{"product_id":"william-optics-ye-m92-63","title":"William Optics M92 to M63 Adapter for William Optics FLT91","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eConnects William Optics FLT91 Telescope to Flat6AIII Flattener\u003c\/li\u003e\n\u003cli\u003eInput Thread: M92 Male\u003c\/li\u003e\n\u003cli\u003eOutput Thread: M63 Female\u003c\/li\u003e\n\u003cli\u003eOptical Path Length: 10.5 mm\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\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\u003eM92 to M63 Adapter for William Optics FLT91\u003c\/h2\u003e\n      \u003cp\u003eThis M92 to M63 adapter provides the essential 10.5 mm of optical path length required to connect a William Optics Flat6AIII flattener to an FLT91 refractor. It is a purpose-built component designed to achieve precise back focus for a flat, corrected field of view.\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\u003eA Purpose-Built Connection for the FLT91 and Flat6AIII at 10.5mm\u003c\/h3\u003e\n      \u003cp\u003eThis is not a generic thread converter; it is an essential optical component for imagers using the William Optics FLT91 telescope with the Flat6AIII flattener\/reducer. The adapter's 10.5 mm length is precisely calculated to establish the correct spacing between the telescope's optics and the flattener, which is critical for achieving sharp stars across the entire imaging sensor.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eTelescope-Side Connection:\u003c\/strong\u003e The male M92 thread attaches directly to the focuser drawtube of the FLT91 telescope.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eFlattener-Side Connection:\u003c\/strong\u003e The female M63 thread accepts the nosepiece of the Flat6AIII flattener\/reducer.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eCritical Spacing:\u003c\/strong\u003e By consuming exactly 10.5 mm of the optical path, this adapter ensures the flattener is positioned at its design distance for optimal field correction.\u003c\/li\u003e\n      \u003c\/ul\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\"\u003eWhat is the primary purpose of this M92 to M63 Adapter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThis adapter is designed specifically to connect the \u003cstrong\u003eWilliam Optics FLT91\u003c\/strong\u003e telescope to the \u003cstrong\u003eFlat6AIII\u003c\/strong\u003e flattener\/reducer. Its primary function is to provide a precise \u003cstrong\u003e10.5 mm\u003c\/strong\u003e of spacing, which is required to achieve the correct back focus for a flat imaging field.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I use this adapter with my William Optics FLT91 and Flat6AIII?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eYou thread the \u003cstrong\u003eM92 male\u003c\/strong\u003e side of the adapter directly onto the focuser of your FLT91 telescope. Then, you thread the Flat6AIII flattener into the \u003cstrong\u003eM63 female\u003c\/strong\u003e side of the adapter. This configuration establishes the correct mechanical and optical connection between the two components.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the 10.5 mm optical length of this M92 to M63 adapter important?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe \u003cstrong\u003e10.5 mm\u003c\/strong\u003e optical length is the most critical specification. Field flatteners must be placed at an exact distance from the telescope's objective to work correctly. This adapter consumes 10.5 mm of the back focus to ensure the Flat6AIII is positioned perfectly relative to the FLT91's focal plane, resulting in sharp stars from edge to edge.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs this M92 to M63 adapter a universal part for other telescopes?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo, this is a specialized component. While the M92 and M63 threads may be used on other equipment, the \u003cstrong\u003e10.5 mm\u003c\/strong\u003e optical length is specifically calculated for the FLT91 and Flat6AIII combination. Using it with other equipment will likely result in incorrect spacing and poor image quality.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eDoes installing this adapter set the final back focus for my FLT91 imaging train?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eNo. This adapter correctly spaces the \u003cstrong\u003eflattener relative to the telescope\u003c\/strong\u003e. You must still add the correct spacers between the flattener and your camera sensor to meet the flattener's own back focus requirement (typically 55 mm, but always check your flattener's manual).\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat are the exact thread specifications for this adapter?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe adapter features the following threads:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eLight-In Side (Telescope):\u003c\/strong\u003e M92 male thread\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eLight-Out Side (Accessory):\u003c\/strong\u003e M63 female thread\u003c\/li\u003e\n    \u003c\/ul\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\u003eLight-In Side Thread\u003c\/td\u003e\n\u003ctd\u003eM92 (male)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eLight-Out Side Thread\u003c\/td\u003e\n\u003ctd\u003eM63 (female)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eOptical Length\u003c\/td\u003e\n\u003ctd\u003e10.5 mm\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    \u003cli class=\"DAV-grid-item\"\u003e\n      \u003cdiv\u003e\n        \u003cp class=\"DAV-item-title\"\u003eM92 to 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  \u003c\/ul\u003e\n\u003c\/li\u003e\n\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":"Default Title","offer_id":52853692006685,"sku":"WO-YE-M92-63","price":88.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/WilliamOptics-M92-M63-Adapter-1_672f1295-9774-4879-8339-50e40156acb6.jpg?v=1788457926","url":"https:\/\/davidastro.com\/fr-eu\/products\/william-optics-ye-m92-63","provider":"David Astro","version":"1.0","type":"link"}