{"product_id":"zwo-ff90-90mm-apo-refractor-ff90-apo","title":"ZWO FF90 - 90mm f\/6.8 Flat Field APO Refractor - FF90-APO","description":"\u003ch3 style=\"text-align: center;\"\u003eZWO FF90 APO \u003cbr\u003eFlat-Field Apochromatic Refractor \u003c\/h3\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Hero_Banner.jpg?v=1780684949\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Highlight_Icons.jpg?v=1780684978\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eMain Features\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Text_Highlights.jpg?v=1780685020\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch4\u003e\u003cb\u003eFlexible Connectivity for Multiple Configurations\u003c\/b\u003e\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/70APO_Scene.jpg?v=1780680274\"\u003e\u003c\/p\u003e\n\u003ch4\u003e\u003cb\u003eLightweight \u0026amp; Compact\u003c\/b\u003e\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Lightweight_Compact_611b1e94-ec56-4466-bd2f-0cb06a20ef63.jpg?v=1780685072\" alt=\"\"\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.\u003c\/p\u003e\n\u003cp\u003eThe optical tube weighs just 3.92 kg, with a total system weight of 4.52 kg including mounting rings and dovetail plate.\u003c\/p\u003e\n\u003ch4\u003e\u003cb\u003eFour-Element Optical Design\u003c\/b\u003e\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/70APO_Four-ElementOpticalDesign.jpg?v=1780680275\"\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.\u003c\/p\u003e\n\u003cp\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\u003ch4\u003e\u003cb\u003e44 mm Image Circle — Full-Frame Support\u003c\/b\u003e\u003c\/h4\u003e\n\u003cp style=\"text-align: left;\"\u003e\u003cb\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/70APO_Full-FrameSupport.jpg?v=1780680276\"\u003e\u003c\/b\u003eWith a 44 mm image circle, the FF90 APO fully supports full-frame sensors and a wide range of imaging setups.\u003c\/p\u003e\n\u003cp\u003eIt delivers sharp star fields with excellent edge-to-edge performance, ensuring consistent image quality across the entire frame.\u003c\/p\u003e\n\u003ch4\u003eNative Flat-Field Design\u003c\/h4\u003e\n\u003cp\u003eThe FF90 APO features a native flat-field optical design, eliminating the need for an additional field flattener.\u003c\/p\u003e\n\u003cp\u003eNo complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eConvenient Design\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cb\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Focus_Rotator.jpg?v=1780685220\" alt=\"\"\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003ch4 style=\"text-align: left;\"\u003eCoarse \u0026amp; fine focus adjustment\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/70APO_Focusadjustment.jpg?v=1780680275\"\u003e\u003c\/p\u003e\n\u003cp\u003eEquipped with a rigid 3\" rack-and-pinion focuser, the FF90 APO offers precise control with a 1:10 coarse \u0026amp; fine focus adjustment mechanism.\u003c\/p\u003e\n\u003cp\u003eA built-in 360° rotator at the rear allows for smooth and accurate camera angle adjustments.\u003c\/p\u003e\n\u003ch4\u003eRetractable Dew Shield\u003cspan class=\"Apple-converted-space\"\u003e \u0026amp; Quick Release Mounting Rings\u003c\/span\u003e\n\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Dew_Rings.jpg?v=1780685290\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003eThe FF90 APO features a retractable dew shield, reducing overall length for improved portability.\u003c\/p\u003e\n\u003cp\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\u003eThe mounting rings are detachable, allowing for quick and easy setup or teardown of the telescope.\u003c\/p\u003e\n\u003ch4\u003ePhotography Extension Tube\u003cspan class=\"Apple-converted-space\"\u003e \u003c\/span\u003e\n\u003c\/h4\u003e\n\u003cp style=\"text-align: left;\"\u003e\u003cspan class=\"Apple-converted-space\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/70APO_Extensiontube.jpg?v=1780680275\"\u003e\u003c\/span\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.\u003c\/p\u003e\n\u003cp\u003eThis allows for easy integration with a wide range of imaging accessories.\u003c\/p\u003e\n\u003ch3\u003e\n\u003cb\u003ePerformance\u003c\/b\u003e\u003cb\u003e\u003c\/b\u003e\n\u003c\/h3\u003e\n\u003ch4\u003e\u003cb\u003eRay Tracing\u003c\/b\u003e\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cb\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Ray_Tracing.jpg?v=1780685380\" alt=\"\"\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003ch4 style=\"text-align: left;\"\u003eSpot Diagram\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Spot_Diagram.jpg?v=1780685610\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch4\u003eMechanical Drawing\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Mech_Drawing.jpg?v=1780685650\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch4 style=\"text-align: left;\"\u003e\n\u003cb\u003eSpecifications\u003c\/b\u003e\u003cb\u003e\u003c\/b\u003e\n\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cb\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_Specifications.jpg?v=1780685685\" alt=\"\"\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003ch4 style=\"text-align: left;\"\u003eWhat's in the box?\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_WITB.jpg?v=1780685711\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch4\u003eFF Series Telescope Comparison\u003c\/h4\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/FF_Series_Comparison.jpg?v=1780680275\"\u003e\u003c\/p\u003e","brand":"ZWO","offers":[{"title":"Default Title","offer_id":43310383530097,"sku":"ZWO-FF90-APO","price":1409.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/90APO_4.jpg?v=1780685736","url":"https:\/\/khanscope.com\/products\/zwo-ff90-90mm-apo-refractor-ff90-apo","provider":"Khan Scope Centre","version":"1.0","type":"link"}