{"id":34222,"date":"2025-11-17T15:31:31","date_gmt":"2025-11-17T14:31:31","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&#038;p=34222"},"modified":"2026-08-25T15:11:45","modified_gmt":"2026-08-25T13:11:45","slug":"william-optics-flat7a-adjustable-flattener-reducer","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/william-optics-flat7a-adjustable-flattener-reducer\/","title":{"rendered":"William Optics Flat7A Adjustable Flattener Reducer"},"content":{"rendered":"<h2 class=\"wp-block-heading has-text-align-center\"><strong>William Optics Flat7A Adjustable Flattener Reducer: flat field and 0.8x focal reduction in one<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The William Optics Flat7A combines two functions: it flattens the image field and shortens the focal length by a factor of 0.8x. Every refractor naturally produces a slightly curved image plane; a flat camera sensor cuts through that, causing stars in the corners to stretch into streaks. A flattener corrects this curvature so that stars remain small and round all the way to the corners. The reducer also makes your telescope one stop faster: shorter total exposure time for the same result.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The optics are a triplet made of Japanese Ohara glass with a full FMC coating: maximum sharpness and contrast, minimal reflections. Made for refractors from f\/5 to f\/7 and calculated for large DSLR sensors.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-3 is-cropped wp-block-gallery-1 is-layout-flex wp-block-gallery-is-layout-flex\"><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-1.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-2.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-3.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-4.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-5.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-6.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-7.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-8.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure><\/figure>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-8d39b2df wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:38%\">\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-2.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:62%\">\n<h4 class=\"wp-block-heading\">Adjustable, without loose extensions<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">You mount the Flat7A directly onto the M92 thread of your focuser and adjust the distance to the optics with the adjustable locking ring. No fussing with spacer rings: twist, lock, done.<\/p>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-8d39b2df wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:38%\">\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/www.telescoop.nl\/wp-content\/uploads\/2025\/11\/William-Optics-Flat7A-Adjustable-Flattener-Reducer-3.jpg\" alt=\"William Optics Flat7A adjustable flattener reducer\" title=\"\"><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:62%\">\n<h4 class=\"wp-block-heading\">The camera train<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">The camera side is T2, for the T2 ring for your camera brand. The 45 mm extension tube positions the sensor at the calculated distance, and the integrated M48 filter thread accommodates your filter in the assembly.<\/p>\n<\/div>\n<\/div>\n\n\n\n<h3 class=\"wp-block-heading\">Featured accessories<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Combine the Flat7A with the 45 mm Flat68II\/Flat7A adapter and the T2 ring for your camera brand for a complete, tilt-free setup.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">For whom yes and for whom no<\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li>\u2713 Astrophotographers with an f\/5 to f\/7 refractor with M92 focuser<\/li><li>\u2713 Who wants speed gain and field correction in one element<\/li><li>\u2717 Owners of focusers without an M92 connection: check your thread size first<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Specifications<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Type<\/strong><\/td><td>Adjustable field flattener-reducer<\/td><\/tr><tr><td><strong>Reduction factor<\/strong><\/td><td>0,8x<\/td><\/tr><tr><td><strong>Optics<\/strong><\/td><td>Triplet, Ohara glass, fully FMC-coated<\/td><\/tr><tr><td><strong>Suitable for<\/strong><\/td><td>Refractors f\/5 to f\/7<\/td><\/tr><tr><td><strong>Telescope silk<\/strong><\/td><td>M92<\/td><\/tr><tr><td><strong>Camera side<\/strong><\/td><td>T2<\/td><\/tr><tr><td><strong>Filter thread<\/strong><\/td><td>M48, integrated<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">You can find more accessories for this brand at the <a href=\"\/en\/brands\/william-optics\/\">William Optics brand page<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"<p>William Optics Flat7A adjustable 0.8x flattener-reducer: Ohara triplet with FMC coating, M92 telescope side, T2 camera side and M48 filter thread. For f\/5 to f\/7 refractors.<\/p>","protected":false},"featured_media":97607,"comment_status":"open","ping_status":"closed","template":"","meta":{"_acf_changed":false},"product_brand":[643],"product_cat":[56,469,3107,3105,3104,3106],"product_tag":[],"class_list":["post-34222","product","type-product","status-publish","has-post-thumbnail","product_brand-william-optics","product_cat-telescoop-accessoires","product_cat-astro-fotografie","product_cat-flatteners","product_cat-optische-accessoires","product_cat-overige-astrofotografie-accessoires","product_cat-reducers","first","instock","taxable","shipping-taxable","purchasable","product-type-simple"],"bundled_by":[],"bundle_stock_status":"instock","bundle_stock_quantity":null,"bundle_virtual":false,"bundle_layout":"","bundle_add_to_cart_form_location":"","bundle_editable_in_cart":false,"bundle_sold_individually_context":"","bundle_item_grouping":"","bundle_min_size":"","bundle_max_size":"","bundle_price":[],"bundled_items":[],"bundle_sell_ids":[33973],"acf":[],"jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":34228,"url":"https:\/\/www.telescoop.nl\/en\/william-optics-flat6a-iii-reducer-flattener-adjustable-2-inch\/","url_meta":{"origin":34222,"position":0},"title":"William Optics Flat6A III Reducer Flattener Adjustable 50.8 mm","author":"","date":"17-11-2025","format":false,"excerpt":"William Optics Flat6AIII adjustable flattener-reducer 0.8x: Ohara glass, M63 telescope side, M48 camera side, 48mm filter thread and distance scale. 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