{"product_id":"sharpstar-sca310","title":"Sharpstar SCA310 f\/3.8 Aspherical Cassegrain Astrograph","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e310mm Aperture Aspherical Primary Mirror\u003c\/li\u003e\n\u003cli\u003e1178mm Focal Length at a Fast f\/3.8\u003c\/li\u003e\n\u003cli\u003e55mm Corrected Image Circle for Medium Format Sensors\u003c\/li\u003e\n\u003cli\u003eTriplet Corrector with one ED Glass Element\u003c\/li\u003e\n\u003cli\u003eLightweight Carbon Fiber Tube Construction\u003c\/li\u003e\n\u003cli\u003e3.5-inch Rack-and-Pinion Focuser with 360° Rotator\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\u003eSharpstar SCA310 f\/3.8 Aspherical Cassegrain Astrograph\u003c\/h2\u003e\n\u003cp\u003eThe Sharpstar SCA310 combines a massive 310mm aspherical primary mirror with a fast f\/3.8 focal ratio to deliver exceptional light-gathering power in a compact design. Its integrated triplet corrector produces a flat, coma-free 55mm image circle, fully illuminating medium-format sensors. With a tube length of just 721mm and a total weight of 23.5kg, this astrograph provides the deep-sky imaging capability of a much larger instrument.\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\u003e310mm f\/3.8 Aspherical Optics: A 55mm Corrected Image Circle\u003c\/h3\u003e\n\u003cp\u003eAt the core of the SCA310 is a 310mm aspherical primary mirror, precisely figured to eliminate spherical aberration for sharp, point-like stars. Paired with a thermally stable secondary, this system achieves a 1178mm focal length. A permanently integrated 3-element corrector, featuring one ED glass element, flattens the field and corrects for coma, producing a 55mm image circle capable of covering the largest full-frame and medium-format CMOS sensors with near 100% illumination.\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\u003e721mm Carbon Fiber Tube: Thermal Stability at 23.5kg\u003c\/h3\u003e\n\u003cp\u003eThe SCA310's optical path is housed in a carbon fiber tube, which offers a superior stiffness-to-weight ratio and minimal thermal expansion. This ensures that focus remains stable during temperature drops over a long imaging session. The entire optical tube assembly is only 721mm long, a significant advantage for portability and mount requirements compared to other designs of similar aperture, and weighs a substantial 23.5kg.\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\u003e3.5-inch Focuser: 30mm Travel and 360° Rotation\u003c\/h3\u003e\n\u003cp\u003eTo handle modern heavy imaging trains, the SCA310 is equipped with a 3.5-inch high-rigidity rack-and-pinion focuser. This unit provides 30mm of travel with a 1:10 dual-speed knob for precise adjustments and can support heavy camera and filter wheel combinations without slippage. A 360° rotator allows for easy framing of your target, and the rear is equipped with M68, M54, and M48 adapters for direct connection to your camera. The M48 adapter also includes a built-in thread for 2-inch filters.\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\u003eIntegrated Cooling: 3 Fans for Rapid Thermal Equilibrium\u003c\/h3\u003e\n\u003cp\u003eTo maximize image quality from the start of your session, the SCA310 integrates three cooling fans behind the primary mirror. Activating these fans before you begin imaging rapidly brings the 310mm primary mirror to ambient temperature. This minimizes tube currents and ensures the sharpest possible views, significantly improving efficiency and overall imaging results.\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\u003eSCA310 vs. 12\" Newtonian Astrographs: The Cassegrain Advantage\u003c\/h3\u003e\n\u003cp\u003eWhile a 12\" (approx. 300mm) f\/4 Newtonian offers similar aperture and speed, the SCA310's Cassegrain design provides distinct advantages for the dedicated astrophotographer.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompactness:\u003c\/strong\u003e The SCA310's 721mm tube is over 400mm shorter than a typical 12\" f\/4 Newtonian OTA. This makes it easier to transport, balance, and house in an observatory, and it places less strain on the mount.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntegrated Correction:\u003c\/strong\u003e The SCA310's corrector is a permanent, optimized part of the optical design. You do not need to purchase or install a separate coma corrector, and the back focus is fixed and simple to work with.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStray Light and Dew:\u003c\/strong\u003e The closed carbon fiber tube offers superior protection against stray light and dew formation compared to the open-truss or single-wall design of most large Newtonians.\u003c\/li\u003e\n\u003c\/ul\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 makes the Sharpstar SCA310's f\/3.8 Cassegrain design unique?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SCA310 uses an \u003cstrong\u003easpherical primary mirror\u003c\/strong\u003e in a Cassegrain configuration. This allows it to achieve a fast f\/3.8 focal ratio and a long 1178mm focal length within a very short 721mm tube. Combined with its integrated triplet corrector, it delivers a large, flat, and coma-free field for serious deep-sky imaging.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the SCA310's integrated corrector handle large sensors?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 3-element corrector is specifically designed to produce a \u003cstrong\u003e55mm image circle\u003c\/strong\u003e. This is large enough to cover medium-format sensors and provides excellent, pinpoint stars from edge to edge on full-frame sensors without vignetting, making it ideal for large-format cameras.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan the Sharpstar SCA310 fully illuminate a camera like the ZWO ASI2600MC Pro?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The ZWO ASI2600MC Pro has an APS-C sensor with a diagonal of about 28mm. The SCA310's \u003cstrong\u003e55mm image circle\u003c\/strong\u003e will fully illuminate this sensor with plenty of room to spare, ensuring a bright, flat field without any vignetting caused by the optics.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDo I need to calculate back focus for the Sharpstar SCA310?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. According to Sharpstar, the SCA310's optical structure is optimized so that you do not need to perform additional back focus calculations. The included M68, M54, and M48 adapters are designed to place your sensor at the correct distance, simplifying the imaging process significantly.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the SCA310's 1178mm focal length perform on small targets like the Dumbbell Nebula (M27)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e1178mm focal length\u003c\/strong\u003e is excellent for framing planetary nebulae like M27 or galaxies like the Whirlpool Galaxy (M51). When paired with a camera using small pixels, you can achieve high-resolution sampling to capture fine structural details in these smaller deep-sky objects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat class of mount is required for the 23.5kg Sharpstar SCA310?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWith a gross weight of \u003cstrong\u003e23.5kg (51.8 lbs)\u003c\/strong\u003e before adding a camera, guide scope, and other accessories, the SCA310 requires a high-capacity equatorial mount. You should look for a mount with a stated instrument capacity of at least 70-80 lbs (approx. 32-36 kg) to ensure stable, flexure-free tracking for long-exposure astrophotography.\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\u003c\/td\u003e\n\u003ctd\u003e310mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e1178mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/3.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eResolution\u003c\/td\u003e\n\u003ctd\u003e0.37\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Circle\u003c\/td\u003e\n\u003ctd\u003e55mm (Medium Format)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Mirror Type\u003c\/td\u003e\n\u003ctd\u003eAspherical\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Mirror Diameter\u003c\/td\u003e\n\u003ctd\u003e184mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector Type\u003c\/td\u003e\n\u003ctd\u003eTriplet design (with one ED glass element)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eCarbon Fiber\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Outer Diameter\u003c\/td\u003e\n\u003ctd\u003e378mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e721mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGross Weight\u003c\/td\u003e\n\u003ctd\u003e23.5kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRear Thread Adapters\u003c\/td\u003e\n\u003ctd\u003eM68, M54, M48 (with M48x0.75 filter thread)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBack Focus Range\u003c\/td\u003e\n\u003ctd\u003eSupports 38-66mm\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\/SharpStar_SCA310_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":"SharpStar Optics","offers":[{"title":"Default Title","offer_id":52851347718429,"sku":"SSO-SCA310","price":7995.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Askar-SCA310-1_df2ed418-69a4-4967-82b4-11f294440cc2.jpg?v=1788401926","url":"https:\/\/davidastro.com\/en-us\/products\/sharpstar-sca310","provider":"David Astro","version":"1.0","type":"link"}