{"product_id":"svbony-sv191-7-2-21-6mm-zoom-eyepiece-125in","title":"SVBONY SV191 7.2-21.6mm Zoom Eyepiece - 1.25\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e7.2mm to 21.6mm Zoom Focal Length\u003c\/li\u003e\n\u003cli\u003e42° to 65° Apparent Field of View\u003c\/li\u003e\n\u003cli\u003e18mm to 20mm Long Eye Relief\u003c\/li\u003e\n\u003cli\u003eStandard 1.25\" Barrel Diameter\u003c\/li\u003e\n\u003cli\u003eLightweight 167g Construction\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\u003eSVBONY SV191 7.2-21.6mm Zoom Eyepiece - 1.25\"\u003c\/h2\u003e\n\u003cp\u003eThe SVBONY SV191 Zoom Telescope Eyepiece replaces a case full of eyepieces with a single, versatile unit, offering a continuous 7.2mm to 21.6mm focal length range in a standard 1.25\" barrel. Its 7-element, 4-group optical system delivers an apparent field of view that expands from 42° to a wide 65° as you zoom out. With a generous 18-20mm of eye relief and a net weight of only 167g, it provides comfortable, fatigue-free viewing sessions without creating balance issues on your telescope.\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\u003eA 3x Zoom Range: 7.2mm to 21.6mm in One Eyepiece\u003c\/h3\u003e\n\u003cp\u003eThe core of the SV191 is its ability to adjust magnification instantly. Start at the 21.6mm setting for a low-power, wide-field view to easily locate your target, then simply twist the barrel to zoom in to 7.2mm for high-power views of planetary details or tight double stars. This eliminates the need to swap eyepieces, saving time and reducing the chance of dropping accessories in the dark.\u003c\/p\u003e\n\u003cp\u003eThis all-in-one design is ideal for public outreach, introducing beginners to astronomy, or for \"grab-and-go\" setups where minimizing gear is a priority. The smooth zoom mechanism allows you to perfectly frame objects like the Moon or match the magnification to changing atmospheric seeing conditions without ever taking your eye from the telescope.\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\u003e42°-65° Field with 7-Element, Multi-Coated Optics\u003c\/h3\u003e\n\u003cp\u003eThe SV191's apparent field of view dynamically changes as you zoom, offering a wide 65° at the 21.6mm setting and a more focused 42° at 7.2mm. The 7-element, 4-group lens structure is fully multi-coated to maximize light transmission and contrast. Blackened lens edges further suppress internal reflections, ensuring the background sky remains dark and object details stand out.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFully Multi-Coated Lenses:\u003c\/strong\u003e Increases brightness and contrast compared to single-coated or uncoated optics, which is critical for resolving faint details.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e16mm Field Stop:\u003c\/strong\u003e Defines the sharp edge of the field at the lowest magnification, providing a clean boundary for your view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eM28.5*0.6 Filter Threads:\u003c\/strong\u003e The standard 1.25\" filter thread allows you to easily add planetary, nebula, or moon filters to enhance your observations.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e18-20mm Eye Relief and a 167g Lightweight Body\u003c\/h3\u003e\n\u003cp\u003eComfort is essential for extended observing, and the SV191 delivers with 18-20mm of long eye relief across its entire zoom range. This makes it an excellent choice for eyeglass wearers, who can see the entire field of view without having to press their glasses against the lens. A metal, twist-up eyecup allows non-eyeglass wearers to find the perfect eye position and helps block stray light.\u003c\/p\u003e\n\u003cp\u003eAt just 167g (5.87oz), the SV191 is exceptionally lightweight for a zoom eyepiece. This minimizes the need to rebalance your telescope when changing magnifications, a common issue when switching between small and large fixed-focal-length eyepieces. Its compact form factor makes it an easy addition to any accessory case.\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\u003eSV191 Zoom vs. Fixed Plössls: Convenience vs. Field of View\u003c\/h3\u003e\n\u003cp\u003eWhile a set of individual Plössl eyepieces might offer slightly sharper edge performance, the SV191 provides a level of convenience that is unmatched. The primary trade-off is often in the field of view at lower powers.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFixed Eyepieces Advantage:\u003c\/strong\u003e A typical 20mm Plössl eyepiece has a 50°-52° AFOV. At its 21.6mm setting, the SV191 offers a wider 65° field, bucking the typical trend for zoom eyepieces. However, at the high-power end, the SV191's 42° field is narrower than the ~52° of a standalone 7mm Plössl.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSV191 Zoom Advantage:\u003c\/strong\u003e You get every magnification between 7.2mm and 21.6mm, allowing you to fine-tune your view perfectly. It's lighter, more compact, and more cost-effective than buying three or four separate eyepieces to cover the same range. For lunar, planetary, and solar observing, the ability to quickly adjust magnification is a significant practical benefit.\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\"\u003eHow does the SVBONY SV191 perform on the Moon with an 8\" Dobsonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV191 is an excellent lunar eyepiece for an 8\" f\/6 Dobsonian. At 21.6mm, you can frame the entire lunar disc. You can then zoom in smoothly to the 7.2mm setting for high-power views of specific craters like Copernicus or the rilles near Plato, all without changing eyepieces, which is a major convenience on a manually-tracked scope.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the SV191 to find and zoom in on the Orion Nebula (M42)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. You would start at the 21.6mm setting, which provides the lowest magnification and widest field of view (65°) to easily locate and center the Orion Nebula (M42). Once centered, you can twist the eyepiece to increase magnification, allowing you to resolve the four stars of the Trapezium cluster at the nebula's core.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the SVBONY SV191 eyepiece need to be refocused after zooming?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV191 is largely par-focal, meaning it should hold focus reasonably well across its zoom range. However, slight changes in your telescope's focus or your own eye may require minor adjustments with the focuser knob after a large change in magnification for optimal sharpness.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 18-20mm eye relief on the SV191 comfortable for eyeglass wearers?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAbsolutely. The \u003cstrong\u003e18-20mm eye relief\u003c\/strong\u003e is considered very long and is a key feature of this eyepiece. It allows users who wear glasses for astigmatism to see the entire apparent field of view comfortably without removing their spectacles. The twist-up eyecup also helps set the proper distance for those who do not wear glasses.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use standard 1.25\" filters with the SV191 zoom eyepiece?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The barrel of the SVBONY SV191 is threaded for standard 1.25\" astronomical filters (\u003cstrong\u003eM28.5*0.6 thread standard\u003c\/strong\u003e). You can easily attach color filters for planetary viewing, a moon filter to reduce glare, or a light pollution filter for observing nebulae.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs a zoom eyepiece like the SV191 good for planetary viewing?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, it's very practical for planets. Atmospheric \"seeing\" can change from moment to moment. A zoom eyepiece allows you to instantly dial back the magnification when the view gets blurry and push it higher during moments of steady air to catch fine detail on Jupiter or Saturn, without fumbling for different eyepieces in the dark.\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\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e7.2mm - 21.6mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApparent Field of View\u003c\/td\u003e\n\u003ctd\u003e42° - 65°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEye Relief\u003c\/td\u003e\n\u003ctd\u003e18mm - 20mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLens Structure\u003c\/td\u003e\n\u003ctd\u003e7-Elements \/ 4-Groups\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eField Stop Diameter\u003c\/td\u003e\n\u003ctd\u003e16mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Threads\u003c\/td\u003e\n\u003ctd\u003eM28.5 x 0.6 (Standard 1.25\")\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eFully Multi-Coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBlackened Lens Edges\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyecup Type\u003c\/td\u003e\n\u003ctd\u003eTwist-Up\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyecup Material\u003c\/td\u003e\n\u003ctd\u003eMetal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet Weight\u003c\/td\u003e\n\u003ctd\u003e167g \/ 5.87oz \/ 0.367lb\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\"\u003eSVBONY SV191 7.2-21.6mm Zoom Eyepiece\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\n\u003cli\u003e\u003ca href=\"https:\/\/davidastro.com\/pages\/svbony-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eSVBONY Warranty Policy\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SVBONY","offers":[{"title":"Default Title","offer_id":52861232152861,"sku":"SV-W9150A","price":94.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV191-Zoom-Telescope-Eyepiece-Super-Wide-Angle-Black-1-25inch-1_2e8768ee-ce59-4ea3-8570-274a874431af.jpg?v=1788659823","url":"https:\/\/davidastro.com\/products\/svbony-sv191-7-2-21-6mm-zoom-eyepiece-125in","provider":"David Astro","version":"1.0","type":"link"}