{"product_id":"askar-90mm-f-5-6-quintuplet-petzval-flat-field-astrograph-fra600","title":"Askar FRA600 - 108 mm f\/5.6 Quintuplet Astrograph - FRA600","description":"\u003ch2 class=\"ast-product-hero-info__short-desc\" style=\"text-align: center;\" data-mce-fragment=\"1\"\u003e\u003cspan class=\"metafield-multi_line_text_field\" data-mce-fragment=\"1\"\u003eAskar FRA600 f\/5.6 Quintuplet Astrograph - FRA600\u003c\/span\u003e\u003c\/h2\u003e\n\u003cdiv class=\"ast-product-hero-info__short-desc\" data-mce-fragment=\"1\"\u003e\u003cspan class=\"metafield-multi_line_text_field\" data-mce-fragment=\"1\"\u003e\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv class=\"ast-product-hero-info__short-desc\" data-mce-fragment=\"1\"\u003e\u003cspan class=\"metafield-multi_line_text_field\" data-mce-fragment=\"1\"\u003eSometimes there's no substitute for extra aperture. This 108mm refractor can gather a lot of light and will bring out extraordinary detail in the faintest deep sky objects. This is a great astrograph for any astrophotographer.\u003c\/span\u003e\u003c\/div\u003e\n\u003cdiv class=\"ast-product-hero-info__highlights\" data-mce-fragment=\"1\"\u003e\n\u003cdiv class=\"metafield-rich_text_field\" data-mce-fragment=\"1\"\u003e\n\u003cul data-mce-fragment=\"1\"\u003e\n\u003cli data-mce-fragment=\"1\"\u003e108mm aperture\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003e600mm focal length\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eQuintuplet air-spaced APO design\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eFull frame camera support\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eNo need for flattener\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003e0.7x Reducer (optional)\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eNo need to calculate backfocus length\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eRetractable lens hood\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eMulti-Functional handle\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003e4.2\" large rack-pinion focuser\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003e1:10 fine adjustment\u003c\/li\u003e\n\u003cli data-mce-fragment=\"1\"\u003eVarious adapters\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eProduct Description\u003c\/h2\u003e\n\u003cp\u003eFollowing the excellent optical performance of its first FRA400\/5.6, the FRA600\/5.6 is an evolution of the FRA series. An upgraded lens has a 108mm aperture and a 600mm focal length, the f\/ratio is still f\/5.6, and the image circle is 66mm surpass the full frame!\u003c\/p\u003e\n\u003cp\u003eThis FRA600 Quintuplet Refractor is built on a Petzval design, comprising a front triplet and rear doublet lenses, two pieces of which are ED glass. This combination provides a high level of apochromatic performance for astroimaging.\u003c\/p\u003e\n\u003cp\u003eWith wonderful optical design, the FRA600 astrograph provides a 66mm image circle to ensure excellent star shape across the entire field whilst controlling chromatic aberration, minimizing the distortion. The two lenses in the rear group have a diameter of 80mm, effectively counterbalancing the effect of decreasing field illumination. With the precise manufacturing, they obtain optimal sharpness nearly to the theoretical level, bringing you beautiful clear detailed images with round-shape stars.\u003c\/p\u003e\n\u003cp\u003eThe FRA600 comes with a large 4.2\" rack-and-gear-based focuser which includes a standard 1:10 focal adjustment knob, the focuser greatly enhances the payload to a pro level, offering smooth operation without slipping when heavy imaging equipment and accessories are attached. The focuser allows multiple connections. Besides, Askar also offers a standard conical extender with threads of M54×0.75 and M48×0.85 to connect various astrophotographic equipment.\u003c\/p\u003e\n\u003cp\u003eMechanically, the FRA600 has a tube diameter of 120mm and a retractable dew-shield. With the dew-shield retracted, the total length is only 493mm, making it a great portable 4\" astrograph.\u003c\/p\u003e\n\u003cp\u003eA set of multifunctional red anodized tube rings includes mounting points on three sides, making itself easy for attachment of accessories such as guider scope for backyard viewing.\u003c\/p\u003e\n\u003cp\u003eIn addition to supporting wide field astrophotography, the FRA600 is also perfect for high quality observation, providing exquisite chromatic aberration correction and creating images with impressive contrast comparable to visual experience.\u003c\/p\u003e\n\u003cp\u003eThe excellent performance would already justify its price if the FRA600 was a mere triplet APO refractor. But our FRA600 is a 4.3\" Super APO Quintuplet Astrograph, its ingenuity has already exceeded its counterparts falling in the same price range.\u003c\/p\u003e\n\u003cp\u003e \u003cbr\u003e\u003c\/p\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e108mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e600mm\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 Type\u003c\/td\u003e\n\u003ctd\u003eQuintuplet flat-field APO (Including two ED elements)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Circle\u003c\/td\u003e\n\u003ctd\u003e66mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus\u003c\/td\u003e\n\u003ctd\u003e160mm (from the end of the rotator M90x1 thread)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOverall Length\u003c\/td\u003e\n\u003ctd\u003e493mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight\u003c\/td\u003e\n\u003ctd\u003e6.5kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStandard Packing Weight\u003c\/td\u003e\n\u003ctd\u003e7.8kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack-End Adpdater\u003c\/td\u003e\n\u003ctd\u003e\n\u003cul\u003e\n\u003cli\u003eM108x1 male thread (no rotator)\u003c\/li\u003e\n\u003cli\u003eM90x1 male thread\u003c\/li\u003e\n\u003cli\u003e2\" adapter\/1.25\" adapter\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eConical Adapter\u003c\/td\u003e\n\u003ctd\u003e\n\u003cul\u003e\n\u003cli\u003eM90x1 to M54x0.75\u003c\/li\u003e\n\u003cli\u003eM54x0.75 to M48x0.75\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0610\/7702\/9116\/files\/askar600-4-sw_480x480.jpg?v=1685339679\" alt=\"\"\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Askar","offers":[{"title":"Default Title","offer_id":40252544548977,"sku":"ASK-FRA600","price":2335.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0851\/2766\/files\/as-fra600-3s.jpg?v=1776459304","url":"https:\/\/khanscope.com\/en-fr\/products\/askar-90mm-f-5-6-quintuplet-petzval-flat-field-astrograph-fra600","provider":"Khan Scope Centre","version":"1.0","type":"link"}