{"product_id":"orion-optics-uk-ct8-optical-tube-assembly","title":"Orion Optics UK CT8 Optical Tube Assembly","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e200mm (8\") Aperture\u003c\/li\u003e\n\u003cli\u003e900mm Focal Length (f\/4.5)\u003c\/li\u003e\n\u003cli\u003e1\/10 PV Wavefront Certified Optics\u003c\/li\u003e\n\u003cli\u003eCarbon Fiber Sandwich Tube Construction\u003c\/li\u003e\n\u003cli\u003e7kg Optical Tube Weight\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 CT8 Optical Tube Assembly\u003c\/h2\u003e\n      \u003cp\u003eThe Orion Optics UK CT8 combines a fast f\/4.5 focal ratio with a 200mm aperture, built around a hand-figured Suprax primary mirror certified to a 1\/10 PV wavefront accuracy. This instrument is engineered for high-resolution imaging, weighing only 7kg thanks to its carbon fiber sandwich tube construction which measures 860mm in length. Every optical surface features Enhanced Hilux coatings for maximum light transmission, delivering views where contrast is limited only by atmospheric seeing, not the telescope's optical precision.\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\u003eUltra-Grade Optics: A Certified 1\/10 PV Wavefront System\u003c\/h3\u003e\n      \u003cp\u003eThe heart of the CT8 is its 200mm primary mirror, figured to Orion Optics UK's highest \"Ultra\" grade of 1\/10 PV wavefront. This is not a theoretical standard; each CT8 is delivered with its own Zygo laser interferometry report, verifying that its optical surface deviates from a perfect parabola by a fraction of a wavelength of light. The Suprax primary mirror, with its low thermal expansion, is finished with Enhanced Hilux coatings to ensure maximum reflectivity for capturing faint deep-sky detail.\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 Fiber Construction: A 7kg Tube with Zero Thermal Expansion\u003c\/h3\u003e\n      \u003cp\u003eThe optical tube is a sandwich-construction carbon fiber design, providing extreme rigidity and near-zero thermal expansion. This physical stability is critical for a fast f\/4.5 system, as it maintains a constant focal plane even as ambient temperatures change during an imaging session. At a mere 7kg, the 860mm long tube is easily managed by mid-range equatorial mounts, making it an accessible choice for imagers who demand optical perfection without requiring a massive support system.\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\u003eImaging-Ready Mechanics: 9-Point Cell and Precision 2\" Focuser\u003c\/h3\u003e\n      \u003cp\u003eEvery mechanical component is designed to support the optical system's potential. The primary mirror rests on a 9-point flotation CNC machined cell that prevents flexure and is supported by a fan cooling system for rapid thermal stabilization. Upfront, a 2\" focuser with reduction gearing allows for fine, repeatable focus adjustments, while the 63mm secondary mirror is held by a fully adjustable 4-vane spider and rotatable holder, ensuring precise collimation.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eCNC Tube Rings:\u003c\/strong\u003e A pair of anodised black, CNC machined rings weighing 1kg provides a secure mounting platform for the OTA.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eIncluded Finder:\u003c\/strong\u003e An 8x50 achromatic finderscope helps in locating and centering targets before imaging.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eExtension Tube:\u003c\/strong\u003e A 40mm screw-threaded extension tube is included to help achieve focus with a variety of cameras and accessories.\u003c\/li\u003e\n      \u003c\/ul\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 1\/10 PV Advantage: What You See vs. Standard 1\/4 PV Optics\u003c\/h3\u003e\n      \u003cp\u003eWhile many telescopes are described as \"diffraction-limited\" (equivalent to 1\/4 PV wavefront), a 1\/10 PV system delivers a fundamentally higher level of image fidelity. This difference is most apparent on high-contrast planetary and lunar targets. With 1\/10 PV optics, you resolve finer, more stable detail within Jupiter's cloud bands, see the Cassini Division in Saturn's rings as a sharp black gap, and discern subtle rilles on the Moon that would be blurred or invisible in a lesser instrument.\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 does the 1\/10 PV wavefront of the CT8 mean for planetary viewing?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eA \u003cstrong\u003e1\/10 PV wavefront\u003c\/strong\u003e means the mirror surface is exceptionally close to a perfect parabola. For planetary observers, this translates to higher contrast and sharper detail. You will see more subtle features in Jupiter's atmosphere, crisper definition in Saturn's rings, and finer details in lunar craters compared to standard 1\/4 PV optics, especially during moments of good atmospheric seeing.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the f\/4.5 focal ratio of the CT8 benefit deep-sky imaging of the Orion Nebula (M42)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe fast \u003cstrong\u003ef\/4.5 focal ratio\u003c\/strong\u003e allows the 200mm aperture to gather light very quickly. When imaging a bright, extended object like the Orion Nebula (M42), this means you can capture significant detail in shorter sub-exposures. This reduces the demands on your mount's tracking accuracy and allows you to build up a deep, high-signal image in less total time.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the CT8's carbon fiber tube worth it over an aluminum tube?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, particularly for astrophotography. Carbon fiber has virtually \u003cstrong\u003ezero thermal expansion\u003c\/strong\u003e. As temperatures drop overnight, a metal tube will shrink, causing the focal point to shift and requiring refocusing. The CT8's carbon fiber tube holds focus stable throughout the night, which is a critical advantage for long imaging sessions.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount is needed for the 7kg CT8 optical tube?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe CT8 optical tube weighs \u003cstrong\u003e7kg\u003c\/strong\u003e, and the rings add another \u003cstrong\u003e1kg\u003c\/strong\u003e. A total payload of 8kg plus your camera and guide scope (likely 10-11kg total) requires a stable equatorial mount. Mounts in the EQ6\/CEM40 class or larger are recommended for astrophotography to ensure tracking accuracy and stability.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the CT8 come with eyepieces or a diagonal?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. The CT8 is supplied as an optical tube assembly optimized for astrophotography. It does not include eyepieces, a diagonal, or a barlow lens. You will need to supply your own 1.25\" or 2\" eyepieces for visual use. A quality coma corrector is also highly recommended for imaging with its fast f\/4.5 optics.\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 9-point mirror cell on the CT8?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \u003cstrong\u003e9-point suspension mirror cell\u003c\/strong\u003e provides uniform support to the back of the 200mm primary mirror. This prevents the mirror from sagging or deforming under its own weight as the telescope points to different parts of the sky, which would degrade the image. This precise mechanical support is essential to maintaining the certified 1\/10 PV optical quality in practice.\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\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e200mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e900mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/4.5\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eOptical Grade\u003c\/td\u003e\n\u003ctd\u003e1\/10 PV wavefront\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Glass\u003c\/td\u003e\n\u003ctd\u003eSuprax\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eOptical Coatings\u003c\/td\u003e\n\u003ctd\u003eEnhanced Hilux\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Size\u003c\/td\u003e\n\u003ctd\u003e63mm\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\u003e860mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eOptical Tube Weight\u003c\/td\u003e\n\u003ctd\u003e7kg\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e2\" focuser with reduction gearing\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\u003eSpider\u003c\/td\u003e\n\u003ctd\u003eAdjustable 4-vane, stainless steel\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSecondary Holder\u003c\/td\u003e\n\u003ctd\u003eMachined aluminium, rotatable\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eFinderscope\u003c\/td\u003e\n\u003ctd\u003e8x50\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eExtension Tubes\u003c\/td\u003e\n\u003ctd\u003e40mm long, screw threaded\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTube Rings\u003c\/td\u003e\n\u003ctd\u003eCNC machined, anodised black\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eWeight of Rings\u003c\/td\u003e\n\u003ctd\u003e1kg\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eBoxed Dimensions\u003c\/td\u003e\n\u003ctd\u003e87x48x48mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eBoxed Weight\u003c\/td\u003e\n\u003ctd\u003e10.7kg\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\"\u003eCT8 Carbon Tube OTA\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\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\"\u003e8x50 Finderscope with Bracket\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\"\u003e40mm Extension Tube\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\"\u003eZygo Interferometry Test Report\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":52942379417885,"sku":"OOUK-CT8-OPTICAL-TUBE-ASSEMBLY","price":3132.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_3d62404a-c67e-4a94-b599-38773701bfec.jpg?v=1789607180","url":"https:\/\/davidastro.com\/fr\/products\/orion-optics-uk-ct8-optical-tube-assembly","provider":"David Astro","version":"1.0","type":"link"}