{"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","url":"https:\/\/davidastro.com\/products\/orion-optics-uk-odk14tr-optical-tube-assembly","provider":"David Astro","version":"1.0","type":"link"}