{"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","url":"https:\/\/davidastro.com\/products\/orion-optics-uk-odk16-optical-tube-assembly","provider":"David Astro","version":"1.0","type":"link"}