{"product_id":"svbony-sv198-50mm-mini-guide-scope","title":"SVBONY SV198 50mm Mini Guide Scope","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e50mm Aperture\u003c\/li\u003e\n\u003cli\u003e206.6mm Focal Length (f\/4.1)\u003c\/li\u003e\n\u003cli\u003eDual Helical Focuser with 12mm Travel\u003c\/li\u003e\n\u003cli\u003e1.25\" and T2 Thread Connections\u003c\/li\u003e\n\u003cli\u003eIncludes 45mm T2 Extension Tube\u003c\/li\u003e\n\u003cli\u003eVixen-Style Mounting Base\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 SV198 50mm Mini Guide Scope Finder\u003c\/h2\u003e\n\u003cp\u003eThe Svbony SV198 guide scope combines a bright 50mm f\/4.1 optical system with a precise dual helical focuser to deliver reliable, accurate autoguiding for long-exposure astrophotography. Its 206.6mm focal length provides an ideal image scale for guiding long-focal-length telescopes, while the entire aluminum package weighs just 557g. The focuser offers 12mm of fine adjustment, ensuring your guide camera achieves critical focus without rotation or flexure.\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\u003e50mm f\/4.1 Optics: Brighter Guide Stars, Better Tracking\u003c\/h3\u003e\n\u003cp\u003eThe SV198's 50mm aperture gathers significantly more light than smaller 30mm guide scopes, allowing your guide camera to detect fainter stars in any given field of view. This is a critical advantage when imaging in light-polluted skies or targeting areas of the sky with few bright stars. The 2-element achromat lens is fully multi-coated with blackened lens edges to maximize contrast, ensuring your software locks onto sharp, high-contrast stars for sub-pixel guiding accuracy.\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\u003eDual Helical Focuser: 12mm of Precise, No-Flex Focus Travel\u003c\/h3\u003e\n\u003cp\u003eAchieving and holding perfect focus is non-negotiable for autoguiding. The SV198 features a dual-action focuser that combines a sliding drawtube for coarse adjustment with a fine-threaded helical focuser for the final, critical turn. This design provides 12mm of precise focusing stroke and, unlike simple drawtube focusers, does not rotate the attached camera, preserving your guide star calibration. The result is a rigid, repeatable focus that won't shift during an imaging session.\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\u003eFlexible Back Focus: Adapting for Cameras and Eyepieces\u003c\/h3\u003e\n\u003cp\u003eThe SV198 is engineered for adaptability right out of the box. It includes a 45mm T2-extension tube that provides the correct spacing to bring most modern guide cameras to focus. For visual use as a finder scope, simply remove the extension tube to achieve focus with standard 1.25\" eyepieces. This dual-purpose functionality makes it a valuable tool for both imaging and visual setups.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eGuide Camera Use:\u003c\/strong\u003e Install the included 45mm T2 extension tube to reach focus with popular guide cameras that have short back-focus requirements.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEyepiece Use:\u003c\/strong\u003e Remove the extension tube to use the SV198 as a high-quality 50mm finder scope with your favorite 1.25\" eyepieces.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSecure Mounting:\u003c\/strong\u003e The integrated bracket features a Vixen-standard dovetail bar for direct attachment to most telescope saddles and adapters.\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\u003eSV198 50mm vs. 30mm Guide Scopes: Why Aperture Matters\u003c\/h3\u003e\n\u003cp\u003eWhile smaller guide scopes are lighter, the SV198's 50mm aperture offers a distinct advantage in light-gathering power. This translates directly to a greater selection of usable guide stars, which is crucial for the success of your autoguiding. More available stars mean your software can use multi-star guiding for higher accuracy and is less likely to lose its lock if a single star is momentarily obscured by clouds.\u003c\/p\u003e\n\u003cp\u003eThe trade-off for this capability is a modest increase in weight to 557g. However, for imagers using Schmidt-Cassegrains, Ritchey-Chrétiens, or refractors over 1000mm in focal length, the improved guiding reliability from a brighter guide scope far outweighs the added mass.\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\"\u003eHow does the SV198 help when guiding a long focal length SCT on a faint galaxy like the Pinwheel Galaxy (M101)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eFor a target like M101, which is in a star field that can be sparse, the \u003cstrong\u003e50mm aperture\u003c\/strong\u003e of the SV198 is a major asset. It pulls in fainter stars than a smaller guide scope, giving your guiding software more options to lock onto. This ensures consistent, accurate tracking throughout a long imaging session required for faint galaxies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use the Svbony SV198 as a finder scope with an eyepiece on my 8\" Dobsonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. By removing the included \u003cstrong\u003e45mm T2-extension tube\u003c\/strong\u003e, the SV198 is configured to reach focus with standard 1.25\" eyepieces. Its 206.6mm focal length will give you a wide field of view, making it an excellent optical finder. You would just need a Vixen-style saddle on your telescope to mount it.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I achieve focus with the SV198 using a guide camera versus an eyepiece?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV198 is designed for both. For most guide cameras, you will need to install the included \u003cstrong\u003e45mm T2-extension tube\u003c\/strong\u003e between the focuser and the camera. For use with a 1.25\" eyepiece, you must remove the extension tube.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of the SV198's helical focuser?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA helical focuser provides fine, precise focus adjustments without rotating the attached camera. This is critical for autoguiding, as it prevents you from having to recalibrate your guide software every time you touch the focus. It is a much more stable and accurate method than a simple push-pull or single-knob drawtube focuser.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat kind of telescopes can I mount the Svbony SV198 to?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SV198 comes with a mounting bracket that has a \u003cstrong\u003eVixen-standard dovetail foot\u003c\/strong\u003e. This will fit into any Vixen-style saddle, which is a common standard on many telescope rings, handles, and dedicated mounting platforms.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eAt 557g, is the SV198 too heavy for my portable setup?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eWhile the SV198 is heavier than ultra-light 30mm guide scopes, its \u003cstrong\u003e557g (1.23 lbs)\u003c\/strong\u003e weight is still very manageable for most portable mounts rated for astrophotography (e.g., Sky-Watcher Star Adventurer GTI, iOptron SkyGuider Pro). The significant improvement in guiding from the 50mm aperture is often worth the modest weight increase for achieving sharp, long exposures.\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\u003e50mm \/ 1.97in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e206.6mm \/ 8.13in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/4.1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptics Type\u003c\/td\u003e\n\u003ctd\u003eAchromat Refractor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLens Structure\u003c\/td\u003e\n\u003ctd\u003e2-Elements \/ 1 Group\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLens Coating\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\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003eDual Helical + Telescopic Design\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocusing Stroke\u003c\/td\u003e\n\u003ctd\u003e12mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCamera\/Eyepiece Connection\u003c\/td\u003e\n\u003ctd\u003e1.25\" and T2 Thread\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting Base\u003c\/td\u003e\n\u003ctd\u003eVixen standard interface\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Material\u003c\/td\u003e\n\u003ctd\u003eAluminum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNet Weight\u003c\/td\u003e\n\u003ctd\u003e557g\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\"\u003eSV198 50mm f\/4.1 mini Guide Scope\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 Bracket with Vixen-style foot\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\"\u003e45mm T2-Extension Tube\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 Plug\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\"\u003eSilicone Objective Lens 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\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/svbony-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eSvbony 1-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SVBONY","offers":[{"title":"Default Title","offer_id":52861232840989,"sku":"SV-W9155A","price":150.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/SVBONY-SV198-50mm-Mini-Guide-Scope-Finder-with-Dual-Helical-Focuser-1_dbacade0-639a-4989-8530-ccb3d5cd9625.jpg?v=1788659903","url":"https:\/\/davidastro.com\/products\/svbony-sv198-50mm-mini-guide-scope","provider":"David Astro","version":"1.0","type":"link"}