{"product_id":"orion-optics-uk-85mm-fixed-adaptor-ring-10mm-bfd","title":"Orion Optics UK 85mm Fixed Adaptor Ring - 10mm BFD","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eDesigned for 85mm optical trains\u003c\/li\u003e\n\u003cli\u003eProvides a fixed 10mm of back focus distance (BFD)\u003c\/li\u003e\n\u003cli\u003eEnsures rigid, non-flexing spacing for astrophotography\u003c\/li\u003e\n\u003cli\u003eMachined for precise component alignment\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 85mm Fixed Adaptor Ring - 10mm BFD\u003c\/h2\u003e\n\u003cp\u003eThe Orion Optics UK 85mm Fixed Adaptor Ring provides a precise 10mm of back focus distance (BFD), a critical component for achieving the exact spacing required by field flatteners and coma correctors in an 85mm optical train. This ring ensures your camera sensor is placed at the optimal focal plane, a non-negotiable requirement for sharp, aberration-free stars across the entire field of view.\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\u003ePrecision 10mm Spacing for 85mm Imaging Systems\u003c\/h3\u003e\n\u003cp\u003eIn astrophotography, back focus is not an approximation. This fixed 10mm adaptor provides a solid, non-flexing extension to guarantee that the distance from your corrector to your sensor is exact. Unlike variable or sliding adapters, this solid ring eliminates a potential source of tilt, ensuring your optical components remain perfectly parallel to the sensor.\u003c\/p\u003e\n\u003cp\u003eEngineered by Orion Optics UK for their high-end imaging systems, this 85mm ring is the solution for building a rigid and reliable optical train. It is an essential part for imagers who need repeatable, perfect spacing session after session without the uncertainty of adjustable components.\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 is the purpose of the Orion Optics UK 85mm Fixed Adaptor Ring?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThis adaptor ring serves one critical function: to add exactly \u003cstrong\u003e10mm of spacing\u003c\/strong\u003e into an \u003cstrong\u003e85mm\u003c\/strong\u003e-threaded optical train. This is most often required to achieve the precise back focus distance specified by a coma corrector or field flattener to ensure a flat, sharp field of view for astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I know if I need the 10mm BFD adaptor ring for my setup?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYou need this 10mm ring if the total back focus requirement of your corrector (e.g., 55mm) minus the back focus of your camera and other accessories (like a filter wheel or off-axis guider) leaves a 10mm gap. Always calculate the total spacing of your existing components first to determine the exact extension length you need.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of a fixed 10mm ring over a variable spacer?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA fixed ring like this Orion Optics UK 85mm adaptor offers superior \u003cstrong\u003erigidity and stability\u003c\/strong\u003e. Variable spacers can introduce flex or tilt into the imaging train, which can ruin an image by causing elongated stars in the corners. A fixed, solid ring ensures all components are held perfectly parallel, which is crucial for high-resolution imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the 85mm fixed adaptor ring introduce tilt in my imaging train?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the primary benefit of a high-quality fixed adaptor is its ability to \u003cstrong\u003eprevent tilt\u003c\/strong\u003e. It is machined to tight tolerances to ensure flat, parallel faces. This provides a much more secure and orthogonal connection between optical components than adjustable or multi-part solutions, preserving the alignment of your imaging system.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eI'm using an Orion Optics UK ODK telescope. Is the 10mm BFD ring the right part to achieve focus with my camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt depends entirely on your specific corrector and camera combination. Orion Optics UK systems have precise back focus requirements. You must consult the documentation for your specific corrector (e.g., the Optimized Dall-Kirkham's corrector) to find its required back focus distance, then measure the back focus of your camera and any other accessories. This 10mm ring is the correct choice only if your calculation reveals a 10mm spacing deficit.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs this 85mm adaptor ring compatible with accessories from other brands?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile designed by Orion Optics UK, this adaptor should be compatible with any component that uses a standard 85mm thread. However, it is crucial to verify the thread pitch and type (e.g., M85x1) of your existing components to ensure a proper fit. Compatibility is based on matching mechanical dimensions, not brand names.\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\u003eAdaptor Diameter\u003c\/td\u003e\n\u003ctd\u003e85mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpacing Provided\u003c\/td\u003e\n\u003ctd\u003e10mm\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":52942408974621,"sku":"OOUK-85MM-FIXED-ADAPTOR-RING-10MM","price":198.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Orion-Optics-UK-Logo_630036c9-fcc9-4e6f-827c-2632c5b1318e.jpg?v=1789607525","url":"https:\/\/davidastro.com\/fr\/products\/orion-optics-uk-85mm-fixed-adaptor-ring-10mm-bfd","provider":"David Astro","version":"1.0","type":"link"}