{"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","url":"https:\/\/davidastro.com\/products\/orion-optics-uk-odk10tr-optical-tube-assembly","provider":"David Astro","version":"1.0","type":"link"}