{"title":"Focuser Adapters","description":"\u003cp\u003eTelescope-side adapters for robotic and manual focusers — PrimaLuceLab ESATTO and SESTO SENSO, Starlight Instruments Feather Touch, and Hexafocuser fittings, matched to specific optical tubes.\u003c\/p\u003e\u003cp\u003eGoods ship factory-sealed. Tell us your focuser model and telescope and we'll confirm the adapter before you order.\u003c\/p\u003e","products":[{"product_id":"explore-scientific-rack-and-pinion-focuser-2-extension-tube","title":"Explore Scientific ESRPEXT2 1.5-Inch Extension Tube for 2-Inch Rack and Pinion Focusers","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is an Explore Scientific extension tube for the 2-inch rack-and-pinion focusers fitted to their ED APO telescopes, carried under item number ESRPEXT2. It adds 1.5 inches of additional travel to the focuser, which lets an imaging or visual train reach focus in configurations that would otherwise run past the end of the focuser's native range.\u003c\/p\u003e\n\u003cp\u003eIt is a plain machined tube. There is no glass in it, no moving part and no electronics — it sits between the focuser and whatever follows it, and its only job is to place that equipment 1.5 inches further back.\u003c\/p\u003e\n\u003cp\u003eEvery telescope brings light to focus a fixed distance behind the focuser flange. A visual eyepiece in a diagonal usually lands inside the focuser's travel comfortably; a camera, a binoviewer, a filter wheel or a long adapter stack often does not, and the focuser reaches the end of its outward travel before the image is sharp. An extension tube moves the whole train outward by a known amount so that focus falls back inside the range the focuser actually has.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOwners of Explore Scientific ED APO telescopes with 2-inch rack-and-pinion focusers,\u003c\/strong\u003e which is the fitment this tube is specified for.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAnyone whose focuser runs out of outward travel\u003c\/strong\u003e before an image comes to focus — the classic symptom being a focuser racked fully out with the stars still soft.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBinoviewer users:\u003c\/strong\u003e a binoviewer consumes a large amount of light path, and reaching focus with one is a common reason to add a fixed extension.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImagers assembling a train:\u003c\/strong\u003e when the sum of camera, filter wheel, spacers and adapter comes up short of the required distance, a fixed extension is the simplest way to make up the difference.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdds 1.5 inches of travel\u003c\/strong\u003e to the focuser's native range.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMade for 2-inch rack-and-pinion focusers\u003c\/strong\u003e on Explore Scientific ED APO telescopes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMachined tube with no optical elements:\u003c\/strong\u003e nothing in the light path to add aberration, reflection or colour.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo moving parts:\u003c\/strong\u003e a fixed spacer holds its length exactly, which is what makes it predictable in an imaging train where spacing is arithmetic.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eItem number ESRPEXT2,\u003c\/strong\u003e the designation to quote when checking fitment against a particular telescope.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSupplied on its own\u003c\/strong\u003e — the vendor lists no additional included accessories with it.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eReaching focus with a binoviewer, which typically needs more light path than a single eyepiece.\u003c\/li\u003e\n\u003cli\u003eAdding length to an imaging train that falls short of the required backfocus distance.\u003c\/li\u003e\n\u003cli\u003eRestoring focus after a diagonal has been removed from a visual setup, which shortens the path considerably.\u003c\/li\u003e\n\u003cli\u003eGiving a camera enough standoff from the focuser that the focuser is not working at the very end of its travel, where a rack-and-pinion is least well supported.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitment:\u003c\/strong\u003e specified for the 2-inch rack-and-pinion focusers used on Explore Scientific ED APO telescopes. If you are unsure which focuser your tube carries, send us the model and we will check it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLength added:\u003c\/strong\u003e 1.5 inches, which is 38.1mm. That is the figure to use when adding up an imaging train.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDirection of the change:\u003c\/strong\u003e an extension pushes the focus point outward. Where a setup already reaches focus with the drawtube well in, adding this tube pushes it further out and may take some setups past their inward range instead — which is why extensions are added to trains that come up short rather than as a default.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical effect:\u003c\/strong\u003e none of its own. There is no glass, so it changes distance and nothing else.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilters:\u003c\/strong\u003e the vendor does not publish a filter thread for this tube, so that row is absent from the specifications rather than estimated.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eGood to Know Before You Order\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThe vendor lists this item under two names.\u003c\/strong\u003e Explore Scientific titles it a 1.5-inch extension tube while the part is catalogued as the 2-inch rack-and-pinion focuser extension — the 2 inches refers to the focuser it fits and the 1.5 inches to the travel it adds. Item number ESRPEXT2 identifies it either way.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExplore Scientific publishes no dimensional or weight specification for this part.\u003c\/strong\u003e Outer diameter, thread type, material and mass are not given, so those rows are absent below rather than estimated. If a specific figure decides the purchase for you, ask us and we will put the question to our Explore Scientific rep.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAn extension solves a shortfall, not a surplus.\u003c\/strong\u003e Where a train already focuses with room to spare, adding length works against you. The useful check is whether the focuser currently runs out of outward travel before the image sharpens.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAny extension adds a joint to the light path.\u003c\/strong\u003e With a heavy camera on the end, that additional cantilever is worth accounting for in how the train is supported — keeping the heaviest item as close to the focuser as the spacing allows is the usual approach.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitment is worth checking once rather than guessing.\u003c\/strong\u003e Send us your telescope model and the accessories going behind it and we will tell you whether this is the right part before it ships.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs it difficult to set up?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. It threads or slots into the 2-inch rack-and-pinion focuser and the eyepiece, diagonal or camera goes on after it. There is nothing to adjust, align or calibrate, and refocusing after fitting it is the only step.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much length does it add?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e1.5 inches, which is 38.1mm.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it degrade the image?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThere is no glass in it, so it introduces no aberration of its own. What it changes is the distance between the focuser and everything behind it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow do I know whether I need one?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe usual sign is a focuser racked all the way out with the image still soft — the focus point is falling behind where the drawtube can reach. Send us a list of what is in your train and we will work out whether 1.5 inches is the right amount.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it work with a binoviewer?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eBinoviewers are one of the common reasons to add a fixed extension, because they consume a substantial amount of light path. Whether 1.5 inches is enough depends on the particular binoviewer, so send us the model and we will check.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it fit a focuser from another brand?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt is specified for Explore Scientific 2-inch rack-and-pinion focusers. Other 2-inch focusers vary in how they accept accessories, so tell us what you have and we will look at it before you order.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a simple machined extension that adds 1.5 inches of travel to the 2-inch rack-and-pinion focusers on Explore Scientific ED APO telescopes, with no glass and nothing to adjust — the straightforward fix when a camera, binoviewer or adapter stack pushes focus beyond the focuser's reach. Send us your telescope and the accessories behind it and we will tell you whether this is the piece that closes the gap.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":44013540311151,"sku":"ESRPEXT2","price":54.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/ESRPEXT2_Bottom_1800x1800__39608.jpg?v=1766555687"},{"product_id":"adapter-esatto-2-for-telescopes-with-large-3-3-sc-thread","title":"Adapter ESATTO 2\" for telescopes with large 3.3\" SC thread","description":"\u003cspan style=\"font-family: Arial; font-size: 14px; text-align: justify; background-color: rgb(255, 255, 255);\"\u003eSC 3.3” adapter for ESATTO 2\" allows you to connect the ESATTO 2\" to Celestron SCT (11\" and 14\") and EdgeHD (925, 1100, and 1400) models. Since the ESATTO has a depth of 67mm and the 3.3” adapter has only 2mm of optical thickness, this leaves 77mm of backfocus for your camera and accessories, also when used together with the Celestron EdgeHD .7x focal reducers for 925, 1100 and 1400 models.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial; font-size: 14px; text-align: justify; background-color: rgb(255, 255, 255);\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial; font-size: 14px; text-align: justify; background-color: rgb(255, 255, 255);\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013545226351,"sku":"PL3600212","price":92.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-2-for-telescopes-with-large-3-3-sc-thread__24982.jpg?v=1766556041"},{"product_id":"sesto-senso-2-37mm-adapter","title":"SESTO SENSO 2 37mm adapter","description":"\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003eThis 37mm adapter allow you to install SESTO SENSO 2 on focusers that come with 37mm diameter large shaft, like the 3,5\" FeatherTouch and FSQ-130 (or other focusers with 37mm diameter large shaft). SESTO SENSO 2 as standard connects to focusers that comes with 25mm diameter shaft (that are the most of the focusers on the market): in order to connect it to focusers that comes with 37mm diameter large shaft, you need to add this adapter.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\n\u003cp style=\"box-sizing: border-box; margin: 1em 0px; line-height: 1.5; min-height: 1em; background-color: rgb(255, 255, 255); text-align: justify; outline: none !important;\"\u003e\u003cspan style=\"box-sizing: border-box; outline: none !important; font-family: Arial; font-size: 10pt;\"\u003eThis 37mm adapter is installed on the focuser instead of the 2 knobs (macrometric and micrometric), then you can install SESTO SENSO. Together with this adapter, you will find in the package the longer bushing that is used to connect SESTO SENSO to the focuser. You will also find installation instructions (in english and italian).\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"box-sizing: border-box; margin: 1em 0px; line-height: 1.5; min-height: 1em; background-color: rgb(255, 255, 255); text-align: justify; outline: none !important;\"\u003e\u003cspan style=\"font-family: Arial; font-size: 10pt;\"\u003e\u003cimg alt=\"SESTO SENSO 2 37mm adapter\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adattatore-33mm-per-SESTO-SENSO-descrizione1_4f65a794-52be-46e7-98d1-d9f5045f9cf6.jpg?v=1766556070\" title=\"SESTO SENSO 2 37mm adapter\" style=\"box-sizing: border-box; outline: none !important; border: 0px; vertical-align: top; max-width: 100%;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Primaluce Lab","offers":[{"title":"SESTO SENSO 2 33mm adapter","offer_id":44013545521263,"sku":"SESTOSENSO-AD37II","price":129.2,"currency_code":"CAD","in_stock":true},{"title":"SESTO SENSO 2 26mm adapter for ES telescopes","offer_id":44013545554031,"sku":"SESTOSENSO-AD37II","price":129.2,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adattatore-37mm-per-sesto-senso__03740.jpg?v=1766556072"},{"product_id":"sesto-senso-2-33mm-adapter","title":"SESTO SENSO 2 33mm adapter","description":"\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003eThis 33mm adapter allow you to install SESTO SENSO 2 on focusers that come with 33mm diameter large shaft, like the 2,5\" and 3\" FeatherTouch (or other focusers with 33mm diameter large shaft). SESTO SENSO 2 as standard connects to focusers that comes with 25mm diameter shaft (that are the most of the focusers on the market): in order to connect it to focusers that comes with 33mm diameter large shaft, you need to add this adapter.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: \" open sans font-size: text-align: justify background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003eThis 33mm adapter is installed on the focuser instead of the 2 knobs (macrometric and micrometric), then you can install SESTO SENSO 2. Together with this adapter, you will find in the package the longer bushing that is used to connect SESTO SENSO 2 to the focuser. You will also find installation instructions (in english and italian).\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"color: rgb(119, 119, 119); font-family: \" open sans font-size: small text-align: justify background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adattatore-33mm-per-SESTO-SENSO-descrizione1_9a52567e-538d-4524-b667-3f5cf313b7f7.jpg?v=1766556079\" alt=\"SESTO SENSO 2 33mm adapter\"\u003e\u003c\/div\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013545586799,"sku":"SESTOSENSO-AD33II","price":104.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adattatore-33mm-per-sesto-senso_2__51568.jpg?v=1766556081"},{"product_id":"adapter-from-m56-to-t2-with-stop-ring-for-esatto-2","title":"Adapter from M56 to T2 with stop ring for ESATTO 2\"","description":"\u003cspan style=\"font-family: Arial;\"\u003eAdapter from M56 to T2 with stop ring for ESATTO 2\" allows you to connect any camera or accessory with T2 (M42x0.75) female thread. Just thread this adapter to the M56 thread of the ESATTO 2\" draw tube. Thanks to the T2 stop ring for ESATTO 2\" you can also fix the camera at a precise angle in order to better frame your camera sensor at the desired object.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013557710959,"sku":"PL3600218","price":134.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-from-m56-to-t2-with-stop-ring-for-esatto-2_1__97952.jpg?v=1766556388"},{"product_id":"adapter-from-m56-to-m48-with-stop-ring-for-esatto-2","title":"Adapter from M56 to M48 with stop ring for ESATTO 2\"","description":"\u003cspan style=\"font-family: Arial;\"\u003eM48x0.75 adapter for ESATTO 2\" allows you to connect any camera or accessory with M48x0.75 female thread. Just thread this adapter to the M56 thread of the ESATTO 2\" draw tube. Thanks to the M48 stop ring for ESATTO 2\" you can also fix the camera at a precise angle in order to better frame your camera sensor at the desired object.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013557809263,"sku":"PL3600216","price":134.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-from-m56-to-m48-with-stop-ring-for-esatto-2_1__28028.jpg?v=1766556394"},{"product_id":"adapter-from-m56-to-sc-with-stop-ring-for-esatto-2","title":"Adapter from M56 to SC with stop ring for ESATTO 2\"","description":"\u003cspan style=\"font-family: Arial;\"\u003eThe SC thread adapter for ESATTO 2\" allows you to connect any accessory with SC female thread, like the SC focal reducers to ESATTO. Just thread this adapter to the M56 thread in the ESATTO 2\" focuser draw tube. Thanks to the SC stop ring for ESATTO 2\" you can also fix the camera at a precise angle in order to better frame your camera sensor at the desired object.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\n\u003cp style=\"box-sizing: border-box; margin: 1em 0px; line-height: 1.5; min-height: 1em; font-family: \" open sans font-size: background-color: rgb text-align: justify outline: none\u003e\u003cspan style=\"box-sizing: border-box; font-size: 12pt; font-family: Arial; outline: none !important;\"\u003eOptical length of adapter from M56 to SC with stop ring for ESATTO 2\" is 4mm (1,5mm adapter + 2,5mm stop ring).\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"box-sizing: border-box; margin: 1em 0px; line-height: 1.5; min-height: 1em; font-family: \" open sans font-size: background-color: rgb text-align: justify outline: none\u003e\u003c\/p\u003e\n\u003cp style=\"box-sizing: border-box; margin: 1em 0px; line-height: 1.5; min-height: 1em; color: rgb(119, 119, 119); font-family: \" open sans font-size: background-color: rgb text-align: center outline: none\u003e\u003cimg alt=\"SC thread adapter for ESATTO 2\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Adapter-ESATTO-2-for-telescopes-with-SC-thread-descrizione1-EN_89304d20-6600-484e-94f4-ab9d97251220.jpg?v=1766556399\" title=\"SC thread adapter for ESATTO 2\" style=\"box-sizing: border-box; outline: none !important; border: 0px; vertical-align: top; max-width: 100%;\"\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013560463471,"sku":"PL3600225","price":129.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-from-m56-to-sc-with-stop-ring-for-esatto-2__94853.jpg?v=1766556401"},{"product_id":"adapter-from-m56-to-m54-with-stop-ring-for-esatto-2","title":"Adapter from M56 to M54 with stop ring for ESATTO 2\"","description":"\u003cspan style=\"font-family: Arial;\"\u003eAdapter from M56 to M54 with stop ring for ESATTO 2\" allows you to connect any camera or accessory with M54x0.75 female thread. Just thread this adapter to the M56 thread of the ESATTO 2\" draw tube. Thanks to the M54 stop ring for ESATTO 2\" you can also fix the camera at a precise angle in order to better frame your camera sensor at the desired object.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013560594543,"sku":"PL3600242","price":134.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-from-m56-to-m54-with-stop-ring-for-esatto-2__92960.jpg?v=1766556406"},{"product_id":"adapter-from-m56-to-m57-with-stop-ring-for-esatto-2","title":"Adapter from M56 to M57 with stop ring for ESATTO 2\"","description":"\u003cspan style=\"font-family: Arial;\"\u003eAdapter from M56 to M57 with stop ring for ESATTO 2\" allows you to connect any camera or accessory with M57x0.75 female thread. Just thread this adapter to the M56 thread of the ESATTO 2\" focuser draw tube. Thanks to the M57 stop ring for ESATTO 2\" you can also fix the camera at a precise angle in order to better frame your camera sensor at the desired object.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013560758383,"sku":"PL3600227","price":134.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-from-m56-to-m57-with-stop-ring-for-esatto-2__34915.jpg?v=1766556411"},{"product_id":"adapter-esatto-2-for-gso-orion-tpo-ritchey-chretien-6-and-8-inches","title":"Adapter ESATTO 2\" for GSO\/Orion\/TPO Ritchey-Chretien 6 and 8 inches","description":"\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003eIf you are searching for the most precise motorized focuser to use the GSO\/Orion\/\/iOptron\/TPO Ritchey-Chretien 152mm f\/9 or 203mm f\/8 (both aluminum and carbon tubes) for astrophotography, this adapter allows you to connect ESATTO 2\" to this telescope. You can use the standard extensions that come with the RC telescope in order to install the focuser at a precise distance from the OTA. Based on the camera and accessories train you want to connect, you may need extenders to reach the focus with your camera.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013569179759,"sku":"PL3600235","price":112.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-2-for-gso-orion-tpo-ritchey-chretien-6-and-8-inches__08961.jpg?v=1766556536"},{"product_id":"adapter-esatto-2-for-skywatcher-orion-newton-250-f4-and-f5","title":"Adapter ESATTO 2\" for SkyWatcher\/Orion Newton 250 f4 and f5","description":"\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003eIf you are searching for the most precise motorized focuser to use the SkyWatcher\/Orion Newton 250 f4 and f5 reflector for astrophotography, this adapter allows you to connect ESATTO 2\" to this telescope. With this adapter the focuser thickness is the same of the original focuser (excluded camera adapter or visual back for ESATTO) in order to allow you easily reach prime focus. More, this adapter has the holes for tube installation that correspond to the original ones so it is not necessary to make new holes on the optical tubes. This adapter has screws for adjusting focuser's orthogonality with respect to the optical axis of the telescope in order to perfectly adjust ESATTO to your telescope.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013581959279,"sku":"PL3600237","price":234.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-2-for-skywatcher-orion-newton-250-f4-and-f5_1__16944.jpg?v=1766556924"},{"product_id":"65mm-extension-tube-for-esatto-3","title":"65mm extension tube for ESATTO 3\"","description":"\u003cspan style=\"font-family: Arial;\"\u003eWhen installing ESATTO 3\" in a telescope with a long travel focuser (such as those usually found on refractors), it is necessary to take into account the lower travel of ESATTO 3\" since it's a micrometric focuser. For this reason we have designed this 65mm extension that can be installed between ESATTO 3\" and the telescope tube. A precise dovetail coupling system with 3 screws set at 120° allows you to manually rotate the focuser.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013590184047,"sku":"PL3600284","price":195.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/prolunga-65mm-per-esatto-3-pollici__32723.jpg?v=1766557139"},{"product_id":"sesto-senso-2-26mm-adapter-for-es-telescopes","title":"SESTO SENSO 2 26mm adapter for ES telescopes","description":"\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003eThis 26mm adapter allows you to install SESTO SENSO 2 on focusers that come with a 26mm diameter shaft, like focusers from Explorer Scientific (or other focusers with a 26mm diameter shaft). Out of the box, SESTO SENSO 2 connects to focusers that come with a 25mm diameter shaft (the most common diameter on the market). In order to connect it to focusers with a 26mm diameter shaft, you will need to include this adapter.\u003c\/span\u003e     \u003cdiv\u003e\u003cspan style=\"font-family: Arial; font-size: 12pt; text-align: justify; background-color: rgb(255, 255, 255);\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adattatore-26mm-per-SESTO-SENSO-2-descrizione1_37c565a3-2a52-4abe-937e-8baa73c3a415.jpg?v=1766557300\" alt=\"SESTO SENSO 2 26mm adapter\"\u003e\u003c\/div\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013595197551,"sku":"SESTOSENSO-AD26II","price":89.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adattatore-26mm-per-sesto-senso-2__48986.jpg?v=1766557302"},{"product_id":"c11-c14-adapter-for-prodigy-microfocuser","title":"C11 \/ C14 adapter for Prodigy Microfocuser","description":"\u003cspan style=\"font-family: Arial;\"\u003eAttach the Prodigy Microfocuser to you C11 or C14 Edge Telescope.\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial;\"\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"font-family: Arial;\"\u003eCan be used to Celestron Edge C 9.25 in combination with Celestron’s focal reducer only. Focal reducer has to be mounted first on the telescope.\u003c\/span\u003e\u003c\/div\u003e","brand":"Pegasus Astro","offers":[{"title":"Default Title","offer_id":44013686554735,"sku":"PEG-PRDG-C11","price":109.2,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/c11-c14-adapter__56565.png?v=1766559725"},{"product_id":"adapter-for-gso-rc-10-12-14-16-for-prodigy-microfocuser","title":"Adapter for GSO RC 10'', 12'', 14'', 16''' for Prodigy Microfocuser","description":"\u003cspan style=\"font-family: Arial;\"\u003eAttach the Prodigy Microfocuser to you iOptron, \u003c\/span\u003e\u003cspan style=\"color: rgb(68, 68, 68); font-family: \" open sans rgb font-size:=\"\" background-color:=\"\"\u003eGSO, Astrotech, Omegon, TS or similar \u003c\/span\u003e\u003cspan style=\"box-sizing: border-box; font-weight: 700; color: rgb(68, 68, 68); font-family: \" open sans rgb font-size:=\"\" background-color:=\"\"\u003eRC 10”, 12” , 14”, 16\u003c\/span\u003e\u003cdiv\u003e\u003cspan style=\"box-sizing: border-box; font-weight: 700; color: rgb(68, 68, 68); font-family: \" open sans font-size: background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e\u003cdiv\u003e\u003cspan style=\"box-sizing: border-box; font-weight: 700; color: rgb(68, 68, 68); font-family: \" open sans font-size: background-color: rgb\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/div\u003e","brand":"Pegasus Astro","offers":[{"title":"Default Title","offer_id":44013686587503,"sku":"PEG-PRDG-GSO117","price":126.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/c11-c14-adapter__84272.png?v=1766559730"},{"product_id":"adapter-esatto-2-for-telescopes-with-sc-thread","title":"Adapter ESATTO 2\" for telescopes with SC thread","description":"\u003cspan style=\"font-family: Arial;\"\u003eThanks to its low profile, the ESATTO 2\" is the perfect motorized focuser for Schmidt-Cassegrain telescopes like the 8” and 9.25” Celestron SCT and EdgeHD 800 models. By adding the SC adapter, you can thread the ESATTO 2\" focuser directly onto the back of these telescopes, and use the ESATTO to achieve more precise focus, avoiding focus shift and mirror flop by leaving the primary mirror locked (if locks are available). The low profile of the ESATTO leaves you enough back focus to use the the EdgeHD or other SC threaded focal reducers.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013691240559,"sku":"PL3600209","price":49.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-2-for-sc__06120.jpg?v=1766559858"},{"product_id":"adapter-esatto-4-for-takahashi-fsq-106edx-3-and-4","title":"Adapter ESATTO 4\" for Takahashi FSQ-106EDX 3 and 4","description":"\u003cspan style=\"color: rgb(51, 51, 51); font-family: \" open sans sans-serif justify rgb font-size:=\"\" text-align:=\"\" background-color:=\"\"\u003eAdapter ESATTO 4\" for Takahashi FSQ-106EDX 3 and 4 allows you to install ESATTO 4\" instead of the original Takahashi focuser. This adapter has 35mm optical thickness and it is designed to have, when used together with ESATTO 4\", the same thickness of the original focuser (100.5mm) in order to allow you to reach focus with the telescope. Not compatible with standard FSQ-106.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013737738351,"sku":"PL3600324","price":234.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-4-for-takahashi-fsq-106edxiv__64513.jpg?v=1766561310"},{"product_id":"adapter-from-m81-to-m68-female-for-esatto-3-and-arco-3","title":"Adapter from M81 to M68 female for ESATTO 3\" and ARCO 3\"","description":"Adapter from M81 to M68 female for ESATTO 3\" and ARCO 3\"","brand":"Ontario Telescope and Accessories","offers":[{"title":"Default Title","offer_id":44013754810479,"sku":"PL3600289","price":125.0,"currency_code":"CAD","in_stock":true}]},{"product_id":"m110-35mm-extension-tube-for-esatto-4","title":"M110 35mm extension tube for ESATTO 4\"","description":"\u003cspan style=\"color: rgb(51, 51, 51); font-family: \" open sans sans-serif justify rgb font-size:=\"\" text-align:=\"\" background-color:=\"\"\u003eThe M110 35mm extension tube can be directly threaded to the ESATTO 4\" draw tube and allows you to fix camera and accessories further away from the ESATTO microfocuser. This M110 extension tube has 35mm thickness, it's made up of aluminum, black anodized and it has a M110 female on the camera side this way you can connect all the ESATTO 4\" camera adapters.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013780828271,"sku":"3173","price":139.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/m110-35mm-extension-tube-for-esatto-4__57405.jpg?v=1766562575"},{"product_id":"m110-35mm-extension-tube-for-esatto-4-1","title":"M110 35mm extension tube for ESATTO 4\"-1","description":"\u003cspan style=\"font-family: Arial;\"\u003eThe M110 35mm extension tube can be directly threaded to the ESATTO 4\" draw tube and allows you to fix camera and accessories further away from the ESATTO microfocuser. This M110 extension tube has 35mm thickness, it's made up of aluminum, black anodized and it has a M110 female on the camera side this way you can connect all the ESATTO 4\" camera adapters.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013785546863,"sku":"PL3600325","price":139.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/m110-35mm-extension-tube-for-esatto-4_252520_25281_2529__52516.1682636009.1280.1280.jpg?v=1766562631"},{"product_id":"adapter-esatto-3-for-borg-90fl-and-107fl-f3-9","title":"Adapter ESATTO 3\" for Borg 90FL and 107FL f3.9","description":"\u003cspan style=\"font-family: Arial;\"\u003eIf you are searching for the most precise motorized focuser for Borg 90FL and 107FL f3.9, this adapter allows you to connect ESATTO 3\" to these telescopes. Remove the original focuser of the Borg 90FL and 107FL f3.9 and install ESATTO 3\". In order to reach the focus you can use the same photo adapters that you use with the standard focuser.\u003c\/span\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44013791641711,"sku":"PL3600268","price":276.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-3-for-borg-107fl-f3-9__92811.jpg?v=1766562861"},{"product_id":"adapter-esatto-3-5-lp-for-telescopes-with-sc-thread","title":"Adapter ESATTO 3,5\" LP for telescopes with SC thread","description":"\u003cp\u003e\u003cspan\u003eBy adding this adapter, you can connect the ESATTO 3,5\" LP low profile robotic focuser directly onto the back of SC telescopes. Optical thickness of this adapter is just 10mm.\u003c\/span\u003e\u003c\/p\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44014041596015,"sku":"PL3600366","price":134.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-35-lp-for-telescopes-with-sc-thread__96423.jpg?v=1766568622"},{"product_id":"adapter-from-m98-to-m68-with-stop-ring-for-esatto-3-5-lp","title":"Adapter from M98 to M68 with stop ring for ESATTO 3,5” LP","description":"\u003cp\u003e\u003cspan\u003eAdapter from M98 to M68 with stop ring for ESATTO 3,5\" LP allows you to connect any camera or accessory with M68 female thread. Just thread this adapter to the M98 thread of the ESATTO 3,5\" LP draw tube. Thanks to the M68 stop ring for ESATTO 3,5\" LP you can also fix the camera at a precise angle in order to better frame your camera sensor at the desired object. Optical thickness is 4mm.\u003c\/span\u003e\u003c\/p\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44014041661551,"sku":"PL3600363","price":177.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-from-m98-to-m68-with-stop-ring-for-esatto-35__43464.jpg?v=1766568628"},{"product_id":"adapter-esatto-3-5-lp-for-telescopes-with-large-3-3-sc-thread","title":"Adapter ESATTO 3,5” LP for telescopes with large 3.3\" SC thread","description":"\u003cp\u003e\u003cspan\u003eAdapter ESATTO 3,5” LP for telescopes with large 3.3\" SC thread allows you to connect the ESATTO 3,5\" LP to Celestron SCT (11\" and 14\") and EdgeHD (925, 1100, and 1400) models. Since the ESATTO has a depth of 32mm and the 3.3” adapter has only 2mm of optical thickness, this leaves 112mm of backfocus for your camera and accessories, also when used together with the Celestron EdgeHD .7x focal reducers for 925, 1100 and 1400 models.\u003c\/span\u003e\u003c\/p\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44014041923695,"sku":"PL3600362","price":134.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-35-for-telescopes-with-large-33-sc-thread__98327.jpg?v=1766568634"},{"product_id":"adapter-esatto-3-5-lp-for-officinastellare-veloce-rh200","title":"Adapter ESATTO 3,5” LP for OfficinaStellare Veloce RH200","description":"\u003cp\u003e\u003cspan\u003eThe adapter ESATTO 3,5” LP for OfficinaStellare Veloce RH200 allows you to install ESATTO 3,5\" LP focuser to Veloce RH200 telescopes by Officina Stellare. Optical thickness of this adapter is 9mm. \u003c\/span\u003e\u003c\/p\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44014042120303,"sku":"PL3600365","price":276.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-35-for-veloce-rh200__93442.jpg?v=1766568645"},{"product_id":"adapter-esatto-3-5-lp-for-officinastellare-veloce-rh300","title":"Adapter ESATTO 3,5” LP for OfficinaStellare Veloce RH300","description":"\u003cp\u003e\u003cspan\u003eThe adapter ESATTO 3,5” LP for OfficinaStellare Veloce RH300 allows you to install ESATTO 3,5\" LP focuser to Veloce RH300 telescopes by Officina Stellare. Optical thickness 9mm.\u003c\/span\u003e\u003c\/p\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44014042153071,"sku":"PL3600361","price":418.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-35-lp-for-officinastellare-veloce-rh300__48769.jpg?v=1766568650"},{"product_id":"adapter-esatto-3-5-lp-for-gso-orion-tpo-ritchey-chretien-10-12-14-and-16-inches","title":"Adapter ESATTO 3.5\" LP for GSO\/Orion\/TPO Ritchey-Chretien 10, 12, 14 and 16 inches","description":"\u003cp\u003e\u003cspan\u003eIf you are searching for the most precise but low profile robotic focuser to use the GSO\/Orion\/TPO Ritchey-Chretien 10, 12, 14 and 16 inches (both aluminum and carbon tubes) for astrophotography, this adapter allows you to connect ESATTO 3,5\" LP to the M117 thread of these telescope. Based on the camera and imaging train you want to connect, you may need extenders to reach the focus with your camera. Optical thickness of this adapter is just 3mm.\u003c\/span\u003e\u003c\/p\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44014042316911,"sku":"PL3600367","price":177.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-esatto-35-lp-for-gsooriontpo-ritchey-chretien-10-12-14-and-16-inches__98541.jpg?v=1766568655"},{"product_id":"adapter-from-m98-to-m72-female-for-esatto-3-5-lp","title":"Adapter from M98 to M72 female for ESATTO 3,5” LP","description":"\u003cp\u003e\u003cspan\u003eAdapter from M98 to M72 female for ESATTO 3,5\" LP allows you to connect any camera or accessory with M72 male thread. Just thread this adapter to the M98 thread of the ESATTO 3,5\" LP draw tube. This adapter adds no optical thickness.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cimg title=\"Adapter from M98 to M72 female for ESATTO 3,5” LP\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/Adapter-from-M98_20to-M72-female-for-ESATTO-3-5-LP-dimensions_d4ea7959-de85-43f9-b4a5-4239c9d52b28.png?v=1766570357\" alt=\"Adapter from M98 to M72 female for ESATTO 3,5” LP\" width=\"1000\" height=\"616\"\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Primaluce Lab","offers":[{"title":"Default Title","offer_id":44014083997807,"sku":"PL3600385","price":177.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/adapter-from-m98-to-m72-female-for-esatto-35-lp__08750.jpg?v=1766570359"},{"product_id":"adapter-2-0-for-meade-10-12-14-sct-telescopes-for-ftf2015bcr","title":"Adapter 2.0\" for MEADE 10, 12, 14\" SCT telescopes for FTF2015BCR","description":"\u003cp\u003e\u003cspan\u003eScope specific adapter that threads directly to the large Visual Back of the Meade 10, 12, 14″ SCT telescopes.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eUse with focuser FTF2015BCR\u003cbr\u003eKnown To Fit Meade 10″, 12″, 14″\u003cbr\u003eThread on Entry (OTA | FRONT) Side of Draw Tube 3.27X16 tpi Large Thread\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"Starlight Instruments","offers":[{"title":"Default Title","offer_id":44014138228847,"sku":"A20-213","price":159.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/A20-213__00246.jpg?v=1766572666"},{"product_id":"explore-scientific-half-inch-extension-tube-2-inch-rack-and-pinion-focuser","title":"Explore Scientific Half-Inch Extension Tube for 2-inch Rack and Pinion Focusers","description":"\u003ch2\u003eProduct Overview\u003c\/h2\u003e\n\u003cp\u003eThis is Explore Scientific's extension tube for their 2-inch rack and pinion focusers, catalogued as item ESRPEXT1. Explore Scientific describe it in a single line on their own product page: it adds half an inch to the 2-inch rack and pinion focusers fitted to their ED APO telescopes. It is a short, fixed-length spacer that sits in the focuser's optical train and moves the focal plane outwards, and it is the standard remedy when an accessory stack cannot quite reach focus on one of those refractors.\u003c\/p\u003e\n\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eEvery telescope has a fixed amount of back focus, and every accessory you put behind the focuser spends some of it. A star diagonal, a camera with a long flange distance, a filter wheel, an off-axis guider, a binoviewer, or a field flattener each add optical path, and at some point you run the focuser all the way in and the star image is still not sharp. The opposite problem happens too: you rack the drawtube almost fully out to reach focus, which is exactly where a rack and pinion focuser is least rigid and most prone to sag with a heavy camera hanging off it.\u003c\/p\u003e\n\u003cp\u003eA short extension tube solves both. Adding half an inch of fixed spacing shifts the whole focus range outwards so the drawtube can sit closer to the middle of its travel, where it is well supported and the pinion has good engagement. That is a small change on paper and a large one at the eyepiece: better mechanical stiffness, less differential flexure across a long exposure sequence, and a focuser that is not fighting its own end stops. If you have ever found that a particular diagonal and eyepiece combination will not come to focus on your ED APO while a shorter one will, this is the part you were missing.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features \u0026amp; Design\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eAdds half an inch of fixed spacing to the optical train, per Explore Scientific's published description.\u003c\/li\u003e\n\u003cli\u003eDesigned by Explore Scientific specifically for their own 2-inch rack and pinion focusers.\u003c\/li\u003e\n\u003cli\u003eIntended for the ED APO refractor range that ships with those focusers.\u003c\/li\u003e\n\u003cli\u003eFixed length, with no moving parts, threads to work loose, or clamping mechanism to introduce slop.\u003c\/li\u003e\n\u003cli\u003eShort enough to shift the focus range without meaningfully increasing the cantilevered load on the drawtube.\u003c\/li\u003e\n\u003cli\u003eExplore Scientific item number ESRPEXT1.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eMechanical Design\u003c\/h2\u003e\n\u003cp\u003eAn extension tube does nothing optically. It has no glass in it and it does not change focal length, focal ratio, or image scale. What it changes is geometry. The focal plane of a refractor sits a fixed distance behind the objective, and the focuser's job is to place your eyepiece or sensor at that plane. The drawtube can only travel so far in each direction, so the set of accessory stacks that can reach focus is bounded at both ends. Inserting a rigid half-inch spacer between the focuser and the accessory adds a constant to the optical path, which translates the entire usable focus window outwards by that same half inch. Anything that previously needed the drawtube racked further in than it could go now falls inside the range. The trade-off is symmetric and worth knowing: the same half inch comes off the other end, so a short-path accessory that used to focus with the drawtube nearly fully out may no longer reach focus with the extension fitted. This is why extensions are treated as a per-configuration part rather than something you leave in permanently.\u003c\/p\u003e\n\n\u003ch2\u003eRecommended Uses\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eRecovering focus with a long-path accessory stack such as a binoviewer, filter wheel, or off-axis guider.\u003c\/li\u003e\n\u003cli\u003eMoving the drawtube back towards the middle of its travel for better rigidity under an imaging load.\u003c\/li\u003e\n\u003cli\u003eFine-tuning spacing when a diagonal and eyepiece combination will not quite come to focus.\u003c\/li\u003e\n\u003cli\u003eBuilding out a repeatable imaging train where a fixed spacer is preferable to a variable one.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eCompatibility and Accessory Notes\u003c\/h2\u003e\n\u003cp\u003eExplore Scientific state that this extension is for their 2-inch rack and pinion focusers on their ED APO telescopes. They do not publish a list of specific telescope or focuser model numbers on the product page, nor do they publish the fitting's thread or barrel dimensions, so we cannot promise a fit on a third-party focuser or on an Explore Scientific focuser of a different type such as their dual-speed Crayford units. If you tell our team in Bolton which telescope and which focuser you have, we will confirm compatibility with you before it ships rather than have you guess. It is also worth working out how much extra spacing you actually need first, because extensions are only useful in the right length and stacking two short ones is rarely as rigid as fitting one of the correct size.\u003c\/p\u003e\n\n\u003ch2\u003eGood to Know Before You Order\u003c\/h2\u003e\n\u003cp\u003eOne point of honesty about the naming. This item is listed in some catalogues, including the vendor price sheet we work from, as a 1-inch extension tube, but Explore Scientific's own live product page for item ESRPEXT1 describes it as adding half an inch and titles it as a half-inch extension. We have written this listing to the figure the manufacturer currently publishes. If the exact optical length is critical to your imaging train, contact us before ordering and we will measure the part in hand and confirm it for you. Beyond that, this is the extension tube alone with no adapters, compression rings, or spacers included, and it is a spacer rather than a focuser upgrade, so it will not add travel or improve the feel of an existing focuser. Explore Scientific publishes no shipping weight for this item, so we are confirming it on our own scales before the listing goes live. That is why it is currently unpublished. Contact us and we will give you a shipping figure for your address.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eWill this let my camera reach focus?\u003c\/strong\u003e It will if the reason you cannot focus is that your accessory stack is too short and the drawtube is already racked fully out, or if you need to shift the focus window outwards. If you are running out of inward travel instead, an extension makes the problem worse rather than better. Tell us your imaging train and we will work out which direction you need to go.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it fit a Crayford or a third-party focuser?\u003c\/strong\u003e Explore Scientific specify it for their own 2-inch rack and pinion focusers only, and they do not publish the fitting dimensions, so we cannot confirm a fit on anything else. Ask us with your focuser model and we will check.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill it degrade the image?\u003c\/strong\u003e No. There is no glass in an extension tube, so it introduces no aberration of its own. The only optical consideration is that it changes where the focal plane sits relative to your focuser travel.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I stack two of them?\u003c\/strong\u003e Mechanically you can, but each additional joint is another place for tilt and flexure to creep in, which matters for imaging. If you need more than half an inch, we would rather find you a single spacer of the right length.\u003c\/p\u003e\n\n\u003ch2\u003eBottom Line\u003c\/h2\u003e\n\u003cp\u003eA half-inch spacer is a small part that quietly fixes a frustrating problem, letting a stubborn accessory stack come to focus and keeping the drawtube in the stiffer part of its travel. Explore Scientific publish very little about it beyond its purpose, so if the exact length or the fit on your particular focuser matters, contact us and we will confirm both before you order.\u003c\/p\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":53958600720495,"sku":"ESRPEXT1","price":41.95,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/ESRPEXT1_Side.jpg?v=1785960632"}],"url":"https:\/\/ontariotelescope.com\/collections\/focuser-adapters.oembed?page=2","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}