{"title":"Takahashi FOA","description":"\u003cp\u003eThe Takahashi FOA line, listed by aperture. Part of \u003ca href=\"\/collections\/takahashi-telescopes\"\u003eTakahashi Telescopes\u003c\/a\u003e.\u003c\/p\u003e","products":[{"product_id":"takahashi-foa-60-60mm-f-8-8-ortho-apochromatic-refractor-ota","title":"Takahashi FOA-60 60mm f\/8.8 Ortho Apochromatic Refractor OTA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60 is Takahashi's Ortho Apochromat — a 60 mm fluorite doublet built for correction quality rather than field width, with a published Strehl ratio in excess of 96%, a figure normally associated with Takahashi's larger TOA series. At 530 mm focal length and f\/8.8 it is a slower, more deliberate design than the FS-60 line, in a retractable-dew-shield tube that weighs 1.8 kg.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if what you want from a 60 mm refractor is correction quality — tight, well-controlled stars for lunar and planetary detail and demanding double-star splits — rather than the widest possible field. It suits observers and imagers who already own a wide-field instrument and want a second, high-precision tube for close work, and anyone who wants a compact travel scope that performs like a considerably larger apochromat on the moon and planets.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOrtho Apochromat design:\u003c\/strong\u003e a two-element air-spaced fluorite doublet optimized for correction over field width — a published Strehl ratio above 96%.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e530 mm at f\/8.8:\u003c\/strong\u003e 60 mm aperture in a compact 500 mm tube.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e175.5 mm of back focus:\u003c\/strong\u003e ample working distance for a diagonal or camera train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRetractable dew shield:\u003c\/strong\u003e extends to 80 mm over a slim 68 mm tube for transport.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e84 mm drawtube extension\u003c\/strong\u003e on a rack-and-pinion focuser.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUpgrade path:\u003c\/strong\u003e the 1.7x EX extender converts it to the FOA-60Q configuration — 900 mm at f\/15 with a 44 mm image circle.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60 uses the same two-element, air-spaced fluorite doublet family as the rest of the FS\/FC line, but Takahashi has specified and figured it as an Ortho Apochromat — a design tier aimed at the correction levels normally reserved for the TOA triplets. The published Strehl ratio, in excess of 96% at prime focus and over 99% with the 1.7x extender fitted, describes how closely the wavefront approaches a theoretically perfect optic; in practice it shows up as tighter Airy disks and cleaner diffraction rings on planets and double stars than a standard doublet at this aperture delivers.\u003c\/p\u003e\u003cp\u003eHard multicoatings protect the fluorite element, and the 175.5 mm of back focus — generous for a 60 mm scope — is what leaves room for the FL 0.93x flattener or the EX 1.7xR extender to reach focus without running out of drawtube travel.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLunar and planetary observing:\u003c\/strong\u003e at 530 mm and f\/8.8, or extended to 900 mm and f\/15 with the EX 1.7xR extender.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDouble-star splitting:\u003c\/strong\u003e the high Strehl ratio is most visible on close, even-magnitude pairs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact travel observing:\u003c\/strong\u003e a 500 mm tube and 1.8 kg weight that packs down with the retractable dew shield.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlat-field imaging:\u003c\/strong\u003e with the FL 0.93x flattener, 495 mm at f\/8.2 across a 44 mm circle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh-resolution planetary imaging:\u003c\/strong\u003e with the EX 1.7xR extender, 900 mm at f\/15 across an 88 mm circle — the FOA-60Q configuration.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60's system chart and extender chart, both in the Downloads tab, list the exact adapters and distances for the flattener and extender configurations. Our \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e collects the same figures for the whole Takahashi range.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack focus:\u003c\/strong\u003e 175.5 mm at prime focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eField flattener:\u003c\/strong\u003e FL 0.93x — 495 mm, f\/8.2, 44 mm circle, 56.0 mm back focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtender:\u003c\/strong\u003e EX 1.7xR — converts the tube to the FOA-60Q configuration, 900 mm, f\/15, 88 mm circle, 208.1 mm back focus. The extender has its own system chart, included below.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMount:\u003c\/strong\u003e sold as an OTA — no mount, rings or dovetail included. At 1.8 kg it suits small to mid-sized equatorial and travel mounts.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you already own the EX 1.7xR extender or are considering it, send us your camera and filter setup and we will confirm the back focus with you.\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 an optical tube assembly.\u003c\/strong\u003e Mount, tripod, rings, dovetail, diagonal, eyepiece and finder are sold separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA flat field for imaging needs the FL 0.93x flattener.\u003c\/strong\u003e At prime focus the field curves, as on any doublet refractor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e60 mm still sets the light grasp.\u003c\/strong\u003e The Ortho design improves correction, not aperture — its strength is image quality on bright, small targets rather than reach on faint deep-sky objects.\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 — at prime focus it is a diagonal and eyepiece and you are observing. The flattener and extender configurations are documented on Takahashi's system charts in the Downloads tab, which list the parts and distances.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eLunar and planetary observing, double-star splitting, and high-resolution imaging once extended to the FOA-60Q configuration.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat does Ortho Apochromat mean, and how is this different from the FS-60CB?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt is a correction-focused design tier — a published Strehl ratio above 96% versus a standard doublet's typical figures — aimed at planetary and double-star performance rather than the FS-60CB's wide-field flexibility.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan this become a FOA-60Q?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — fitting the EX 1.7xR extender converts it to the FOA-60Q's 900 mm f\/15 configuration with an 88 mm image circle.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it need a flattener for astrophotography?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eFor a flat field to the edge of frame, yes — the FL 0.93x flattener corrects the native field curvature.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 60 mm fluorite Ortho Apochromat at 530 mm and f\/8.8, with a Strehl ratio above 96%, 175.5 mm of back focus, and an upgrade path to 900 mm f\/15 with the EX 1.7xR extender.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047053545583,"sku":"TAK-TFA06010","price":1791.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TFA06010_FOA-60_OTA_1.jpg?v=1786911866"},{"product_id":"takahashi-foa-60q-60mm-f-15-ortho-apochromatic-refractor-ota","title":"Takahashi FOA-60Q 60mm f\/15 Ortho Apochromatic Refractor OTA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60Q is the FOA-60's Ortho Apochromat objective with the 1.7x EX extender built permanently into the optical path — a 6-element, 4-group design running natively at 900 mm and f\/15, with an 88 mm corrected image circle. Takahashi publishes a theoretical Strehl ratio of 99.8% for this configuration, a figure the company states exceeds its own TOA-130 and TOA-150 triplets. The tube weighs 2.1 kg and extends to 707 mm.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you want the FOA-60's correction quality at long focal length without assembling the extender yourself — planetary and lunar observers chasing fine detail at high power, and double-star observers splitting close, faint pairs where wavefront quality matters as much as aperture. It suits imagers doing high-resolution planetary and lunar work who want a compact, dedicated long-focal-length apochromat rather than a general-purpose wide-field tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOrtho Apochromat with built-in extender:\u003c\/strong\u003e six elements in four groups — the FOA-60 doublet plus a permanently mounted 1.7x extender group.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e900 mm at f\/15:\u003c\/strong\u003e native focal length and ratio, with an 88 mm corrected image circle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e99.8% theoretical Strehl ratio,\u003c\/strong\u003e per Takahashi — correction Takahashi states exceeds its TOA-130 and TOA-150 triplets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e208.1 mm of back focus:\u003c\/strong\u003e ample room for a diagonal or imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e84 mm drawtube extension\u003c\/strong\u003e on a rack-and-pinion focuser.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2.1 kg:\u003c\/strong\u003e compact for the focal length, in a tube that extends to 707 mm.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe front two elements are the FOA-60's Ortho Apochromat fluorite doublet — already specified for correction levels associated with Takahashi's TOA triplets — with a four-element 1.7x extender group permanently mated behind it, rather than sold as a separate accessory. The combination is what produces the published 99.8% theoretical Strehl ratio, and Takahashi's own comparison places that figure above the TOA-130 and TOA-150.\u003c\/p\u003e\u003cp\u003eHard multicoatings protect the fluorite surfaces, and the 208.1 mm of back focus — generous for a 60 mm-aperture tube — is what makes room for a diagonal, filter wheel or high-resolution planetary camera without running short on drawtube travel. Because the extender is integrated rather than an add-on, there is no shorter native configuration on this tube — removing the extender group returns it to a standard FOA-60.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh-power planetary and lunar observing:\u003c\/strong\u003e at 900 mm and f\/15, where the high Strehl ratio shows up as tighter, cleaner diffraction detail.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClose double-star splitting:\u003c\/strong\u003e correction quality matters as much as aperture for faint, tight pairs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigh-resolution planetary imaging:\u003c\/strong\u003e the long native focal length suits lucky-imaging style planetary cameras without an additional Barlow.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompact long-focal-length visual work:\u003c\/strong\u003e 900 mm in a tube that still travels, at 2.1 kg.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60Q's system chart and extender-specific chart, both in the Downloads tab, list the adapters and distances Takahashi publishes for this configuration. Our \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e collects the same figures for the whole Takahashi range.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack focus:\u003c\/strong\u003e 208.1 mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImage circle:\u003c\/strong\u003e 88 mm, corrected.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVisual train:\u003c\/strong\u003e a 1.25-inch or 2-inch diagonal and eyepiece attach through the matching Takahashi visual adapter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMount:\u003c\/strong\u003e sold as an OTA — no mount, rings, finder or dovetail included. At 2.1 kg it suits small to mid-sized equatorial mounts, though 900 mm of focal length asks more of tracking accuracy than a wide-field scope.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you are planning a planetary imaging train and want to confirm your camera's back focus, send us the details and we will work it out with you.\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 an optical tube assembly.\u003c\/strong\u003e Mount, tripod, rings, dovetail, diagonal, eyepiece and finder are sold separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe extender is built in, not removable as a separate accessory purchase.\u003c\/strong\u003e There is no shorter native configuration on this specific tube listing — for that, the FOA-60 without the extender is the base model.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e60 mm still sets the light grasp.\u003c\/strong\u003e The Ortho design and extender improve correction and reach, not aperture — its strength is planetary and double-star detail rather than faint deep-sky targets.\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 — at prime focus it is a diagonal and eyepiece and you are observing. The system chart in the Downloads tab lists the adapters and distances for imaging.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eHigh-power lunar and planetary observing and imaging, and close double-star splitting, where the 99.8% theoretical Strehl ratio is most visible.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the difference between the FOA-60 and FOA-60Q?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe FOA-60Q has the 1.7x extender permanently built into the optical path — 900 mm at f\/15 instead of the FOA-60's native 530 mm at f\/8.8 — rather than being added as a separate accessory.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it need additional accessories for imaging?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe 88 mm image circle and 208.1 mm of back focus are already corrected for this configuration; a planetary or lunar camera attaches through the standard visual train without an additional flattener.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill it work on a small mount?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAt 2.1 kg the tube is light, but 900 mm of focal length benefits from steady tracking. Tell us which mount you are using and we will confirm the fit.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 60 mm fluorite Ortho Apochromat running natively at 900 mm and f\/15, with an 88 mm image circle, 208.1 mm of back focus, and a published 99.8% theoretical Strehl ratio built for high-resolution planetary and lunar work.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047056986223,"sku":"TAK-TFA06110","price":2341.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TFA06110_FOA-60Q_OTA_1.jpg?v=1786912003"},{"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-foa-60-extender-1-7xr","title":"Takahashi FOA-60 Extender 1.7XR","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60 Extender 1.7XR converts Takahashi's FOA-60 Ortho Apochromat to the same 900mm f\/15.0 configuration published for the dedicated FOA-60Q optical tube, with the image circle opening to 88mm and back focus extending to 208.1mm. It is built into the optical path the same way the FOA-60Q's factory objective is, rather than mounting on the drawtube as a Barlow would.\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 the FOA-60Q's long-focal-length performance — high-resolution lunar and planetary imaging and high-power visual observing — without buying a second optical tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eConverts FOA-60 to FOA-60Q spec:\u003c\/strong\u003e 530mm f\/8.8 becomes 900mm f\/15.0, matching Takahashi's own FOA-60Q tube exactly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e88mm image circle\u003c\/strong\u003e at the extended focal length, with 208.1mm back focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePreserves the FOA-60's correction:\u003c\/strong\u003e Takahashi states the resulting system holds a Strehl ratio above 99% across nearly the full visible spectrum.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupports high magnification:\u003c\/strong\u003e Takahashi rates it for visual magnifications up to 300x while keeping the image clean.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60's 60mm fluorite doublet objective is built for correction quality over field width; the 1.7XR extender lengthens the light path to 900mm at f\/15.0 — identical to the factory FOA-60Q configuration — while the doublet's inherent correction keeps the Strehl ratio high through the extended path. This is the same route Takahashi uses to build the FOA-60Q itself, applied to an FOA-60 already in the field.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eHigh-resolution lunar and planetary imaging, and high-magnification visual observing of the Moon, planets, and double stars, on an FOA-60.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi publishes this pairing for the FOA-60 specifically.\u003c\/p\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eTelescope\u003c\/th\u003e\n\u003cth\u003eNative\u003c\/th\u003e\n\u003cth\u003eWith EX 1.7xR\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\u003e900mm f\/15.0\u003c\/td\u003e\n\u003ctd\u003eΦ88mm\u003c\/td\u003e\n\u003ctd\u003e208.1mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eThe resulting figures match Takahashi's own FOA-60Q optical tube exactly. It is not combined with the FOA-60 0.93x Flattener, which serves the opposite, wide-field configuration of the same tube. See the \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e for general spacing reference.\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 0.93x Flattener:\u003c\/strong\u003e the two accessories serve opposite configurations of the FOA-60 and are not used together.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — it installs into the optical path the same way the FOA-60Q's factory objective assembly does, with the resulting 208.1mm back focus fixed by the conversion.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eHigh-resolution lunar and planetary imaging and high-power visual observing.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes this make my FOA-60 an FOA-60Q?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eOptically, yes — the resulting focal length, ratio, image circle, and back focus match Takahashi's FOA-60Q tube exactly.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I still use the FOA-60 at its native focal length afterward?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe extender is a conversion rather than a drop-in accessory; if you want to switch back and forth between native and extended configurations, send us your setup and we will confirm what that involves.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FOA-60 Extender 1.7XR turns an FOA-60 into the optical equivalent of Takahashi's FOA-60Q — 900mm at f\/15.0 with an 88mm image circle and 208.1mm of back focus, for high-resolution lunar and planetary work.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047122686063,"sku":"TAK-TKA28595","price":818.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TKA28595_1.jpg?v=1786914498"}],"url":"https:\/\/ontariotelescope.com\/collections\/takahashi-foa.oembed","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}