLR or Mirrorless Camera\u003c\/span\u003e\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eFLT132: 14.24 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eFLT156: 10.29 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eGT102: 15.6 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eGT153: 10.41 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eZ126: 12.76 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cp style=\"box-sizing: border-box; padding: 0px; margin: 0px 0px 16px; font-family: Lato, sans-serif; line-height: 1.5; font-size: 16px; transition: none 0s ease 0s;\"\u003e\u003cspan style=\"box-sizing: border-box; font-weight: bolder;\"\u003eBack Focus\u003c\/span\u003e\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eFLT132: 69.24 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eFLT156: 65.3 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eGT102: 70.6 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eGT153: 65.4 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eZ126: 67.76 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cp style=\"box-sizing: border-box; padding: 0px; margin: 0px 0px 16px; font-family: Lato, sans-serif; line-height: 1.5; font-size: 16px; transition: none 0s ease 0s;\"\u003e\u003cspan style=\"box-sizing: border-box; font-weight: bolder;\"\u003eImage Circle\u003c\/span\u003e\u003c\/p\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eFLT132: ? 44.4 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eFLT156: ? 44.4 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eGT102: ? 44.4 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eGT153: ? 44.4 mm\u003c\/li\u003e\u003c\/ul\u003e\u003cul style=\"box-sizing: border-box; font-family: Lato, sans-serif; font-size: 16px;\"\u003e\u003cli style=\"box-sizing: border-box;\"\u003eZ126: ? 43.4 mm\u003c\/li\u003e\u003c\/ul\u003e","brand":"Ontario Telescope and Accessories","offers":[{"title":"Default Title","offer_id":44013744062575,"sku":"P-FLAT7A","price":832.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/img_4902__75715.png?v=1766561516"},{"product_id":"skywatcher-0-85x-reducer-flattener-for-evostar-72ed","title":"Skywatcher 0.85x Reducer\/Flattener for EvoStar 72ED","description":"\u003cul\u003e\n\u003cli\u003eCompatible with both APS-C and full frame sensors, APS-C (crop sensors) and smaller recommended\u003c\/li\u003e\n\u003cli\u003e55mm back focus\u003c\/li\u003e\n\u003cli\u003eDrops f\/ratio from native f\/5.8 (420mm) to f\/4.93 (355mm)\u003c\/li\u003e\n\u003cli\u003eReduces exposure time by 38% compared to native f\/5.8\u003c\/li\u003e\n\u003cli\u003e5.8 x 3.87-degree field of view when used with a full frame camera\u003c\/li\u003e\n\u003cli\u003e3.79 x 2.53-degree field of view when used with APS-C crop sensor \u003c\/li\u003e\n\u003cli\u003eIncludes thread-on adapter to mount reducer to Evostar 72ED focuser\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":44013893582959,"sku":"S20212","price":580.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/S20212_Evostar72_Reducer_wIncludedAdapter2web_1800x1800__90537.jpg?v=1766565888"},{"product_id":"apex-ed-s-0-65x-reducer-flattener","title":"Apex ED 0.65x Reducer \/ Flattener - Short","description":"\u003cp\u003eWith the Apex ED reducer, an f\/5.5 apo refractor becomes an incredibly fast f\/3.6 astrograph. A slower f\/9 telescope like an RC becomes a speedy f\/5.9 system. The reduction factor provides a 1.5x wider field of view and shortens exposure times by a factor of 2.4x!\u003c\/p\u003e\n\u003cp\u003eThe Apex ED reducer features extra-low disperion glass to eliminate chromatic aberration and to provide sharp star images over a 30mm image circle, capable of working with most popular CCD, CMOS and DSLR cameras up to APS-C format.\u003c\/p\u003e\n\u003cp\u003eThe Apex ED reducer fits into a standard 2\" focuser. It has M42 T-threads on the camera side, and it can accept a standard 2\" (M48) filter on the telescope side for easy use of light-pollution or other filters. On Meade ACF telescopes, the Apex can be attached using a 2\" visual back.\u003c\/p\u003e\n\u003cp\u003eFor select refractors, we make\u003cspan\u003e optional threaded adapters\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003eto allow direct threaded attachment of the Apex reducer, eliminating the possibility of tilt introduced by the standard focuser clamp ring.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\"L\" and \"S\" Versions\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eTo optimize the Apex ED for the best possible performance, there are two versions of the lens. The \"L\" version is designed for telescopes with focal lengths 500mm and longer. This includes most larger (100mm+) refractors and all RC and ACF telescopes. The \"S\" version is for telescopes with focal lengths from 300-500mm, including most 60-80mm apo refractors.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eBackfocus\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe nominal backfocus distance from the Apex ED reducer's T-threads to the image sensor depends slightly on the focal length of the telescope. It is at least 55mm in all configurations. The table below shows the optimum backfocus for various focal lengths. Please contact us for help in choosing the right adapters or spacers necessary for your setup.\u003c\/p\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Apex-Chart_71daf9d2-16b6-4c77-9025-1666de0faac1.png?v=1766566099\" alt=\"Apex Backfocus Chart\"\u003e\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/threaded-adapter-set-up_072ffe11-4b39-4d08-a552-51d7b1eac34a.jpg?v=1766566100\"\u003e\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eSpecifications:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eReduction Factor\u003c\/strong\u003e: 0.65x\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImage Circle\u003c\/strong\u003e: 30mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus\u003c\/strong\u003e: 55-62mm (depending on telescope focal length)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical Design\u003c\/strong\u003e: 5 elements with ED glass, fully multi-coated\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBarrel Diameter\u003c\/strong\u003e: 2\"\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCamera Thread\u003c\/strong\u003e: M42 (T-thread)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilter Thread\u003c\/strong\u003e: M48 (2\" filter)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length (Apex ED L)\u003c\/strong\u003e: 2.97\"\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight (Apex ED L)\u003c\/strong\u003e: 0.7 lbs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOverall Length (Apex ED S)\u003c\/strong\u003e: 3.26\";\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight (Apex ED S)\u003c\/strong\u003e: 0.72 lbs\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Starizona","offers":[{"title":"Default Title","offer_id":44013907476591,"sku":"APEXED-S","price":649.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/apex-1_650x650__62967.jpg?v=1766566103"},{"product_id":"apex-ed-0-65x-reducer-flattener-long","title":"Apex ED 0.65x Reducer \/ Flattener Long","description":"\u003cp\u003eWith the Apex ED reducer, an f\/5.5 apo refractor becomes an incredibly fast f\/3.6 astrograph. A slower f\/9 telescope like an RC becomes a speedy f\/5.9 system. The reduction factor provides a 1.5x wider field of view and shortens exposure times by a factor of 2.4x!\u003c\/p\u003e\n\u003cp\u003eThe Apex ED reducer features extra-low disperion glass to eliminate chromatic aberration and to provide sharp star images over a 30mm image circle, capable of working with most popular CCD, CMOS and DSLR cameras up to APS-C format.\u003c\/p\u003e\n\u003cp\u003eThe Apex ED reducer fits into a standard 2\" focuser. It has M42 T-threads on the camera side, and it can accept a standard 2\" (M48) filter on the telescope side for easy use of light-pollution or other filters. On Meade ACF telescopes, the Apex can be attached using a 2\" visual back.\u003c\/p\u003e\n\u003cp\u003eFor select refractors, we make\u003cspan\u003e optional threaded adapters\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003eto allow direct threaded attachment of the Apex reducer, eliminating the possibility of tilt introduced by the standard focuser clamp ring.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\"L\" and \"S\" Versions\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eTo optimize the Apex ED for the best possible performance, there are two versions of the lens. The \"L\" version is designed for telescopes with focal lengths 500mm and longer. This includes most larger (100mm+) refractors and all RC and ACF telescopes. The \"S\" version is for telescopes with focal lengths from 300-500mm, including most 60-80mm apo refractors.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eBackfocus\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe nominal backfocus distance from the Apex ED reducer's T-threads to the image sensor depends slightly on the focal length of the telescope. It is at least 55mm in all configurations. The table below shows the optimum backfocus for various focal lengths. Please contact us for help in choosing the right adapters or spacers necessary for your setup.\u003c\/p\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Apex-Chart_51002c38-5d32-4c33-85c4-519d049754ac.png?v=1766568599\" alt=\"Apex Backfocus Chart\"\u003e\u003c\/div\u003e","brand":"Starizona","offers":[{"title":"Default Title","offer_id":44014041170031,"sku":"APEXED-L","price":649.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/apex-1_650x650__62967__23491.jpg?v=1766568601"},{"product_id":"william-optics-flat-6aiii-0-8x-reducer-flattener","title":"William Optics FLAT 6AIII 0.8x Reducer Flattener","description":"\u003cp\u003eThe \u003cstrong\u003eWilliam Optics FLAT 6AIII\u003c\/strong\u003e is a 0.8x reducer flattener designed for astrophotographers who want a wider field of view, faster imaging speed, and improved edge-to-edge star correction with compatible William Optics refractors.\u003c\/p\u003e\u003ch2\u003eWho Is This Product Best For?\u003c\/h2\u003e\u003cp\u003eBest for deep-sky astrophotographers using compatible William Optics refractors who want to reduce focal length while flattening the imaging field.\u003c\/p\u003e\u003ch2\u003eWhy Choose This Product?\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e0.8x reduction:\u003c\/strong\u003e Widens the field of view and speeds up imaging.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField correction:\u003c\/strong\u003e Helps improve star shape from centre to edge.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImaging-focused design:\u003c\/strong\u003e Built for camera-based astrophotography setups.\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\u003eFaster imaging with compatible refractors\u003c\/li\u003e\n\u003cli\u003eImproving corner star quality\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eUse with compatible William Optics refractors and the correct adapter\/backfocus spacing for your camera system. Check camera adapter, T-ring, filter wheel, and spacing requirements before imaging.\u003c\/p\u003e\u003ch2\u003eImportant Limitations\u003c\/h2\u003e\u003cp\u003eThis is 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 6AIII reduce focal length?\u003c\/h3\u003e\u003cp\u003eYes. It provides 0.8x reduction.\u003c\/p\u003e\u003ch3\u003eWhat problem does it solve?\u003c\/h3\u003e\u003cp\u003eIt helps flatten the field and improves edge star shape while widening the image field.\u003c\/p\u003e\u003ch2\u003eOur Recommendation\u003c\/h2\u003e\u003cp\u003eChoose the FLAT 6AIII if your compatible William Optics refractor needs a reducer\/flattener for faster wide-field deep-sky imaging.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":53154238988399,"sku":"P-FLAT6AIII","price":371.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/william-optics-flat-6aiii-reducer.jpg?v=1779654753"},{"product_id":"william-optics-flat-7a-0-8x-reducer-flattener","title":"William Optics FLAT 7A 0.8x Reducer Flattener","description":"\u003cp\u003eThe \u003cstrong\u003eWilliam Optics FLAT 7A\u003c\/strong\u003e is a 0.8x reducer\/flattener for compatible William Optics refractors. It is designed to widen the field of view, speed up the optical system, and improve edge-to-edge star correction for astrophotography.\u003c\/p\u003e\u003ch2\u003eWho Is This Product Best For?\u003c\/h2\u003e\u003cp\u003eBest for astrophotographers using compatible William Optics refractors who want faster wide-field imaging and flatter stars across the frame.\u003c\/p\u003e\u003ch2\u003eWhy Choose This Product?\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e0.8x reduction:\u003c\/strong\u003e Widens the field and speeds up imaging.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField correction:\u003c\/strong\u003e Helps improve corner star shape.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCamera-focused design:\u003c\/strong\u003e Built for deep-sky astrophotography systems.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eDeep-sky imaging\u003c\/li\u003e\n\u003cli\u003eWide-field astrophotography\u003c\/li\u003e\n\u003cli\u003eCompatible William Optics refractor setups\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eConfirm telescope compatibility, adapter thread, camera connection, 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 7A when your compatible William Optics refractor needs 0.8x focal reduction and field flattening for deep-sky imaging.\u003c\/p\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":53154247901295,"sku":"P-FLAT7A","price":1087.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/william-optics-flat-7a-reducer.jpg?v=1779654860"},{"product_id":"sky-watcher-0-77x-reducer-flattener-for-esprit-120ed","title":"Sky-Watcher 0.77x Reducer\/Flattener for Esprit 120ED","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Esprit 120ED Reducer\/Flattener is Sky-Watcher's 0.77x corrector for the Esprit 120ED. It does two jobs in one optic: it flattens the curved focal surface the triplet objective produces so corner stars stay round, and it shortens the system. Sky-Watcher publishes the change as a drop from native f\/7 (840mm) to f\/5.4 (647mm).\u003c\/p\u003e\n\u003cp\u003eThat faster ratio is the reason most people fit one. Sky-Watcher publishes a 68% reduction in exposure time compared with native f\/7 — the same signal arrives in a fraction of the integration, which shows up as more usable subs per night rather than as a change in what the telescope can resolve.\u003c\/p\u003e\n\u003cp\u003eThe field grows with it. Sky-Watcher publishes a 3.18 x 2.12-degree field of view on a full-frame camera and 2.08 x 1.39 degrees on an APS-C crop sensor, with a 34 mm fully illuminated field that the vendor states can handle full frame as well.\u003c\/p\u003e\n\u003cp\u003eThis is the reducing corrector for the Esprit 120ED. The Esprit 120EDX Flattener (S20218) is a different part — it flattens at native focal length and publishes no reduction.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is for Esprit 120ED owners imaging wide targets: large emission nebulae, open clusters with surrounding nebulosity, star fields, and anything that runs off the edge of the frame at 840 mm. At 647 mm and f\/5.4 the same telescope frames a noticeably wider field and gathers it faster.\u003c\/p\u003e\n\u003cp\u003eIt also suits anyone working from a site with limited clear time or heavy light pollution, where the 68% shorter exposure Sky-Watcher publishes translates directly into finishing a target in fewer nights.\u003c\/p\u003e\n\u003cp\u003eIf the goal is maximum image scale on small targets instead — galaxies, globulars, planetary nebulae — a plain flattener at native focal length is the part that serves 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\u003e0.77x reduction, published end to end:\u003c\/strong\u003e Sky-Watcher states the result as f\/7 (840mm) dropping to f\/5.4 (647mm) on the Esprit 120ED, so the working figures are the vendor's own rather than an estimate.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReducer and flattener in one optic:\u003c\/strong\u003e field curvature correction and focal reduction happen in the same unit, so only one element joins the imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e34 mm fully illuminated field:\u003c\/strong\u003e the vendor's published figure, with the note that it can handle full frame as well.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo backfocus configurations:\u003c\/strong\u003e 95 mm back-focus as supplied, or 55 mm with the back focus spacer and M48 ring installed — the 55 mm figure is the standard astro-camera spacing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBuilt-in 2\" filter cell:\u003c\/strong\u003e a 2-inch filter threads into the corrector itself, putting the filter in the light path without a separate drawer or spacer stack.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePublished fields of view:\u003c\/strong\u003e 3.18 x 2.12 degrees on full frame, 2.08 x 1.39 degrees on APS-C.\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 120ED imaging field, combined with a 0.77x focal reduction. Without a corrector, stars in the corners stretch radially while the frame centre focuses cleanly; this optic flattens that surface onto the sensor plane and shortens the system at the same time.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eResulting focal length and focal ratio:\u003c\/strong\u003e Sky-Watcher publishes the change as native f\/7 (840mm) to f\/5.4 (647mm). Both figures are the vendor's, stated for the Esprit 120ED specifically.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrected image circle:\u003c\/strong\u003e 34 mm fully illuminated, with Sky-Watcher noting it can handle full frame as well. A full-frame sensor's 43.3 mm diagonal sits outside the 34 mm fully illuminated circle, so the far corners of a full-frame chip fall in the region the vendor describes as usable rather than fully illuminated; an APS-C sensor at roughly 28 mm diagonal sits entirely inside it. The published fields of view follow from that — 3.18 x 2.12 degrees full frame, 2.08 x 1.39 degrees APS-C.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRequired backfocus:\u003c\/strong\u003e 95 mm as supplied, or 55 mm when the back focus spacer and M48 ring are installed. 55 mm is the distance most cooled astronomical cameras and filter wheels are built around, so the reconfigured setting is the one most imaging trains land on.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThread interface:\u003c\/strong\u003e M48, by way of the M48 ring that pairs with the 55 mm back focus configuration.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFilter mounting:\u003c\/strong\u003e the 2\" filter cell is built into the corrector, so a 2-inch filter sits inside the reduced light path rather than adding length to the train.\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 large emission and reflection nebulae, cluster-plus-nebulosity fields and Milky Way regions that overflow the native 840 mm frame.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShort-session and light-polluted imaging:\u003c\/strong\u003e the published 68% exposure reduction against native f\/7 puts more finished data into each clear night.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrowband work:\u003c\/strong\u003e the faster ratio offsets the transmission cost of narrow filters, and the built-in 2\" cell holds the filter in the light path.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAPS-C and full-frame imaging:\u003c\/strong\u003e APS-C sits inside the 34 mm fully illuminated field; full frame is covered by the vendor's stated capability with the published 3.18 x 2.12-degree frame.\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 publishes this corrector for the Esprit 120ED, and the reduction figures — f\/7 (840mm) to f\/5.4 (647mm) — are stated for that telescope. Other Esprit models pair with their own correctors, including the separate Esprit 120EDX Flattener, and refractors from other makers have their own. Send us the exact model printed on your tube and we will confirm which corrector belongs on it.\u003c\/p\u003e\n\u003cp\u003eThe two published backfocus settings shape the rest of the train. At 55 mm, with the back focus spacer and M48 ring installed, the corrector meets the standard most cooled astro cameras and filter wheels are dimensioned for. At 95 mm as supplied, the extra distance has to be filled by whatever sits between corrector and sensor. Send us your camera, filter wheel or drawer, off-axis guider and any adapters, and we will add the train up with you and confirm which configuration your setup wants.\u003c\/p\u003e\n\u003cp\u003eFilters thread into the built-in 2\" cell, so a 2-inch filter needs no separate drawer. Cameras with their own internal filter wheel simply leave that cell empty.\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\u003eThe published figures are for the Esprit 120ED.\u003c\/strong\u003e 840mm to 647mm and f\/7 to f\/5.4 are stated for that telescope. Other refractors reduce by their own numbers with their own correctors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus decides corner star shape.\u003c\/strong\u003e The corrector delivers 95 mm as supplied and 55 mm with the back focus spacer and M48 ring installed; the imaging train is built to whichever of those two figures you use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e34 mm is the fully illuminated field.\u003c\/strong\u003e Sky-Watcher states it can handle full frame as well, so a full-frame sensor's outer corners lie beyond the fully illuminated circle in the region the vendor describes as usable.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilter cell takes 2-inch filters.\u003c\/strong\u003e The built-in cell is sized for 2\" filters; other filter sizes go elsewhere in the train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is the reducing corrector, not the flattener.\u003c\/strong\u003e The Esprit 120EDX Flattener is a separate part that works at native focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVendor publishes no barcode for this SKU.\u003c\/strong\u003e The UPC we carry is 050234202091.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVendor lists 2.0 lb for this item.\u003c\/strong\u003e That is the published weight; no separate optic-only mass appears 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\u003eThe optic threads into the imaging train once and stays there. The decision that matters is which backfocus you build to — 95 mm as supplied, or 55 mm with the back focus spacer and M48 ring installed — and then adding the camera, filter wheel and adapters up to that number. Send us your components and we will do that arithmetic with you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat focal length and focal ratio do I end up with?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes the Esprit 120ED as dropping from native f\/7 (840mm) to f\/5.4 (647mm) with this reducer\/flattener fitted.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much faster is it in practice?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes a 68% reduction in exposure time compared with native f\/7 for the same result.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it cover a full-frame sensor?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes a 34 mm fully illuminated field and states it can handle full frame as well, quoting a 3.18 x 2.12-degree field of view on a full-frame camera and 2.08 x 1.39 degrees on APS-C.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat thread does it use?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eM48, via the M48 ring that goes with the 55 mm back focus configuration.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — there is a built-in 2\" filter cell for mounting filters, so a 2-inch filter sits in the light path without a separate drawer.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eSky-Watcher's own 0.77x corrector for the Esprit 120ED: f\/7 (840mm) becomes f\/5.4 (647mm), exposure time drops by a published 68%, the field opens to 3.18 x 2.12 degrees on full frame, and a 2\" filter threads straight into the corrector. Tell us what camera and filters you are running and we will confirm the 55 mm or 95 mm spacing with you before it ships.\u003c\/p\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":53896771436655,"sku":"S20209","price":730.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/S20209_Esprit120_RedFlat_web.jpg?v=1785253815"},{"product_id":"sky-watcher-0-77x-reducer-flattener-for-esprit-150ed","title":"Sky-Watcher 0.77x Reducer\/Flattener for Esprit 150ED","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe Esprit 150ED Reducer\/Flattener is Sky-Watcher's 0.77x corrector for the Esprit 150ED. It flattens the curved focal surface the triplet objective produces, so stars stay round out to the corners, and shortens the system at the same time. Sky-Watcher publishes the change as a drop from native f\/7 (1050mm) to f\/5.4 (810mm).\u003c\/p\u003e\n\u003cp\u003eOn the largest tube in the Esprit line, that shift matters most in time. Sky-Watcher publishes a 68% reduction in exposure time compared with native f\/7 — a 1050 mm f\/7 system is a demanding place to collect photons, and f\/5.4 turns the same target into a materially shorter project.\u003c\/p\u003e\n\u003cp\u003eThe frame widens with the reduction. Sky-Watcher publishes a 2.54 x 1.7-degree field of view on a full-frame camera and 1.66 x 1.11 degrees on APS-C, backed by a 36 mm fully illuminated field the vendor states is compatible with both APS-C and full frame sensors.\u003c\/p\u003e\n\u003cp\u003eThis is the reducing corrector for the Esprit 150ED. The Esprit 150EDX Flattener (S20219) is a separate part that flattens at native focal length and publishes no reduction.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is for Esprit 150ED owners who want the tube's aperture without its native 1050 mm framing — large emission nebulae, extended cluster fields, bright galaxy groups, anything that crowds the edges at f\/7. At 810 mm and f\/5.4 the same telescope covers 2.54 x 1.7 degrees on a full-frame sensor.\u003c\/p\u003e\n\u003cp\u003eIt also fits anyone whose clear nights are the scarce resource. The published 68% exposure reduction against native f\/7 is the difference between finishing a narrowband target over a season and finishing it over a few weeks.\u003c\/p\u003e\n\u003cp\u003eIf maximum image scale on small targets is the aim instead, a flattener working at the native 1050 mm is the part 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\u003e0.77x reduction, published end to end:\u003c\/strong\u003e Sky-Watcher states the result as f\/7 (1050mm) dropping to f\/5.4 (810mm) on the Esprit 150ED, so both working figures come from the vendor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReducer and flattener in one optic:\u003c\/strong\u003e curvature correction and focal reduction in a single unit, adding one element to the imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e36 mm fully illuminated field:\u003c\/strong\u003e Sky-Watcher's published figure, stated as compatible with both APS-C and full frame sensors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo backfocus configurations:\u003c\/strong\u003e 90 mm back-focus as supplied, or 55 mm with the back focus spacer and M48 ring installed — 55 mm being the spacing most cooled astro cameras are built around.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBuilt-in 2\" filter cell:\u003c\/strong\u003e a 2-inch filter mounts into the light path inside the corrector rather than in a separate drawer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComplete in the box:\u003c\/strong\u003e Sky-Watcher lists the reducer, metal thread-on caps, back focus spacer and M48 thread adapter as included.\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 150ED imaging field, combined with a 0.77x focal reduction. Uncorrected, the corners of a large sensor show stars stretched radially while the frame centre is sharp; this optic flattens that surface onto the sensor plane and shortens the system in the same pass.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eResulting focal length and focal ratio:\u003c\/strong\u003e Sky-Watcher publishes the change as native f\/7 (1050mm) to f\/5.4 (810mm), stated for the Esprit 150ED specifically.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrected image circle:\u003c\/strong\u003e 36 mm fully illuminated, which the vendor states is compatible with both APS-C and full frame sensors. An APS-C sensor's roughly 28 mm diagonal sits inside the fully illuminated circle; a full-frame sensor spans 43.3 mm, so its extreme corners fall outside the 36 mm figure in the region Sky-Watcher covers with the full-frame compatibility statement. The published fields follow — 2.54 x 1.7 degrees full frame, 1.66 x 1.11 degrees APS-C.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRequired backfocus:\u003c\/strong\u003e 90 mm as supplied, or 55 mm with the back focus spacer and M48 ring installed. 55 mm is the distance most cooled astronomical cameras and filter wheels are dimensioned to, so that is where most imaging trains settle.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThread interface:\u003c\/strong\u003e M48, via the included M48 thread adapter that pairs with the 55 mm back focus configuration.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFilter mounting:\u003c\/strong\u003e the built-in 2\" filter cell holds a 2-inch filter in the light path without adding a drawer or extra spacers to the train.\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 large emission and reflection nebulae, extended cluster fields and galaxy groups that run past the frame at 1050 mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNarrowband imaging:\u003c\/strong\u003e the faster f\/5.4 ratio offsets the transmission cost of narrow filters, and the built-in 2\" cell carries the filter in the light path.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLimited clear-sky sites:\u003c\/strong\u003e the published 68% exposure reduction against native f\/7 puts more finished signal into each usable night.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull-frame and APS-C imaging:\u003c\/strong\u003e the 36 mm fully illuminated field is published as compatible with both, at 2.54 x 1.7 and 1.66 x 1.11 degrees respectively.\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 publishes this corrector for the Esprit 150ED, and the f\/7 (1050mm) to f\/5.4 (810mm) figures are stated for that telescope. Other Esprit models pair with their own correctors — including the separate Esprit 150EDX Flattener — and refractors from other makers have theirs. Send us the exact model printed on your tube and we will confirm which corrector belongs on it.\u003c\/p\u003e\n\u003cp\u003eThe box covers most of the spacing work: reducer, metal thread-on caps, back focus spacer and M48 thread adapter are all included. With the spacer and M48 adapter fitted, the corrector presents 55 mm of back focus, which is what a typical cooled camera plus filter wheel is built to consume. As supplied without them, it presents 90 mm, and that distance is filled by whatever sits between corrector and sensor.\u003c\/p\u003e\n\u003cp\u003eSend us your camera, filter wheel or drawer, off-axis guider and adapters and we will add the imaging train up with you and confirm which of the two configurations your setup wants. Filters thread into the built-in 2\" cell; cameras with an internal filter wheel simply leave that cell empty.\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\u003eThe published figures are for the Esprit 150ED.\u003c\/strong\u003e 1050mm to 810mm and f\/7 to f\/5.4 are stated for that telescope. Other refractors reduce by their own numbers with their own correctors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfocus sets corner star shape.\u003c\/strong\u003e The corrector presents 90 mm as supplied and 55 mm with the back focus spacer and M48 ring installed; the rest of the train is built to whichever figure you use.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e36 mm is the fully illuminated field.\u003c\/strong\u003e Sky-Watcher states compatibility with both APS-C and full frame sensors, with a full-frame sensor's outer corners lying beyond the 36 mm fully illuminated circle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilter cell takes 2-inch filters.\u003c\/strong\u003e The built-in cell is sized for 2\" filters; other filter sizes go elsewhere in the train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is the reducing corrector, not the flattener.\u003c\/strong\u003e The Esprit 150EDX Flattener is a separate part working at native focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVendor publishes no barcode for this SKU.\u003c\/strong\u003e The UPC we carry is 050234202152.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVendor lists 2.0 lb for this item.\u003c\/strong\u003e That is the published weight; no separate optic-only mass appears 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\u003eThe reducer threads into the imaging train once and stays there, and the parts that set the spacing — the back focus spacer and the M48 thread adapter — come in the box. The one decision is which backfocus you build to, 90 mm or 55 mm, and then adding camera, filter wheel and adapters up to that figure. Send us your components and we will do that arithmetic with you.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat focal length and focal ratio do I end up with?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes the Esprit 150ED as dropping from native f\/7 (1050mm) to f\/5.4 (810mm) with this reducer\/flattener fitted.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much time does it save?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes a 68% reduction in exposure time compared with native f\/7.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it cover a full-frame sensor?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher publishes a 36 mm fully illuminated field described as compatible with both APS-C and full frame sensors, quoting 2.54 x 1.7 degrees on a full-frame camera and 1.66 x 1.11 degrees on APS-C.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat comes in the box?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eSky-Watcher lists the reducer, metal thread-on caps, back focus spacer and M48 thread adapter.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use filters with it?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — a built-in 2\" filter cell mounts filters into the light path, so a 2-inch filter needs no separate drawer.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eSky-Watcher's own 0.77x corrector for the Esprit 150ED: f\/7 (1050mm) becomes f\/5.4 (810mm), exposure time drops by a published 68%, the frame opens to 2.54 x 1.7 degrees on full frame, and the back focus spacer, M48 adapter and thread-on caps are in the box. Tell us what camera and filters you run and we will confirm the 55 mm or 90 mm spacing with you before it ships.\u003c\/p\u003e","brand":"Sky-Watcher","offers":[{"title":"Default Title","offer_id":53896779858031,"sku":"S20215","price":730.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/S20215_Esprit150_RedFlat_web.jpg?v=1785253906"},{"product_id":"explore-scientific-m48-adapter-3-inch-field-flattener-0-7x-reducer","title":"Explore Scientific M48 x 0.75 Camera Adapter for 3-inch Field Flattener and 0.7x Focal Reducer","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThis is the wide-thread camera adapter for Explore Scientific's 3-inch Field Flattener and 0.7x Focal Reducer, the corrector usually shortened to FFFR (item FFFR507X-00). The FFFR ships with an M42 x 0.75 adapter for CCD and DSLR cameras; this part replaces it with an M48 x 0.75 thread, opening up the camera end of the corrector. Explore Scientific states plainly that it must be purchased separately from the FFFR, and publishes a weight of 0.15 lb (0.08 kg). Vendor item number M48-0750.7x.\u003c\/p\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThis exists to solve one specific and frustrating problem: you bought a focal reducer to get a wider, faster field, and then discovered the corners of that wider field were dim. The 0.7x FFFR does its job well, compressing the image circle and dropping the focal ratio so that a given exposure goes further, but the standard M42 adapter that comes in the box presents a throat of only about 39 mm to the camera. A full-frame sensor measures 43.3 mm across the diagonal. The reducer is delivering a field the adapter behind it cannot pass, and the result is corner falloff that no amount of flat framing fully rescues.\u003c\/p\u003e\u003cp\u003eSwapping in this M48 x 0.75 adapter widens that final aperture so the corrector can actually deliver what it was designed to deliver. If you are running an APS-C or smaller sensor you may never need it, since a 28 mm diagonal fits through an M42 throat without complaint. If you have moved to a full-frame body, or you are running the FFFR on a fast scope where corner illumination is already working hard, this is the part that stops the adapter from being the limiting element in your imaging train. It is also the right choice if the rest of your train is already standardised on M48 and you would rather not stack step rings behind an expensive corrector.\u003c\/p\u003e\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eM48 x 0.75 camera thread, the wide standard used by Explore Scientific's M48 camera rings and 2-inch filters\u003c\/li\u003e\n\u003cli\u003eDirect replacement for the M42 x 0.75 CCD camera adapter supplied as standard with the 3-inch Field Flattener and 0.7x Focal Reducer\u003c\/li\u003e\n\u003cli\u003ePurpose-made for the FFFR507X-00, so it mates with the corrector's own fitting rather than relying on a stack of generic step rings\u003c\/li\u003e\n\u003cli\u003eRemoves the narrow M42 throat as the bottleneck in a reduced, wide-field imaging train\u003c\/li\u003e\n\u003cli\u003ePublished weight of 0.15 lb (0.08 kg), adding nothing meaningful to the load behind the focuser\u003c\/li\u003e\n\u003cli\u003eAll-threaded connection at both ends, so there is no compression ring to slip and no camera rotation mid-sequence\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eOptical and Mechanical Design\u003c\/h2\u003e\u003cp\u003eA focal reducer works by shortening the effective focal length, which shrinks the image scale and simultaneously widens the illuminated circle projected onto the sensor. The 0.7x factor means a scope at f\/7 becomes roughly f\/4.9, and the field being poured onto the sensor grows accordingly. That is precisely why the camera-side aperture matters more after a reducer than before one: you have deliberately made the light cone wider and shallower, and the last mechanical opening it passes through now sets your corner illumination. An M42 x 0.75 thread caps that opening at roughly 39 mm; M48 x 0.75 raises it well past the 43.3 mm full-frame diagonal. The second half of the design question is spacing. Every corrector has a designed distance from its rear element to the sensor, and missing it produces elongated or misshapen stars in the corners — the same symptom people often misread as collimation or tracking error. Because Explore Scientific presents this as a swap for the adapter the FFFR already ships with, it is intended to sit in the same place in the train rather than to change the corrector's spacing. Explore Scientific does not publish a light path length for it, so if you are working to an exact back focus figure, treat that number as something to confirm rather than assume.\u003c\/p\u003e\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eFull-frame DSLR, mirrorless or CCD imaging behind the Explore Scientific 3-inch Field Flattener and 0.7x Focal Reducer\u003c\/li\u003e\n\u003cli\u003eWide-field deep-sky work where corner illumination and flat field both matter\u003c\/li\u003e\n\u003cli\u003eStandardising an existing imaging train on M48 x 0.75 to remove step rings from behind the corrector\u003c\/li\u003e\n\u003cli\u003eReplacing the supplied M42 adapter after upgrading from a crop-sensor body to full frame\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\u003cp\u003eThis is a dedicated part for the Explore Scientific 3-inch Field Flattener and 0.7x Focal Reducer, FFFR507X-00. It is not a general-purpose thread ring, and that distinction is worth holding onto, because Explore Scientific also sells a general M48-to-M42 reduction adapter that sounds similar and does something quite different — that one bridges the two standards anywhere in a train, while this one is the camera-side fitting for one particular corrector. If you do not own the FFFR, this is almost certainly not the part you want. On the camera side you will need something with an M48 x 0.75 thread: Explore Scientific's M48 camera rings for Canon EOS and Nikon are the natural partners, and the M48 junction will also accept a 2-inch filter, since 2-inch astrophotography filters are cut to M48 x 0.75. Bear in mind that the ring only helps if it is the narrowest point you have fixed; a T2 ring left further down the chain will reimpose the same bottleneck. Spacing and fit behind a corrector are genuinely model-dependent, so tell our team in Bolton which camera and which scope you are running the FFFR on and we will confirm the combination before you order.\u003c\/p\u003e\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\u003cp\u003eThe most important thing to understand is that this is sold separately from the FFFR and is not an upgrade you receive with it — Explore Scientific says so directly on their own page. Buying the corrector does not get you this adapter. The camera ring is not included either, nor is any filter. Explore Scientific does not publish dimensions or a light path length for this item, only the 0.15 lb weight, so if your imaging train is tuned to a specific back focus we would rather measure it here than have you discover a discrepancy under clear skies; contact us and we will do that. Finally, this widens the camera end of the corrector only. It cannot improve illumination that was already lost further up the optical train, and it does not change the FFFR's optical performance in any way — it simply stops the mechanics from throwing away the field the glass is producing.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eDoes the 3-inch Field Flattener and 0.7x Focal Reducer already come with this?\u003c\/strong\u003e No. The FFFR ships with an M42 x 0.75 adapter for CCD cameras. This M48 version replaces it and must be bought separately, which Explore Scientific states explicitly.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need it if I shoot an APS-C camera?\u003c\/strong\u003e Probably not. A crop sensor has a diagonal of around 28 mm, comfortably inside what the standard M42 adapter passes. The M48 upgrade earns its place with full-frame sensors, or if you want the whole train on one thread standard.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this the same as the M48 to M42 reduction adapter?\u003c\/strong\u003e No. That is a general-purpose ring for joining the two thread standards anywhere in an imaging train. This is the camera-side adapter made specifically for the FFFR507X-00 corrector.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat do I screw onto the M48 end?\u003c\/strong\u003e An M48 x 0.75 camera ring for your body — Explore Scientific makes them for Canon EOS and Nikon — or a 2-inch filter, since 2-inch filters share the M48 x 0.75 thread.\u003c\/p\u003e\u003ch2\u003eBottom Line\u003c\/h2\u003e\u003cp\u003eIf you own the Explore Scientific 3-inch Field Flattener and 0.7x Focal Reducer and a full-frame camera, this is the adapter that lets the corrector finish the job it started, by taking the narrow M42 throat out of the light path. It is a small, purpose-built part and not a general thread ring, so make sure the FFFR is what you are fitting it to. Our team in Bolton will confirm the spacing and the camera-side parts with you before you order.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958709313647,"sku":"M48-0750.7x","price":50.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/M48-0750.7x_1.jpg?v=1785960903"},{"product_id":"takahashi-mewlon-focal-reducer-flattener","title":"Takahashi Mewlon Focal Reducer\/Flattener (M-FLRD)","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe M-FLRD is Takahashi's combined reducer, flattener, and corrector for the Mewlon Dall-Kirkham Cassegrain line. On the Mewlon-180C it brings the native 2160mm f\/12.0 down to 1760mm f\/9.8; on the Mewlon-210 it brings 2415mm f\/11.5 down to 1961mm f\/9.3, in both cases correcting the field to a 30mm image circle at the same time.\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 Mewlon-180C or Mewlon-210 and want a faster, flatter field for imaging rather than the native long-focal-length Cassegrain configuration typically used for planetary and lunar visual work.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThree functions in one unit:\u003c\/strong\u003e reduces the focal ratio, flattens the field, and corrects residual aberration for the Mewlon Cassegrain design.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMewlon-180C:\u003c\/strong\u003e 2160mm f\/12.0 native becomes 1760mm f\/9.8.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMewlon-210:\u003c\/strong\u003e 2415mm f\/11.5 native becomes 1961mm f\/9.3.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e30mm corrected image circle\u003c\/strong\u003e on both telescopes, with a matched 56.2mm back focus.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Mewlon's Dall-Kirkham Cassegrain design is optimized natively for long-focal-length planetary and lunar work; the M-FLRD trades some of that reach for a faster, corrected field better suited to deep-sky imaging on both the 180C and 210. Because it is a shared design across both apertures, the resulting f-ratio differs slightly between them — f\/9.8 on the 180C and f\/9.3 on the 210 — while the 30mm image circle and 56.2mm back focus hold constant.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eDeep-sky imaging on a Mewlon-180C or Mewlon-210 where a faster, flatter field is preferred over the native long-focus Cassegrain configuration; galaxy and planetary nebula framing at a more forgiving focal ratio.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi publishes this reducer\/flattener for two Mewlon models.\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eNative\u003c\/th\u003e\n\u003cth\u003eWith M-FLRD\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\u003eMewlon-180C\u003c\/td\u003e\n\u003ctd\u003e2160mm f\/12.0\u003c\/td\u003e\n\u003ctd\u003e1760mm f\/9.8\u003c\/td\u003e\n\u003ctd\u003eΦ30mm\u003c\/td\u003e\n\u003ctd\u003e56.2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMewlon-210\u003c\/td\u003e\n\u003ctd\u003e2415mm f\/11.5\u003c\/td\u003e\n\u003ctd\u003e1961mm f\/9.3\u003c\/td\u003e\n\u003ctd\u003eΦ30mm\u003c\/td\u003e\n\u003ctd\u003e56.2mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eFor spacing this reducer correctly with your camera, see 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 for Mewlon-250CRS or Mewlon-300CRS:\u003c\/strong\u003e those larger Mewlon CRS telescopes use the separate Reducer-CR and Extender-CR line rather than the M-FLRD.\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 to the Mewlon's rear cell in place of the standard visual back, with the 56.2mm back focus fixed by the unit rather than something to measure out separately.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eDeep-sky imaging on the Mewlon-180C or Mewlon-210 at a faster, corrected focal ratio.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the same part work on both the Mewlon-180C and Mewlon-210?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — it is a shared design, with a slightly different resulting f-ratio on each telescope.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it work on the Mewlon-250CRS or 300CRS?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — those models use the separate Reducer-CR\/Extender-CR line. If you are unsure which corrector matches your Mewlon, send us the model and we will confirm it.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe M-FLRD is the matched reducer, flattener, and corrector for the Mewlon-180C and Mewlon-210, trading some of the Mewlon's native reach for a faster, flatter 30mm image circle suited to deep-sky imaging.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047117475951,"sku":"TAK-TKA70581","price":549.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tmc1800_2_6.jpg?v=1786914202"}],"url":"https:\/\/ontariotelescope.com\/collections\/fr-reducer-flatteners.oembed","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}