{"title":"Orion Optics UK Astrographs","description":"\u003cp\u003eOrion Optics UK astrographs are telescopes designed first for deep-sky imaging, in two families. The AG series are fast Newtonian astrographs, such as the AG8 at f\/3.8, from the AG8 to the AG20, used with a Wynne corrector for wide fields. The ODK series are corrected Dall-Kirkham telescopes from the ODK10 to the ODK20Tr, in closed tube and truss versions.\u003c\/p\u003e\u003cp\u003eChoose an AG for large nebulae and wide fields, or an ODK for galaxies and small targets at long focal length.\u003c\/p\u003e","products":[{"product_id":"orion-optics-uk-ag8-optical-tube-assembly-only","title":"Orion Optics UK AG8 f\/3.8 Astrograph OTA","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e200mm (8-inch) Primary Mirror\u003c\/li\u003e\n\u003cli\u003e760mm Focal Length\u003c\/li\u003e\n\u003cli\u003eExtremely Fast f\/3.8 Focal Ratio\u003c\/li\u003e\n\u003cli\u003e45mm Corrected Flat Field Circle\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e3\" Ceres Rack and Pinion Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK AG8 f\/3.8 Astrograph OTA\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK AG8 Optical Tube Assembly is a dedicated imaging instrument, combining a fast 200mm f\/3.8 primary mirror with a 4-lens ED corrector to produce a 45mm flat image circle. Its 760mm focal length frames large deep-sky targets, while the carbon fibre sandwich tube construction maintains focus stability at a low weight of approximately 6kg. With tight stellar spot sizes of just 4.1µm on-axis and 8.1µm at the edge of the field, the AG8 delivers sharp, coma-free stars across full-frame sensors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFast f\/3.8 Optics: The 200mm Primary and 4-Lens Corrector\u003c\/h3\u003e\n\u003cp\u003eThe AG8 is built for speed. The 200mm primary mirror operates at a native f\/3.8, drastically reducing exposure times compared to f\/5 or f\/6 systems and allowing you to capture more data in a single night. This aggressive focal ratio is managed by an integrated 4-lens ED corrector, which eliminates off-axis coma and produces a flat field, ensuring that stars remain pinpoint across the entire frame.\u003c\/p\u003e\n\u003cp\u003eThe 90mm secondary mirror provides even illumination over the 45mm image circle, a necessary design choice for a fast, wide-field astrograph. While this large central obstruction compromises some contrast for high-resolution planetary viewing, it is an essential trade-off for achieving the bright, wide-field performance required for deep-sky imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eAstrograph Engineering: Carbon Fibre Tube and 3\" Ceres Focuser\u003c\/h3\u003e\n\u003cp\u003eAn imaging platform must be mechanically rigid and thermally stable. The AG8's tube is constructed from a carbon fibre sandwich material, which has a near-zero coefficient of thermal expansion. This prevents the 760mm focal length from shifting as temperatures drop overnight, keeping your images perfectly focused. The entire optical tube weighs only approximately 6kg, placing less demand on your equatorial mount.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e3\" Ceres Focuser:\u003c\/strong\u003e This heavy-duty rack and pinion focuser provides a rigid, flex-free connection for your imaging train. The 10:1 fine-focus knob allows for precise adjustments, critical for achieving sharp focus at f\/3.8.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e9-Point Mirror Cell:\u003c\/strong\u003e The primary mirror rests on a CNC machined, 9-point flotation cell that provides uniform support without introducing astigmatism or other optical distortions.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFull-Frame Imaging: A 45mm Flat Field with 8.1µm Edge Spots\u003c\/h3\u003e\n\u003cp\u003eThe AG8 is designed to illuminate large sensors without compromise. The optical system delivers a fully corrected, flat image circle of 45mm in diameter, easily covering full-frame (36x24mm) and many medium-format CMOS and CCD sensors. This allows you to capture vast targets like the North American Nebula (NGC 7000) or the Andromeda Galaxy (M31) in a single frame.\u003c\/p\u003e\n\u003cp\u003eThe optical correction is quantified by the stellar spot sizes. On-axis, stars are focused to a tight 4.1µm, and even at the extreme edge of the 45mm field, the spot size is only 8.1µm. This ensures that whether your guide star is in the center or the corner of your off-axis guider, the stars in your final image are round and sharp.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eActive Thermal Control: 3 Integrated Cooling Fans\u003c\/h3\u003e\n\u003cp\u003eRapidly cooling the 200mm primary mirror to match the ambient air temperature is crucial for achieving the best image sharpness. The AG8 includes three controllable fans integrated into the rear mirror cell. By actively circulating air across the back of the mirror, you can dramatically reduce the cooling time, minimizing tube currents and ensuring your telescope is ready for imaging almost immediately after setup.\u003c\/p\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eComparing the Optical Grades\u003c\/h3\u003e\n\u003cp\u003eThe images below show the same view of Saturn captured through the included Professional grade and the optional Ultra (Lambda\/10 PV) upgrade, under identical conditions -- a visual illustration of the difference in contrast and fine detail the upgrade delivers.\u003c\/p\u003e\n\u003cdiv class=\"DAV-comparison-grid\"\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_6-PV.jpg\" alt=\"Saturn viewed through 1\/6 PV Professional grade optics\"\u003e\n\u003cp\u003e1\/6 PV (Professional)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_10-PV.jpg\" alt=\"Saturn viewed through the Ultra (Lambda\/10 PV) grade optics upgrade\"\u003e\n\u003cp\u003eLambda\/10 PV (Ultra)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of camera sensor is the Orion Optics UK AG8 designed for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG8 is optimized for large-format sensors. Its integrated corrector produces a \u003cstrong\u003e45mm flat image circle\u003c\/strong\u003e, which is large enough to fully illuminate full-frame sensors (36mm x 24mm) and many popular APS-C and smaller medium-format astronomy cameras without vignetting or distorted stars at the edges.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the f\/3.8 focal ratio of the AG8 affect my imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAn f\/3.8 focal ratio is extremely fast, allowing the telescope to gather light much more quickly than systems with higher f-ratios. This means you can achieve the same image brightness with significantly shorter sub-exposure times, reducing the demands on your mount's tracking accuracy and allowing you to collect more data on a target in a single session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 3\" Ceres focuser on the AG8 strong enough for a heavy camera and filter wheel?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The \u003cstrong\u003e3\" Ceres Rack and Pinion focuser\u003c\/strong\u003e is a heavy-duty unit designed specifically to handle the weight and leverage of modern imaging trains. Its rack and pinion design prevents the slippage and flexure common with Crayford-style focusers when under heavy load, ensuring your camera, filter wheel, and off-axis guider remain perfectly aligned.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of the AG8's carbon fibre tube?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG8's \u003cstrong\u003ecarbon fibre sandwich tube\u003c\/strong\u003e provides two main advantages for astrophotography. First, it has an extremely low thermal expansion coefficient, meaning it won't shrink or expand significantly with temperature changes, which keeps the focus stable throughout the night. Second, it has a high stiffness-to-weight ratio, resulting in a rigid tube that weighs only \u003cstrong\u003eapprox. 6kg\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the AG8 perform when imaging the Andromeda Galaxy (M31) with a full-frame DSLR?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG8 is an excellent choice for this target. Its \u003cstrong\u003e760mm focal length\u003c\/strong\u003e provides a good image scale for capturing detail in M31's dust lanes and star-forming regions. More importantly, the \u003cstrong\u003e45mm corrected image circle\u003c\/strong\u003e will fully cover your full-frame sensor, allowing you to capture the galaxy and its satellite companions, M32 and M110, in a single, wide, flat field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat back focus distance do I need to maintain for the AG8's corrector?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Orion Optics UK AG8 requires a precise spacing from the corrector to your camera sensor to achieve its specified image quality. You must maintain a back focus distance of \u003cstrong\u003e79mm\u003c\/strong\u003e from the mounting flange of the corrector to the focal plane (your camera's sensor).\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the AG8 available in a higher optical grade?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG8 ships with Orion Optics UK's Professional (1\/6 PV) hand-figured optics as standard, each supplied with its own Zygo interferometer test report. For imagers who want the tightest possible star images, an Ultra (Lambda\/10 PV) hand-figured optics upgrade is available, further reducing the spot sizes across the field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e200mm (8\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e760mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Image Circle\u003c\/td\u003e\n\u003ctd\u003e45mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e4.1µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e8.1µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus Distance\u003c\/td\u003e\n\u003ctd\u003e79mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Ceres Rack and Pinion with 10:1 Reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003e4-lens ED\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e90mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminum, 9-point suspension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e255mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e635mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eApprox. 6kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Hardware\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminum cradles \u0026amp; dovetail\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Professional (1\/6 PV)","offer_id":52942359200029,"sku":"OOUK-AG8-OPTICAL-TUBE-ASSEMBLY-ONLY","price":7586.0,"currency_code":"CAD","in_stock":true},{"title":"Ultra (Lambda\/10 PV)","offer_id":52942359232797,"sku":"OOUK-AG8-OPTICAL-TUBE-ASSEMBLY-ONLY-2","price":7720.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_39d816cf-1a11-40e9-8b68-941f5ac4ae6f.jpg?v=1789606569"},{"product_id":"orion-optics-uk-ag10-optical-tube-assembly-only","title":"Orion Optics UK AG10 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e250mm (10-inch) Primary Mirror\u003c\/li\u003e\n\u003cli\u003e950mm Focal Length\u003c\/li\u003e\n\u003cli\u003eExtremely Fast f\/3.8 Focal Ratio\u003c\/li\u003e\n\u003cli\u003e50mm Fully Corrected Flat Image Field\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e3-inch Ceres Rack and Pinion Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK AG10 Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK AG10 Astrograph combines a 250mm primary mirror with an exceptionally fast f\/3.8 focal ratio to dramatically reduce exposure times. Its integrated 4-lens ED corrector produces a 50mm flat field, delivering pinpoint stars from a 3.0µm on-axis spot size to just 7.2µm at the edge of the frame. Housed in a rigid carbon fibre sandwich tube weighing approximately 12kg, the AG10 is a purpose-built instrument for serious deep-sky imagers using large-format sensors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFast f\/3.8 Optics with a 50mm Corrected Field\u003c\/h3\u003e\n\u003cp\u003eThe core of the AG10 is its optical speed. At f\/3.8, you can capture deep signal on faint targets in a fraction of the time required by f\/8 or f\/10 systems. This speed is made usable by a sophisticated 4-lens ED corrector integrated into the optical path. This design delivers a 50mm diameter, fully-corrected image circle, ensuring your images are free of coma and field curvature even on full-frame and larger sensors.\u003c\/p\u003e\n\u003cp\u003eThe optical correction is engineered to produce incredibly tight stars, with a measured spot size of only 3.0µm on-axis and 7.2µm at the field edge. This level of correction allows you to take full advantage of the resolving power of modern, small-pixel CMOS and CCD cameras, capturing fine details in distant galaxies and nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fibre Sandwich Tube: 12kg of Thermal Stability\u003c\/h3\u003e\n\u003cp\u003eTo maintain precise focus through changing temperatures, the AG10 is built with a carbon fibre sandwich tube. This material exhibits a near-zero coefficient of thermal expansion, preventing the 950mm focal length from shifting as the night air cools. The entire optical tube assembly weighs approximately 12kg, placing it within the capacity of many mid-range equatorial mounts.\u003c\/p\u003e\n\u003cp\u003eThe tube measures 810mm in length with a 300mm diameter, providing ample rigidity to support the optical components without flexure. All mechanical components, including the mirror cell and mounting hardware, are CNC machined from aluminum for a precise, stable fit.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e3-inch Ceres Focuser and 9-Point Mirror Cell\u003c\/h3\u003e\n\u003cp\u003eThe AG10 is equipped with a robust 3-inch Ceres rack and pinion focuser. This large-aperture focuser is designed to carry heavy imaging trains, including large cameras, filter wheels, and off-axis guiders, without sagging or shifting. The 10:1 dual-speed reduction allows for extremely fine focus adjustments, which is critical for achieving sharp stars at such a fast focal ratio.\u003c\/p\u003e\n\u003cp\u003eThe 250mm primary mirror is supported by a 9-point suspension mirror cell, also CNC machined. This cell distributes the weight of the mirror evenly to prevent astigmatism and other optical distortions, preserving the hand-figured quality of the primary optic regardless of the telescope's orientation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eActive Thermal Management: 3 Integrated Cooling Fans\u003c\/h3\u003e\n\u003cp\u003eA large primary mirror must reach thermal equilibrium with the ambient air to deliver sharp images. The AG10 accelerates this process with three controllable cooling fans built directly into the rear mirror cell. This active cooling system dramatically reduces the time it takes for the 250mm mirror to acclimate, letting you start imaging sooner and minimizing the effects of tube currents.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOrion Optics AG10 vs. a 10-inch Ritchey-Chrétien Astrograph\u003c\/h3\u003e\n\u003cp\u003eImagers considering a 10-inch astrograph often compare the AG10 Newtonian to a similarly-sized Ritchey-Chrétien (RC). While both are excellent instruments, they serve different priorities.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdvantage RC:\u003c\/strong\u003e A well-collimated RC offers excellent correction across a large field without a corrector in the optical train and is inherently free of coma. They typically have longer focal lengths, making them well-suited for smaller targets like planetary nebulae and galaxies.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdvantage AG10:\u003c\/strong\u003e The primary advantage is speed. At f\/3.8, the AG10 gathers light over four times faster than a typical f\/8 RC, meaning a 5-minute exposure on the AG10 is equivalent to a 20-minute exposure on the RC. The AG10's built-in 4-lens corrector delivers a 50mm flat field out of the box, whereas an RC often requires an additional, costly field flattener or reducer to achieve similar performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eComparing the Optical Grades\u003c\/h3\u003e\n\u003cp\u003eThe images below show the same view of Saturn captured through the included Professional grade and the optional Ultra (Lambda\/10 PV) upgrade, under identical conditions -- a visual illustration of the difference in contrast and fine detail the upgrade delivers.\u003c\/p\u003e\n\u003cdiv class=\"DAV-comparison-grid\"\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_6-PV.jpg\" alt=\"Saturn viewed through 1\/6 PV Professional grade optics\"\u003e\n\u003cp\u003e1\/6 PV (Professional)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_10-PV.jpg\" alt=\"Saturn viewed through the Ultra (Lambda\/10 PV) grade optics upgrade\"\u003e\n\u003cp\u003eLambda\/10 PV (Ultra)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main advantage of the AG10's f\/3.8 focal ratio?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage of an \u003cstrong\u003ef\/3.8 focal ratio\u003c\/strong\u003e is the significant reduction in exposure time. Compared to a more common f\/8 system, the AG10 captures the same amount of light on a target in approximately one-quarter of the time. This allows you to gather more data in a single night and reduces the demands on your mount's tracking accuracy.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow large a sensor can the Orion Optics AG10 fully illuminate and correct?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG10 is designed to produce a \u003cstrong\u003e50mm flat, corrected image circle\u003c\/strong\u003e. This is large enough to accommodate full-frame sensors (36x24mm) and even some medium-format sensors without significant vignetting or distortion at the corners, making it ideal for capturing wide-field mosaics of targets like the North America Nebula (NGC 7000).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill I need to collimate the AG10 frequently?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eLike all fast Newtonians, the AG10 requires precise collimation for optimal performance. However, its rigid carbon fibre tube and CNC-machined components provide excellent stability. While you should check collimation before each imaging session, the telescope is designed to hold that alignment well during transport and use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount is required for the AG10 Optical Tube?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG10 OTA weighs approximately \u003cstrong\u003e12kg (26.5 lbs)\u003c\/strong\u003e. For astrophotography, you will also add a camera, guider, and other accessories, likely bringing the total payload to 15-18kg. A mount with a rated payload capacity of at least 45-50 lbs (approx. 20-23kg) is recommended to ensure stable, precise tracking for long exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the AG10 perform on a target like the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG10 is exceptionally well-suited for large targets like the Andromeda Galaxy (M31). Its \u003cstrong\u003e950mm focal length\u003c\/strong\u003e and \u003cstrong\u003e50mm corrected field\u003c\/strong\u003e allow you to frame the entire galaxy and its companions (M32 and M110) on a full-frame sensor. The fast f\/3.8 optics will capture faint outer dust lanes and star-forming regions with relatively short sub-exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the AG10 come with a specific optical grade like 1\/8 PV?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG10 ships with Orion Optics UK's Professional (1\/6 PV) hand-figured optics as standard, confirmed by Zygo interferometer testing and supplied with its own test report. For imagers who want the tightest possible star images, an Ultra (Lambda\/10 PV) hand-figured optics upgrade is available. The tight \u003cstrong\u003e3.0µm on-axis spot size\u003c\/strong\u003e is a direct result of this precision manufacturing process.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e250mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e950mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Construction\u003c\/td\u003e\n\u003ctd\u003eCarbon Fibre Sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eApprox. 12kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e810mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e300mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e100mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminum, 9-point suspension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Ceres Rack and Pinion with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003e4-lens ED\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e50mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocus Distance to Image Plane\u003c\/td\u003e\n\u003ctd\u003e79mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e3.0µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e7.2µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Hardware\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminum cradles and dovetail\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAG10 Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eCNC Tube Rings (Cradles)\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 2\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDovetail Mounting Bar\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Professional (1\/6 PV)","offer_id":52942360084765,"sku":"OOUK-AG10-OPTICAL-TUBE-ASSEMBLY-ONLY","price":9949.0,"currency_code":"CAD","in_stock":true},{"title":"Ultra (Lambda\/10 PV)","offer_id":52942360117533,"sku":"OOUK-AG10-OPTICAL-TUBE-ASSEMBLY-ONLY-2","price":10104.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_cf105491-29bd-4e55-b4cf-e5613b077b53.jpg?v=1789606641"},{"product_id":"orion-optics-uk-ag12-optical-tube-assembly-only","title":"Orion Optics UK AG12 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e300mm (12\") Primary Mirror\u003c\/li\u003e\n\u003cli\u003e1140mm Focal Length\u003c\/li\u003e\n\u003cli\u003eFast f\/3.8 Focal Ratio\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e\u0026gt;50mm Corrected Flat Field\u003c\/li\u003e\n\u003cli\u003e3\" Ceres Rack and Pinion Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK AG12 Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK AG12 Astrograph combines a 300mm primary mirror with a fast 1140mm focal length (f\/3.8) to capture faint deep-sky objects with significantly shorter exposures. Its integrated 4-lens ED corrector delivers a flat field greater than 50mm, producing pinpoint stars with spot sizes as small as 1.7µm on-axis and 4.6µm at the edge of the field. The entire optical tube weighs approximately 16kg and is housed in a rigid 980mm carbon fibre sandwich tube for thermal and mechanical stability.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFast f\/3.8 Optics: A 300mm Aperture with a \u0026gt;50mm Flat Field\u003c\/h3\u003e\n\u003cp\u003eThe AG12 is engineered for wide-field deep-sky imaging, pairing a large 300mm aperture with an aggressive f\/3.8 focal ratio. This combination gathers immense amounts of light quickly, reducing the required sub-exposure time and allowing you to capture more data in a single night. The integrated 4-lens ED corrector flattens the field across an image circle greater than 50mm, fully illuminating large format CMOS and CCD sensors without vignetting or distorted stars at the edges.\u003c\/p\u003e\n\u003cp\u003eThe optical correction delivers incredibly tight star images, with a measured spot size of just 1.7µm on-axis and 4.6µm at the field edge. This ensures that whether you are imaging the vast star clouds of the Milky Way or the faint outer arms of a distant galaxy, the AG12 resolves fine details across the entire frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fibre Construction: A 16kg Tube with 3-Fan Active Cooling\u003c\/h3\u003e\n\u003cp\u003eTo maintain precise focus through changing temperatures, the AG12 utilizes a carbon fibre sandwich tube. This material exhibits minimal thermal expansion, preventing the focal plane from shifting during long imaging sessions. The optical tube assembly weighs approximately 16kg and has a length of 980mm, requiring a robust equatorial mount for stable imaging.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e9-Point Mirror Cell:\u003c\/strong\u003e The primary mirror is supported by a CNC machined 9-point suspension cell, which prevents flexure and maintains collimation as the telescope moves across the sky.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eActive Cooling:\u003c\/strong\u003e Three controllable fans are integrated into the mirror cell to accelerate the cooling of the primary mirror, helping you reach thermal equilibrium faster for sharper images at the start of your session.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e110mm Secondary Mirror:\u003c\/strong\u003e The large secondary mirror is necessary to fully illuminate the wide, corrected field of the f\/3.8 system, ensuring bright, even fields for large-sensor cameras.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eImaging-Ready Focus System: 3\" Ceres Focuser and 79mm of Back Focus\u003c\/h3\u003e\n\u003cp\u003eThe AG12 comes standard with the robust 3\" Ceres rack and pinion focuser. This heavy-duty focuser is designed to carry complex imaging trains without slipping or flexing, ensuring your camera, filter wheel, and off-axis guider remain perfectly aligned. The 10:1 dual-speed reduction knob allows for incredibly fine adjustments, making it easy to achieve critical focus.\u003c\/p\u003e\n\u003cp\u003eA generous 79mm of back focus (focus distance to image plane) provides ample room to install a variety of accessories. This space is critical for accommodating filter wheels, off-axis guiders, and adaptive optics systems between the corrector and your camera sensor, giving you complete flexibility in configuring your imaging setup.\u003c\/p\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eComparing the Optical Grades\u003c\/h3\u003e\n\u003cp\u003eThe images below show the same view of Saturn captured through the included Professional grade and the optional Ultra (Lambda\/10 PV) upgrade, under identical conditions -- a visual illustration of the difference in contrast and fine detail the upgrade delivers.\u003c\/p\u003e\n\u003cdiv class=\"DAV-comparison-grid\"\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_6-PV.jpg\" alt=\"Saturn viewed through 1\/6 PV Professional grade optics\"\u003e\n\u003cp\u003e1\/6 PV (Professional)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_10-PV.jpg\" alt=\"Saturn viewed through the Ultra (Lambda\/10 PV) grade optics upgrade\"\u003e\n\u003cp\u003eLambda\/10 PV (Ultra)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat size imaging sensor can the Orion Optics AG12 fully illuminate?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG12 is designed with a \u003cstrong\u003e4-lens ED corrector\u003c\/strong\u003e that produces a corrected, flat image circle \u003cstrong\u003egreater than 50mm\u003c\/strong\u003e in diameter. This is large enough to accommodate full-frame sensors (43mm diagonal) and even some medium-format sensors without significant vignetting or loss of star sharpness at the corners.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of telescope mount is required for the AG12 OTA?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG12 optical tube weighs approximately \u003cstrong\u003e16kg\u003c\/strong\u003e and has a length of \u003cstrong\u003e980mm\u003c\/strong\u003e. When you add a large camera, guide scope, and other accessories, the total payload will be significantly higher. A robust equatorial mount with a payload capacity of at least 25-30kg (55-66 lbs) is recommended for stable, long-exposure astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the f\/3.8 focal ratio of the AG12 benefit imaging the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe fast \u003cstrong\u003ef\/3.8 focal ratio\u003c\/strong\u003e allows the AG12 to collect light very rapidly. For a large, relatively bright target like the Andromeda Galaxy (M31), this means you can capture its faint outer arms and dust lanes with much shorter sub-exposures compared to a slower f\/8 or f\/10 system. The \u003cstrong\u003e1140mm focal length\u003c\/strong\u003e provides an ideal image scale for framing the entire galaxy on a full-frame sensor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the AG12 a good choice for high-magnification planetary imaging of Jupiter or Saturn?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile the AG12's 300mm aperture provides high theoretical resolution, its primary design is for wide-field, deep-sky imaging. The large \u003cstrong\u003e110mm secondary mirror\u003c\/strong\u003e creates a significant central obstruction (approx. 37%), which reduces contrast on fine planetary details compared to a telescope with a smaller obstruction. For optimal planetary results, a Barlow lens would be required to increase the effective focal length.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the three cooling fans on the AG12's mirror cell?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe three controllable fans are part of the AG12's active cooling system. They draw ambient air across the back of the 300mm primary mirror, helping it reach the outside temperature more quickly. This process minimizes internal tube currents and ensures the sharpest possible images from the very start of an observing session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow much space does the AG12 provide for an imaging train?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG12 provides \u003cstrong\u003e79mm\u003c\/strong\u003e of distance from the focuser's connection point to the corrected focal plane. This is known as back focus and is critical for astrophotography. This generous distance allows you to easily install accessories like an off-axis guider (OAG), a filter wheel, and any necessary adapters while still being able to bring your camera to a sharp focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the AG12 available in a higher optical grade?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG12 ships with Orion Optics UK's Professional (1\/6 PV) hand-figured optics as standard, each supplied with its own Zygo interferometer test report. For imagers who want the tightest possible star images, an Ultra (Lambda\/10 PV) hand-figured optics upgrade is available, further reducing the spot sizes across the field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e300mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e1140mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;50mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e1.7µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e4.6µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e79mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eApprox. 16kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e980mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e350mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon Fibre Sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e110mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Cell\u003c\/td\u003e\n\u003ctd\u003eCNC Machined Aluminium, 9-point suspension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Ceres Rack and Pinion, 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003e4-lens ED\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Hardware\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium cradles and dovetail\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAG12 Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eCNC Machined Aluminium Cradles\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1 set\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDovetail Plate\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Professional (1\/6 PV)","offer_id":52942361067805,"sku":"OOUK-AG12-OPTICAL-TUBE-ASSEMBLY-ONLY","price":13253.0,"currency_code":"CAD","in_stock":true},{"title":"Ultra (Lambda\/10 PV)","offer_id":52942361100573,"sku":"OOUK-AG12-OPTICAL-TUBE-ASSEMBLY-ONLY-2","price":13449.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_5650e8c0-f065-4511-a557-7988771ce545.jpg?v=1789606706"},{"product_id":"orion-optics-uk-ag14-optical-tube-assembly-only","title":"Orion Optics UK AG14 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e350mm Primary Mirror Diameter\u003c\/li\u003e\n\u003cli\u003e1330mm Focal Length (f\/3.8)\u003c\/li\u003e\n\u003cli\u003e\u0026gt;50mm Corrected Flat Field\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e3.4µm On-Axis Spot Size\u003c\/li\u003e\n\u003cli\u003e3\" Ceres Rack and Pinion Focuser\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOrion Optics UK AG14 Optical Tube Assembly\u003c\/h2\u003e\n      \u003cp\u003eThe Orion Optics UK AG14 Optical Tube Assembly combines a massive 350mm primary mirror with an incredibly fast f\/3.8 focal ratio to dramatically reduce exposure times on faint deep-sky objects. Its integrated 4-lens ED corrector delivers a flat field larger than 50mm, producing sharp stars with spot sizes as small as 3.4µm on-axis and 4.7µm at the field edge. This 1330mm focal length astrograph is engineered for the largest modern sensors, providing professional-grade results from a precision-built instrument.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003ef\/3.8 Corrected Newtonian Optics: A \u0026gt;50mm Flat Field\u003c\/h3\u003e\n      \u003cp\u003eThe AG14's optical system is designed for one purpose: wide-field imaging. The fast f\/3.8 primary mirror gathers immense amounts of light, while the custom-designed 4-lens ED corrector eliminates coma and field curvature. This results in a corrected image circle greater than 50mm, fully illuminating full-frame and larger format astronomy cameras without vignetting or distorted stars at the edge of the frame.\u003c\/p\u003e\n      \u003cp\u003eWith measured spot sizes of just 3.4µm on-axis and 4.7µm at the field edge, the AG14 delivers resolution capable of matching the smallest pixels on modern CMOS sensors. This ensures that every star is a tight, focused point, capturing maximum detail in galactic dust lanes and nebular structures.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eCarbon Fibre Tube \u0026amp; 9-Point Mirror Support\u003c\/h3\u003e\n      \u003cp\u003eTo maintain optical precision, the AG14 is built around a carbon fibre sandwich tube with a diameter of 400mm. This material offers exceptional rigidity at a manageable weight of approximately 24kg and, more importantly, exhibits near-zero thermal expansion. As temperatures drop during an imaging session, the 1203mm tube length remains constant, preventing focus shift that can ruin long exposures.\u003c\/p\u003e\n      \u003cp\u003eThe 350mm primary mirror is held securely by a CNC-machined aluminum 9-point suspension cell, which provides uniform support to prevent gravitational flexure as the telescope tracks across the sky. For rapid thermal stabilization, the mirror cell is equipped with three controllable fans to bring the primary mirror to ambient temperature quickly, minimizing tube currents and ensuring sharp images from the start of your session.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003e3\" Ceres Focuser with 79mm Back Focus\u003c\/h3\u003e\n      \u003cp\u003eThe AG14 comes standard with a robust 3\" Ceres rack and pinion focuser, designed to handle the weight of large cameras and heavy accessory stacks without slipping or tilting. A 10:1 reduction fine-focus knob allows for precise adjustments critical for achieving perfect focus with the fast f\/3.8 optical system. The focuser provides a generous 79mm of distance from its flange to the image plane, offering ample room for off-axis guiders, filter wheels, and rotators in your imaging train.\u003c\/p\u003e\n    \u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eComparing the Optical Grades\u003c\/h3\u003e\n\u003cp\u003eThe images below show the same view of Saturn captured through the included Professional grade and the optional Ultra (Lambda\/10 PV) upgrade, under identical conditions -- a visual illustration of the difference in contrast and fine detail the upgrade delivers.\u003c\/p\u003e\n\u003cdiv class=\"DAV-comparison-grid\"\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_6-PV.jpg\" alt=\"Saturn viewed through 1\/6 PV Professional grade optics\"\u003e\n\u003cp\u003e1\/6 PV (Professional)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_10-PV.jpg\" alt=\"Saturn viewed through the Ultra (Lambda\/10 PV) grade optics upgrade\"\u003e\n\u003cp\u003eLambda\/10 PV (Ultra)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat cameras are suitable for the AG14's \u0026gt;50mm image circle?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe AG14 is designed to work with large-format sensors. Its \u003cstrong\u003e\u0026gt;50mm flat field size\u003c\/strong\u003e will fully illuminate full-frame (36x24mm) and even larger medium-format CCD or CMOS cameras, ensuring you can utilize the entire field of view without significant vignetting or loss of sharpness at the corners.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow critical is collimation for an f\/3.8 system like the AG14?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eExtremely critical. Fast optical systems like this \u003cstrong\u003ef\/3.8 astrograph\u003c\/strong\u003e have a very small tolerance for optical misalignment. Precise collimation is essential to achieve the advertised spot sizes and edge-to-edge sharpness. It is recommended to use a high-quality laser collimator and check collimation regularly, especially after transport.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main benefit of the AG14's carbon fibre tube?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe primary benefit is \u003cstrong\u003ethermal stability\u003c\/strong\u003e. Carbon fibre has a very low coefficient of thermal expansion, meaning the \u003cstrong\u003e1203mm focal length\u003c\/strong\u003e will not change significantly as the ambient temperature drops overnight. This prevents focus shift, a common problem with metal tubes that can soften images during long-exposure astrophotography.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the AG14 perform on a large target like the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe AG14 is ideal for a target like M31. Its \u003cstrong\u003e1330mm focal length\u003c\/strong\u003e and \u003cstrong\u003e\u0026gt;50mm corrected field\u003c\/strong\u003e allow you to frame the entire galaxy and its companions (M32 and M110) on a full-frame sensor. The fast \u003cstrong\u003ef\/3.8 focal ratio\u003c\/strong\u003e would allow you to capture faint outer dust lanes and star clouds with significantly shorter total integration time compared to a slower f\/8 or f\/10 system.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan the AG14 resolve fine detail in the Orion Nebula's Trapezium (M42)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes. While it's a wide-field instrument, the AG14's optical quality is high enough for detailed work. The extremely small \u003cstrong\u003e3.4µm on-axis spot size\u003c\/strong\u003e means it can produce very tight, sharp stars. When paired with a camera with small pixels and good seeing conditions, it can resolve the individual stars within the Trapezium cluster and the fine, wispy details in the surrounding nebulosity.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount is required for the AG14 OTA?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWith a tube weight of approximately \u003cstrong\u003e24kg\u003c\/strong\u003e, plus the added weight of a large camera, filter wheel, and guide scope, you will need a high-capacity equatorial mount. A mount with an instrumental payload capacity of at least 45kg (100 lbs) is recommended to ensure stability and precise tracking for long-exposure imaging.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the AG14 available in a higher optical grade?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe AG14 ships with Orion Optics UK's Professional (1\/6 PV) hand-figured optics as standard, each supplied with its own Zygo interferometer test report. For imagers who want the tightest possible star images, an Ultra (Lambda\/10 PV) hand-figured optics upgrade is available, further reducing the spot sizes across the field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e350mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e1330mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.8\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003e4 lens ED\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFlat Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;50mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSpot Size (On Axis)\u003c\/td\u003e\n\u003ctd\u003e3.4µm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e4.7µm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e120mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFocus Distance to Image Plane\u003c\/td\u003e\n\u003ctd\u003e79mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Ceres Rack and Pinion, 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 24kg\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e1203mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e400mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium, 9 point suspension\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMirror \/ Tube Cooling\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans, heaters optional\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMounting Hardware\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium cradles + dovetail\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eProduct Note\u003c\/td\u003e\n\u003ctd\u003eAG14 Optical Tube Assembly Only. Specifications may belong to other variants in the series.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eAG14 Optical Tube Assembly\u003c\/p\u003e\n        \u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Professional (1\/6 PV)","offer_id":52942363099421,"sku":"OOUK-AG14-OPTICAL-TUBE-ASSEMBLY-ONLY","price":16623.0,"currency_code":"CAD","in_stock":true},{"title":"Ultra (Lambda\/10 PV)","offer_id":52942363132189,"sku":"OOUK-AG14-OPTICAL-TUBE-ASSEMBLY-ONLY-2","price":17100.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_6daa2d2f-71a9-45e6-a37b-fbc4bd3b64eb.jpg?v=1789606763"},{"product_id":"orion-optics-uk-ag16-optical-tube-assembly-only","title":"Orion Optics UK AG16 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e400mm (16\") Primary Mirror Diameter\u003c\/li\u003e\n\u003cli\u003e1520mm Focal Length at a fast f\/3.8 Focal Ratio\u003c\/li\u003e\n\u003cli\u003eCorrected Flat Field Size \u0026gt;50mm\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e3\" Ceres Rack and Pinion Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003cli\u003eApproximate Tube Weight of 33kg\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK AG16 Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK AG16 Astrograph is an imaging instrument engineered for large-format sensors, combining a massive 400mm primary mirror with a fast f\/3.8 focal ratio. Its integrated 4-lens ED corrector delivers a flat field greater than 50mm, producing on-axis spot sizes of just 4.1µm. The entire optical system is housed in a rigid, 1320mm carbon fibre sandwich tube weighing approximately 33kg, providing the thermal stability required for consistent focus through long imaging sessions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe 400mm f\/3.8 Optical System: A \u0026gt;50mm Flat Field Astrograph\u003c\/h3\u003e\n\u003cp\u003eAt the heart of the AG16 is a 400mm primary mirror operating at an aggressive f\/3.8 focal ratio, designed to capture faint signal from deep-sky objects in significantly shorter exposure times. To manage this fast optical train, a computer-designed 4-lens ED corrector is permanently installed, yielding a corrected image circle greater than 50mm in diameter. This comfortably illuminates large full-frame and medium-format astronomy sensors, ensuring sharp stars across the entire frame.\u003c\/p\u003e\n\u003cp\u003eThe optical correction achieves spot sizes of just 4.1µm on-axis and 6.6µm at the edge of the field. This level of precision allows you to resolve fine details with modern, small-pixel CMOS and CCD cameras, transforming the AG16's light-gathering power into high-resolution data.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fibre Construction: Thermal Stability and Active Cooling at 33kg\u003c\/h3\u003e\n\u003cp\u003eThe AG16's optical components are housed in a 450mm diameter carbon fibre sandwich tube, a material chosen for its exceptional stiffness and low coefficient of thermal expansion. This construction minimizes focus shift as ambient temperatures change during the night, a critical factor for maintaining sharpness in an f\/3.8 system. At approximately 33kg, the tube assembly remains manageable for observatory-class mounts.\u003c\/p\u003e\n\u003cp\u003eTo accelerate mirror cooling and reduce tube currents, the primary mirror cell is equipped with three controllable fans. This active cooling system allows the large 400mm mirror to reach thermal equilibrium with the surrounding air more quickly, stabilizing the image for sharp, high-contrast viewing and imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eImaging-Ready Mechanics: 3\" Ceres Focuser and 9-Point Mirror Cell\u003c\/h3\u003e\n\u003cp\u003eThe AG16 comes standard with the robust 3\" Ceres Rack and Pinion focuser, featuring a 10:1 reduction for fine focus control. This heavy-duty focuser is designed to carry large camera packages, filter wheels, and off-axis guiders without flexure or image shift. With 79mm of focus distance available to the image plane, you have ample room to configure a complete imaging train.\u003c\/p\u003e\n\u003cp\u003eThe 400mm primary mirror is supported by a CNC machined aluminum 9-point suspension cell. This design distributes the mirror's weight evenly, preventing gravitational sag and preserving the precise optical figure required for high-resolution imaging, regardless of the telescope's orientation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe AG16 Advantage: 400mm Aperture vs. Portability\u003c\/h3\u003e\n\u003cp\u003eCompared to smaller astrographs in the AG series, the AG16's primary advantage is its immense 400mm aperture. This provides a significant increase in light-gathering power and resolution over 12\" or 14\" models, allowing for deeper images with shorter sub-exposures and the ability to resolve finer details in galactic structures and planetary nebulae.\u003c\/p\u003e\n\u003cp\u003eThe trade-off for this capability is size and mass. At approximately 33kg and 1320mm in length, the AG16 demands a heavy-duty, observatory-grade mount with a substantial payload capacity. While smaller AG models offer greater portability and more modest mounting requirements, the AG16 is the choice for imagers seeking the ultimate in light collection and resolving power from a fixed installation.\u003c\/p\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eComparing the Optical Grades\u003c\/h3\u003e\n\u003cp\u003eThe images below show the same view of Saturn captured through the included Professional grade and the optional Ultra (Lambda\/10 PV) upgrade, under identical conditions -- a visual illustration of the difference in contrast and fine detail the upgrade delivers.\u003c\/p\u003e\n\u003cdiv class=\"DAV-comparison-grid\"\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_6-PV.jpg\" alt=\"Saturn viewed through 1\/6 PV Professional grade optics\"\u003e\n\u003cp\u003e1\/6 PV (Professional)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-comparison-item\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Saturn-1_10-PV.jpg\" alt=\"Saturn viewed through the Ultra (Lambda\/10 PV) grade optics upgrade\"\u003e\n\u003cp\u003eLambda\/10 PV (Ultra)\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat class of mount is required for the Orion Optics AG16 OTA?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith an approximate tube weight of 33kg (73 lbs) before adding a camera, guidescope, and other accessories, the Orion Optics AG16 requires a high-capacity, observatory-class equatorial mount. For reliable imaging, you should look for mounts rated to carry at least 45-50 kg (100-110 lbs) for astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the AG16's f\/3.8 focal ratio affect imaging of faint nebulae like the Cygnus Loop?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe fast \u003cstrong\u003ef\/3.8 focal ratio\u003c\/strong\u003e is a major advantage for large, faint emission nebulae like the Cygnus Loop (including NGC 6960 and NGC 6992). Compared to a slower f\/8 system, the AG16 gathers light much more rapidly, allowing you to capture deep signal in a fraction of the time. This means you can achieve a higher signal-to-noise ratio with shorter individual sub-exposures, reducing the demands on your mount's tracking accuracy.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of the \u0026gt;50mm flat field on the AG16?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e\u0026gt;50mm corrected flat field\u003c\/strong\u003e ensures that stars remain sharp and round across very large imaging sensors, including full-frame (36x24mm) and some medium-format chips. Without this correction, stars at the corners of a large sensor would appear elongated or comatic in a fast Newtonian system. This makes the AG16 ideal for creating wide-field mosaics and imaging large targets like the Andromeda Galaxy (M31) without compromise.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the optical quality of the AG16's primary mirror?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis AG16 model is built with Orion Optics UK's hand-figured optics, guaranteed to a minimum accuracy of 1\/6 PV (Professional grade) wavefront as standard. The company is renowned for its rigorous testing using Zygo interferometers, and every mirror is supplied with its own test report. For imagers who want the tightest possible star images, an Ultra (Lambda\/10 PV) hand-figured optics upgrade is available.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the three cooling fans on the AG16 mirror cell?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe three controllable fans are part of an active cooling system for the \u003cstrong\u003e400mm primary mirror\u003c\/strong\u003e. Large mirrors have significant thermal mass and can take hours to cool to ambient temperature. The fans accelerate this process, which is critical for two reasons: it minimizes tube currents that can degrade image sharpness, and it helps prevent focus shift caused by the mirror changing shape as it cools.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use a different focuser with the AG16 instead of the included Ceres?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. While the included \u003cstrong\u003e3\" Ceres focuser\u003c\/strong\u003e is a high-quality unit designed for heavy loads, Orion Optics UK can supply customized adapters for other focusers, such as the FLI Atlas. They also offer a 'FocusForm' reinforcement option to further eliminate any potential for flexure with exceptionally heavy imaging trains.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e400mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e1520mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon Fibre Sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e1320mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e450mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 33kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e130mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium, 9-point suspension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003e4-lens ED\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;50mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e4.1µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e6.6µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e79mm (from corrector)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Ceres Rack and Pinion with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable primary mirror fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium cradles \u0026amp; dovetail plate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAG16 Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eCNC Machined Aluminium Cradles\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1 Pair\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDovetail Plate\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Professional (1\/6 PV)","offer_id":52942364115229,"sku":"OOUK-AG16-OPTICAL-TUBE-ASSEMBLY-ONLY","price":19523.0,"currency_code":"CAD","in_stock":true},{"title":"Ultra (Lambda\/10 PV)","offer_id":52942364147997,"sku":"OOUK-AG16-OPTICAL-TUBE-ASSEMBLY-ONLY-2","price":20393.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_8c93370b-66bc-43d6-a5d3-dda57e7c2380.jpg?v=1789606822"},{"product_id":"orion-optics-uk-ag20-optical-tube-assembly-only","title":"Orion Optics UK AG20 Optical Tube Assembly Only","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eLargest model in the AG Astrograph range\u003c\/li\u003e\n\u003cli\u003eCarbon-fibre-sandwich tube\u003c\/li\u003e\n\u003cli\u003eCERES 3\" (76.2mm) focuser standard\u003c\/li\u003e\n\u003cli\u003eBuilt to order in the UK\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAG20 Astrograph\u003c\/h2\u003e\n\u003cp\u003eThe AG20 is the largest model in Orion Optics UK's AG Astrograph range -- a precision computer-designed, hand-built carbon-fibre-sandwich astrograph with a wide, flat field, supplied as standard with the CERES 3\" (76.2mm) focuser.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThe Largest AG Astrograph\u003c\/h3\u003e\n\u003cp\u003eAir cooling fans are fitted as standard in the main mirror cell. Individually built to order in the UK; contact Orion Optics UK for full AG20 specification.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eRange\u003c\/td\u003e\n\u003ctd\u003eAG Astrograph\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003eCERES 3\" (76.2mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAG20 Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942364705053,"sku":"OOUK-AG20-OPTICAL-TUBE-ASSEMBLY-ONLY","price":41659.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_1ffa1374-c08a-4323-a6df-a457d4cd2a5a.jpg?v=1789606871"},{"product_id":"orion-optics-uk-odk10-optical-tube-assembly","title":"Orion Optics UK ODK10 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e250mm (10\") Corrected Dall-Kirkham Optics\u003c\/li\u003e\n\u003cli\u003e1700mm Focal Length at f\/6.8\u003c\/li\u003e\n\u003cli\u003e50mm Fully Corrected Flat Image Circle\u003c\/li\u003e\n\u003cli\u003e3.5μm On-Axis Spot Size\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e3\" Crayford Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK10 Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK10 is an astrograph engineered for the dedicated imager, combining a 250mm primary mirror and a fast f\/6.8 focal ratio to capture deep-sky objects with exceptional detail. Its integrated 3-lens corrector delivers a 50mm flat field, producing spot sizes as small as 3.5μm on-axis and 6.2μm at the edge of the frame. With a generous 213mm of back focus and a thermally inert carbon fibre tube, the ODK10 supports complex imaging trains and maintains stable focus across temperature changes during a long night of imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK f\/6.8 Optical Design: 250mm Aperture and 1700mm Focal Length\u003c\/h3\u003e\n\u003cp\u003eThe heart of the ODK10 is its Corrected Dall-Kirkham optical system. This design uses a 250mm primary mirror to achieve a 1700mm focal length, striking a balance between wide-field deep-sky imaging and high-resolution planetary work. The native f\/6.8 focal ratio is significantly faster than standard Schmidt-Cassegrains, allowing you to collect more light in less time and reduce total exposure duration for faint targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eFull-Frame Imaging: A 50mm Flat Field with 6.2μm Edge Spots\u003c\/h3\u003e\n\u003cp\u003eUnlike conventional reflector designs that suffer from off-axis coma, the ODK10 incorporates a multi-coated 3-lens corrector to produce a natively flat 50mm image circle. This is large enough to accommodate full-frame (35mm) sensors without vignetting or distortion. The optical correction is superb, yielding tight, round stars with a spot size of just 6.2μm at the very edge of the field, ensuring your images are sharp from corner to corner.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThermally Stable Engineering: Carbon Fibre Tube and 3 Cooling Fans\u003c\/h3\u003e\n\u003cp\u003eFocus stability is critical for long-exposure astrophotography. The ODK10 addresses this with a carbon fibre sandwich tube that exhibits virtually zero thermal expansion, preventing the focal plane from shifting as ambient temperature drops. Weighing approximately 12kg and measuring only 530mm long, the open-tube design is further enhanced by three controllable fans behind the primary mirror, ensuring rapid thermal acclimation and minimizing tube currents.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eHeavy-Duty Imaging Train: 3\" Focuser and 213mm of Back Focus\u003c\/h3\u003e\n\u003cp\u003eThe ODK10 is built to carry modern imaging loads. It features a robust 3\" Crayford focuser with a 10:1 fine reduction knob for precise focus adjustments, even with heavy equipment. An exceptionally generous 213mm of back focal distance provides ample room to install complex imaging trains, including off-axis guiders, large filter wheels, and camera rotators, without running out of focus travel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK10 vs. a 10\" SCT: The Benefits of a Corrected Astrograph\u003c\/h3\u003e\n\u003cp\u003eWhile a 10\" Schmidt-Cassegrain Telescope (SCT) is a capable instrument, the ODK10 offers distinct advantages for the serious imager. The SCT's primary mirror focusing can introduce image shift, a problem eliminated by the ODK10's fixed mirror and external focuser.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNative Speed and Field:\u003c\/strong\u003e The ODK10's native f\/6.8 is faster than a typical f\/10 SCT, reducing exposure times. More importantly, its 50mm corrected flat field is built-in, whereas an SCT requires an additional, expensive reducer\/corrector to achieve a similar result.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThermal Management:\u003c\/strong\u003e The ODK10's open tube and three cooling fans allow it to reach thermal equilibrium much faster than a closed-tube SCT, resulting in sharper images sooner.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack Focus:\u003c\/strong\u003e With 213mm of back focus, the ODK10 easily accommodates more accessories than most standard SCTs, providing greater flexibility for your imaging setup.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat camera sensor size is the ODK10 designed for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Orion Optics UK ODK10 is engineered to fully illuminate a \u003cstrong\u003e50mm image circle\u003c\/strong\u003e. This makes it ideal for cameras with full-frame (36x24mm) sensors and other large-format astronomy cameras, ensuring sharp stars and no vignetting across the entire field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ODK10's carbon fibre tube benefit astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe carbon fibre sandwich tube has a near-zero coefficient of thermal expansion. This is a critical feature for long-exposure imaging, as it prevents the telescope's focus from shifting due to temperature changes throughout the night. This thermal stability means you spend less time refocusing and more time imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 12kg weight of the ODK10 manageable for a mid-range mount?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. At approximately \u003cstrong\u003e12kg\u003c\/strong\u003e, the ODK10 optical tube is well within the payload capacity of mid-range equatorial mounts, such as those in the Sky-Watcher EQ6-R or Celestron CGX class, especially when used for imaging. Its short \u003cstrong\u003e530mm tube length\u003c\/strong\u003e also results in a lower moment arm, making it easier for the mount to guide accurately.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the 213mm back focus on the ODK10 allow me to do?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe generous \u003cstrong\u003e213mm of back focus\u003c\/strong\u003e provides extensive flexibility for building your imaging train. It allows you to easily incorporate multiple accessories between the focuser and the camera, such as:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eOff-Axis Guiders (OAGs)\u003c\/li\u003e\n\u003cli\u003eLarge filter wheels (e.g., 7-position 2\" carousels)\u003c\/li\u003e\n\u003cli\u003eAdaptive optics units\u003c\/li\u003e\n\u003cli\u003eCamera rotators\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the ODK10 perform on the Andromeda Galaxy (M31) with a full-frame camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK10 is an excellent choice for a target like the Andromeda Galaxy (M31). The \u003cstrong\u003e1700mm focal length\u003c\/strong\u003e provides enough image scale to resolve intricate dust lanes and star-forming regions in the spiral arms, while the \u003cstrong\u003e50mm flat field\u003c\/strong\u003e ensures that the entire galaxy and its satellite companions, M32 and M110, are framed with pinpoint stars from edge to edge on a full-frame sensor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the ODK10 for high-resolution imaging of Jupiter?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. While designed as a deep-sky astrograph, the \u003cstrong\u003e250mm aperture\u003c\/strong\u003e of the ODK10 provides significant resolving power for planetary imaging. When paired with a high-quality Barlow lens (e.g., 2x or 3x) and a high-frame-rate planetary camera, the \u003cstrong\u003e1700mm focal length\u003c\/strong\u003e can be effectively increased to resolve fine details like the Great Red Spot, cloud bands, and festoons on Jupiter.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eCorrected Dall-Kirkham (ODK)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e250mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e1700mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e50mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e3.5μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e6.2μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e213mm (from rear of mirror cell, ±1mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector\u003c\/td\u003e\n\u003ctd\u003eMulti-coated 3 lens system\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e96mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e530mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e300mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 12kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC machined aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans (heaters optional)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium dovetail with supports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942364967197,"sku":"OOUK-ODK10-OPTICAL-TUBE-ASSEMBLY","price":8334.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/OrionOpticsUK-ODK10-Optical-Tube-Assembly-1_808c12cc-b42b-4e31-ae8d-fe1ed81ca9ac.jpg?v=1789606889"},{"product_id":"orion-optics-uk-odk12-optical-tube-assembly","title":"Orion Optics UK ODK12 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e300mm (12\") Optimised Dall-Kirkham Optics\u003c\/li\u003e\n\u003cli\u003e2040mm Focal Length at a fast f\/6.8 Focal Ratio\u003c\/li\u003e\n\u003cli\u003eCovers a greater than 52mm flat imaging circle\u003c\/li\u003e\n\u003cli\u003eDelivers 1.8µm on-axis spot sizes\u003c\/li\u003e\n\u003cli\u003eGenerous 218mm of back focal distance\u003c\/li\u003e\n\u003cli\u003eThermally stable carbon fibre sandwich tube construction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK12 Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK12 is an astrograph engineered for large-format imaging, combining a 300mm primary mirror and a 2040mm focal length into a fast f\/6.8 system. Its integrated multi-coated 3-lens corrector produces a flat field greater than 52mm in diameter, delivering pinpoint stars with a spot size of just 1.8µm on-axis. The entire optical system is housed in a 625mm long carbon fibre sandwich tube that weighs approximately 19kg, ensuring thermal stability for critical imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK Astrograph: 52mm Flat Field with 1.8µm Stars\u003c\/h3\u003e\n\u003cp\u003eThe Optimised Dall-Kirkham (ODK) design is built from the ground up for astrophotography. The ODK12 uses a 300mm primary mirror and a matched 120mm secondary, with a built-in 3-lens corrector group to eliminate off-axis coma and field curvature. This results in a corrected image circle larger than 52mm, capable of illuminating the largest commercially available astronomy camera sensors without vignetting or distortion.\u003c\/p\u003e\n\u003cp\u003eThe optical correction delivers incredibly tight stars across this massive field. On-axis spot sizes are a mere 1.8µm, and even at the extreme edge of the field, stars remain compact at 5.6µm. This level of correction ensures that you are capturing all the resolution the 300mm aperture can provide, making the ODK12 a premier instrument for high-resolution mosaics and large-field imaging of nebulae and galaxy clusters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fiber Tube \u0026amp; Active Cooling at 19kg\u003c\/h3\u003e\n\u003cp\u003eTo maintain focus stability during temperature drops, the ODK12 features a carbon fibre sandwich tube. This material has virtually zero thermal expansion, preventing the 2040mm focal plane from shifting during long exposures or throughout an imaging session. The tube's open design and short 625mm length promote rapid thermal acclimation.\u003c\/p\u003e\n\u003cp\u003eThis process is accelerated by three controllable cooling fans mounted behind the honeycomb CNC-machined primary mirror cell. This active cooling system quickly brings the 300mm mirror to ambient temperature, minimizing tube currents and ensuring the sharpest possible images from the moment you begin observing. At approximately 19kg, the OTA is manageable for observatory-class mounts rated for higher payloads.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e218mm Back Focus with a 3\" Crayford Focuser\u003c\/h3\u003e\n\u003cp\u003eA critical feature for serious imagers is ample back focus, and the ODK12 provides an exceptionally long 218mm of working distance from the rear of the mirror cell. This generous space allows you to assemble a complete imaging train with any combination of accessories—including off-axis guiders, large filter wheels, rotators, and adaptive optics—without concern for reaching focus.\u003c\/p\u003e\n\u003cp\u003eFocusing is controlled by a robust 3\" Crayford focuser with a 10:1 dual-speed reduction mechanism for precise adjustments. This heavy-duty focuser is designed to carry the weight of modern large-format cameras and accessory stacks without flexure or slippage, ensuring your focal plane remains locked and perfectly orthogonal to the optical axis.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK12 vs. 12\" Ritchey-Chrétien: Collimation and Correction\u003c\/h3\u003e\n\u003cp\u003eThe ODK12 is often compared to Ritchey-Chrétien (RC) astrographs of similar aperture. While RCs are renowned for their corrected fields, they have a key disadvantage.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRC Advantage:\u003c\/strong\u003e Ritchey-Chrétien telescopes typically feature longer focal ratios (f\/8 or slower), which can provide more image scale for smaller targets without the need for Barlow lenses.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eODK12 Advantage:\u003c\/strong\u003e The ODK is significantly easier to collimate. Unlike an RC, which requires precise alignment of both the primary and secondary mirrors, the ODK's primary mirror is fixed. Collimation is achieved by adjusting the secondary mirror only, a much simpler and more stable process. Furthermore, the ODK's 3-lens corrector is an integrated part of the design, whereas many RCs require an additional, separate corrector to achieve a fully flat field.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat class of mount is required for the ODK12 OTA?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a tube weight of approximately \u003cstrong\u003e19kg (42 lbs)\u003c\/strong\u003e, the ODK12 requires a robust, observatory-grade equatorial mount. For imaging, you should select a mount with a payload capacity of at least 60-70 lbs to comfortably handle the OTA plus the additional weight of your camera, guider, and accessories.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhich cameras are best suited for the ODK12's 52mm image circle?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK12's greater than \u003cstrong\u003e52mm flat field\u003c\/strong\u003e is designed for cameras with large, full-frame (36x24mm) or larger sensors. Cameras like the ZWO ASI6200, QHY600, or models with the KAF-16803 sensor will be fully illuminated, allowing you to capture vast fields of view, such as the entire Andromeda Galaxy (M31) and its companions in a single frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ODK12's f\/6.8 focal ratio benefit deep-sky imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003ef\/6.8\u003c\/strong\u003e focal ratio is a sweet spot for deep-sky imaging. It is fast enough to collect significant signal on faint nebulae and galaxies in shorter sub-exposures compared to slower f\/8 or f\/10 systems. At the same time, its \u003cstrong\u003e2040mm focal length\u003c\/strong\u003e provides enough image scale to resolve fine details in targets like the Whirlpool Galaxy (M51) or planetary nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the ODK12's 218mm back focal distance allow me to do?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e218mm back focal distance\u003c\/strong\u003e provides enormous flexibility for building your imaging train. It ensures you can fit a full stack of accessories, such as an off-axis guider, a large 3\" filter wheel, a camera rotator, and your camera, and still easily reach focus. This is a critical feature that many other astrographs lack.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs collimating the ODK12 difficult?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the ODK12 is designed for straightforward collimation. Unlike Ritchey-Chrétien designs that require careful alignment of both mirrors, the ODK's primary mirror is fixed. You only need to adjust the secondary mirror, which is a much simpler and more stable procedure, making it easier to maintain perfect optical alignment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill I experience focus shift with the ODK12's carbon fiber tube?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003ecarbon fibre sandwich\u003c\/strong\u003e tube material is specifically chosen for its near-zero coefficient of thermal expansion. This means that as the ambient temperature changes during an imaging session, the \u003cstrong\u003e625mm\u003c\/strong\u003e tube will not shrink or expand, keeping the focal plane stable and eliminating the need for constant refocusing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e300mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e2040mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;52mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e1.8µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e5.6µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e120mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focal Distance\u003c\/td\u003e\n\u003ctd\u003e218mm (from rear of mirror cell)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003eMulti-coated 3 lens\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e625mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e350mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 19kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC machined aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium dovetail with supports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942365131037,"sku":"OOUK-ODK12-OPTICAL-TUBE-ASSEMBLY","price":13321.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/OrionOpticsUK-ODK12-Optical-Tube-Assembly-1_99c581f4-5562-4d1c-8b5f-39440e50ce50.jpg?v=1789606897"},{"product_id":"orion-optics-uk-odk14-optical-tube-assembly","title":"Orion Optics UK ODK14 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrimary Mirror Diameter:\u003c\/strong\u003e 350mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal Ratio:\u003c\/strong\u003e f\/6.8\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorrected Image Circle:\u003c\/strong\u003e \u0026gt;52mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTube Material:\u003c\/strong\u003e Carbon Fibre Sandwich\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBack Focus:\u003c\/strong\u003e 210mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTube Weight:\u003c\/strong\u003e approx. 26kg\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK14 Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK14 is an imaging instrument designed for large-format sensors, combining a 350mm primary mirror and a fast f\/6.8 focal ratio to capture deep-sky objects with exceptional detail. Its integrated three-lens corrector delivers a flat field greater than 52mm in diameter, producing round stars with a spot size of just 5.6µm at the edge of the field. The generous 210mm of back focus and a robust 3\" Crayford focuser accommodate complex imaging trains, while the 720mm carbon fiber tube maintains thermal stability across long exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA 350mm f\/6.8 Astrograph with a \u0026gt;52mm Flat Field\u003c\/h3\u003e\n\u003cp\u003eThe core of the ODK14 is its Optimized Dall-Kirkham optical design, engineered specifically for astrophotography. The 350mm primary mirror gathers significant light, while the 2380mm focal length provides the image scale needed for high-resolution views of galaxies and nebulae. Unlike standard reflectors, the ODK14 incorporates a permanent three-lens corrector, which creates a diffraction-limited, color-corrected field of over 52mm—large enough to serve medium-format CCDs and full-frame CMOS sensors without vignetting or distortion.\u003c\/p\u003e\n\u003cp\u003eThis optical correction results in remarkably tight stars across the entire frame. On-axis, stars are focused to a spot size of just 2.1µm, expanding to only 5.6µm at the extreme edge of the field. This ensures that whether you are imaging the core of the Hercules Cluster (M13) or the faint outer arms of the Triangulum Galaxy (M33), every star is a pinpoint.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e400mm Carbon Sandwich Tube and CNC Cell\u003c\/h3\u003e\n\u003cp\u003eTo maintain optical precision, the ODK14 is built around a carbon fiber sandwich tube with a 400mm diameter. This material provides extreme rigidity at a manageable weight of approximately 26kg and, more importantly, has a near-zero coefficient of thermal expansion. This prevents the 2380mm focal plane from shifting as temperatures drop overnight, eliminating the need for constant refocusing during an imaging session.\u003c\/p\u003e\n\u003cp\u003eThe 350mm primary mirror is supported by a honeycomb, CNC-machined aluminum cell that prevents flexure at any orientation. To achieve rapid thermal equilibrium, three controllable fans are positioned behind the mirror cell, quickly cooling the primary mirror to ambient temperature for sharp, stable views. This open-tube design cools down significantly faster than a comparable closed-tube Schmidt-Cassegrain.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e210mm of Back Focus and a 3\" Crayford Focuser\u003c\/h3\u003e\n\u003cp\u003eThe ODK14 is designed to integrate seamlessly into a modern imaging setup. It provides a massive 210mm of back focal distance, measured from the rear of the mirror cell. This generous spacing allows you to easily install any combination of accessories in the optical train, including off-axis guiders, large filter wheels, rotators, and adaptive optics units, without concern for reaching focus.\u003c\/p\u003e\n\u003cp\u003eFocusing is controlled by a heavy-duty 3\" Crayford focuser with a 10:1 reduction for precise fine adjustments. This focuser is capable of supporting heavy, large-format camera packages without slipping or tilting, ensuring the sensor remains perfectly orthogonal to the light path. The entire assembly is mounted using a CNC-machined aluminum dovetail system for a secure connection to your equatorial mount.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK14 vs. Ritchey-Chrétien: Corrected Field and Collimation\u003c\/h3\u003e\n\u003cp\u003eThe primary competitor for an astrograph like the ODK14 is a traditional Ritchey-Chrétien (RC) telescope. While RCs are known for their coma-free fields, they typically require a separate, costly field flattener to correct for significant off-axis astigmatism and produce a truly flat field for imaging.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntegrated Correction:\u003c\/strong\u003e The ODK14's built-in three-lens corrector delivers a flat, \u0026gt;52mm corrected field out of the box. An RC of similar aperture often requires an additional corrector, adding complexity and cost to the imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpot Size:\u003c\/strong\u003e Thanks to its corrective elements, the ODK14 maintains tight, round stars to the edge of the field, with a specified spot size of only 5.6µm. This is often superior to what an RC with a generic flattener can achieve.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCollimation:\u003c\/strong\u003e Ritchey-Chrétien telescopes are notoriously sensitive to collimation, requiring precise alignment of both the primary and secondary hyperbolic mirrors. The ODK design is generally more forgiving to align, allowing you to spend more time imaging and less time adjusting optics.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount is required for the ODK14 OTA?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a tube weight of approximately \u003cstrong\u003e26kg (57 lbs)\u003c\/strong\u003e, the ODK14 requires a high-capacity equatorial mount. For reliable imaging, you should choose a mount with a rated instrument capacity of at least 40kg (90 lbs) to comfortably handle the OTA plus a full imaging train. Mounts in the class of a 10Micron GM2000, Software Bisque Paramount ME II, or Astro-Physics 1100GTO are appropriate.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ODK14's 2380mm focal length perform on small galaxies like the Whirlpool Galaxy (M51)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 2380mm focal length is ideal for targets like M51, especially when paired with modern CMOS cameras with small pixels (e.g., 2.9µm to 3.76µm). The combination provides an excellent image scale for resolving fine details like individual HII regions, dust lanes, and the tidal bridge connecting M51 to its companion galaxy, NGC 5195.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of the ODK14's 210mm back focus?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e210mm back focus\u003c\/strong\u003e distance provides ample room to install a complete, modern imaging train. This allows you to use accessories such as an off-axis guider (OAG), a large-format filter wheel (for LRGB and narrowband filters), an electronic rotator, and your primary imaging camera without running out of focus travel. It eliminates the need for extenders and ensures maximum flexibility.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy does the ODK14 use a carbon fiber tube?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA carbon fiber sandwich tube offers two key advantages for high-resolution imaging. First, it has a \u003cstrong\u003enear-zero coefficient of thermal expansion\u003c\/strong\u003e, which prevents the telescope's focus from shifting as the ambient temperature changes during the night. Second, it has a very high stiffness-to-weight ratio, ensuring the optical elements remain perfectly aligned regardless of the telescope's orientation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan the ODK14 be used for planetary imaging of Jupiter or Saturn?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The large \u003cstrong\u003e350mm aperture\u003c\/strong\u003e provides incredible resolving power, capable of revealing fine details in Jupiter's cloud bands, the Great Red Spot, and the Cassini Division in Saturn's rings. While the native f\/6.8 focal ratio is fast for planetary work, adding a 2.5x or 3x Barlow lens will increase the effective focal length to an ideal range for high-frame-rate planetary cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the \u0026gt;52mm corrected field of the ODK14 mean for my camera choice?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e\u0026gt;52mm fully corrected image circle\u003c\/strong\u003e means the ODK14 can illuminate and provide sharp, pinpoint stars across the largest commercially available astronomy sensors. This includes:\n\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull-Frame Sensors:\u003c\/strong\u003e (e.g., Sony IMX571, IMX455) which have a diagonal of ~43mm.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMedium-Format Sensors:\u003c\/strong\u003e (e.g., KAF-16803) which have a diagonal of 52.1mm.\u003c\/li\u003e\n\u003c\/ul\u003e\nYou can use any of these large sensors without worrying about vignetting or distorted stars in the corners of your images.\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e350mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e2380mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;52mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e2.1µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e5.6µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003eMulti-coated 3 lens\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e210mm (from rear of mirror cell, ±1mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e720mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e400mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 26kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e136mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC machined aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror \u0026amp; Tube Cooling\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans (heaters optional)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment Method\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium dovetail with supports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eODK14 Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942365425949,"sku":"OOUK-ODK14-OPTICAL-TUBE-ASSEMBLY","price":18116.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/OrionOpticsUK-ODK14-Optical-Tube-Assembly-1_dab33d06-5f04-4966-84bc-ef40b7061d52.jpg?v=1789606905"},{"product_id":"orion-optics-uk-odk16-optical-tube-assembly","title":"Orion Optics UK ODK16 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e400mm (16\") Primary Mirror Diameter\u003c\/li\u003e\n\u003cli\u003e2720mm Focal Length at f\/6.8\u003c\/li\u003e\n\u003cli\u003eCorrected Dall-Kirkham Optical Design\u003c\/li\u003e\n\u003cli\u003e\u0026gt;52mm Flat Field Image Circle\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e216mm of Back Focal Distance\u003c\/li\u003e\n\u003cli\u003e3\" Crayford Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eDownloads\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK16 Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK16 combines a massive 400mm primary mirror with a fast f\/6.8 focal ratio to create a formidable deep-sky imaging platform. Its integrated 3-lens corrector delivers a fully flat field greater than 52mm in diameter, producing pinpoint stars from a 2.4µm on-axis spot size out to just 6.0µm at the edge of the field. With a focal length of 2720mm and a thermally stable carbon fibre tube, the ODK16 is engineered to resolve fine detail on distant galaxies and planetary surfaces with professional-grade optical accuracy.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e400mm f\/6.8 Optics: A \u0026gt;52mm Flat Field for Large Format Sensors\u003c\/h3\u003e\n\u003cp\u003eThe heart of the ODK16 is its corrected Dall-Kirkham optical system. The 400mm primary mirror gathers immense light, while the f\/6.8 focal ratio allows for shorter exposure times on faint nebulae compared to slower designs. A factory-matched, multi-coated 3-lens corrector is permanently integrated into the optical path, eliminating the need for third-party flatteners and ensuring the system performs to its full potential.\u003c\/p\u003e\n\u003cp\u003eThis design produces a corrected image circle greater than 52mm, fully illuminating the largest full-frame CMOS and CCD sensors without vignetting or field curvature. With spot sizes as small as 2.4µm, you can leverage the resolution of modern high-pixel-density cameras to capture incredibly sharp, detailed images across the entire frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eZero-Expansion Carbon Tube: Thermal Stability Across a 835mm Tube\u003c\/h3\u003e\n\u003cp\u003eTo maintain precise focus during temperature drops, the ODK16's 835mm tube is constructed from a carbon fibre sandwich material. This advanced composite has virtually zero thermal expansion, preventing the focal plane from shifting during long imaging sessions or throughout the night. The result is consistently sharp stars without the need for constant refocusing.\u003c\/p\u003e\n\u003cp\u003eThe open-tube design, combined with three controllable fans behind the honeycomb CNC-machined primary mirror cell, ensures rapid thermal acclimation. This active cooling system quickly brings the 400mm mirror to ambient temperature, minimizing tube currents and delivering stable, high-contrast views sooner.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eImaging Integration: 216mm of Back Focus and a 3\" Crayford\u003c\/h3\u003e\n\u003cp\u003eThe ODK16 is built from the ground up for serious astrophotography. It provides a generous 216mm of back focal distance measured from the rear of the mirror cell, offering ample room for complex imaging trains. You can easily accommodate off-axis guiders, large filter wheels, rotators, and adaptive optics systems without concern for reaching focus.\u003c\/p\u003e\n\u003cp\u003eFocusing is managed by a robust 3\" Crayford focuser, featuring 10:1 fine reduction for critical adjustments. This large-aperture focuser provides a rigid, flexure-free connection point for heavy camera packages, ensuring the optical axis remains perfectly aligned throughout your exposure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK16 vs. Ritchey-Chrétien: The Advantage of an Integrated Corrector\u003c\/h3\u003e\n\u003cp\u003eWhile Ritchey-Chrétien (RC) telescopes are known for their coma-free fields, they typically operate at f\/8 or slower and require a separate, often expensive, field flattener or reducer to produce sharp stars on large sensors. The ODK16's primary advantage is its fully integrated, optimized optical system.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBuilt-in Correction:\u003c\/strong\u003e The ODK16's 3-lens corrector is designed as part of the optical train, not an add-on. This guarantees a \u0026gt;52mm flat field out of the box, with performance optimized for its native f\/6.8 focal ratio.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFaster Imaging:\u003c\/strong\u003e At f\/6.8, the ODK16 requires significantly less exposure time to reach the same signal-to-noise ratio as a comparable f\/8 RC, allowing you to gather more data in a single night.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo Spacing guesswork:\u003c\/strong\u003e With an integrated corrector, you avoid the trial-and-error of finding the perfect corrector-to-sensor spacing that is often required with third-party accessories on an RC.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat camera sensors can the ODK16's \u0026gt;52mm image circle cover?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK16's image circle of over 52mm is large enough to fully illuminate and correct for full-frame sensors (36x24mm, 43mm diagonal) and even larger medium-format sensors. This makes it an ideal match for popular full-frame astronomy cameras, ensuring you have pinpoint stars and no vignetting across the entire field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount is required for the ODK16's 36kg weight?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith an approximate tube weight of 36kg, plus the added weight of a large camera, guider, and accessories, the ODK16 requires a high-capacity equatorial mount. You should look for a mount in the 100 lb (45 kg) payload class or higher to ensure stable, precise tracking for long-exposure astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ODK16's carbon fibre tube benefit imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe carbon fibre sandwich construction has a near-zero coefficient of thermal expansion. As temperatures change overnight, a metal tube will shrink, causing the focal point to shift and requiring you to refocus. The ODK16's tube holds focus rigidly, keeping your images sharp throughout long automated imaging sequences.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the 216mm back focus on the ODK16 allow me to install?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 216mm of back focus is extremely generous and provides ample space for a complete imaging train. You can easily fit components such as:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAn off-axis guider (OAG)\u003c\/li\u003e\n\u003cli\u003eA large-format filter wheel (e.g., 5-position or 7-position 2\")\u003c\/li\u003e\n\u003cli\u003eAn electronic rotator\u003c\/li\u003e\n\u003cli\u003eAn adaptive optics unit\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the ODK16 perform on small targets like the Dumbbell Nebula (M27)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a 2720mm focal length, the ODK16 provides significant image scale, making it perfect for resolving detail in smaller deep-sky objects. M27 and other planetary nebulae or smaller galaxies will be framed beautifully, allowing you to capture intricate structural details that are inaccessible to shorter focal length instruments.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ODK16's f\/6.8 focal ratio a good compromise for different targets?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, f\/6.8 is an excellent \"all-around\" focal ratio for a large imaging instrument. It is fast enough to capture faint, extended objects like the Veil Nebula (NGC 6960) in reasonable time, while the 2720mm focal length still provides the high resolution needed for detailed views of Jupiter's cloud bands or Saturn's rings.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e400mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e2720mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focal Distance\u003c\/td\u003e\n\u003ctd\u003e216mm (from rear of mirror cell, ±1mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 36kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e835mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e450mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e152mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003eMulti-coated 3 lens\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Flat Field\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;52mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e2.4µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e6.0µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC machined aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment Method\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium dovetail with supports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eODK16 Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eNo product-specific manual or software is available for the Orion Optics UK ODK16 Optical Tube Assembly at this time.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942365524253,"sku":"OOUK-ODK16-OPTICAL-TUBE-ASSEMBLY","price":25212.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_dfa4a989-71b5-41e6-9a89-14f8b8b82677.jpg?v=1789606914"},{"product_id":"orion-optics-uk-odk10tr-optical-tube-assembly","title":"Orion Optics UK ODK10Tr Truss Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e250mm (10-inch) Optimized Dall-Kirkham optics\u003c\/li\u003e\n\u003cli\u003e1700mm focal length at a native f\/6.8 focal ratio\u003c\/li\u003e\n\u003cli\u003e50mm fully corrected, flat image circle for large sensors\u003c\/li\u003e\n\u003cli\u003e3.5μm on-axis spot size for sharp stars\u003c\/li\u003e\n\u003cli\u003eCarbon fiber truss tube construction weighing only 12kg\u003c\/li\u003e\n\u003cli\u003e3-inch Crayford focuser with 10:1 fine focus control\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK10Tr Truss Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK10Tr is an imaging instrument designed for uncompromising optical clarity, delivering a 50mm flat field from its 250mm f\/6.8 corrected Dall-Kirkham optics. With a focal length of 1700mm, it achieves pinpoint stars measuring just 3.5μm on-axis and 6.2μm at the edge of the field, ensuring full use of modern high-resolution sensors. Its carbon fiber truss construction keeps the weight to approximately 12kg, providing exceptional rigidity and thermal stability for serious astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCorrected Dall-Kirkham: 50mm Flat Field with 3.5μm Spot Sizes\u003c\/h3\u003e\n\u003cp\u003eThe heart of the ODK10Tr is its optical system, which pairs an elliptical primary mirror with a spherical secondary and a dedicated 3-lens corrector. This design produces a 50mm diameter, fully illuminated and corrected image circle, free of coma and field curvature. You can confidently use full-frame (35mm format) sensors and even larger medium-format chips without vignetting or distorted stars at the corners.\u003c\/p\u003e\n\u003cp\u003eThe optical correction delivers incredibly tight star images, with a measured spot size of only 3.5μm at the center of the field and 6.2μm at the very edge. This level of correction ensures that the telescope's resolution, not the optics, is the limiting factor, resolving fine detail in galaxies and nebulae even with small-pixel CMOS cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fiber Truss: 12kg of Rigid, Stable Construction\u003c\/h3\u003e\n\u003cp\u003eThe ODK10Tr's open truss structure, built from a carbon fiber sandwich material, provides a superior stiffness-to-weight ratio. At just 12kg, this 10-inch astrograph is manageable for a wide range of equatorial mounts while remaining exceptionally rigid to prevent flexure as it moves across the sky. Carbon fiber's low thermal expansion coefficient also ensures the 1700mm focal length remains stable during temperature drops, minimizing focus shift throughout an imaging session.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eActive Cooling:\u003c\/strong\u003e Three integrated, controllable fans are mounted behind the primary mirror to accelerate thermal acclimation, allowing you to start imaging faster.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCNC Machined Components:\u003c\/strong\u003e Key mechanical parts, including the honeycomb mirror cell and dovetail plate supports, are CNC machined from aluminum for precise, repeatable alignment and durability.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStray Light Control:\u003c\/strong\u003e While the open truss design promotes rapid cooling, it is susceptible to stray light. Using a simple fabric shroud (not included) is recommended to maximize image contrast, especially from light-polluted locations.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eImaging-Ready Mechanics: 3\" Focuser and 213mm Back Focus\u003c\/h3\u003e\n\u003cp\u003eEngineered for demanding imaging setups, the ODK10Tr features a robust 3\" Crayford focuser with a 10:1 reduction ratio for precise fine adjustments. The large-diameter drawtube eliminates vignetting with large sensors and can support heavy camera packages without slipping or tilting. With a generous 213mm of back focus measured from the rear of the mirror cell, you have ample room to install complex imaging trains, including off-axis guiders, large filter wheels, and camera rotators, without concern for reaching focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK10Tr vs. Ritchey-Chrétien: Collimation, Field Correction, and Spot Size\u003c\/h3\u003e\n\u003cp\u003eFor imagers seeking a flat-field instrument, the main alternative to an ODK is a Ritchey-Chrétien (RC). While both are excellent designs, the ODK presents several practical advantages.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompetitor's Advantage (RC):\u003c\/strong\u003e A pure RC design is naturally free from coma, an optical aberration that elongates stars away from the center. However, it suffers from significant astigmatism and field curvature, requiring a separate corrector for serious imaging.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eODK10Tr Advantage:\u003c\/strong\u003e The ODK's integrated 3-lens corrector fully addresses coma, astigmatism, and field curvature across its 50mm image circle. More importantly, the ODK's spherical secondary mirror makes collimation far more forgiving than the hyperbolic secondary of an RC, which requires extremely precise alignment. For most users, the ODK delivers superior edge-of-field star shapes and is significantly easier to maintain in perfect adjustment.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat sensors are a good match for the ODK10Tr's 50mm image circle?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 50mm fully corrected image circle is ideal for full-frame sensors (e.g., Sony IMX455, IMX571 in APS-C format) and even some medium-format CCD or CMOS chips. You can use any sensor up to a 50mm diagonal without experiencing significant vignetting or distorted stars at the corners.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use the 213mm of back focus on the ODK10Tr?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e213mm back focus\u003c\/strong\u003e is measured from the rear plate of the mirror cell. You will need to use extension tubes between the focuser and your camera to place the sensor at the correct focal plane. This generous distance ensures you can fit any combination of accessories like an off-axis guider, filter wheel, and adaptive optics unit into your imaging train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow difficult is it to collimate the ODK10Tr compared to an RC?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK10Tr is significantly easier to collimate. Its spherical secondary mirror is much less sensitive to tilt errors than the hyperbolic secondary of a Ritchey-Chrétien. This makes achieving and maintaining perfect optical alignment a much simpler process, which is a major practical advantage for field use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need a shroud for the ODK10Tr's truss design?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile not strictly required, a light shroud is highly recommended. The open truss design is excellent for thermal management but can allow stray light to hit the focal plane, reducing contrast. A shroud also helps protect the mirrors from dew and dust. It is an essential accessory for getting the best possible performance from the telescope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the ODK10Tr perform on a large target like the Andromeda Galaxy (M31) with a full-frame camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK10Tr is exceptionally well-suited for this scenario. Its 1700mm focal length provides the ideal image scale for capturing detail in the galaxy's dust lanes and core, while the 50mm flat image circle allows a full-frame sensor to capture the full expanse of M31 in a single frame with sharp stars from edge to edge.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ODK10Tr's f\/6.8 focal ratio suitable for imaging smaller planetary nebulae like the Ring Nebula (M57)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The \u003cstrong\u003ef\/6.8 focal ratio\u003c\/strong\u003e and \u003cstrong\u003e1700mm focal length\u003c\/strong\u003e provide excellent image scale for resolving details in smaller targets like the Ring Nebula (M57) or the Dumbbell Nebula (M27). The high optical quality and small spot sizes will allow you to capture fine structural details within these objects, especially when paired with a camera that has small pixels.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eOptimized Dall-Kirkham (ODK) with 3-Lens Corrector\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e250mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e1700mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e50mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e3.5μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e6.2μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e96mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e213mm (from rear of mirror cell)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 Reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon Fibre Sandwich Truss\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e475mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e300mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 12kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC Machined Aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cooling\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment\u003c\/td\u003e\n\u003ctd\u003eCNC Machined Aluminium Dovetail Plate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eODK10Tr Truss Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942365688093,"sku":"OOUK-ODK10TR-OPTICAL-TUBE-ASSEMBLY","price":11316.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_e23803b0-3de1-43d0-a3a8-278a610b3ea1.jpg?v=1789606922"},{"product_id":"orion-optics-uk-odk12tr-optical-tube-assembly","title":"Orion Optics UK ODK12Tr Truss Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e300mm (12\") Optimized Dall-Kirkham Astrograph\u003c\/li\u003e\n\u003cli\u003e2040mm Focal Length (f\/6.8)\u003c\/li\u003e\n\u003cli\u003e\u0026gt;52mm Flat, Corrected Image Circle\u003c\/li\u003e\n\u003cli\u003e1.8µm On-Axis Spot Size\u003c\/li\u003e\n\u003cli\u003eCarbon Fiber Truss Tube Construction\u003c\/li\u003e\n\u003cli\u003e218mm of Back Focus\u003c\/li\u003e\n\u003cli\u003e3\" Crayford Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK12Tr Truss Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK12Tr Truss is a dedicated imaging platform built around a 300mm primary mirror with a 2040mm focal length. Its f\/6.8 corrected Dall-Kirkham design delivers incredibly small 1.8µm spot sizes on-axis and maintains a flat field greater than 52mm in diameter. The entire carbon fiber truss assembly weighs approximately 19kg and provides a generous 218mm of back focal distance for complex accessory stacks.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e300mm f\/6.8 Optics: 5.6µm Spots Across a \u0026gt;52mm Field\u003c\/h3\u003e\n\u003cp\u003eThe ODK12Tr's optical system is engineered for large-format sensors. The 300mm primary mirror operates at f\/6.8, providing enough image scale for detailed views of distant galaxies without demanding excessively long exposure times. A built-in, multi-coated 3-lens corrector flattens the field, delivering pinpoint stars with a spot size of just 5.6µm at the edge of a massive 52mm image circle—fully illuminating full-frame and larger sensors.\u003c\/p\u003e\n\u003cp\u003eThe 120mm secondary mirror provides this wide-field illumination, creating a 40% central obstruction by diameter. This is a necessary trade-off for edge-to-edge performance on large chips and has minimal impact on deep-sky imaging, where light grasp and field flatness are paramount.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fiber Truss: A 19kg Platform for Stable Imaging\u003c\/h3\u003e\n\u003cp\u003eConstructed from a carbon fiber sandwich material, the ODK12Tr's open truss frame offers exceptional thermal and mechanical stability. Weighing approximately 19kg, the tube assembly is rigid enough to support heavy imaging loads without flexure. The carbon fiber's near-zero coefficient of thermal expansion means the 2040mm focal length remains constant as temperatures drop, preventing focus shift during long imaging sessions.\u003c\/p\u003e\n\u003cp\u003eThe open truss design allows the 300mm primary mirror to acclimate to ambient temperatures quickly, aided by three controllable fans integrated into the honeycomb CNC-machined mirror cell. This active thermal management ensures your images are sharp from the start of the night to the end.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e218mm Back Focus \u0026amp; 3\" Focuser: Ready for Any Imaging Train\u003c\/h3\u003e\n\u003cp\u003eThe ODK12Tr is designed to accommodate any modern imaging accessory. It provides 218mm of back focal distance measured from the rear of the mirror cell, offering ample room for off-axis guiders, filter wheels, rotators, and large-format cameras. You won't need to compromise on your ideal setup due to spacing constraints.\u003c\/p\u003e\n\u003cp\u003eTo carry this load, the OTA is equipped with a robust 3\" Crayford focuser featuring a 10:1 reduction for precise, repeatable fine adjustments. The large drawtube diameter prevents vignetting with large sensors and ensures your entire imaging train is held securely throughout the night.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK12Tr vs. Ritchey-Chrétien: Collimation and Field Correction\u003c\/h3\u003e\n\u003cp\u003eUnlike Ritchey-Chrétien (RC) telescopes that use two difficult-to-align hyperbolic mirrors, the Optimized Dall-Kirkham (ODK) design employs an elliptical primary and a spherical secondary. This makes collimation significantly more forgiving and stable, saving valuable clear-sky time.\u003c\/p\u003e\n\u003cp\u003eWhile a classic Dall-Kirkham suffers from off-axis coma, the ODK12Tr's integrated 3-lens corrector completely eliminates it, producing a wide, flat, coma-free field that rivals the best RCs. The result is an astrograph that combines the optical simplicity and collimation stability of the DK design with the professional, wide-field imaging results of a corrected RC.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat sensor size can the ODK12Tr fully illuminate and correct?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK12Tr provides a fully corrected, flat field size of \u003cstrong\u003eover 52mm in diameter\u003c\/strong\u003e. This is large enough to cover full-frame (36x24mm) and even larger format astronomy sensors without significant vignetting or distortion at the corners.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ODK12Tr's carbon fiber truss help with astrophotography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe carbon fiber construction offers two key benefits. First, it has an extremely low coefficient of thermal expansion, which means the telescope's \u003cstrong\u003e2040mm focal length does not change\u003c\/strong\u003e as temperatures drop overnight, preventing focus shift. Second, the open truss design allows the primary mirror to cool down to ambient temperature much faster, aided by the \u003cstrong\u003ethree integrated cooling fans\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the ODK12Tr perform on a large target like the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK12Tr is an excellent choice for M31. Its \u003cstrong\u003e2040mm focal length\u003c\/strong\u003e and \u003cstrong\u003e300mm aperture\u003c\/strong\u003e provide the necessary resolution to capture fine dust lanes and star-forming regions within the galaxy's spiral arms. The \u003cstrong\u003e\u0026gt;52mm corrected field\u003c\/strong\u003e allows you to frame a significant portion of the galaxy and its companions in a single shot with a large-format camera.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the benefit of the ODK12Tr's 218mm of back focus?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e218mm of back focus\u003c\/strong\u003e is exceptionally generous and provides critical flexibility for building your imaging train. It ensures you have enough space to install multiple accessories—such as an off-axis guider, a filter wheel, an adaptive optics unit, and a rotator—between the focuser and the camera sensor without running out of focus travel.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ODK12Tr's f\/6.8 focal ratio good for imaging smaller targets like the Ring Nebula (M57)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the f\/6.8 focal ratio is a versatile sweet spot. For a target like M57, the \u003cstrong\u003e2040mm focal length\u003c\/strong\u003e yields a large enough image scale to clearly resolve the nebula's ring structure and the faint central star. The focal ratio is still fast enough to capture significant signal in reasonable sub-exposure times, making it efficient for both broadband and narrowband imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy choose the ODK12Tr over a comparable Ritchey-Chrétien astrograph?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage of the ODK12Tr is its ease of collimation. Ritchey-Chrétien designs use two hyperbolic mirrors that are notoriously difficult to align perfectly. The ODK's elliptical primary and spherical secondary are far more tolerant, holding collimation better and being easier to adjust. With its integrated corrector, the ODK provides the flat, coma-free field of an RC without the collimation challenges.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eOptimized Dall-Kirkham (Corrected)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e300mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e2040mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;52mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e1.8µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e5.6µm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e120mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e218mm (from rear of mirror cell)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e615mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e350mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 19kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC machined aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium dovetail plate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942365786397,"sku":"OOUK-ODK12TR-OPTICAL-TUBE-ASSEMBLY","price":16006.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_4e6790da-dd7f-4ac3-a55a-cf0778c4f563.jpg?v=1789606931"},{"product_id":"orion-optics-uk-odk14tr-optical-tube-assembly","title":"Orion Optics UK ODK14Tr Truss Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e350mm (14\") Optimized Dall-Kirkham Optics\u003c\/li\u003e\n\u003cli\u003e2380mm Focal Length (f\/6.8)\u003c\/li\u003e\n\u003cli\u003e\u0026gt;52mm Fully Illuminated and Corrected Image Circle\u003c\/li\u003e\n\u003cli\u003e2.1µm On-Axis Spot Size\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Truss Tube Construction\u003c\/li\u003e\n\u003cli\u003e210mm of Back Focus\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK14Tr Truss Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK14Tr is an astrograph engineered for large-format imaging, combining a 350mm primary mirror with a fast f\/6.8 focal ratio to deliver a 2380mm focal length ideal for detailed views of deep-sky objects. Its Optimized Dall-Kirkham design employs a multi-coated 3-lens corrector to produce a flat field greater than 52mm in diameter, achieving pinpoint stars with spot sizes as small as 2.1μm on-axis. The open carbon fibre truss structure weighs approximately 26kg and is built for thermal stability, supported by three controllable fans for rapid mirror cooling.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK Optics: A 350mm f\/6.8 System with a \u0026gt;52mm Corrected Field\u003c\/h3\u003e\n\u003cp\u003eThe heart of the ODK14Tr is its Optimized Dall-Kirkham optical system, which pairs an ellipsoidal primary mirror with a spherical secondary. This configuration is inherently easier to figure to a high degree of smoothness than more complex aspheric designs. The system's native coma is fully addressed by a dedicated, multi-coated 3-lens corrector, resulting in a diffraction-limited, flat field across a massive \u0026gt;52mm image circle.\u003c\/p\u003e\n\u003cp\u003eThis optical design delivers incredibly sharp stars, with a measured spot size of just 2.1μm on-axis and 5.6μm at the edge of the field. This ensures that the telescope's resolution is not the limiting factor, even when paired with modern CMOS cameras that have very small pixels. The 350mm aperture gathers significant light, while the f\/6.8 focal ratio provides a balance of image scale and exposure speed suitable for imaging everything from distant galaxy clusters to faint nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eTruss Structure: Carbon Fibre Sandwich Construction at 26kg\u003c\/h3\u003e\n\u003cp\u003eThe ODK14Tr utilizes an open truss framework made from a carbon fibre sandwich material, a design choice that offers superior thermal performance and rigidity. Unlike a solid tube, the open design prevents the formation of tube currents and allows the optics to acclimate to ambient temperatures quickly. The carbon fibre construction minimizes focus shift caused by temperature changes, a critical factor for maintaining sharpness over long imaging sessions.\u003c\/p\u003e\n\u003cp\u003eDespite its large 400mm tube diameter, the OTA weighs approximately 26kg and has a compact length of 700mm, making it manageable for high-capacity observatory-class mounts. The primary mirror is housed in a honeycomb CNC machined aluminum cell, providing rigid support without inducing mechanical stress on the optics.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eThermal Control: Active Cooling with 3 Controllable Fans\u003c\/h3\u003e\n\u003cp\u003eAchieving thermal equilibrium is essential for high-resolution imaging, and the ODK14Tr addresses this directly with an integrated active cooling system. Three controllable fans are positioned behind the primary mirror to accelerate the cooling process, drawing air across the back of the 350mm mirror to bring it to ambient temperature rapidly.\u003c\/p\u003e\n\u003cp\u003eBy minimizing the temperature differential between the glass and the surrounding air, this system drastically reduces mirror seeing—the localized turbulence that can soften fine details. This allows you to start imaging sooner and maintain optimal optical performance throughout the night. For observers in dew-prone locations, optional heaters can be integrated for complete environmental control.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eImaging Train Support: 210mm Back Focus and a 3\" Crayford Focuser\u003c\/h3\u003e\n\u003cp\u003eThe ODK14Tr is designed to accommodate complex and heavy imaging trains. It provides a generous 210mm of back focus, measured from the rear of the mirror cell. This extensive travel leaves ample room for accessories like off-axis guiders, large filter wheels, rotators, and large-format cameras without concern for reaching focus.\u003c\/p\u003e\n\u003cp\u003eFocusing is handled by a robust 3\" Crayford focuser with a 10:1 reduction ratio. The large diameter prevents vignetting on full-frame and larger sensors, while the fine-focus knob allows for the precise adjustments necessary to achieve critical focus at the 2380mm focal length. The entire assembly attaches to your mount via a sturdy, CNC-machined aluminum dovetail plate with integrated supports for maximum stability.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK14Tr vs. CDK Designs: Understanding Astrograph Trade-Offs\u003c\/h3\u003e\n\u003cp\u003eWhen choosing a high-end astrograph, the Orion Optics UK Optimized Dall-Kirkham (ODK) is often compared to Corrected Dall-Kirkham (CDK) designs. Both aim for a large, flat, coma-free field, but they achieve it through different optical philosophies.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eODK Approach:\u003c\/strong\u003e The ODK uses an ellipsoidal primary and a spherical secondary. A spherical surface is the simplest to manufacture to an extremely high degree of smoothness, minimizing scatter. The significant off-axis coma inherent in this design is then eliminated with a dedicated 3-lens corrector placed before the focal plane.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCDK Approach:\u003c\/strong\u003e A CDK typically uses an ellipsoidal primary and an aspheric (hyperbolic) secondary, along with a corrector. The aspheric secondary corrects for coma natively, reducing the workload of the corrector lenses. The trade-off is the increased complexity and cost of figuring the aspheric secondary surface.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe ODK14Tr's design represents a pragmatic choice, prioritizing the manufacturability of its core components to achieve exceptional surface quality while using a powerful, modern corrector to deliver a final image that is sharp and flat across its \u0026gt;52mm field.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount is required for the ODK14Tr OTA?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith an approximate weight of \u003cstrong\u003e26kg\u003c\/strong\u003e for the optical tube alone, plus the added weight of a large camera, filter wheel, and guider, a heavy-duty, observatory-class mount is required. Look for a German equatorial mount with a stated instrument capacity of at least 50kg (110 lbs) to ensure stable, accurate tracking for long-exposure astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the ODK14Tr perform on a large target like the Andromeda Galaxy (M31) with a full-frame sensor?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK14Tr is an excellent instrument for such a target. Its \u003cstrong\u003e\u0026gt;52mm corrected image circle\u003c\/strong\u003e fully illuminates a standard full-frame sensor (43mm diagonal) with no vignetting. The \u003cstrong\u003e2380mm focal length\u003c\/strong\u003e provides enough image scale to resolve individual dust lanes, star-forming regions, and globular clusters within M31, while still being wide enough to capture a significant portion of the galaxy's sprawling disk.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the 210mm back focus of the ODK14Tr allow me to do?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e210mm of back focus\u003c\/strong\u003e provides exceptional flexibility for building a comprehensive imaging train. It allows you to easily incorporate multiple accessories between the focuser and the camera sensor, such as:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAn off-axis guider (OAG)\u003c\/li\u003e\n\u003cli\u003eA large-format filter wheel (e.g., 5- or 7-position 50mm square)\u003c\/li\u003e\n\u003cli\u003eAn electronic field rotator\u003c\/li\u003e\n\u003cli\u003eAn adaptive optics unit\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis generous spacing is a key feature for advanced imagers who need to accommodate a full suite of equipment without compromising the ability to reach focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do the 3 cooling fans on the ODK14Tr improve imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e3 controllable fans\u003c\/strong\u003e are crucial for thermal management. They actively pull air across the back of the 350mm primary mirror, forcing it to cool down to the ambient nighttime temperature much faster than it would passively. This minimizes \"mirror seeing,\" the image-degrading turbulence created by warm air rising from a mirror that is still warmer than its surroundings. The result is sharper images, sooner in your observing session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ODK14Tr's f\/6.8 focal ratio suitable for imaging faint nebulae like the Elephant's Trunk Nebula (IC 1396)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, \u003cstrong\u003ef\/6.8\u003c\/strong\u003e is a very capable focal ratio for faint nebulae, especially when paired with a large \u003cstrong\u003e350mm aperture\u003c\/strong\u003e. While not as fast as dedicated hyper-widefield systems, it offers a superb balance, collecting a great deal of light while providing the high resolution needed to capture intricate details in structures like the pillars and Bok globules within IC 1396. Modern, low-noise CMOS sensors make this focal ratio highly efficient for both broadband and narrowband imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat do the spot sizes of 2.1μm and 5.6μm mean for my images with the ODK14Tr?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThese figures quantify the sharpness of the telescope. A \u003cstrong\u003e2.1μm spot size on-axis\u003c\/strong\u003e and \u003cstrong\u003e5.6μm at the field edge\u003c\/strong\u003e means that the telescope focuses starlight into incredibly tight, concentrated points. Most modern astronomy cameras have pixel sizes between 2.5μm and 9μm. Because the ODK14Tr's spot sizes are smaller than or comparable to these pixel sizes, it ensures that the telescope's optics will not be the limiting factor in your image resolution; you will get the full benefit of your camera's sensor, with sharp, pinpoint stars across the entire frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eOptimized Dall-Kirkham (ODK)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e350mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e2380mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector\u003c\/td\u003e\n\u003ctd\u003eMulti-coated 3-lens design\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFlat Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;52mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (On-Axis)\u003c\/td\u003e\n\u003ctd\u003e2.1μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size (Field Edge)\u003c\/td\u003e\n\u003ctd\u003e5.6μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e136mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e210mm (from rear of mirror cell, ±1mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e700mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e400mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 26kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC machined aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling System\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans (heaters optional)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment Method\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium dovetail with supports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eODK14Tr Truss Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942366572829,"sku":"OOUK-ODK14TR-OPTICAL-TUBE-ASSEMBLY","price":20225.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_a024eb5b-9702-4d62-82e4-d3c70289f9df.jpg?v=1789606940"},{"product_id":"orion-optics-uk-odk16tr-optical-tube-assembly","title":"Orion Optics UK ODK16Tr Truss Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e400mm (16\") Optimized Dall-Kirkham Optics\u003c\/li\u003e\n\u003cli\u003e2720mm Focal Length (f\/6.8)\u003c\/li\u003e\n\u003cli\u003e\u0026gt;52mm Fully Corrected and Illuminated Image Circle\u003c\/li\u003e\n\u003cli\u003e2.4µm On-Axis Spot Size\u003c\/li\u003e\n\u003cli\u003eCarbon Fibre Sandwich Truss Tube Construction\u003c\/li\u003e\n\u003cli\u003e3\" Crayford Focuser with 10:1 Reduction\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eOrion Optics UK ODK16Tr Truss Optical Tube Assembly\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK ODK16Tr is an observatory-class astrograph, combining a 400mm primary mirror with a fast f\/6.8 focal ratio to deliver professional imaging results. Its 3-lens corrector illuminates a flat field greater than 52mm in diameter, producing pinpoint stars with a 2.4µm spot size on-axis and 6.0µm at the field edge. The entire optical system is housed in a thermally stable carbon fibre sandwich truss tube weighing approximately 36kg and supported by a robust 3\" Crayford focuser.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK16Tr: A 400mm f\/6.8 Corrected Dall-Kirkham Astrograph\u003c\/h3\u003e\n\u003cp\u003eThe ODK16Tr's optical design starts with a 400mm primary mirror in an optimized Dall-Kirkham configuration, which uses an elliptical primary and a spherical secondary. This combination is precisely figured in-house by Orion Optics UK's master opticians. To eliminate the off-axis coma inherent in the standard DK design, a dedicated multi-coated 3-lens corrector is permanently installed, creating a coma-free, flat-field instrument with a 2720mm focal length.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eA \u0026gt;52mm Flat Field with 2.4µm On-Axis Spots\u003c\/h3\u003e\n\u003cp\u003eThis instrument is engineered for large-format sensors. The optical system produces a fully illuminated and corrected image circle greater than 52mm, comfortably covering full-frame (43mm diagonal) and many medium-format astrophotography cameras. The correction is exceptional, delivering an incredibly tight 2.4µm spot size on-axis and maintaining 6.0µm spots at the extreme edge of the field, ensuring that every pixel on your large sensor captures a sharp, aberration-free star.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eCarbon Fibre Truss and 3-Fan Cooling\u003c\/h3\u003e\n\u003cp\u003eMechanical and thermal stability are critical at this scale. The ODK16Tr uses a carbon fibre sandwich material for its truss tube, which offers superior stiffness and a near-zero coefficient of thermal expansion to hold focus through temperature changes. The open truss design, weighing approximately 36kg, allows the 400mm primary mirror to acclimate rapidly, a process accelerated by three controllable cooling fans integrated into the CNC-machined honeycomb mirror cell. For maximum contrast, an optional light shroud is recommended to block stray light.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e3\" Crayford Focuser and 216mm of Back Focus\u003c\/h3\u003e\n\u003cp\u003eThe imaging train is anchored by a heavy-duty 3\" Crayford focuser with a 10:1 fine-adjustment knob, capable of supporting large cameras, filter wheels, and off-axis guiders without flexure. The system provides a generous 216mm of back focal distance measured from the rear of the mirror cell. This ample spacing gives you complete flexibility to configure your ideal imaging setup with rotators, adaptive optics, and other accessories while still reaching perfect focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eODK16Tr vs. Ritchey-Chrétien: Field Correction and Spot Size\u003c\/h3\u003e\n\u003cp\u003eWhile the Ritchey-Chrétien (RC) is a common choice for two-mirror astrographs, the corrected Dall-Kirkham offers distinct advantages. An RC naturally corrects for coma but leaves off-axis astigmatism, which can elongate stars at the edge of the field. The ODK16Tr's integrated 3-lens corrector is specifically designed to eliminate both coma and astigmatism, resulting in rounder stars and smaller spot sizes across its entire \u0026gt;52mm field of view. This design delivers a higher level of performance for imagers using the largest available sensors.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat size camera sensor can the ODK16Tr fully illuminate?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK16Tr is designed to fully illuminate and correct an image circle \u003cstrong\u003egreater than 52mm\u003c\/strong\u003e in diameter. This comfortably covers professional full-frame sensors (e.g., Sony IMX455, 43mm diagonal) and even larger medium-format sensors like the KAF-16803 (39mm diagonal) with no vignetting from the optical system.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat class of mount is required for the ODK16Tr OTA?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a tube weight of approximately \u003cstrong\u003e36kg (around 80 lbs)\u003c\/strong\u003e before adding a camera and accessories, the ODK16Tr requires a high-capacity, observatory-grade equatorial mount. Look for mounts with a specified instrument capacity of at least 100-120 lbs (45-55 kg) to ensure stability for long-exposure imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ODK16Tr's design help maintain focus during temperature drops?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe ODK16Tr uses a \u003cstrong\u003ecarbon fibre sandwich\u003c\/strong\u003e material for its truss tube. Carbon fibre has an extremely low coefficient of thermal expansion, meaning it does not shrink or expand significantly as temperatures change overnight. This keeps the distance between the primary and secondary mirrors constant, preventing focus shift and ensuring sharp images throughout your session.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ODK16Tr's f\/6.8 focal ratio suitable for imaging faint nebulae like the Veil Nebula (NGC 6960)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. While f\/6.8 is not as \"fast\" as some dedicated wide-field refractors, the ODK16Tr's massive \u003cstrong\u003e400mm aperture\u003c\/strong\u003e gathers a tremendous amount of light. This light-gathering power makes it highly effective for narrowband imaging of faint emission nebulae, resolving fine filamentary details in targets like the Veil Nebula or the Cygnus Loop with impressive signal-to-noise ratios.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the ODK16Tr's 2720mm focal length frame a target like the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e2720mm focal length\u003c\/strong\u003e provides a high-magnification view ideal for detailed studies of smaller deep-sky objects or for creating mosaics of large ones. A full-frame camera on the ODK16Tr would frame the bright core of the Andromeda Galaxy (M31) in incredible detail, resolving individual dust lanes and star-forming regions, but it would not capture the entire 3-degree span of the galaxy in a single shot.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need to add a light shroud to the ODK16Tr's truss tube?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, a light shroud is highly recommended. The open truss design promotes rapid cooling but is susceptible to stray light from external sources and can be more prone to dew formation on the secondary mirror. A fabric light shroud will significantly improve image contrast by creating a dark interior and will also help protect the optics from dew.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e400mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e2720mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Design\u003c\/td\u003e\n\u003ctd\u003eMulti-coated 3 lens\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFlat Field Size\u003c\/td\u003e\n\u003ctd\u003e\u0026gt;52mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size on Axis\u003c\/td\u003e\n\u003ctd\u003e2.4μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpot Size at Field Edge\u003c\/td\u003e\n\u003ctd\u003e6.0μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e152mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focal Distance\u003c\/td\u003e\n\u003ctd\u003e216mm (from rear of mirror cell, ±1mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e3\" Crayford with 10:1 reduction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon fibre sandwich\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e820mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e450mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003eapprox. 36kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror Cell\u003c\/td\u003e\n\u003ctd\u003eHoneycomb CNC machined aluminium\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMirror \u0026amp; Tube Cooling\u003c\/td\u003e\n\u003ctd\u003e3 controllable fans, heaters optional\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAttachment Method\u003c\/td\u003e\n\u003ctd\u003eCNC machined aluminium dovetail with supports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eODK16Tr Truss Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942368145693,"sku":"OOUK-ODK16TR-OPTICAL-TUBE-ASSEMBLY","price":27897.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_689b3e0d-88fa-4a57-8d85-797329a5a5a8.jpg?v=1789606948"},{"product_id":"orion-optics-uk-odk18tr-optical-tube-assembly","title":"Orion Optics UK ODK18Tr Truss Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eOptimized Dall-Kirkham (ODK) Optical Design\u003c\/li\u003e\n\u003cli\u003eOpen Truss Tube Framework\u003c\/li\u003e\n\u003cli\u003ePrimary and Secondary Mirrors by Orion Optics UK\u003c\/li\u003e\n\u003cli\u003eEngineered for Astrophotography\u003c\/li\u003e\n\u003cli\u003eAvailable with Multiple Optical Precision Grades\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOrion Optics UK ODK18Tr Truss Optical Tube Assembly\u003c\/h2\u003e\n      \u003cp\u003eThe Orion Optics UK ODK18Tr is an imaging-first instrument built around the advanced Optimized Dall-Kirkham optical design. Its open truss structure is engineered for rapid thermal equalization and mechanical rigidity, providing a stable platform for demanding astrophotography. This OTA combines a corrected, coma-free field with the meticulous, hand-finished optical quality Orion Optics UK is known for, delivering professional-grade results from a permanent observatory or a portable deep-sky setup.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eThe Optimized Dall-Kirkham Advantage\u003c\/h3\u003e\n      \u003cp\u003eThe ODK18Tr employs an Optimized Dall-Kirkham (ODK) design, a significant advancement over the classical Dall-Kirkham. While the base design uses an elliptical primary and spherical secondary, the ODK incorporates a corrector lens group to eliminate off-axis coma and deliver a flat, sharp field of view. This makes the ODK18Tr exceptionally well-suited for use with modern large-format CMOS and CCD sensors, ensuring point-like stars across the entire frame without the need for an additional external coma corrector.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n  \n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eOpen Truss Framework for Thermal Stability\u003c\/h3\u003e\n      \u003cp\u003eUnlike a solid-tube design, the ODK18Tr's open truss framework allows ambient air to circulate freely around the primary mirror. This design minimizes the risk of tube currents and allows the optics to reach thermal equilibrium with the night air much faster. The result is a more stable image, free from the distortions caused by trapped warm air, enabling you to start high-resolution imaging sooner and maintain focus throughout the night.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eOrion Optics UK Hand-Figured Optics: A Choice of Precision Grades\u003c\/h3\u003e\n      \u003cp\u003eAt the heart of every ODK18Tr are primary and secondary mirrors manufactured and hand-figured in the Orion Optics UK workshop. Rather than relying solely on machine polishing, skilled opticians refine each optical surface to an exceptional standard of accuracy. This process allows Orion Optics UK to offer several grades of optical precision, measured in Peak-to-Valley (PV) wavefront error, allowing you to select the level of optical perfection your imaging demands.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eStandard Optics (1\/4 PV):\u003c\/strong\u003e The minimum grade, offering excellent performance for general deep-sky imaging.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eProfessional Optics (1\/6 PV):\u003c\/strong\u003e A significant step up, providing higher contrast and sharper detail, ideal for more serious imagers.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eResearch Grade (1\/8 PV):\u003c\/strong\u003e A premium level of correction that reveals finer planetary detail and resolves tighter star clusters.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eUltra Grade (1\/10 PV):\u003c\/strong\u003e The highest level of precision offered, for those who require the most accurate and high-contrast images possible from the aperture.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is an Optimized Dall-Kirkham (ODK) and how does the ODK18Tr benefit from it?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eAn \u003cstrong\u003eOptimized Dall-Kirkham (ODK)\u003c\/strong\u003e is a type of Cassegrain telescope that uses an elliptical primary mirror, a spherical secondary mirror, and a small corrector lens group near the focuser. This design corrects for off-axis coma and field curvature, producing a wide, flat, and sharp field of view that is ideal for astrophotography with large sensor cameras.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat are the advantages of the ODK18Tr's truss tube design?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe ODK18Tr's open truss design offers two primary benefits. First, it promotes \u003cstrong\u003erapid thermal acclimation\u003c\/strong\u003e by allowing air to flow freely over the optics, reducing cooldown time and minimizing image-degrading tube currents. Second, a well-designed truss structure provides exceptional \u003cstrong\u003estiffness and rigidity\u003c\/strong\u003e, which helps maintain precise optical alignment regardless of the telescope's orientation.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I choose the right Orion Optics UK optical grade for the ODK18Tr?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe choice depends on your primary observing goals and budget.\n      \u003c\/p\u003e\n\u003cul\u003e\n        \u003cli\u003eFor general deep-sky imaging, the \u003cstrong\u003e1\/4 PV Standard\u003c\/strong\u003e optics will deliver excellent results.\u003c\/li\u003e\n        \u003cli\u003eFor those seeking higher contrast and resolving finer details, the \u003cstrong\u003e1\/6 PV Professional\u003c\/strong\u003e grade is a worthwhile upgrade.\u003c\/li\u003e\n        \u003cli\u003eFor planetary imaging or scientific work where maximum resolution is critical, the \u003cstrong\u003e1\/8 PV Research\u003c\/strong\u003e or \u003cstrong\u003e1\/10 PV Ultra\u003c\/strong\u003e grades ensure the highest possible optical performance.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ODK18Tr OTA suitable for visual astronomy?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile the ODK18Tr is optically optimized for imaging, its high-contrast, coma-free views are also superb for visual observation. The large aperture will provide stunning views of deep-sky objects like the Orion Nebula (M42) and distant galaxies, while the high-quality optics will reveal intricate detail on Jupiter and Saturn. Its primary design focus, however, remains astrophotography.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount is required for the ODK18Tr OTA?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eAn 18-inch truss tube OTA is a large and heavy instrument. It requires a substantial, observatory-class German equatorial mount with a high payload capacity. You should consider mounts from manufacturers like Software Bisque, Astro-Physics, or 10Micron capable of handling the telescope's weight and moment arm to ensure stable, accurate tracking for long-exposure astrophotography.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the open truss design of the ODK18Tr require a light shroud?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, for best results, a light shroud is highly recommended. The open truss tube can allow stray light from external sources (like house lights or the moon) to enter the optical path, which can reduce contrast in your images. A fabric light shroud blocks this stray light while still allowing for air circulation, preserving both image contrast and thermal stability.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n      \n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n    \n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942368637213,"sku":"OOUK-ODK18TR-OPTICAL-TUBE-ASSEMBLY","price":43433.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_4ecd5251-bae0-4ed8-a630-f69508cd963f.jpg?v=1789606956"},{"product_id":"orion-optics-uk-odk20tr-optical-tube-assembly","title":"Orion Optics UK ODK20Tr Optical tube assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e500mm truss-tube Dall-Kirkham\u003c\/li\u003e\n\u003cli\u003ef\/6.8 carbon-fibre-sandwich optics\u003c\/li\u003e\n\u003cli\u003eOpen truss for shorter packed length\u003c\/li\u003e\n\u003cli\u003eBuilt to order in the UK\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eODK20Tr Truss Telescope\u003c\/h2\u003e\n\u003cp\u003eThe ODK20Tr is a 500mm truss-tube Dall-Kirkham telescope in Orion Optics UK's ODKTr range -- the same f\/6.8 carbon-fibre-sandwich optical design as the standard ODK range, in an open truss configuration for a shorter packed tube length.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eTruss Design for Transport\u003c\/h3\u003e\n\u003cp\u003eThe open truss structure packs down to a shorter length than the standard ODK tube while keeping the same f\/6.8 optical design. Individually built to order in the UK; contact Orion Optics UK for full ODK20Tr specification.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e500mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube design\u003c\/td\u003e\n\u003ctd\u003eOpen truss\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eODK20Tr Optical Tube Assembly\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942368702749,"sku":"OOUK-ODK20TR-OPTICAL-TUBE-ASSEMBLY","price":53215.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_29a85537-4e31-4600-96a7-4a87bdef9420.jpg?v=1789606965"},{"product_id":"orion-optics-uk-odk24tr-optical-tube-assembly","title":"Orion Optics UK ODK24Tr Truss Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eOptimized Dall-Kirkham (ODK) Optical Design\u003c\/li\u003e\n\u003cli\u003eCorrected, Coma-Free Flat Field for Imaging\u003c\/li\u003e\n\u003cli\u003eOpen Truss Tube for Thermal Stability and Rigidity\u003c\/li\u003e\n\u003cli\u003eHand-Finished Primary and Secondary Mirrors\u003c\/li\u003e\n\u003cli\u003eManufactured by Orion Optics UK\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section-center\"\u003e\n      \u003ch2\u003eOrion Optics UK ODK24Tr Truss Optical Tube Assembly\u003c\/h2\u003e\n      \u003cp\u003eThe Orion Optics UK ODK24Tr Truss Optical Tube Assembly represents a pinnacle of astrographic design, combining a large-aperture, flat-field Optimized Dall-Kirkham (ODK) optical system with a rigid, thermally stable open truss framework. Engineered for serious imagers, the ODK24Tr leverages Orion Optics UK's renowned expertise in hand-figuring large optics to deliver professional-grade astronomical performance.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eOptimized Dall-Kirkham: A Coma-Free, Flat-Field Astrograph\u003c\/h3\u003e\n      \u003cp\u003eThe ODK optical system is an advanced version of the Dall-Kirkham design, featuring an elliptical primary mirror, a spherical secondary, and a built-in corrector lens group. This configuration produces a wide, flat, and fully illuminated field of view that is free from off-axis coma, making the ODK24Tr ideal for use with modern large-format CMOS and CCD cameras.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n    \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eOpen Truss Framework: Thermal Stability and Rigidity\u003c\/h3\u003e\n      \u003cp\u003eThe open truss structure of the ODK24Tr provides exceptional mechanical rigidity while minimizing weight compared to a solid tube. This design allows the primary mirror to acclimate rapidly to ambient nighttime temperatures, reducing tube currents and ensuring the sharpest possible images. While the open frame excels at thermal management, using a light shroud is recommended to block stray light and protect the optics from dew.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eOrion Optics UK Hand-Figured Optics: The Path to Wavefront Accuracy\u003c\/h3\u003e\n      \u003cp\u003eAt the heart of the ODK24Tr are optics hand-finished by Orion Optics UK's master opticians. Every mirror is subjected to rigorous testing with a Zygo laser interferometer to ensure its surface accuracy meets exacting standards. This commitment to precision is what separates OOUK from mass-produced instruments.\u003c\/p\u003e\n      \u003cp\u003eOrion Optics UK offers multiple grades of optical accuracy, from their excellent 1\/4 PV wavefront Standard optics to their near-perfect 1\/10 PV wavefront Ultra grade. This dedication to quantifiable optical quality ensures that the telescope's performance is limited only by the seeing conditions, not by the mirror itself.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is an \"Optimized Dall-Kirkham\" (ODK) design on the ODK24Tr?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \u003cstrong\u003eOptimized Dall-Kirkham (ODK)\u003c\/strong\u003e is a specialized Cassegrain-style telescope designed for astrophotography. It uses an elliptical primary mirror, a spherical secondary, and a corrector lens system. This combination corrects for optical aberrations like coma and provides a flat focal plane, resulting in sharp, pinpoint stars across a wide, well-illuminated field of view, which is critical for imaging with large sensors.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat are the advantages of the ODK24Tr's truss tube design?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe truss design offers two main benefits for a large telescope like the ODK24Tr:\u003c\/p\u003e\n    \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eThermal Stability:\u003c\/strong\u003e The open frame allows air to circulate freely around the primary mirror, letting it cool down to the ambient temperature much faster than a solid tube. This minimizes internal air currents (tube seeing) that can degrade image sharpness.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHigh Rigidity-to-Weight Ratio:\u003c\/strong\u003e The truss structure provides a very stiff platform to maintain optical alignment without the immense weight of a comparable solid tube, making it more manageable on a high-capacity mount.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does Orion Optics UK's mirror quality mean for the ODK24Tr?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eOrion Optics UK (OOUK) is renowned for its hand-figured and finished mirrors, which are tested on a Zygo interferometer to guarantee a specific level of wavefront accuracy (e.g., 1\/4 PV, 1\/6 PV, or higher). For the ODK24Tr, this means the optics are crafted to an extremely high standard of precision, delivering maximum contrast and sharpness for demanding planetary and deep-sky imaging.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the ODK24Tr perform for imaging a large target like the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe ODK24Tr is exceptionally well-suited for large targets like the Andromeda Galaxy (M31). Its flat-field, coma-corrected optics are designed to illuminate large camera sensors evenly, ensuring that stars are sharp from the galaxy's core to its outermost spiral arms. The large aperture gathers immense amounts of light, revealing faint dust lanes and star-forming regions with shorter exposure times.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the ODK24Tr suitable for planetary viewing, for example, observing the Cassini Division on Saturn?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eAbsolutely. While designed as an astrograph, the high-precision optics of the ODK24Tr make it a superb planetary instrument. The certified wavefront accuracy from Orion Optics UK ensures maximum image contrast, which is essential for resolving fine details like the Cassini Division in Saturn's rings, cloud bands on Jupiter, or surface features on Mars.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is thermal management important for a large telescope like the ODK24Tr?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eFor any large-aperture telescope, thermal management is critical. If the primary mirror is warmer than the surrounding air, it creates a boundary layer of turbulent air directly in the light path, which blurs the image—a phenomenon known as \"mirror seeing.\" The ODK24Tr's open truss design helps prevent this by allowing the mirror to reach thermal equilibrium with the environment quickly, preserving the telescope's high-resolution capabilities.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003ctable class=\"DAV-specifications\"\u003e\n    \u003ctbody\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n  \u003cul class=\"DAV-grid\"\u003e\n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/orion-optics-uk-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eOrion Optics UK 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Orion Optics UK","offers":[{"title":"Default Title","offer_id":52942368932125,"sku":"OOUK-ODK24TR-OPTICAL-TUBE-ASSEMBLY","price":118331.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_f71c6b05-8e6e-4145-9358-b4b28aa1f910.jpg?v=1789606973"}],"url":"https:\/\/davidastro.com\/en-us\/collections\/orion-optics-uk-astrographs.oembed","provider":"David Astro","version":"1.0","type":"link"}