{"product_id":"ff131-apo-astronomical-telescope","title":"FF131 APO Flat-Field Apochromatic Refractor","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO1.jpg?v=1780994168\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO2.jpg?v=1780994165\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e*Focus can be achieved within a back focus range of 42–73 mm, measured from the M54–M48 interface shoulder.\u003c\/p\u003e\n\u003ch3\u003eMain Features\u003c\/h3\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO3.jpg?v=1780994170\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eFlexible Connectivity for Multiple Configurations\u003c\/h3\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO4.jpg?v=1780994169\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eUniqueness\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e 1. Four-Element Optical Design\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\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.\u003cbr\u003eOne ED (extra-low dispersion) glass element is incorporated to effectively reduce chromatic aberration, resulting in improved color correction and image clarity.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO5.jpg?v=1780994172\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003e\u003cspan lang=\"EN-US\"\u003e2.  \u003c\/span\u003e\u003c\/b\u003e\u003cb\u003e\u003cspan lang=\"EN-US\" style=\"mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;\"\u003e\u003cspan style=\"mso-list: Ignore;\"\u003e\u003cspan style=\"font: 7.0pt 'Times New Roman';\"\u003e \u003c\/span\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/b\u003e\u003c!--[endif]--\u003e\u003cb\u003e\u003cspan lang=\"EN-US\"\u003e44 mm Image Circle — Full-Frame Support\u003c\/span\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN-US\"\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 class=\"MsoNormal\"\u003e\u003cspan lang=\"EN-US\"\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\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO6.jpg?v=1780994169\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.  Native Flat-Field Design\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe FF131 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\/130APO7.jpg?v=1780994171\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003eConvenient Design\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\" style=\"mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;\"\u003e\u003cspan style=\"mso-list: Ignore;\"\u003e\u003cspan style=\"font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 7pt; line-height: normal; font-family: 'Times New Roman';\"\u003e  \u003c\/span\u003e\u003c\/span\u003e\u003c\/span\u003e\u003cspan lang=\"EN-US\"\u003e4. Coarse \u0026amp; fine focus adjustment\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cspan lang=\"EN-US\"\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 class=\"MsoNormal\"\u003e\u003cspan lang=\"EN-US\"\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 src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO8.jpg?v=1780994169\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e5. Retractable Dew Shield \u003c\/strong\u003e\u003cbr\u003eThe FF131 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\u003e6. Quick-Release Mounting Rings\u003c\/strong\u003e\u003cbr\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\/130APO9.jpg?v=1780994166\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3\u003ePhotography Extension Tube\u003c\/h3\u003e\n\u003cp\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.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO10.jpg?v=1780994171\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch3 class=\"MsoNormal\" align=\"left\" style=\"text-align: left; mso-pagination: widow-orphan;\"\u003e\n\u003cb\u003e\u003cspan lang=\"EN-US\" style=\"font-size: 13.0pt; font-family: 'Helvetica Neue'; mso-fareast-font-family: 'Helvetica Neue'; mso-bidi-font-family: 'Helvetica Neue'; color: black; mso-font-kerning: 0pt; mso-bidi-language: AR;\"\u003ePerformance\u003c\/span\u003e\u003c\/b\u003e\u003cspan lang=\"EN-US\" style=\"font-size: 13.0pt;\"\u003e\u003c\/span\u003e\n\u003c\/h3\u003e\n\u003cp class=\"MsoNormal\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eOptical Layout\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO11.jpg?v=1780994168\" 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\/130APO12.jpg?v=1780994166\" 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\/130APO13.jpg?v=1780994171\" alt=\"\"\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/130APO14.jpg?v=1780994166\" 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\/130APO15.jpg?v=1780994170\" 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\/130APO17.jpg?v=1780994165\" 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\/130APO16.jpg?v=1780994171\" alt=\"\"\u003e\u003c\/p\u003e","brand":"ZWO ASTRO USA","offers":[{"title":"FF131 APO","offer_id":42880229113918,"sku":"ZWO FF131-APO","price":1999.0,"currency_code":"USD","in_stock":true},{"title":"FF131+AM5N+Free TC40+ Free PE200","offer_id":42880229146686,"sku":"ZH131APO-1","price":4298.0,"currency_code":"USD","in_stock":true},{"title":"FF131+AM7+Free TC40+ Free PE200","offer_id":42880229179454,"sku":"ZH131APO-2","price":4998.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0588\/0817\/2606\/files\/FF130APO1.jpg?v=1780993424","url":"https:\/\/us.zwoastro.com\/products\/ff131-apo-astronomical-telescope","provider":"ZWO ASTRO USA","version":"1.0","type":"link"}