{"product_id":"zwo-131mm-quad-apo-refractor","title":"ZWO 131mm Quad APO Refractor","description":"\u003ch2 dir=\"ltr\"\u003e\u003cspan\u003eZWO FF131 APO\u003c\/span\u003e\u003c\/h2\u003e\n\u003ch2 dir=\"ltr\"\u003e\u003cspan\u003eFlat-Field Apochromatic Refractor\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image1_7d711ce8-338d-421c-916b-e15151240520.jpg?v=1781048454\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image3_4fb33c62-aaf2-497e-8b9a-9ff74adfdda9.jpg?v=1781048454\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003e*Focus can be achieved within a back focus range of 42–73 mm, measured from the M54–M48 interface shoulder.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch4\u003e\u003cb id=\"docs-internal-guid-5b2ee0c4-7fff-e1d2-2938-e281cb57d6a7\"\u003e\u003cspan\u003eMain Features\u003c\/span\u003e\u003c\/b\u003e\u003c\/h4\u003e\n\u003cp\u003e\u003cb\u003e\u003cspan\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image2_9f2348f4-73d4-4e3b-b620-774a59933a57.jpg?v=1781048454\"\u003e\u003c\/span\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003ch4\u003e\u003cb\u003e\u003cspan\u003e\u003cb id=\"docs-internal-guid-d5a3a2cf-7fff-afdc-c577-4aa99e6d4450\"\u003eFlexible Connectivity for Multiple Configurations\u003c\/b\u003e\u003c\/span\u003e\u003c\/b\u003e\u003c\/h4\u003e\n\u003cp\u003e\u003cb\u003e\u003cspan\u003e\u003cb\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image5_dd39a7f4-cafd-4050-8745-d70b432b6b19.jpg?v=1781048455\"\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003ch4 dir=\"ltr\"\u003e\u003cspan\u003eUniqueness\u003c\/span\u003e\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli dir=\"ltr\" role=\"presentation\"\u003e\u003cem\u003eFour-Element Optical Design\u003c\/em\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eThe FF131 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\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eOne ED (extra-low dispersion) glass element is incorporated to effectively reduce chromatic aberration, resulting in improved color correction and image clarity.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image4_95aedea1-078c-4fca-a752-f73f428948d7.jpg?v=1781048455\" alt=\"\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli style=\"font-style: italic;\" role=\"presentation\" dir=\"ltr\"\u003e\u003cem\u003e44 mm Image Circle — Full-Frame Support\u003c\/em\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eWith a 44 mm image circle, the FF131 APO fully supports full-frame sensors and a wide range of imaging setups.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eIt delivers sharp star fields with excellent edge-to-edge performance, ensuring consistent image quality across the entire frame.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image7_1fb681bb-f7f8-4716-a192-c408e3355b92.jpg?v=1781048454\"\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli dir=\"ltr\" role=\"presentation\"\u003e\u003cem\u003eNative Flat-Field Design\u003c\/em\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eThe FF131 APO features a native flat-field optical design, eliminating the need for an additional field flattener.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eNo complex back focus calculations or spacing adjustments are required—simply attach your imaging setup and start capturing once focus is achieved.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image6_b493c447-a81f-4859-8aa4-0721e65ec2cb.jpg?v=1781048455\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch4 dir=\"ltr\"\u003e\u003cspan\u003eConvenient Design\u003c\/span\u003e\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli dir=\"ltr\" role=\"presentation\"\u003e\u003cspan\u003eCoarse \u0026amp; fine focus adjustment\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eEquipped with a rigid 3-inch rack-and-pinion focuser, the FF131 APO offers precise control with a 1:10 coarse \u0026amp; fine focus adjustment mechanism.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eA built-in 360° rotator at the rear allows for smooth and accurate camera angle adjustments.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image9_ab697dcd-a768-470c-88fe-ea448875041c.jpg?v=1781048455\"\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cem\u003eRetractable Dew Shield \u003c\/em\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eThe FF131 APO features a retractable dew shield, reducing overall length for improved portability.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\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\/span\u003e\u003cb\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli style=\"font-style: italic;\" dir=\"ltr\"\u003e\u003cem\u003eQuick-Release Mounting Rings\u003c\/em\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eThe mounting rings are detachable, allowing for quick and easy setup or teardown of the telescope.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image8_d26143d9-0b76-4cb1-808f-d8f44539d94f.jpg?v=1781048455\" alt=\"\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli dir=\"ltr\"\u003e\u003cem\u003ePhotography Extension Tube\u003c\/em\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003eThe FF131 APO is designed for seamless integration with modern imaging systems, and includes a standard four-section photographic extension tube with a 2-inch filter thread. Rear adapters in both M48x0.75 and M54x0.75 formats are also included, making it easy to connect a wide range of cameras, filters, and astrophotography accessories for a clean, flexible setup right out of the box.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cspan\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image12_1e206542-b17b-40d0-a9f2-0da8d8d330a6.jpg?v=1781048455\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003ch4 dir=\"ltr\"\u003e\u003cspan\u003ePerformance\u003c\/span\u003e\u003c\/h4\u003e\n\u003cp dir=\"ltr\"\u003e\u003cem\u003eOptical Layout\u003c\/em\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cem\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image10_36641e33-73bd-4886-9616-8862b405aece.jpg?v=1781048455\" alt=\"\"\u003e\u003c\/em\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cb id=\"docs-internal-guid-9644c8d6-7fff-b4f1-ddc8-a14d9b974021\"\u003e\u003cspan\u003eStar Field Map\u003c\/span\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cb\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/Bitmap_image.jpg?v=1781062120\" alt=\"\"\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cb id=\"docs-internal-guid-9644c8d6-7fff-b4f1-ddc8-a14d9b974021\"\u003e\u003cspan\u003eProduct \u003c\/span\u003e\u003c\/b\u003e\u003cb\u003eDiagram\u003c\/b\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image13_4a58f3d4-5768-4349-afd1-b0151e6ac536.jpg?v=1781048454\"\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image14_9d0159e1-6c15-4a79-bb59-8beff9908898.jpg?v=1781048455\"\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cb id=\"docs-internal-guid-1ed699a1-7fff-86bd-5b9f-2ec8ee424333\"\u003e\u003cspan\u003eSpecifications\u003c\/span\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cb\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image15_65c0e969-b150-45c0-8a66-98f021a390f1.jpg?v=1781048455\"\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cb\u003e\u003cb id=\"docs-internal-guid-43e91f37-7fff-0753-86cf-840c524d2254\"\u003e\u003cspan\u003eWhat's in the Box?\u003c\/span\u003e\u003c\/b\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\"\u003e\u003cb\u003e\u003cb\u003e\u003cspan\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/image16_63eac4e6-8a33-419c-93c1-e619ae262dd7.jpg?v=1781048455\" alt=\"\"\u003e\u003c\/span\u003e\u003c\/b\u003e\u003c\/b\u003e\u003c\/p\u003e","brand":"ZWO","offers":[{"title":"Default Title","offer_id":48334294483203,"sku":"ZWO FF131-APO","price":1999.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/FF130APO1_1296x_583a2fe2-82aa-454f-bdb1-cfc28ec7e43b.webp?v=1781122209","url":"https:\/\/milehighastro.com\/products\/zwo-131mm-quad-apo-refractor","provider":"Mile High Astronomy","version":"1.0","type":"link"}