{"product_id":"william-optics-zenithstar-81-wifd-telescope","title":"William Optics Zenithstar 81 WIFD Telescope","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003ePatented William Optics Internal Focus Design (WIFD)\u003c\/li\u003e\n\u003cli\u003eRigid M92 Rear Thread with M63 Adapter Included\u003c\/li\u003e\n\u003cli\u003eVixen\/Arca-Swiss Dual-Sided Mounting Plate\u003c\/li\u003e\n\u003cli\u003eIntegrated Handle Bar and Mounting Rings\u003c\/li\u003e\n\u003cli\u003eSoft Padded Carry Case for Transport and Storage\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\u003eWilliam Optics Zenithstar 81 WIFD Telescope\u003c\/h2\u003e\n\u003cp\u003eThe William Optics Zenithstar 81 WIFD Telescope delivers exceptional optical stability for astrophotography by eliminating drawtube sag with its patented internal focusing mechanism. The robust rear M92 thread, which converts to M63 with the included adapter, provides a solid, flex-free connection for heavy cameras and complex imaging trains.\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\u003eThe Patented WIFD: A Revolution in Internal Focusing\u003c\/h3\u003e\n\u003cp\u003eWilliam Optics' innovative Internal Focus Design (WIFD) is the centerpiece of the Zenithstar 81. Unlike traditional focusers that move an external drawtube, the WIFD moves the optics internally, ensuring the camera and other accessories remain fixed. This design completely prevents the image shift and tilt that can ruin long exposures, especially when using heavy filter wheels or off-axis guiders.\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\u003eAstrophotography-Ready Mechanics from Case to Mount\u003c\/h3\u003e\n\u003cp\u003eThis telescope is engineered for immediate use in the field. It arrives with a pre-installed dual-side mounting plate compatible with both Vixen-style and Arca-Swiss saddles, offering broad mount compatibility. The package also includes a sturdy mounting ring, a combination handle bar and guidescope saddle, and a high-quality soft carry case for safe transport to your dark-sky site.\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\u003eAn Expandable Optical System for Reducers and Guiders\u003c\/h3\u003e\n\u003cp\u003eThe Zenithstar 81 WIFD is designed as the core of a flexible imaging system. While its native optics provide sharp, high-contrast views, it is fully compatible with optional accessories like the Flat6aIII focal reducer for a wider field of view. The integrated handle bar also serves as a saddle for the optional UniGuide series of guidescopes, creating a compact and rigid platform for precise tracking during long-exposure astrophotography.\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 main advantage of the Zenithstar 81 WIFD's internal focuser?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary advantage of the \u003cstrong\u003eWilliam Optics Internal Focus Design (WIFD)\u003c\/strong\u003e is the elimination of focuser sag and tilt. By moving the optics internally and keeping the camera stationary, it provides a completely rigid imaging train that maintains perfect optical alignment, which is critical for sharp stars edge-to-edge when using heavy cameras and accessories.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Zenithstar 81 WIFD with my existing Vixen-style mount?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The Zenithstar 81 WIFD includes a dual-sided mounting plate that is compatible with both \u003cstrong\u003eVixen-style\u003c\/strong\u003e and \u003cstrong\u003eArca-Swiss\u003c\/strong\u003e saddles, allowing you to attach it to a wide variety of astronomical mounts and camera tripods without needing to purchase additional hardware.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat do I need to start guiding the Zenithstar 81 WIFD for long exposures on the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eTo guide the Zenithstar 81 WIFD, you will need a guidescope, such as the optional William Optics UniGuide, and a guide camera. The telescope's integrated handle bar is designed to mount a guidescope directly, creating a solid, parallel setup for accurate tracking of celestial objects like the Andromeda Galaxy (M31).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Zenithstar 81 WIFD come with everything I need to attach it to a mount?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the package includes the essential mounting hardware. It comes with a mounting ring and a dual-sided Vixen\/Arca-Swiss plate, allowing you to secure it to most common astronomical mounts right out of the box.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the internal focuser on the Zenithstar 81 WIFD handle heavy imaging trains?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe internal focuser is exceptionally well-suited for heavy imaging trains. Because the camera and accessories are threaded directly to the rigid M92 rear port of the telescope tube, their weight is not supported by a moving drawtube. This design prevents flexure, ensuring the sensor remains perfectly orthogonal to the light path regardless of the setup's weight or orientation.\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 included M92 to M63 adapter for the Zenithstar 81 WIFD?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Zenithstar 81 WIFD features a large M92 native rear thread for maximum stability. The included \u003cstrong\u003eM92 to M63 adapter\u003c\/strong\u003e allows you to connect a wide range of accessories, including many field flatteners and reducers that use the more common M63 thread standard, providing greater flexibility for building your imaging train.\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\u003eAvailable Options\u003c\/td\u003e\n\u003ctd\u003eGold, Red\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\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eMain 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\"\u003eBahtinov Cap\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\"\u003eM92→M63 Adapter\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\"\u003eDual-side Plate\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\"\u003eMounting Ring \u0026amp; Handle bar\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\"\u003eSoft Carry Case\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\"\u003eAllen Key Set\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\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eNo downloads available for this product.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/william-optics-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eWilliam Optics 2-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Gold","offer_id":51292718235933,"sku":"WO-T-ZS-81GD-WIFD","price":1098.0,"currency_code":"USD","in_stock":true},{"title":"Red","offer_id":51292718203165,"sku":"WO-T-ZS-81RD-WIFD","price":999.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Z-81-WIFD-perspective-gold.jpg?v=1779207603","url":"https:\/\/davidastro.com\/fr-us\/products\/william-optics-zenithstar-81-wifd-telescope","provider":"David Astro","version":"1.0","type":"link"}