{"title":"Takahashi Astrographs","description":"\u003cp\u003eTakahashi astrographs include the Epsilon-130D, E-160ED and E-180ED hyperbolic astrographs at f\/3.3 to f\/2.8, the FSQ-80FC quintuplet and FSQ-85EDX Petzval refractors, and the CCA-250 250mm f\/5 corrected Cassegrain. Part of \u003ca href=\"\/collections\/astrographs\"\u003eAstrograph Telescopes\u003c\/a\u003e.\u003c\/p\u003e","products":[{"product_id":"takahashi-epsilon-e-160ed-160mm-f-3-3-hyperbolic-astrograph-ota","title":"Takahashi Epsilon E-160ED 160mm f\/3.3 Hyperbolic Astrograph OTA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Epsilon-160ED is a 160 mm hyperbolic Newtonian astrograph from Takahashi, built for deep-sky imaging at a native f\/3.3. A hyperbolic primary mirror, flat secondary, and an integrated field-flattening corrector work together inside the tube, so there is no separate flattener to buy, align, or space out. The 530 mm focal length puts a flat 44 mm image circle 56.2 mm behind the focuser, and the published tube weight of 6.9 kg keeps it well inside the payload of a mid-size equatorial mount carrying a full imaging train.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you image deep-sky targets — nebulae, galaxies, and star clusters — and want the light-gathering speed of f\/3.3 without the curved focal plane and flat-field-adapter fuss of a Schmidt camera design. It suits an imager already comfortable with reflector collimation, since a Newtonian-derived optical path benefits from periodic checking. It is not built for eyepiece observing — the fast mirror and integrated flattener are optimized for a sensor at a fixed backfocus, not a diagonal and eyepiece.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHyperbolic primary + flat secondary + integrated flattener:\u003c\/strong\u003e corrects coma and field curvature inside the tube, with no separate corrector lens to purchase or space.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ef\/3.3 native speed:\u003c\/strong\u003e a 530 mm focal length gathers light quickly, shortening exposure times for faint targets compared with a conventional f\/6–f\/8 reflector.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm image circle:\u003c\/strong\u003e covers full-frame and APS-C sensors, with the design holding spot size under roughly 3 micrometers at the field edge.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOversized rack-and-pinion focuser with integrated Camera Angle Adjuster:\u003c\/strong\u003e lets you rotate the imaging train to frame a target without loosening the tube rings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemovable central mirror cover:\u003c\/strong\u003e exposes the primary to ambient air for faster thermal acclimation before a session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOpen spider-vane secondary support:\u003c\/strong\u003e reduces scattered light and diffraction spikes around bright stars.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Epsilon-160ED's optical path combines a 160 mm hyperbolic primary mirror with a flat secondary and a built-in multi-element field flattener, a configuration Takahashi calls a modified hyperbolic Newtonian. Unlike a Schmidt camera, the focal plane is flat and the corrective elements live inside the tube rather than as a separate accessory train, which keeps the back focus fixed at 56.2 mm from the focuser's rear end. At f\/3.3 the design cuts exposure times sharply against slower reflectors while holding the 44 mm image circle flat and coma-free. An optional Ɛ-EX 160ED extender changes the configuration to 800 mm at f\/5.0, with the same 44 mm image circle and 56.2 mm back focus, for imagers who want tighter framing on the same optical tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eWide- to moderate-field deep-sky astrophotography of nebulae, galaxies and star clusters; narrowband and broadband imaging with a cooled CMOS or CCD camera; observatory or portable imaging rigs built around a fast reflector rather than a refractor.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe 56.2 mm back focus is measured from the rear end of the focuser to the focal plane and is fixed by the integrated flattener — there is no field-flattener spacing to calculate for prime focus imaging. Camera trains, filter drawers and off-axis guiders all need to fit inside that figure, so it is worth checking your full imaging stack against it before ordering. The \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e covers this and the Ɛ-EX 160ED extender configuration in detail. Because this is a Newtonian-derived design, periodic collimation is part of ownership — Takahashi's collimating tools work with this tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eNot built for eyepiece observing:\u003c\/strong\u003e the fast mirror and fixed-backfocus flattener are matched to a camera sensor, not a diagonal and eyepiece.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCollimation is periodic maintenance, not a one-time setup:\u003c\/strong\u003e like any fast Newtonian-derived optic, the mirrors benefit from a collimation check after transport, and Takahashi's own collimating eyepiece and telescope handle it directly.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eMount and tripod are not included:\u003c\/strong\u003e this listing is the optical tube assembly only.\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\u003eThe optical side is straightforward — the flattener is built in, so there is no separate corrector to space out. The part that takes practice is collimation, which any fast Newtonian-derived design needs checked periodically; Takahashi's collimating tools are built for this tube.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eDeep-sky astrophotography at a fast focal ratio — nebulae, galaxies and clusters that benefit from short sub-exposures at f\/3.3.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it for visual observing?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt has no real application in a visual eyepiece train; the flattener and back focus are set for a camera sensor.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat cameras does it fit?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAny cooled CMOS or CCD astronomy camera that can reach the 56.2 mm back focus with its own nosepiece, filter wheel or off-axis guider included in that figure — send us your camera and filter setup and we will work it out with you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow is this different from the Epsilon-180ED?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe 180ED steps up to a 180 mm aperture and a faster f\/2.8, with a larger, heavier tube; the 160ED is the lighter, more mount-friendly option at f\/3.3.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 160 mm f\/3.3 hyperbolic astrograph with the flattener built in, delivering a flat 44 mm image circle at a fixed 56.2 mm back focus for fast deep-sky imaging.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047049285743,"sku":"TEK16010","price":5570.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TEK16010_1.jpg?v=1786911556"},{"product_id":"takahashi-fsq-80fc-80mm-f-5-6-quintuplet-astrograph-refractor-ota","title":"Takahashi FSQ-80FC 80mm f\/5.6 Quintuplet Astrograph Refractor OTA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FSQ-80FC is Takahashi's compact 80 mm imaging refractor, built around a 5-element optical design with dual fluorite elements. At a native 450 mm focal length and f\/5.6, it is intended as a wide-field astrograph rather than a visual scope — the flat field and 50 mm image circle cover a full-frame sensor without a separate flattener. Takahashi lists a tube weight of approximately 4.1 kg.\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 a wide-field, grab-and-go imaging refractor that travels light — the compact tube and roughly 4.1 kg weight suit a smaller equatorial mount or a travel setup, and the flat 50 mm image circle covers full-frame sensors without an accessory flattener to buy separately.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e5-element optical design with dual fluorite elements:\u003c\/strong\u003e corrects chromatic aberration and field curvature within the tube, without a separate corrector.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e450 mm focal length at f\/5.6:\u003c\/strong\u003e a fast, wide field of view suited to nebulae, star clusters and large-scale mosaic targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e50 mm image circle:\u003c\/strong\u003e covers full-frame sensors with a flat field, as published by Takahashi.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNative M48 interface with 55 mm back focus:\u003c\/strong\u003e supports direct camera attachment with minimal adapter stacking, reducing flexure in the imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRetracting dew shield:\u003c\/strong\u003e tube length runs 486 mm retracted to 559 mm extended for storage and transport.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRack-and-pinion focuser:\u003c\/strong\u003e holds a full imaging train of camera, filter wheel and guider.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FSQ-80FC carries Takahashi's quintuplet Petzval-derived design — five elements including two fluorite lenses — aimed at flattening the field and correcting color across the frame without a separate flattener accessory. At f\/5.6 and 450 mm focal length it trades focal length for field width and speed, the combination astrographs are built around. The aluminum tube and fully multi-coated optics are typical of the FSQ line's imaging-first design; where Takahashi's other refractors are sold as visual-capable OTAs with an optional flattener, the FSQ-80FC's flattening is built into the base optical prescription.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eWide-field deep-sky astrophotography of nebulae, large star clusters and galaxy fields; full-frame mosaic imaging; travel and portable imaging rigs where tube weight and length matter.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi publishes a 55 mm back focus from the native M48 interface, which is enough to seat most cooled cameras directly or with a thin adapter stack — filter wheels and off-axis guiders add up quickly against that figure, so it is worth checking your full imaging train before ordering.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003ePublished weight is approximate:\u003c\/strong\u003e Takahashi's own listing states \"approx. 4.1 kg\" rather than an exact figure.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eMount and tripod are not included:\u003c\/strong\u003e this listing is the optical tube assembly only.\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 — the flattening is built into the optics, so there is no separate corrector to thread on and space out. The M48 interface accepts a camera directly once your adapter stack is sorted.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eWide-field deep-sky astrophotography where a fast, short-focal-length refractor covers more sky per frame than a longer telescope.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it for visual observing?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt is built and marketed as an imaging astrograph; its native interface and back focus are set for a camera, not an eyepiece.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat cameras does it fit?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAny camera that reaches the 55 mm back focus through the M48 interface, including full-frame cooled CMOS and CCD cameras — send us your camera and filter setup and we will work it out with you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow is this different from the FSQ-85EDX?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThey are separate optical designs, each on its own specification sheet — figures for one do not describe the other.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a compact 80 mm f\/5.6 quintuplet astrograph with a built-in flattener, a 50 mm image circle, and roughly 4.1 kg of travel-friendly weight, built for wide-field imaging over visual use.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047049384047,"sku":"TQE08041","price":6176.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/fsq-80fc_-1-1024x576_jpg.png?v=1786911606"},{"product_id":"takahashi-epsilon-180ed-180mm-f-2-8-hyperbolic-flat-field-astrograph-ota","title":"Takahashi Epsilon 180ED 180mm f\/2.8 Hyperbolic Flat-Field Astrograph OTA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Epsilon-180ED is Takahashi's largest and fastest Epsilon astrograph, a 180 mm hyperbolic Newtonian design running at a native f\/2.8. A hyperbolic primary mirror, flat secondary, and an integrated field-flattening corrector combine inside the tube to put a flat 44 mm image circle 56.2 mm behind the focuser, with no separate corrector to buy or align. The published tube weight is 10.7 kg, putting it toward the upper end of what a mid-to-large equatorial mount should carry with a full imaging train attached.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if your priority is imaging speed — f\/2.8 gathers light quickly enough to shorten exposure times noticeably against slower optics, which matters most for faint, extended nebulosity. It suits an imager already running a fast reflector or astrograph, since the larger 180 mm mirror and 10.7 kg tube ask for a mount with real payload margin and benefit from a user comfortable checking collimation.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHyperbolic primary + flat secondary + integrated flattener:\u003c\/strong\u003e corrects coma and field curvature inside the tube, with no separate corrector to purchase or space.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ef\/2.8 native speed:\u003c\/strong\u003e among the fastest astrograph designs Takahashi builds, cutting exposure times sharply against conventional reflectors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm image circle:\u003c\/strong\u003e covers full-frame and APS-C sensors with a flat field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRack-and-pinion focuser with rotary framing and integrated Camera Angle Adjuster:\u003c\/strong\u003e rotates the imaging train to frame a target without loosening the tube rings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccessible collimation with reference marks on both mirrors:\u003c\/strong\u003e makes checking and adjusting the optical alignment more direct than on a typical Newtonian.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Epsilon-180ED combines a 180 mm hyperbolic primary with a flat secondary and a built-in multi-element field flattener — the same modified-hyperbolic-Newtonian family as the smaller Epsilon-160ED, scaled up to a larger primary and a faster f\/2.8. Takahashi's own comparison places this design's chromatic performance below that of a conventional Schmidt camera at the same speed, while keeping the focal plane flat without a curved plate or field corrector as a separate purchase. Back focus is fixed at 56.2 mm from the focuser's rear end. An optional Ɛ-EX 180ED extender changes the configuration to 780 mm at f\/4.3, holding the same 44 mm image circle and 56.2 mm back focus, for imagers who want a longer effective focal length on the same tube.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eFast deep-sky astrophotography of faint nebulae, galaxies and extended objects where exposure time matters; narrowband and broadband imaging with a cooled CMOS or CCD camera; observatory imaging setups built around a large, fast reflector.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe 56.2 mm back focus is fixed by the integrated flattener and measured from the rear of the focuser to the focal plane — camera body, filter wheel and any off-axis guider all need to fit within that figure together. The \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e covers this figure and the Ɛ-EX 180ED extender configuration, and we're glad to check a specific camera and filter setup against it before you order. As a Newtonian-derived design, the mirrors benefit from a collimation check after transport, and the built-in reference marks make that a more direct process than on many reflectors.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eNot built for eyepiece observing:\u003c\/strong\u003e the fast mirror and fixed-backfocus flattener are matched to a camera sensor.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eA larger mount than the Epsilon-160ED needs:\u003c\/strong\u003e at 10.7 kg published weight, this is a heavier tube than Takahashi's smaller Epsilon models and is worth checking against your mount's imaging payload rating, not just its rated visual capacity.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eMount and tripod are not included:\u003c\/strong\u003e this listing is the optical tube assembly only.\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\u003eThe flattener is built in, so there is no separate corrector to space out. Collimation is the part that takes practice on any fast Newtonian-derived design, and the reference marks on both mirrors here are built to make that check more direct.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eFast deep-sky astrophotography where exposure time and light-gathering speed matter more than reach — faint nebulae, galaxies and wide extended targets.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it for visual observing?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt has no real application in a visual eyepiece train; the flattener and back focus are set for a camera sensor.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat cameras does it fit?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAny cooled CMOS or CCD astronomy camera reaching the 56.2 mm back focus with its own nosepiece, filter wheel or off-axis guider included in that figure — send us your camera and filter setup and we will work it out with you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow is this different from the Epsilon-160ED?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe 180ED is larger and faster — 180 mm aperture at f\/2.8 against 160 mm at f\/3.3 — and correspondingly heavier at 10.7 kg against 6.9 kg.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 180 mm f\/2.8 hyperbolic astrograph with the flattener built in, delivering a flat 44 mm image circle at a fixed 56.2 mm back focus for imagers who want the fastest deep-sky speed Takahashi's Epsilon line offers.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047050498159,"sku":"TEK18010","price":6585.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TEK18010_Epsilon-180ED_OTA_1.jpg?v=1786911699"},{"product_id":"takahashi-epsilon-130d-f-3-3-hyperbolic-astrograph-ota","title":"Takahashi Epsilon-130D f\/3.3 Hyperbolic Astrograph OTA","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Epsilon-130D is Takahashi's 130 mm hyperbolic astrograph — a fast, wide-field imaging system rather than a visual telescope. At 430 mm focal length and f\/3.3 in a 460 mm tube, it covers a 44 mm image circle at native focus and weighs 4.9 kg. The digital-generation redesign of Takahashi's original 1980s Epsilon series, it uses a hyperbolic primary and a digital corrector built specifically for modern CMOS and CCD sensors.\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 speed and field over reach — f\/3.3 gathers light fast enough to shorten exposure times on faint, extended targets, and the 44 mm corrected circle covers full-frame sensors at native focus, no separate flattener needed. It suits imagers working large emission nebulae, wide star fields and the kind of targets that need field, not focal length, and its 4.9 kg weight and airline-transportable design make it a workable travel astrograph.\u003c\/p\u003e\u003cp\u003eIt is not built for eyepiece observing — there is no meaningful visual use case at f\/3.3 with a Newtonian-style light path. If wide-field imaging is the goal, tell us your camera and mount and we will confirm the fit.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHyperbolic primary with digital corrector:\u003c\/strong\u003e a redesigned optical train delivering sub-10 µm spots across the field, tuned for modern digital sensors.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e430 mm at f\/3.3:\u003c\/strong\u003e fast enough to shorten integration time on faint, extended targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e44 mm corrected image circle\u003c\/strong\u003e at native focus — full-frame coverage without a separate flattener.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4.9 kg:\u003c\/strong\u003e light for a fast 130 mm astrograph, and compact enough to check as airline baggage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e23 mm of drawtube extension\u003c\/strong\u003e and a 56.2 mm back focus at prime.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.5x extender compatible:\u003c\/strong\u003e the Ɛ-EX 130D converts the system to 650 mm at f\/5.0, still a 44 mm circle.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe Epsilon-130D uses a hyperbolic primary mirror paired with a multi-element digital corrector positioned ahead of the focal plane — the corrector is what flattens the field and controls coma across a fast f\/3.3 system, delivering sub-10 µm spot sizes at the design wavelengths. This is a purpose-built imaging design: there is no accessible focal plane for a diagonal and eyepiece, and the light path exists to put a flat, corrected image on a sensor.\u003c\/p\u003e\u003cp\u003eThe Ɛ-EX 130D 1.5x extender converts the system to 650 mm at f\/5.0, still with a 44 mm corrected circle and 56.2 mm back focus — useful for tighter framing on smaller targets without leaving the Epsilon-130D's optical train.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field deep-sky imaging:\u003c\/strong\u003e at 430 mm and f\/3.3, large emission nebulae and star fields across a 44 mm circle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFast narrowband imaging:\u003c\/strong\u003e the f\/3.3 speed shortens exposure times where signal is otherwise faint.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTighter framing:\u003c\/strong\u003e with the Ɛ-EX 130D 1.5x extender at 650 mm and f\/5.0, for smaller targets.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTravel astrophotography:\u003c\/strong\u003e compact and light enough for portable rigs and checked baggage.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eBack focus at prime is 56.2 mm, unchanged with the Ɛ-EX 130D extender fitted — a tight figure that camera and filter-wheel stacks need to hit precisely to reach focus and keep the field flat. The Epsilon-130D's own system chart, in the Downloads tab, lists the exact parts and distances for both configurations. Our \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e collects these figures for the whole Takahashi range in one table.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtender:\u003c\/strong\u003e Ɛ-EX 130D 1.5x, 650 mm at f\/5.0, 44 mm circle, sold separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMount:\u003c\/strong\u003e sold as an OTA — no mount, rings, dovetail or camera included. At 4.9 kg plus a full imaging train, a mount rated for 8–10 kg of total payload is a reasonable starting point.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCollimation:\u003c\/strong\u003e as a fast hyperbolic system, collimation accuracy matters more than on a slower Newtonian — Takahashi's modified collimation system on this model is built to make that adjustment manageable.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you are not sure your camera and filter setup will hit 56.2 mm exactly, 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\u003eNot for eyepiece observing.\u003c\/strong\u003e This is an imaging-only optical train with no accessible visual focal plane.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is an optical tube assembly.\u003c\/strong\u003e Mount, rings, dovetail and camera are all sold separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack focus is tight and fixed.\u003c\/strong\u003e 56.2 mm at both native focus and with the 1.5x extender — the system chart in the Downloads tab lists the parts that hit it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCollimation matters more at f\/3.3.\u003c\/strong\u003e A fast hyperbolic system shows collimation error more readily than a slower one; the modified collimation system on this model is built for that adjustment.\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\u003eCollimation needs more attention than on a slower telescope because f\/3.3 shows error more readily, but the modified collimation system is built for that adjustment, and the published system chart names the exact spacing your imaging train needs. Send us your camera and filter setup and we will confirm the train with you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eWide-field deep-sky imaging — large emission nebulae, star fields, and fast narrowband work where the f\/3.3 speed shortens exposure time.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it for visual observing?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo. It has no accessible visual focal plane — this is a dedicated imaging astrograph.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need a flattener?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eNo — the 44 mm image circle is corrected at native focus, covering full-frame sensors without a separate flattener.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat mount does it need?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eAt 4.9 kg before accessories, most imaging mounts in the mid-payload class handle it. Tell us your mount model and full imaging train weight and we will confirm.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow does the 1.5x extender change things?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt converts the system to 650 mm at f\/5.0, still with a 44 mm circle — useful for tighter framing on smaller targets without changing telescopes.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: a 130 mm f\/3.3 hyperbolic astrograph at 430 mm focal length with a 44 mm corrected image circle at native focus, weighing 4.9 kg. It is a dedicated imaging telescope built for wide, fast deep-sky work, with a 1.5x extender available for tighter framing.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eOptical Diagram Reports\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi publishes a spot diagram for the Epsilon-130D at native focus, showing star images across the field at the design wavelengths.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Epsilon-130D_spots.png?v=1786911643\" alt=\"Takahashi Epsilon-130D 130mm hyperbolic astrograph spot diagram\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047056887919,"sku":"TEK13010","price":3624.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TEK13010_Epsilon-130D_OTA_1.jpg?v=1786911987"},{"product_id":"takahashi-fsq-85edx-babyq-85mm-f-5-3-petzval-astrograph-ota-with-1-01x-flattener","title":"Takahashi FSQ-85EDX BabyQ 85mm f\/5.3 Petzval Astrograph OTA with 1.01x Flattener","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FSQ-85EDX — known as the BabyQ — is Takahashi's 85 mm Petzval quadruplet astrograph, sold here as an optical tube assembly bundled with the 1.01x flattener. At 450 mm focal length and f\/5.3 in a 535–613 mm tube, it weighs 3.6 kg and covers a 44 mm image circle. With the included flattener fitted the system runs 455 mm at f\/5.4 with just 56.2 mm of back focus, which is what makes the flattener worth bundling rather than buying separately.\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 a small, genuinely flat-field quadruplet for wide-field deep-sky imaging — four elements in four groups control field curvature and colour across the full 44 mm circle without the compromises a doublet or triplet design makes at this speed. Its 3.6 kg weight and 535 mm collapsed length make it a strong travel astrograph, and the 50 mm drawtube extension gives the focuser room to work with different camera and filter-wheel combinations.\u003c\/p\u003e\u003cp\u003eVisual observers get a genuine apochromat at prime focus with a diagonal and eyepiece, though the FSQ-85EDX is built and priced around imaging. Tell us your camera and filter setup and we will confirm the flattener spacing works for your train.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePetzval quadruplet:\u003c\/strong\u003e four elements in four groups, an ED apochromat design built to control field curvature and colour across a flat field.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e450 mm at f\/5.3:\u003c\/strong\u003e in a 535–613 mm retractable tube, 95 mm across (114 mm dew shield).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.01x flattener included:\u003c\/strong\u003e 455 mm at f\/5.4, 44 mm corrected circle, 56.2 mm back focus — the configuration this kit is built around.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e3.6 kg:\u003c\/strong\u003e light enough for portable and travel mounts once a full imaging train is attached.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e50 mm of drawtube extension\u003c\/strong\u003e for focus travel across different camera setups.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e197.5 mm of back focus at prime\u003c\/strong\u003e — before the flattener is fitted, ample room for accessories.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe FSQ-85EDX objective is a four-element, four-group Petzval quadruplet built around ED glass — a design that inherently controls field curvature better than a doublet or triplet at the same speed, because the rear element group does the flattening work a separate corrector would otherwise need to do. The bundled 1.01x flattener refines that further, correcting the field to 44 mm at 455 mm and f\/5.4 with 56.2 mm of back focus — tight enough that camera spacing needs to be accurate, and generous enough that most imaging trains reach it without extension tubes.\u003c\/p\u003e\u003cp\u003eOther conversion options exist for the FSQ-85EDX platform — the RD QB 0.73x reducer brings it to 330 mm at f\/3.9, and the EX ED 1.5x extender to 680 mm at f\/8.0, both with the same 44 mm circle — though this kit is built and priced around the OTA-plus-flattener configuration.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWide-field deep-sky imaging:\u003c\/strong\u003e at 455 mm and f\/5.4 with the included flattener, a 44 mm corrected circle across the frame.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTravel astrophotography:\u003c\/strong\u003e a 535 mm collapsed tube and 3.6 kg weight suit portable rigs and checked baggage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFaster, wider framing:\u003c\/strong\u003e with the RD QB 0.73x reducer (sold separately) at 330 mm and f\/3.9.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTighter framing:\u003c\/strong\u003e with the EX ED 1.5x extender (sold separately) at 680 mm and f\/8.0.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eBack focus is 197.5 mm at prime, dropping to 56.2 mm once the included 1.01x flattener is fitted — the figure your imaging train needs to hit. Takahashi's system charts for the base configuration, the RD QE 0.73x reducer and the EX ED 1.5x extender are in the Downloads tab, with the exact parts and distances for each. Our \u003ca href=\"\/pages\/takahashi-back-focus-guide\"\u003eTakahashi Back Focus Guide\u003c\/a\u003e collects the same figures for the whole range in one table.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlattener:\u003c\/strong\u003e 1.01x, included in this kit — 455 mm at f\/5.4, 44 mm circle, 56.2 mm back focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReducer:\u003c\/strong\u003e RD QB 0.73x (sold separately), 330 mm at f\/3.9, 44 mm circle, 72.2 mm back focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExtender:\u003c\/strong\u003e EX ED 1.5x (sold separately), 680 mm at f\/8.0, 44 mm circle, 117.5 mm back focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMount:\u003c\/strong\u003e sold as an OTA with flattener — no mount, rings, dovetail, diagonal or eyepiece included. At 3.6 kg plus a full imaging train, most travel and mid-payload mounts handle it.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eIf you are not sure your camera and filter thickness will reach 56.2 mm exactly, send us your imaging train and we will work out the spacing 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 with the flattener included.\u003c\/strong\u003e Mount, rings, dovetail, diagonal and eyepiece are sold separately.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack focus with the flattener is tight.\u003c\/strong\u003e 56.2 mm is generous by imaging-train standards but still worth checking against your camera and filter wheel stack.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe reducer and extender are sold separately.\u003c\/strong\u003e This kit bundles only the OTA and the 1.01x flattener; the RD QB 0.73x and EX ED 1.5x are additional purchases.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTube length varies with the dew shield position.\u003c\/strong\u003e 535 mm retracted, 613 mm extended — worth accounting for in a case.\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. The flattener is included and matched to the tube, so reaching the 56.2 mm back focus is mostly a matter of using the standard adapter stack. The published system chart in the Downloads tab confirms the exact parts, and we can check your specific camera train against it.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is it best used for?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eWide-field deep-sky imaging — nebulae, star fields and Milky Way regions — at 455 mm and f\/5.4 across a flat 44 mm circle.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the kit include everything I need to image?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt includes the OTA and the 1.01x flattener. A mount, camera, and any filter wheel or guider are separate purchases.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it visually?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes, at prime focus with a diagonal and eyepiece, though the telescope and this kit are built and priced around imaging use.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the difference between this and the reducer or extender configurations?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThis kit is built around the 1.01x flattener at 455 mm and f\/5.4. The RD QB 0.73x reducer (330 mm, f\/3.9) and EX ED 1.5x extender (680 mm, f\/8.0) are separate accessories for wider or tighter framing.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhen should this not be the choice?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIf you need faster than f\/5.4 without buying the reducer separately, or a longer native focal length than 450 mm offers before adding the extender.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eIn short: an 85 mm Petzval quadruplet astrograph and its matched 1.01x flattener, together giving 455 mm at f\/5.4 with a 44 mm corrected circle and 56.2 mm of back focus. It weighs 3.6 kg, collapses to 535 mm for travel, and is built for wide-field deep-sky imaging.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eOptical Diagram Reports\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTakahashi publishes a spot diagram for the FSQ-85EDX with the 1.01x flattener fitted — the configuration this kit ships in — showing star images across the field at the design wavelengths.\u003c\/p\u003e\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/FSQ-85EDX_FL101X_spots.png?v=1786911643\" alt=\"Takahashi FSQ-85EDX 85mm Petzval spot diagram with 1.01x flattener\" style=\"max-width:100%;height:auto;\"\u003e\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54047058559087,"sku":"TQE08541","price":4851.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/TQE08541_FSQ-85EDX_OTA_1.jpg?v=1786912043"},{"product_id":"takahashi-cca-250-250mm-f-5-tri-focal-corrected-cassegrain-astrograph","title":"Takahashi CCA-250 250mm f\/5 Tri-Focal Corrected Cassegrain Astrograph","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe CCA-250 replaces Takahashi's Baker-Ritchey-Chrétien BRC-250 as their flagship astrograph. It is a 250 mm aperture instrument working at 1250 mm and f\/5 natively, built in carbon fibre, with electric focus driven by a moving secondary mirror rather than a conventional drawtube.\u003c\/p\u003e\u003cp\u003eThe \"tri-focal\" name describes its three working configurations: \u003cstrong\u003ef\/5 native, f\/3.9 with the reducer, and f\/8\u003c\/strong\u003e. That range covers wide-field deep-sky work at one end and high-resolution imaging at the other, from a single optical tube.\u003c\/p\u003e\u003cp\u003eThe optical performance figures are the headline: a \u003cstrong\u003e2 micron RMS spot radius on axis\u003c\/strong\u003e, and an \u003cstrong\u003eØ88 mm image circle\u003c\/strong\u003e spanning 4° of sky, 60% illuminated at its edge. Limiting stellar magnitude is 14.5.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThis is a good match if you are equipping an observatory or a permanent pier and want one instrument that covers wide-field and high-resolution imaging without changing telescopes. The 88 mm image circle suits large-format sensors, and the computer-controlled focus fits a rig that runs unattended.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e250 mm aperture at f\/5:\u003c\/strong\u003e 1250 mm native focal length.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThree focal ratios:\u003c\/strong\u003e f\/5 native, f\/3.9 with reducer, f\/8.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eØ88 mm image circle:\u003c\/strong\u003e 4° of sky, 60% illuminated at the edge — well beyond full-frame.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2 micron RMS spot radius on axis:\u003c\/strong\u003e the on-axis optical performance figure Takahashi publishes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInternal moving-secondary electric focus:\u003c\/strong\u003e computer-controlled over USB, with no external drawtube to flex.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCarbon fibre tube:\u003c\/strong\u003e holds focus across temperature changes better than metal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack focus 155.4 mm to 193.9 mm\u003c\/strong\u003e with the CAA removed.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eLimiting stellar magnitude 14.5.\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003e\u003cstrong\u003eOptical \/ Mechanical Design\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eTwo design choices set this instrument apart from a conventional Cassegrain astrograph. The first is focusing by moving the secondary mirror internally rather than racking a drawtube: nothing outside the tube moves, so a heavy camera train never loads a focuser, and there is no drawtube flexure to introduce tilt as the telescope tracks. The focus motor is computer-controlled over USB, which is what makes automated focus runs practical on a rig that images unattended.\u003c\/p\u003e\u003cp\u003eThe second is carbon fibre. An aluminium tube changes length as it cools through the night, and on a fast f\/5 system the depth of focus is shallow enough that thermal drift shows up in the stars. Carbon fibre's low coefficient of expansion largely removes that, which matters more here than it would on a slower instrument.\u003c\/p\u003e\u003cp\u003eThe Ø88 mm image circle is the figure that justifies the rest. A full-frame sensor spans 43 mm diagonally, so 88 mm leaves the entire frame well inside the well-corrected field, with room for medium-format sensors too. Combined with a 2 micron on-axis RMS spot, the system is resolving finer detail than most sensors will sample at 1250 mm.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eObservatory-based deep-sky astrophotography across a wide range of targets: extended nebulae and galaxy fields at f\/3.9, general deep-sky work at f\/5, and small galaxies and planetary nebulae at f\/8. Also usable visually.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eThe back focus range is \u003cstrong\u003e155.4 mm to 193.9 mm\u003c\/strong\u003e with the camera angle adjuster removed — generous, and enough to accommodate a filter wheel and off-axis guider in the train. The f\/3.9 configuration requires the matching reducer, which is a separate item. We stock the CCA-250 reducer and the camera angle adjuster; tell us your camera, filter wheel and guiding arrangement and we will map the full train and its spacing with you before you order.\u003c\/p\u003e\u003cp\u003eThe optical tube is supplied without a mount. At 50.16 lb before a camera train, it wants a substantial equatorial mount — we can go through mount options with you.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eMount not included:\u003c\/strong\u003e this is an optical tube assembly. The tube alone is 50.16 lb, and the camera, filter wheel and guider add to that, so the mount is a significant part of the decision. We are happy to work through it with you.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eThe reducer is separate:\u003c\/strong\u003e f\/5 and f\/8 are available from the tube as supplied; f\/3.9 needs the matching reducer, which we stock.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eFocus is computer-controlled:\u003c\/strong\u003e the electric moving-secondary focuser connects over USB to control software. That is a strength for automated imaging, and it does mean a computer is part of the setup rather than an optional extra.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eSize:\u003c\/strong\u003e 34.25″ long and 12.05″ in outside diameter — an observatory or permanent-pier instrument rather than something to carry to a dark site.\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\u003eThe optics need no collimation fuss from you in normal use, and focus is handled by software rather than by hand. The demanding parts are the mount and the pier, which is true of any instrument this size — and we will help you specify both.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the three focal ratios?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003ef\/5 native at 1250 mm, f\/3.9 with the reducer, and f\/8.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat sensor size will it cover?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe Ø88 mm image circle covers full-frame with a wide margin and reaches into medium format.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much back focus do I have to work with?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003e155.4 mm to 193.9 mm with the CAA removed — room for a filter wheel and off-axis guider.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes it need a computer?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe electric focuser is computer-controlled over USB, so yes for focusing.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use it visually?\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eYes — Takahashi describes it as a visual as well as a photographic instrument, though the design priorities are photographic.\u003c\/p\u003e\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\u003cp\u003eA 250 mm carbon fibre astrograph working at f\/3.9, f\/5 and f\/8, with an 88 mm image circle and computer-controlled internal focus — an observatory instrument built to cover most of deep-sky imaging from one tube.\u003c\/p\u003e","brand":"Takahashi","offers":[{"title":"Default Title","offer_id":54086147801199,"sku":"TCK25010","price":22011.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/tck25010_2.jpg?v=1787329293"}],"url":"https:\/\/ontariotelescope.com\/collections\/astrographs-takahashi.oembed","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}