{"product_id":"ff90-apo-flat-field-apochromatic-refractor","title":"FF90 APO Flat-Field Apochromatic Refractor","description":"\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO1.jpg?v=1781004942\"\u003e\u003c\/p\u003e\n\u003cp\u003eLightweight \u0026amp; Compact · Designed for Both Visual Observation and Astrophotography\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO2.jpg?v=1781004940\"\u003e\u003c\/p\u003e\n\u003cp\u003e*Focus can be achieved within a back focus range of 45–75 mm, measured from the M54–M48 interface shoulder.\u003c\/p\u003e\n\u003ch3\u003eMain Features\u003c\/h3\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO3.jpg?v=1781004943\"\u003e\u003c\/p\u003e\n\u003ch4\u003eFlexible Connectivity for Multiple Configurations\u003c\/h4\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO4.jpg?v=1781004944\"\u003e\u003c\/p\u003e\n\u003ch3\u003eUniqueness\u003c\/h3\u003e\n\u003cp\u003e\u003cbr\u003e\u003cstrong\u003e1. Lightweight \u0026amp; Compact\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe ZWO FF90 APO features a 90 mm aperture and 609 mm focal length (f\/6.8), offering an excellent balance between portability and performance.\u003cbr\u003eThe optical tube weighs just 3.92 kg, with a total system weight of 4.52 kg including mounting rings and dovetail plate.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO5.jpg?v=1781004944\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Four-Element Optical Design\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe FF90 APO features a four-element, fully air-spaced apochromatic optical design. All four elements work together to deliver a flat imaging field without the need for an additional field flattener.\u003cbr\u003eOne ED (extra-low dispersion) glass element is incorporated to effectively reduce chromatic aberration, resulting in improved color correction and image clarity.\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO6.jpg?v=1781004945\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. 44 mm Image Circle — Full-Frame Support\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eWith a 44 mm image circle, the FF90 APO fully supports full-frame sensors and a wide range of imaging setups.\u003cbr\u003eIt delivers sharp star fields with excellent edge-to-edge performance, ensuring consistent image quality across the entire frame.\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO7.jpg?v=1781004944\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e4. Native Flat-Field Design\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe FF90 APO features a native flat-field optical design, eliminating the need for an additional field flattener.\u003cbr\u003eNo complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO8.jpg?v=1781004946\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eConvenient Design\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e5. Coarse \u0026amp; fine focus adjustment\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eEquipped with a rigid 3-inch rack-and-pinion focuser, the FF90 APO offers precise control with a 1:10 coarse \u0026amp; fine focus adjustment mechanism.\u003cbr\u003eA built-in 360° rotator at the rear allows for smooth and accurate camera angle adjustments.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO9.jpg?v=1781004945\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e6. Retractable Dew Shield \u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe FF90 APO features a retractable dew shield, reducing overall length for improved portability.\u003cbr\u003ePrecision CNC machining and a high-quality painted finish, combined with an internal anti-reflection coating, help minimize stray light and enhance image contrast.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e7. Quick-Release Mounting Rings\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eThe mounting rings are detachable, allowing for quick and easy setup or teardown of the telescope.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO10.jpg?v=1781004940\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e8. Photography Extension Tube \u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe FF90 APO includes a photography extension tube with a 2-inch filter thread, along with rear adapters in M48×0.75 and M54×0.75 standards.\u003cbr\u003eThis allows for easy integration with a wide range of imaging accessories.\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO11.jpg?v=1781004946\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003ePerformance\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eOptical Layout\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO12.jpg?v=1781004941\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eStar Field Map\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO13.jpg?v=1781004941\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eProduct Diagram\u003c\/h3\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO14.jpg?v=1781004945\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO15.jpg?v=1781004943\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eWhat's in the box?\u003c\/h3\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO16.jpg?v=1781004939\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eFF Series Telescope Comparison\u003c\/h3\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/90APO17.jpg?v=1781004944\" alt=\"\"\u003e\u003c\/p\u003e","brand":"ZWO ASTRO USA","offers":[{"title":"FF90 APO","offer_id":42880366346302,"sku":"ZWO FF90-APO","price":999.0,"currency_code":"USD","in_stock":true},{"title":"FF90+AM3N+Free TC40+ Free PE200","offer_id":42880366379070,"sku":"ZH90APO-1","price":2498.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/FF90APO1.jpg?v=1781004213","url":"https:\/\/us.zwoastro.com\/products\/ff90-apo-flat-field-apochromatic-refractor","provider":"ZWO ASTRO USA","version":"1.0","type":"link"}