{"product_id":"svbony-sv503-70mm-f-6-78-quadruplet-ed-flatfield-refractor-telescope-ota","title":"SVBONY SV503 70mm f\/6.78 Quadruplet ED Flatfield Refractor Telescope OTA","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e70mm Aperture Quadruplet Astrograph\u003c\/li\u003e\n\u003cli\u003e474mm Focal Length (f\/6.78)\u003c\/li\u003e\n\u003cli\u003e32mm Corrected Flat-Field Image Circle\u003c\/li\u003e\n\u003cli\u003e2.5\" Rack-and-Pinion Focuser\u003c\/li\u003e\n\u003cli\u003e127.5mm Working Distance\u003c\/li\u003e\n\u003cli\u003eFPL51 and Lanthanum ED Glass Elements\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\u003eSVBONY SV503 70mm f\/6.78 ED Flatfield Refractor\u003c\/h2\u003e\n\u003cp\u003eThe SVBONY SV503 70 refractor is a purpose-built astrograph, combining a 70mm aperture and 474mm focal length into a compact f\/6.78 optical system. Its 4-element design, featuring FPL51 and lanthanum glass, delivers a fully corrected 32mm flat-field image circle, eliminating the need for a separate flattener. Weighing just 5.9 lbs, this telescope provides a generous 127.5mm of working distance from its 2.5\" focuser for complex imaging trains.\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\u003eQuadruplet Optics: A 32mm Flat-Field Imaging Circle\u003c\/h3\u003e\n\u003cp\u003eThe SV503 70 integrates a 2-element objective with a 2-element corrector, creating a 4-element \"quadruplet\" design that corrects for field curvature internally. This system produces a 32mm diameter image circle with 100% correction, ensuring pinpoint stars across the frame of popular APS-C and smaller astronomy cameras. The use of FPL51 and lanthanum glass in the objective minimizes chromatic aberration for high-contrast images with true-to-life color.\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\u003eImaging-Ready Mechanics: 2.5\" Focuser and 127.5mm Back Focus\u003c\/h3\u003e\n\u003cp\u003eEngineered for astrophotography, the SV503 70 features a robust 2.5\" rack-and-pinion (RAP) focuser capable of supporting heavy camera packages without flexure or slippage. A critical feature for imagers is the 127.5mm (5\") of working distance available from the 2\" receptacle. This generous back focus provides ample room for adding accessories like filter wheels, off-axis guiders, and rotators into your optical train, while the M54x0.75 female thread offers a direct, secure connection.\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\u003eWide-Field Astrograph: 474mm Focal Length for Large Targets\u003c\/h3\u003e\n\u003cp\u003eWith its 474mm focal length, the SV503 70 is ideal for capturing expansive celestial objects that are too large for longer telescopes. This field of view is perfectly suited for framing the entirety of the Andromeda Galaxy (M31), the North American Nebula (NGC 7000), or vast star-forming regions in Cygnus. The f\/6.78 focal ratio provides a good balance between image scale and exposure time, making it an efficient instrument for gathering light on faint deep-sky targets.\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\u003eSV503 70 vs. a Standard ED Doublet: Integrated Flattener Advantage\u003c\/h3\u003e\n\u003cp\u003eWhile a standard 70mm ED doublet refractor may have a lower initial cost, it requires a separate field flattener to achieve the same photographic results as the SV503 70. This adds complexity and potential frustration in getting the spacing correct. The SV503's integrated quadruplet design offers a significant advantage:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo Spacing Calculation:\u003c\/strong\u003e The flattener is built-in and permanently fixed at the optimal distance. You simply attach your camera and focus.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReduced Connections:\u003c\/strong\u003e A simpler, more rigid imaging train means less potential for tilt or flexure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCost-Effective System:\u003c\/strong\u003e When factoring in the price of a quality external flattener, the SV503 70 often represents a better total value for a complete imaging setup.\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 size camera sensor is the SVBONY SV503 70 best suited for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SVBONY SV503 70 provides a fully corrected, flat-field image circle of \u003cstrong\u003e32mm\u003c\/strong\u003e. This is ideal for cameras with APS-C format sensors and any smaller sensors, ensuring sharp, pinpoint stars from corner to corner without vignetting.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the SVBONY SV503 70 for visual observing out of the box?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. This telescope is an astrograph, meaning its focus point is optimized for a camera sensor placed far behind the focuser. To use it visually with an eyepiece, you will need to add a \u003cstrong\u003ediagonal or a 2\" extension tube\u003c\/strong\u003e to achieve focus.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow would the SV503 70 frame a large target like the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe \u003cstrong\u003e474mm focal length\u003c\/strong\u003e of the SV503 70 is perfectly matched for large targets. When paired with a typical APS-C camera, it allows you to capture the entire Andromeda Galaxy (M31) and its satellite galaxies M32 and M110 in a single, well-composed frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat accessories can I connect to the SV503 70's 2.5\" focuser?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe focuser terminates in a 2\" receptacle and also has a female \u003cstrong\u003eM54x0.75 thread\u003c\/strong\u003e for direct connections. With \u003cstrong\u003e127.5mm of back focus\u003c\/strong\u003e, it provides ample space to install a complete imaging train, including:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eFilter wheels or filter drawers\u003c\/li\u003e\n\u003cli\u003eOff-axis guiders (OAGs)\u003c\/li\u003e\n\u003cli\u003eField rotators\u003c\/li\u003e\n\u003cli\u003eYour astronomy camera\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the SVBONY SV503 70 a good choice for imaging nebulae from my backyard?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. Its \u003cstrong\u003ef\/6.78 focal ratio\u003c\/strong\u003e is efficient for collecting data on faint nebulae. From a light-polluted location, pairing the SV503 70 with a duo-narrowband filter is highly effective for isolating the hydrogen-alpha and oxygen-III signals of emission nebulae like the Lagoon Nebula (M8) or the Eagle Nebula (M16).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of mount do I need for the SVBONY SV503 70?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe telescope tube and its included accessories weigh only \u003cstrong\u003e5.9 lbs (2685g)\u003c\/strong\u003e. This lightweight design makes it an excellent match for portable German equatorial mounts with a payload capacity of 10-15 lbs or more, such as a Sky-Watcher Star Adventurer GTi or similar tracker.\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\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eSVBONY\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAperture\u003c\/td\u003e\n\u003ctd\u003e70mm \/ 2.8\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e474mm \/ 18.7\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/6.78\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eObjective Type\u003c\/td\u003e\n\u003ctd\u003e2-Element ED lens with FPL51 and lanthanum special glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrector\u003c\/td\u003e\n\u003ctd\u003e2-element corrector installed in the tube\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Image Circle\u003c\/td\u003e\n\u003ctd\u003e32mm \/ 1.3\" (100% correction)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003e2.5\" RAP focuser with 2\" reduction adapter and M54x0.75 female thread\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWorking Distance\u003c\/td\u003e\n\u003ctd\u003e127.5mm \/ 5\" (from 2\" receptacle)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length (min)\u003c\/td\u003e\n\u003ctd\u003e365mm \/ 14.4\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Diameter\u003c\/td\u003e\n\u003ctd\u003e82mm \/ 3.2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDew Shield Diameter\u003c\/td\u003e\n\u003ctd\u003e93mm \/ 3.7\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Weight (incl. accessories)\u003c\/td\u003e\n\u003ctd\u003e2685g \/ 5.9lb\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\/SVBONY_SV503_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\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eSV503 70mm f\/6.78 OTA\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\"\u003e2\" to 1.25\" 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\"\u003eLens Cover\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\"\u003eTelescope Tube Rings\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1 Pair\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\"\u003eDovetail Plate\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\"\u003e1.25\" Dust Cover\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\/SVBONY_SV503_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\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/svbony-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eSVBONY Warranty Policy\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SVBONY","offers":[{"title":"Default Title","offer_id":52861225042205,"sku":"SV-F9359E","price":359.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-Flatfield-Refractor-Telescope-for-Astrophotography-SV503-70-1_8e5ac16e-a3b5-434c-af5c-80477adf5d6c.jpg?v=1788884053","url":"https:\/\/davidastro.com\/fr-us\/products\/svbony-sv503-70mm-f-6-78-quadruplet-ed-flatfield-refractor-telescope-ota","provider":"David Astro","version":"1.0","type":"link"}