{"product_id":"baader-planetarium-1-25-inch-extension-tube-for-long-focal-length-eyepieces","title":"Baader Planetarium Baader 1.25\" Extension Tube for Long Focal Length Eyepieces","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eEnables Use of 30-42mm Eyepieces in Baader Maxbright Binoviewers\u003c\/li\u003e\n\u003cli\u003eSolves Image Merging Failures with Long Focal Length Designs\u003c\/li\u003e\n\u003cli\u003eExtends Eyepiece Barrel to Achieve Proper Focal Plane Alignment\u003c\/li\u003e\n\u003cli\u003eMaintains Standard 1.25\" Format for Eyepieces and Holders\u003c\/li\u003e\n\u003cli\u003eRequires a Matched Pair (2 pieces) for Binocular Viewing\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\u003eBaader 1.25\" Extension Tube for Long Focal Length Eyepieces\u003c\/h2\u003e\n      \u003cp\u003eThis Baader 1.25\" Extension Tube is the specific mechanical solution required to use long focal length eyepieces, particularly those in the 30mm to 42mm range, with a Baader Maxbright Binoviewer. A set of 2 tubes is mandatory—one for each optical path—to physically reposition the eyepieces outward, allowing your eyes to merge the two light paths into a single, cohesive image.\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\u003eAchieve Image Merge with 30-42mm Eyepieces\u003c\/h3\u003e\n      \u003cp\u003eMany classic long focal length eyepieces, such as 32mm or 40mm Plössls, have a focal plane located deep within their barrel. When used in a binoviewer, the body of the binoviewer can prevent these eyepieces from seating deep enough to reach focus, resulting in an inability to merge the two images. These 1.25\" extension tubes act as simple spacers, moving the eyepieces slightly out from the binoviewer's holders. This adjustment correctly aligns each eyepiece's focal plane with the binoviewer's optical path, solving the merging problem and enabling comfortable, immersive views.\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\"\u003eWhy do I need the Baader 1.25\" Extension Tube for my Maxbright binoviewer?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYou need a pair of these tubes if you use long focal length eyepieces (typically \u003cstrong\u003e30mm to 42mm\u003c\/strong\u003e) that cannot achieve a merged image. Their physical design prevents them from seating deep enough in the binoviewer to align with the optical path. These extensions provide the necessary spacing to correct this and allow for a single, merged view.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use just one Baader 1.25\" Extension Tube?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. For binoviewing, you must use \u003cstrong\u003etwo identical optical trains\u003c\/strong\u003e. You will need a matched pair of these extension tubes, one for each eyepiece, to ensure that both eyes are viewing through an identical setup, which is critical for image merging and avoiding eye strain.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill this extension tube work with eyepieces shorter than 30mm?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThese tubes are generally not necessary for eyepieces with focal lengths shorter than 30mm. Most shorter focal length eyepieces do not have the same deep-set focal plane and will reach focus in the Maxbright binoviewer without any adapters.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Baader 1.25\" Extension Tube add any optical elements or affect image quality?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, this is a purely mechanical adapter. It is a hollow tube that contains no lenses or glass. It simply changes the physical position of your eyepiece and does not alter the optical properties or introduce any degradation to the image quality.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eI have a pair of 32mm Plössls for my Maxbright II binoviewer; will these tubes help me merge the image in my 8\" SCT?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYes, this is the exact scenario these tubes are designed for. A pair of 32mm Plössls is a classic example of an eyepiece that struggles to merge in a binoviewer. Using a pair of these 1.25\" extension tubes will provide the correct spacing to achieve a clean, merged image in your SCT setup.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Baader 1.25\" Extension Tube work with other binoviewers?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile designed specifically for the Baader Maxbright series, this 1.25\" extension tube may work with other binoviewers that exhibit the same issue with long focal length eyepieces. However, compatibility is not guaranteed, as the required spacing can vary between different binoviewer models.\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\u003eNet weight (kg)\u003c\/td\u003e\n\u003ctd\u003e0.05\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Brands\u003c\/td\u003e\n\u003ctd\u003eUNC, Baader Planetarium, Celestron\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner Diameter \/ Clear Aperture (mm)\u003c\/td\u003e\n\u003ctd\u003e28\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuter Diameter\u003c\/td\u003e\n\u003ctd\u003e45\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType of Adapter\u003c\/td\u003e\n\u003ctd\u003eExtension, Filter holder\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical length (mm)\u003c\/td\u003e\n\u003ctd\u003e8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner Connection (eyepiece\/-camera-sided)\u003c\/td\u003e\n\u003ctd\u003eø 1¼\" (31.75 mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner Connection (lens sided)\u003c\/td\u003e\n\u003ctd\u003eM28.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuter Connection (lens sided)\u003c\/td\u003e\n\u003ctd\u003eø 1¼\" (31.75 mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdaptable to\u003c\/td\u003e\n\u003ctd\u003eBaader Maxbright\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    \n  \u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/baader-planetarium-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eBaader Planetarium Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Baader Planetarium","offers":[{"title":"Default Title","offer_id":52913115988253,"sku":"BAA-2456325","price":42.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/BaaderPlanetarium-1-Extension-tube-for-long-focal-length-eyepieces-on-binoviewers-1_8d0863a9-2bea-47cc-be91-eceaf9b5d2a3.jpg?v=1789086387","url":"https:\/\/davidastro.com\/fr-us\/products\/baader-planetarium-1-25-inch-extension-tube-for-long-focal-length-eyepieces","provider":"David Astro","version":"1.0","type":"link"}