{"product_id":"starizona-nexus-75x-reducer-coma-corrector","title":"Starizona Nexus 0.75x Newtonian Focal Reducer\/Coma Corrector","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eFocal Reduction:\u003c\/strong\u003e 0.75x\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorrected Image Circle:\u003c\/strong\u003e 28mm (APS-C Format)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRequired Backfocus:\u003c\/strong\u003e 55mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBarrel Size:\u003c\/strong\u003e 2\"\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCamera Connection:\u003c\/strong\u003e M48 x 0.75 Threads\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilter Threads:\u003c\/strong\u003e M48 (2\")\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\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\u003eStarizona Nexus 0.75x Newtonian Focal Reducer\/Coma Corrector\u003c\/h2\u003e\n\u003cp\u003eThe Starizona Nexus 0.75x Newtonian Focal Reducer\/Coma Corrector transforms your Newtonian into a dedicated astrograph, delivering both a wider field and sharper stars from edge to edge across its 28mm image circle. This dual-purpose optic provides a 0.75x focal reduction while correcting coma, fitting into any standard 2\" focuser and maintaining the common 55mm backfocus distance for modern cameras.\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\u003e0.75x Reduction: Transform Your f\/4 Newtonian into an f\/3 Astrograph\u003c\/h3\u003e\n\u003cp\u003eMost coma correctors maintain a telescope's native focal ratio. The Starizona Nexus accelerates it. The 0.75x reduction factor converts a standard f\/4 imaging Newtonian into a faster f\/3 system, widening your field of view and gathering light 1.8 times faster. This significant reduction in exposure time allows you to capture more data on faint nebulae and galaxies in a single night.\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 28mm Coma-Free Image Circle for APS-C Sensors\u003c\/h3\u003e\n\u003cp\u003eEngineered with extra-low dispersion (ED) glass, the Nexus delivers a flat, coma-free field across a 28mm image circle. This is perfectly matched to the APS-C sensors found in many popular DSLR, mirrorless, and dedicated astronomy cameras, ensuring pinpoint stars across the entire frame without vignetting. The optical design provides professional-grade correction for Newtonians as fast as f\/3.\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\u003eStandard 55mm Backfocus and M48 Threads\u003c\/h3\u003e\n\u003cp\u003eThe Nexus integrates seamlessly into standard imaging trains. It requires 55mm of backfocus from the corrector's M48 x 0.75 male threads to your camera sensor, a distance compatible with DSLRs using a standard T-ring and most CMOS\/CCD camera setups with extension tubes. The telescope side of the 2\" barrel features M48 threads for mounting 2\" filters, while a removable outer lip allows the unit to be seated deeper in the focuser or attached directly via optional threaded adapters.\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\u003eUnderstanding the Parfocal Design and 55mm Requirement\u003c\/h3\u003e\n\u003cp\u003eThe Nexus is designed to be parfocal, meaning it does not shift your telescope's native focal point. If your camera can achieve focus in your Newtonian without the Nexus, it will also reach focus with it. However, this comes with a critical caveat: the entire imaging train, including the Nexus, must maintain 55mm of spacing between the corrector and the sensor.\u003c\/p\u003e\n\u003cp\u003eThis requirement is the primary limiting factor. While most f\/4 Newtonians designed for imaging have ample backfocus, many visual Newtonians (often f\/5 or slower) may not have enough inward focuser travel to accommodate a camera at the required 55mm distance. Always verify your telescope has sufficient backfocus before use.\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\u003eStarizona Nexus vs. Standard 1.0x Coma Correctors\u003c\/h3\u003e\n\u003cp\u003eWhile a high-quality 1.0x coma corrector provides a larger corrected field and maintains your telescope's native image scale for maximum resolution on small targets, it does not reduce your exposure time. The Nexus offers a different set of advantages for wide-field imagers.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose a 1.0x Corrector for:\u003c\/strong\u003e Maximum image scale on galaxies and planetary nebulae; use with full-frame sensors that exceed the Nexus's 28mm image circle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChoose the Starizona Nexus for:\u003c\/strong\u003e Capturing large nebulae, maximizing data acquisition speed with its 0.75x reduction, and turning an f\/4 scope into a faster f\/3 system.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does the Starizona Nexus do for my f\/4 Newtonian?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe Starizona Nexus serves two functions: it corrects coma for sharp stars across the field and reduces the focal ratio by a factor of 0.75x. This makes your f\/4 telescope an f\/3 system, giving you a wider field of view and cutting your exposure times nearly in half (a 1.8x speed increase).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWill the Starizona Nexus work with my full-frame camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo, the Starizona Nexus is not recommended for full-frame sensors. It is designed to produce a corrected \u003cstrong\u003e28mm image circle\u003c\/strong\u003e, which is ideal for APS-C and smaller sensors. A full-frame sensor (typically 42-44mm diagonal) would show significant coma and vignetting in the corners.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow do I achieve the 55mm backfocus with the Starizona Nexus?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe 55mm distance is measured from the base of the M48 threads on the camera side of the Nexus to your camera's sensor. This is a standard distance for most imaging correctors. You can achieve it using a DSLR with a standard 48mm T-ring, or with a dedicated astronomy camera by using a combination of M48 extension rings to make up the required distance.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Starizona Nexus truly parfocal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, in the sense that it doesn't change the telescope's focus position. However, it still requires 55mm of spacing between itself and the camera sensor. Many visual Newtonians lack the focuser in-travel to accommodate this 55mm distance, even though the corrector itself is parfocal. It is primarily designed for imaging Newtonians that have ample backfocus available.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWith an 8\" f\/4 imaging Newtonian, how will the Nexus change my images of the Andromeda Galaxy (M31)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAn 8\" (200mm) f\/4 Newtonian has a focal length of 800mm. With the 0.75x Nexus, this becomes a 600mm f\/3 system. This wider, faster configuration will allow you to frame the entirety of the Andromeda Galaxy (M31) and its companions M32 and M110 more easily on an APS-C sensor, while capturing the faint outer dust lanes with significantly shorter exposures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eMy 10\" f\/5 Dobsonian has limited backfocus. Can I use the Starizona Nexus for imaging?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eIt is unlikely. Most visual telescopes like Dobsonians are not designed with the extra backfocus needed for photographic correctors. The Starizona Nexus requires your camera sensor to be placed 55mm behind it, and a typical Dobsonian focuser cannot rack in far enough to bring this configuration to focus. This corrector is intended for Newtonians built specifically for astrophotography.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Reduction Factor\u003c\/td\u003e\n\u003ctd\u003e0.75x\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCorrected Image Circle\u003c\/td\u003e\n\u003ctd\u003e28mm (APS format)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRequired In-Focus Travel\u003c\/td\u003e\n\u003ctd\u003eNone (parfocal)*\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackfocus from Corrector\u003c\/td\u003e\n\u003ctd\u003e55mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCamera Side Threads\u003c\/td\u003e\n\u003ctd\u003eM48 x 0.75\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTelescope Side Filter Threads\u003c\/td\u003e\n\u003ctd\u003eM48 (for 2\" mounted filters)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel Size\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOverall Length\u003c\/td\u003e\n\u003ctd\u003e3.14\" (80mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.74 lbs (335g)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/starizona-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eStarizona Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Starizona","offers":[{"title":"Default Title","offer_id":68033922793757,"sku":"STZ-NEXUS-075","price":449.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/Starizona-Nexus-0-75x-Newtonian-Focal-Reducer-Coma-Corrector-1_075c64af-8ca3-44f9-b2b4-f913ec6f1704.jpg?v=1794375582","url":"https:\/\/davidastro.com\/en-int\/products\/starizona-nexus-75x-reducer-coma-corrector","provider":"David Astro","version":"1.0","type":"link"}