{"product_id":"askar-fra400c-72mm-f-5-6-quintuplet-apo","title":"Askar FRA400C 72mm f\/5.6 Quintuplet APO","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e72mm Aperture Quintuplet APO Optics\u003c\/li\u003e\n\u003cli\u003e400mm Focal Length at f\/5.6\u003c\/li\u003e\n\u003cli\u003eCovers a 44mm Full-Frame Image Circle\u003c\/li\u003e\n\u003cli\u003eIntegrated 17-Blade Aperture (f\/5.6-f\/22)\u003c\/li\u003e\n\u003cli\u003e2.68kg Optical Tube Weight\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\u003eDownloads\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 FRA400C 72mm f\/5.6 Quintuplet APO\u003c\/h2\u003e\n\u003cp\u003eThe Askar FRA400C is a 72mm f\/5.6 Quintuplet APO astrograph engineered to deliver a flat, corrected 44mm image circle for full-frame sensors. Its 400mm focal length provides an ideal wide-field perspective, while the Petzval-like optical train, featuring two ED glass elements, requires no additional flattener for sharp stars edge-to-edge.\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\u003eFlat-Field f\/5.6 Optics: A 44mm Full-Frame Image Circle\u003c\/h3\u003e\n\u003cp\u003eThe core of the FRA400C is its self-flattening Quintuplet air-spaced APO design. This Petzval-like optical system uses two extra-low dispersion (ED) glass elements to correct for chromatic aberration, producing high-contrast images with no false color. Critically, it delivers a 44mm image circle, fully illuminating full-frame camera sensors without the need for a separate field flattener.\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\u003eHybrid Astrograph \u0026amp; Telephoto: 17-Blade Aperture from f\/5.6 to f\/22\u003c\/h3\u003e\n\u003cp\u003eUnlike most astrographs, the FRA400C includes a manually adjustable aperture, stopping down from f\/5.6 to f\/22. With 17 aperture blades, it produces exceptionally smooth, circular out-of-focus highlights (bokeh) when used as a daytime telephoto lens. This feature, combined with a 5m closest focus distance, makes it a capable dual-purpose instrument for both celestial and terrestrial photography.\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\u003eCompact \u0026amp; Adaptable: 2.68kg OTA with M48 Connectivity\u003c\/h3\u003e\n\u003cp\u003eWeighing just 2.68kg for the optical tube alone, and measuring 370mm with the dew shield retracted, the FRA400C is built for portability. At a total weight of 3.18kg with its handle and dovetail, it's an ideal match for lightweight equatorial mounts. The rear of the focuser provides M72, M54, and a standard M48 adapter, ensuring direct connection to most astronomy cameras and DSLRs with a standard 55mm back focus.\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\u003eAskar FRA400C vs. FRA400: What Does the \"C\" Mean?\u003c\/h3\u003e\n\u003cp\u003eThe FRA400C is positioned as a more accessible version of the original Askar FRA400 astrograph. While both share the same core 72mm f\/5.6 quintuplet optical design and 400mm focal length, the 'C' model achieves a lower price point through a more streamlined mechanical design. The FRA400C is lighter (2.68kg vs. 2.9kg OTA) and more compact, making it an excellent choice for imagers prioritizing portability and value without compromising on the 44mm flat-field optical performance.\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 kind of mount do I need for the Askar FRA400C?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a total weight of \u003cstrong\u003e3.18kg (7 lbs)\u003c\/strong\u003e including the handle and dovetail plate, the Askar FRA400C is very lightweight. It works well on portable tracking mounts with a payload capacity of 15-20 lbs or more, such as the Sky-Watcher Star Adventurer GTi or a Celestron Advanced VX.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the Askar FRA400C require a separate field flattener?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. The Askar FRA400C features a \u003cstrong\u003eQuintuplet Petzval-like optical design\u003c\/strong\u003e that is inherently self-flattening. It is designed to produce a flat field across its 44mm image circle without any additional corrective optics, simplifying your imaging train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I connect my full-frame DSLR to the Askar FRA400C?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe FRA400C includes an \u003cstrong\u003eM48 adapter\u003c\/strong\u003e. To connect a DSLR, you will need a standard M48 T-ring for your camera brand (e.g., Canon EOS or Nikon). The telescope is designed for a \u003cstrong\u003e55mm back focus distance\u003c\/strong\u003e, which is the standard for DSLRs with their corresponding T-ring, allowing for a direct and simple connection.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the field of view of the FRA400C on a full-frame camera when imaging the North American Nebula (NGC 7000)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith its \u003cstrong\u003e400mm focal length\u003c\/strong\u003e, the Askar FRA400C on a full-frame sensor (36x24mm) provides a field of view of approximately 5.1° x 3.4°. This is wide enough to comfortably frame the entire North American Nebula (NGC 7000) and the neighboring Pelican Nebula (IC 5070) in a single shot.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Askar FRA400C for daytime wildlife photography?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The FRA400C is an excellent dual-purpose lens. Its manual aperture can be stopped down from \u003cstrong\u003ef\/5.6 to f\/22\u003c\/strong\u003e to control depth of field, and the \u003cstrong\u003e17 aperture blades\u003c\/strong\u003e create smooth, pleasing bokeh. The \u003cstrong\u003e5m closest focus distance\u003c\/strong\u003e also makes it viable for capturing distant terrestrial subjects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the purpose of the adjustable aperture on the FRA400C?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe adjustable aperture serves two main purposes. For \u003cstrong\u003eterrestrial photography\u003c\/strong\u003e, it allows you to control exposure and depth of field, just like a standard camera lens. For \u003cstrong\u003eastrophotography\u003c\/strong\u003e, while you'll typically shoot wide open at f\/5.6 for maximum light gathering, stopping down can be used to sharpen bright stars or create diffraction spikes for artistic effect, particularly on bright targets like the stars in the Pleiades (M45).\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\u003eAperture Size\u003c\/td\u003e\n\u003ctd\u003e72mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e400mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/5.6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eObjective Lens\u003c\/td\u003e\n\u003ctd\u003eQuintuplet dual ED air-spaced APO\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Circle\u003c\/td\u003e\n\u003ctd\u003e44mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture Blades\u003c\/td\u003e\n\u003ctd\u003e17\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture Range\u003c\/td\u003e\n\u003ctd\u003ef\/5.6 - f\/22\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClosest Focus Distance\u003c\/td\u003e\n\u003ctd\u003e5m\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocusing Mode\u003c\/td\u003e\n\u003ctd\u003eManual Focus\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFront Filter Diameter\u003c\/td\u003e\n\u003ctd\u003eM82\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOTA Weight\u003c\/td\u003e\n\u003ctd\u003e2.68kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTotal Weight\u003c\/td\u003e\n\u003ctd\u003e3.18kg (including handle \u0026amp; dovetail plate)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTotal Length\u003c\/td\u003e\n\u003ctd\u003e370mm (including dew shield), 420mm (without dew shield)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRear Adapters\u003c\/td\u003e\n\u003ctd\u003eM72, M54, M48 (with M48×0.75 filter thread)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e55mm recommended (supports 50-60mm range)\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\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003e1.25\"\/2\" Adapter\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eManual\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\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_FRA400C_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\u003cli class=\"DAV-grid-item\"\u003e\u003ca href=\"https:\/\/www.sharpstar-optics.com\/download_list_1\/7.html\" target=\"_blank\"\u003e\u003csvg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 640 512\" class=\"DAV-img-box\"\u003e\u003cpath fill=\"#0047a7\" d=\"M128 32C92.7 32 64 60.7 64 96l0 256 64 0 0-256 384 0 0 256 64 0 0-256c0-35.3-28.7-64-64-64L128 32zM19.2 384C8.6 384 0 392.6 0 403.2C0 445.6 34.4 480 76.8 480l486.4 0c42.4 0 76.8-34.4 76.8-76.8c0-10.6-8.6-19.2-19.2-19.2L19.2 384z\"\u003e\u003c\/path\u003e\u003c\/svg\u003e \n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eDownload Software\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\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":49856589168925,"sku":"ASK-FRA400C","price":895.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Askar-FRA400C-1.jpg?v=1743617369","url":"https:\/\/davidastro.com\/fr-us\/products\/askar-fra400c-72mm-f-5-6-quintuplet-apo","provider":"David Astro","version":"1.0","type":"link"}