{"product_id":"explore-scientific-epwp7220ed-01","title":"Explore Scientific 72° ED Series 20mm Waterproof Eyepiece","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e20mm Focal Length\u003c\/li\u003e\n\u003cli\u003e72° Apparent Field of View\u003c\/li\u003e\n\u003cli\u003e1.25\" Barrel Diameter\u003c\/li\u003e\n\u003cli\u003eWaterproof \u0026amp; Gas-Purged Construction\u003c\/li\u003e\n\u003cli\u003eExtra-Low Dispersion (ED) Glass\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\u003eExplore Scientific 72° ED Series 20mm Waterproof Eyepiece\u003c\/h2\u003e\n      \u003cp\u003eThe Explore Scientific 72° ED Series 20mm Waterproof Eyepiece combines an immersive 72° apparent field of view with color-faithful Extra-Low Dispersion (ED) glass in a versatile 1.25\" barrel. This 20mm focal length serves as an ideal low-to-mid power scanning eyepiece, delivering bright, expansive views of large celestial objects and rich star fields.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eThe 72° ED Glass Advantage: Chromatic Aberration Control\u003c\/h3\u003e\n      \u003cp\u003eThis eyepiece's optical design centers on Extra-Low Dispersion (ED) glass to minimize chromatic aberration—the false color fringing seen on bright objects like stars and planetary limbs. By correcting for this distortion, the 20mm ED eyepiece produces sharper, higher-contrast images with more natural color rendition across its entire 72° apparent field.\u003c\/p\u003e\n      \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003eHigh-Contrast Views:\u003c\/strong\u003e Suppressing false color results in a darker sky background and makes faint details in nebulae and galaxies easier to discern.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eEdge-to-Edge Sharpness:\u003c\/strong\u003e The ED element helps maintain tight, point-like stars even at the edge of the wide 72° field, creating a more cohesive and immersive viewing experience.\u003c\/li\u003e\n      \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n    \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n      \u003ch3\u003eAll-Weather Scanning: A Waterproof 20mm Eyepiece\u003c\/h3\u003e\n      \u003cp\u003eEngineered for reliability in the field, the 72° ED 20mm eyepiece is fully waterproof and gas-purged. This prevents internal fogging during nights with heavy dew and protects the internal lens coatings from moisture and fungus, ensuring long-term durability.\u003c\/p\u003e\n        \u003cp\u003eThis robust construction, combined with a comfortable eye relief, makes it a workhorse eyepiece for extended observing sessions. Its primary role as a 20mm low-power eyepiece makes it perfect for locating objects and scanning the Milky Way, where changing temperatures and dew are common challenges.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"DAV-bg-light\"\u003e\n    \u003cdiv class=\"DAV-section\"\u003e\n        \u003ch3\u003e72° ED vs. 50° Plössl: A Wider Context for Deep Sky Objects\u003c\/h3\u003e\n        \u003cp\u003eA standard 20mm Plössl eyepiece typically offers a 50-52° apparent field of view. While effective, this narrower field can feel restrictive when viewing large-scale structures. The Explore Scientific 72° ED 20mm eyepiece provides a dramatically larger window on the sky.\u003c\/p\u003e\n        \u003cul\u003e\n            \u003cli\u003e\n\u003cstrong\u003eFraming Large Targets:\u003c\/strong\u003e The 72° field allows you to frame entire objects like the Pleiades (M45) or the Andromeda Galaxy (M31) within a single view, which is often impossible with a standard Plössl at the same magnification.\u003c\/li\u003e\n            \u003cli\u003e\n\u003cstrong\u003eImmersive Experience:\u003c\/strong\u003e The wider field of view enhances the sense of \"space-walking,\" making deep-sky observing more engaging by revealing the surrounding star fields that give context to the main object.\u003c\/li\u003e\n        \u003c\/ul\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\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 is the main advantage of the Explore Scientific 72° ED 20mm eyepiece?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eIts primary advantage is the combination of a \u003cstrong\u003ewide 72° apparent field of view\u003c\/strong\u003e with \u003cstrong\u003eExtra-Low Dispersion (ED) glass\u003c\/strong\u003e. This pairing delivers an immersive, expansive view that is also sharp and free of distracting false color (chromatic aberration), making it ideal for high-contrast deep-sky observing.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the ED glass in the 20mm eyepiece improve the view?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003e\u003cstrong\u003eED glass\u003c\/strong\u003e significantly reduces chromatic aberration, which is the color fringing (often purple or blue) seen around bright stars and the edge of the Moon. By correcting this, the eyepiece produces truer colors, higher contrast, and sharper images from the center to the edge of the field.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eIs the Explore Scientific 20mm ED eyepiece good for planetary viewing?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eWhile the ED glass provides excellent color correction, a 20mm focal length typically provides low-to-medium power, which is not ideal for detailed planetary observation. It is primarily designed for sweeping star fields and viewing large deep-sky objects. For high-magnification planetary views, you would need to pair this eyepiece with a high-quality Barlow lens.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eHow will the 72° field of the 20mm eyepiece help when observing large open clusters like the Pleiades (M45)?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe expansive 72° field of view allows you to see the entire Pleiades star cluster (M45) at once, including its surrounding nebulosity, in most telescopes. A standard eyepiece with a narrower field would require you to pan around to see the full extent of the cluster, losing the impressive context of the object as a whole.\u003c\/p\u003e\n  \u003c\/div\u003e\n    \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWith an 8-inch f\/10 SCT, what can I expect from the Explore Scientific 20mm ED eyepiece?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eIn a typical 8\" f\/10 Schmidt-Cassegrain Telescope (2000mm focal length), the 20mm eyepiece will provide \u003cstrong\u003e100x magnification\u003c\/strong\u003e. This is an excellent medium-power magnification for this type of telescope, perfect for framing globular clusters like M13, resolving details in larger nebulae like the Orion Nebula (M42), and exploring the star clouds of the Milky Way.\u003c\/p\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion\"\u003e\n    \u003ch3 class=\"DAV-accordion-Q\"\u003eWhat does 'waterproof' mean for the Explore Scientific 72° ED 20mm eyepiece?\u003c\/h3\u003e\n  \u003c\/div\u003e\n  \u003cdiv class=\"DAV-accordion-A\"\u003e\n    \u003cp\u003eThe waterproof and gas-purged construction means the eyepiece is sealed against the elements. This prevents moisture, dew, and dust from getting inside the eyepiece, which prevents internal fogging and protects the lens coatings from damage over time. It ensures reliable performance even in damp observing conditions.\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 Length\u003c\/td\u003e\n\u003ctd\u003e20mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eApparent Field of View\u003c\/td\u003e\n\u003ctd\u003e72°\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eBarrel Diameter\u003c\/td\u003e\n\u003ctd\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eLens Construction\u003c\/td\u003e\n\u003ctd\u003eExtra-Low Dispersion (ED) Glass\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eWaterproof\u003c\/td\u003e\n\u003ctd\u003eYes, Gas-Purged\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/li\u003e\n\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\"\u003e72° ED Series 20mm Waterproof 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\n\u003cul class=\"DAV-grid\"\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/explore-scientific-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eExplore Scientific Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":52909353173277,"sku":"ES-EPWP7220ED-01","price":420.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/ExploreScientific-72-ED-Series-20mm-Waterproof-Eyepiece-1_8291e35d-79c6-401e-b2b0-fa8488abcd14.jpg?v=1789061404","url":"https:\/\/davidastro.com\/products\/explore-scientific-epwp7220ed-01","provider":"David Astro","version":"1.0","type":"link"}