{"product_id":"william-optics-zenithstar-81-doublet-apo-f-6-9-a-z81","title":"William Optics ZenithStar 81 Doublet WIFD APO f\/6.9","description":"\u003ch1\u003eWilliam Optics ZenithStar 81 Doublet APO f\/6.9\u003c\/h1\u003e\n\u003cp data-mce-fragment=\"1\"\u003eA premium refractor telescope that offers unparalleled optical precision with its innovative Internal Focus Design (WIFD). Perfect for astrophotography and visual observations, it features a patented internal focusing mechanism that keeps optics perfectly aligned, even with heavy cameras.\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eAvailable in vibrant red or elegant gold, the ZenithStar 81 WIFD boasts a compact and durable build. Enhance your viewing with optional accessories like the Flat6aIII, a 0.8x reducer for broader celestial views, and the 50mm Uniguider for improved tracking accuracy during long exposures.\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003eWith its refined internal focuser, this telescope provides smooth, precise adjustments for consistently sharp images. Whether capturing distant galaxies or observing planetary details, the ZenithStar 81 WIFD is an excellent choice for serious astronomers.\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003e\u003cimg height=\"909\" width=\"1206\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/Z-81_Flat6AIII-Diagram-01.webp?v=1733343366\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch2 data-mce-fragment=\"1\"\u003eNotice on Tension screw:\u003c\/h2\u003e\n\u003cp data-mce-fragment=\"1\"\u003eWhen using the telescope with the motor, please ensure that the tension screw is not over-tightened. Over-tightening the tension screw may cause damage to the focuser.\u003cbr\u003eThink of it like driving a car and pressing the gas pedal while also pressing the brake simultaneously. Just as this action could harm your car's systems, over-tightening the tension screw could compromise the functionality of your telescope's focuser.\u003c\/p\u003e\n\u003ch3 data-mce-fragment=\"1\"\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"446\" style=\"border-collapse: collapse; width: 335pt;\" data-mce-style=\"border-collapse: collapse; width: 335pt;\"\u003e\n\u003ccolgroup\u003e \u003ccol width=\"136\" style=\"mso-width-source: userset; mso-width-alt: 4973; width: 102pt;\" data-mce-style=\"mso-width-source: userset; mso-width-alt: 4973; width: 102pt;\"\u003e \u003ccol width=\"310\" style=\"mso-width-source: userset; mso-width-alt: 11337; width: 233pt;\" data-mce-style=\"mso-width-source: userset; mso-width-alt: 11337; width: 233pt;\"\u003e \u003c\/colgroup\u003e\n\u003ctbody\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" width=\"136\" style=\"height: 15.0pt; width: 102pt;\" data-mce-style=\"height: 15.0pt; width: 102pt;\"\u003eLens Type\u003c\/td\u003e\n\u003ctd width=\"310\" style=\"width: 233pt;\" data-mce-style=\"width: 233pt;\"\u003eDoublet Apochromatic Prime Lens\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e559 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eDiameter\u003c\/td\u003e\n\u003ctd\u003e81 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.9\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eImage circle\u003c\/td\u003e\n\u003ctd\u003e45 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003eWIFD R\u0026amp;P Focuser \/ Compatible with EAF\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eAdapter Included\u003c\/td\u003e\n\u003ctd\u003eM92 Rotator \/ M92 → M63 Adapter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eOptional Flattener\u003c\/td\u003e\n\u003ctd\u003eFLAT 6AIII 0.8x\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eCamera Format\u003c\/td\u003e\n\u003ctd\u003eFull Frame \/ APS-C \/ M4\/3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e\u003cspan style=\"font-variant-ligatures: normal; font-variant-caps: normal; orphans: 2; text-align: start; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\" data-mce-style=\"font-variant-ligatures: normal; font-variant-caps: normal; orphans: 2; text-align: start; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003e526 mm - 607 mm\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eOTA Weight\u003c\/td\u003e\n\u003ctd\u003e3.55 kg \/ 7.82 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003e\n\u003ctd height=\"20\" style=\"height: 15.0pt;\" data-mce-style=\"height: 15.0pt;\"\u003eTotal Weight\u003c\/td\u003e\n\u003ctd\u003e\u003cspan style=\"font-variant-ligatures: normal; font-variant-caps: normal; orphans: 2; text-align: start; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\" data-mce-style=\"font-variant-ligatures: normal; font-variant-caps: normal; orphans: 2; text-align: start; widows: 2; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003e4.56 kg \/ 10.05 lbs\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cdiv data-mce-fragment=\"1\" class=\"data item content\" id=\"description\" data-role=\"content\" aria-labelledby=\"tab-label-description\" role=\"tabpanel\" aria-hidden=\"false\" style=\"margin: 0px 0px 30px; padding: 0px; box-sizing: border-box; display: block !important; float: none; background: #ffffff; border: none; color: #333333; font-family: 'Open Sans', Arial, 'Helvetica Neue', Helvetica, sans-serif; font-size: 17px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\" data-mce-style=\"margin: 0px 0px 30px; padding: 0px; box-sizing: border-box; display: block !important; float: none; background: #ffffff; border: none; color: #333333; font-family: 'Open Sans', Arial, 'Helvetica Neue', Helvetica, sans-serif; font-size: 17px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;\"\u003e\n\u003cdiv data-mce-fragment=\"1\" class=\"product attribute description\" style=\"margin: 0px; padding: 0px;\" data-mce-style=\"margin: 0px; padding: 0px;\"\u003e\n\u003cdiv data-mce-fragment=\"1\" class=\"value\" style=\"margin: 0px; padding: 0px;\" data-mce-style=\"margin: 0px; padding: 0px;\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv data-mce-fragment=\"1\" class=\"value\"\u003e\n\u003ch3 data-mce-fragment=\"1\"\u003eIn the Box\u003c\/h3\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli\u003eZenithStar 81 OTA\u003c\/li\u003e\n\u003cli\u003eBahtinov Cap\u003c\/li\u003e\n\u003cli\u003eM92 to M63 Adapter\u003c\/li\u003e\n\u003cli\u003eDual Mounting Plate\u003c\/li\u003e\n\u003cli\u003eMounting Rings Handle Bar\u003c\/li\u003e\n\u003cli\u003eSoft Carry Case\u003c\/li\u003e\n\u003cli\u003eAllen Key Set\u003cbr\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 data-mce-fragment=\"1\"\u003eWarranty \u0026amp; Manuals\u003c\/h3\u003e\n\u003cp data-mce-fragment=\"1\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0675\/5752\/3673\/files\/Manual-Z-81-WIFD.pdf\" target=\"_blank\" data-mce-href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0675\/5752\/3673\/files\/Manual-Z-81-WIFD.pdf\"\u003eManual\u003c\/a\u003e\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003e\u003ca href=\"https:\/\/istronomyplus.com\/pages\/william-optics-warranty\" target=\"_blank\" data-mce-href=\"https:\/\/istronomyplus.com\/pages\/william-optics-warranty\"\u003eWilliam Optics 2-Year Warranty\u003c\/a\u003e\u003c\/p\u003e\n\u003cp data-mce-fragment=\"1\"\u003e\u003ca href=\"https:\/\/istronomyplus.com\/pages\/william-optics-f-a-q\" target=\"_blank\" data-mce-href=\"https:\/\/istronomyplus.com\/pages\/william-optics-f-a-q\"\u003eWilliam Optics F.A.Q\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/div\u003e","brand":"William Optics","offers":[{"title":"Red","offer_id":43746494873829,"sku":"WO-T-ZS-81RD-WIFD","price":1515.0,"currency_code":"CAD","in_stock":true},{"title":"Gold","offer_id":43746494906597,"sku":"WO-T-ZS-81GD-WIFD","price":1515.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0652\/6245\/2965\/files\/Zenithstar-81-perspective-1.webp?v=1777045852","url":"https:\/\/istronomyplus.com\/products\/william-optics-zenithstar-81-doublet-apo-f-6-9-a-z81","provider":"Astronomy Plus – Telescopes \u0026 Astrophotography Canada","version":"1.0","type":"link"}