{"product_id":"askar-111f","title":"Askar 111F 0.74× Reducer","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003eReduces Telescope Focal Ratio to f\/5.1\u003c\/li\u003e\n\u003cli\u003eCreates a 566mm Focal Length Imaging System\u003c\/li\u003e\n\u003cli\u003eTriplet Optical Design for Field Flattening\u003c\/li\u003e\n\u003cli\u003eProvides Standard 55mm Back Focus\u003c\/li\u003e\n\u003cli\u003eWeighs 0.5kg\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAskar 111F 0.74× Reducer\u003c\/h2\u003e\n\u003cp\u003eThe Askar 111F 0.74× Reducer converts the telescope into a fast f\/5.1 astrograph, shortening the focal length to 566mm for wider fields of view. This triplet reducer establishes a standard 55mm back focus from its M48 male thread and weighs just 0.5kg, ensuring compatibility with a wide range of modern imaging cameras and accessories.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003ef\/5.1 Speed: A 0.74x Reduction for Wider Fields\u003c\/h3\u003e\n\u003cp\u003eBy reducing the focal ratio to f\/5.1, this accessory significantly cuts down the required exposure time for faint deep-sky objects. The corresponding 566mm focal length widens the field of view, allowing you to frame large targets like the Andromeda Galaxy (M31) or the North America Nebula (NGC 7000) in their entirety on a full-frame sensor.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOptical Correction: A 3-Element Design for Flat Fields\u003c\/h3\u003e\n\u003cp\u003eThe internal triplet lens design corrects for field curvature, ensuring stars remain sharp and round from the center to the edge of the frame. This level of correction is critical for modern, large-format CMOS and CCD sensors, eliminating optical distortions that would otherwise elongate stars in the corners of your images.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eMechanical Design: 55mm Back Focus and Integrated Filter Threads\u003c\/h3\u003e\n\u003cp\u003eEngineered for seamless integration, the reducer presents a standard 55mm back focus distance measured from the base of its M48 male camera connection. This simplifies the process of adding off-axis guiders or filter wheels into your imaging train. The reducer attaches to the telescope's focuser via an M68x1 thread, and the camera-side adapter includes threads for standard 2-inch (M48x0.75) filters.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the main benefit of the Askar 111F 0.74x Reducer?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe primary benefit is speed. By converting the Askar 111F to an \u003cstrong\u003ef\/5.1\u003c\/strong\u003e system with a \u003cstrong\u003e566mm\u003c\/strong\u003e focal length, it reduces exposure times by approximately 45% compared to the native focal ratio. This allows you to capture more data on faint objects in less time while also providing a wider field of view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I achieve the correct 55mm spacing for the 111F 0.74x Reducer?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e55mm back focus\u003c\/strong\u003e is measured from the base of the M48 male thread on the reducer to your camera's sensor. Most dedicated astronomy cameras and DSLR\/mirrorless camera T-rings are designed to this 55mm standard, so in many cases, you can connect your camera directly. If you add a filter wheel or off-axis guider, you must use extension rings to ensure the total distance remains exactly 55mm.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use filters with the Askar 111F 0.74x Reducer?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The reducer features a built-in M48x0.75 thread on the camera side, which allows you to directly attach standard \u003cstrong\u003e2-inch astronomical filters\u003c\/strong\u003e. This is ideal for using light pollution, narrowband, or LRGB filters without needing a separate filter drawer or wheel for simple setups.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the 111F 0.74x Reducer change my image of the Andromeda Galaxy (M31) with the Askar 111F?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe native focal length of the Askar 111F is too long to fit the entire Andromeda Galaxy (M31) and its satellite galaxies on a full-frame sensor. By shortening the focal length to \u003cstrong\u003e566mm\u003c\/strong\u003e, the 0.74x Reducer provides a field of view wide enough to capture the full expanse of the galaxy in a single frame, making it an essential accessory for imaging large celestial targets.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the 111F 0.74x Reducer work with my full-frame camera on the Askar 111F?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the \u003cstrong\u003etriplet\u003c\/strong\u003e optical design is corrected for a large image circle sufficient for full-frame sensors. It effectively flattens the field to ensure that stars in the corners of a full-frame image remain sharp and are not affected by coma or field curvature.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Askar 111F 0.74x Reducer compatible with other telescopes?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, this reducer is an optically matched accessory designed specifically for the Askar 111F APO Triplet Refractor. Using it with other telescopes will likely result in poor optical correction and an inability to reach focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eReduced Focal Length\u003c\/td\u003e\n\u003ctd\u003e566mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReduced Focal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/5.1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Design\u003c\/td\u003e\n\u003ctd\u003eTriplet\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e55mm (from base of M48 male thread)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTelescope Connection Thread\u003c\/td\u003e\n\u003ctd\u003eM68x1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.5 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Askar_111F_Flat-Field_Manual.pdf\" target=\"_blank\"\u003e\u003csvg class=\"DAV-img-box\" viewbox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\u003cpath d=\"M0 64C0 28.7 28.7 0 64 0L224 0l0 128c0 17.7 14.3 32 32 32l128 0 0 144-208 0c-35.3 0-64 28.7-64 64l0 144-48 0c-35.3 0-64-28.7-64-64L0 64zm384 64l-128 0L256 0 384 128zM176 352l32 0c30.9 0 56 25.1 56 56s-25.1 56-56 56l-16 0 0 32c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-48 0-80c0-8.8 7.2-16 16-16zm32 80c13.3 0 24-10.7 24-24s-10.7-24-24-24l-16 0 0 48 16 0zm96-80l32 0c26.5 0 48 21.5 48 48l0 64c0 26.5-21.5 48-48 48l-32 0c-8.8 0-16-7.2-16-16l0-128c0-8.8 7.2-16 16-16zm32 128c8.8 0 16-7.2 16-16l0-64c0-8.8-7.2-16-16-16l-16 0 0 96 16 0zm80-112c0-8.8 7.2-16 16-16l48 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 32 32 0c8.8 0 16 7.2 16 16s-7.2 16-16 16l-32 0 0 48c0 8.8-7.2 16-16 16s-16-7.2-16-16l0-64 0-64z\" fill=\"#0047a7\"\u003e\u003c\/path\u003e\u003c\/svg\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Manual\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/askar-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eAskar 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":52851331006749,"sku":"ASK-ASAPO111F","price":2099.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Askar-111F-0-74-Reducer-1_ab87a539-90f5-488c-aeaf-5554073315a8.jpg?v=1788401687","url":"https:\/\/davidastro.com\/fr\/products\/askar-111f","provider":"David Astro","version":"1.0","type":"link"}