{"title":"William Optics SPL and SWAN Eyepieces","description":"\u003cp\u003eWilliam Optics SPL and SWAN eyepieces cover two different jobs at the eyepiece. The SPL 55° 12.5mm is a 1.25\" eyepiece with a moderate apparent field, useful for medium to high magnification on the Moon, planets and double stars.\u003c\/p\u003e\u003cp\u003eThe SWAN 72° 40mm is a 2\" wide-field eyepiece with a long focal length, made for low-power views of large star clusters and nebulae. Together they make a simple two-eyepiece set for a refractor.\u003c\/p\u003e","products":[{"product_id":"william-optics-spl-55-12-5mm-eyepiece-1-25","title":"William Optics SPL 55° 12.5mm Eyepiece - 1.25\"","description":"\u003cul\u003e\n\t\u003cli\u003e\n1.25-inch eyepiece with 55° apparent field of view\n\t\u003c\/li\u003e\n\t\u003cli\u003e\n12.5mm focal length for medium-high magnification viewing\n\t\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\t\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cul class=\"tabs-content\"\u003e\n\t\u003cli class=\"active\"\u003e\n\t\t\u003cp\u003e\nThe William Optics SPL 55° 12.5mm Eyepiece is a high-quality optical accessory designed for astronomical telescopes. This eyepiece offers a comfortable 55-degree apparent field of view, providing clear and detailed views of celestial objects. With its 12.5mm focal length, it's well-suited for medium to high magnification observations of planets, lunar features, and compact deep-sky objects.\n\t\t\u003c\/p\u003e\n\t\t\u003cdiv class=\"warning\"\u003e\n\t\t\t\u003cimg alt=\"Disclaimer\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/warning-logo.svg?v=1714663206\" width=\"25px\"\u003e\n\t\t\t\u003cp\u003e\nDesigned for use with telescopes that accept 1.25-inch eyepieces. Ensure your telescope is compatible before purchasing.\n\t\t\t\u003c\/p\u003e\n\t\t\u003c\/div\u003e\n\t\t\n\t\t\u003cdiv\u003e\n\t\t\t\u003ch3\u003e\nOptical Design\n\t\t\t\u003c\/h3\u003e\n\t\t\t\u003chr\u003e\n\t\t\t\u003cdiv class=\"two-columns-section\"\u003e\n\t\t\t\t\u003cdiv class=\"text-side-2\"\u003e\n\t\t\t\t\t\u003cp\u003e\nIncorporates a sophisticated multi-element design optimized for sharp, high-contrast views. The SPL (Super Planetary Long Eye Relief) series is specifically engineered to provide excellent performance for planetary and lunar observations.\n\t\t\t\t\t\u003c\/p\u003e\n\t\t\t\t\u003c\/div\u003e\n\t\t\t\t\u003cdiv class=\"image-side-2\" data-mce-style=\"text-align: start;\" style=\"text-align: start;\"\u003e\n\t\t\t\t\t\u003cimg alt=\"William Optics SPL 55° 12.5mm Eyepiece - 1.25 inch front view\" src=\"https:\/\/davidastro.com\/cdn\/shop\/products\/William-Optics-SPL-12-5mm-Eyepiece-1-25-inch-E-SPL12.5-1__41551.1596133255.1280.1280_832x832.jpg?v=1684339438\" style=\"margin-bottom: 16px; float: none;\"\u003e\n\t\t\t\t\u003c\/div\u003e\n\t\t\t\u003c\/div\u003e\n\n\t\t\t\u003cdiv data-mce-style=\"backgroundcolor: #0a0001; border-radius: 5px;\" style=\"background-color: #0a0001; border-radius: 5px;\"\u003e\n\t\t\t\t\u003ch3 style=\"color: white!important;\"\u003e\nField of View\n\t\t\t\t\u003c\/h3\u003e\n\t\t\t\t\u003chr\u003e\n\t\t\t\t\u003cdiv class=\"two-columns-section\"\u003e\n\t\t\t\t\t\u003cdiv class=\"image-side-2\" data-mce-style=\"text-align: start;\" style=\"text-align: start;\"\u003e\n\t\t\t\t\t\t\u003cimg alt=\"William Optics SPL 55° 12.5mm Eyepiece - 1.25 inch side view\" src=\"https:\/\/davidastro.com\/cdn\/shop\/products\/William-Optics-SPL-12-5mm-Eyepiece-1-25-inch-E-SPL12.5-2__64331.1596133255.1280.1280_832x832.jpg?v=1684339438\" style=\"margin-bottom: 16px; float: none;\"\u003e\n\t\t\t\t\t\u003c\/div\u003e\n\t\t\t\t\t\u003cdiv class=\"text-side-2\"\u003e\n\t\t\t\t\t\t\u003cp style=\"color: white!important;\"\u003e\nFeatures a 55-degree apparent field of view, offering a comfortable and immersive observing experience. This field of view balances a sense of spatial context with the ability to concentrate on fine details, making it particularly suitable for planetary and lunar observations.\n\t\t\t\t\t\t\u003c\/p\u003e\n\t\t\t\t\t\u003c\/div\u003e\n\t\t\t\t\u003c\/div\u003e\n\t\t\t\u003c\/div\u003e\n\t\t\u003c\/div\u003e\n\n\t\t\u003ch3\u003eFocal Length: \u003c\/h3\u003e\n\t\t\u003chr\u003e\n\t\t\u003cp\u003e\nWith a 12.5mm focal length, this eyepiece provides medium to high magnification, depending on the telescope's focal length. It's excellent for detailed observations of lunar craters, planetary features, double stars, and compact deep-sky objects like globular clusters.\n\t\t\u003c\/p\u003e\n\t\t\n\t\t\u003ch3\u003e\nEye Relief\n\t\t\u003c\/h3\u003e\n\t\t\u003chr\u003e\n\t\t\u003cp\u003e\nOffers generous eye relief, allowing for comfortable viewing, especially beneficial for eyeglass wearers. The \"Long Eye Relief\" design of the SPL series ensures a relaxed and strain-free observing experience, even during extended viewing sessions.\n\t\t\u003c\/p\u003e\n\t\t\n\t\t\u003ch3\u003e\nConstruction\n\t\t\u003c\/h3\u003e\n\t\t\u003chr\u003e\n\t\t\u003cp\u003e\nCrafted with high-quality materials, including a durable metal housing and a soft rubber eye guard for comfort. The 1.25-inch barrel ensures compatibility with a wide range of telescopes and accessories.\n\t\t\u003c\/p\u003e\n\n\t\t\u003ch3\u003e\nCoatings\n\t\t\u003c\/h3\u003e\n\t\t\u003chr\u003e\n\t\t\u003cp\u003e\nFeatures multi-layer anti-reflection coatings on all air-to-glass surfaces to maximize light transmission and reduce glare. This ensures high-contrast views with accurate color rendition, critical for planetary and lunar observations.\n\t\t\u003c\/p\u003e\n\n\t\t\u003ch3\u003e\nVersatility\n\t\t\u003c\/h3\u003e\n\t\t\u003chr\u003e\n\t\t\u003cp\u003e\nWhile optimized for planetary and lunar viewing, this eyepiece is versatile enough for various astronomical applications. Its moderate magnification and comfortable field of view make it suitable for observing a wide range of celestial objects, from planets and double stars to brighter deep-sky objects.\n\t\t\u003c\/p\u003e\n\n\t\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":44967224901917,"sku":"WO-E-SPL12.5","price":156.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/William-Optics-SPL-12-5mm-Eyepiece-1-25-inch-E-SPL12.5-1__41551.1596133255.1280.1280.jpg?v=1684339438"},{"product_id":"william-optics-swan-72-40mm-eyepiece-2","title":"William Optics SWAN 72° 40mm Eyepiece - 2\"","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e40mm Focal Length\u003c\/li\u003e\n\u003cli\u003e72° Apparent Field of View\u003c\/li\u003e\n\u003cli\u003e2\" Diameter Barrel\u003c\/li\u003e\n\u003cli\u003e28mm Long Eye Relief\u003c\/li\u003e\n\u003cli\u003eParfocal Design\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\u003eWilliam Optics SWAN 72° 40mm Eyepiece - 2\"\u003c\/h2\u003e\n\u003cp\u003eThe William Optics SWAN 40mm Eyepiece delivers an expansive 72° apparent field of view in a 2\" barrel, providing the immersive \"spacewalk\" experience typically associated with much more expensive designs. With a generous 28mm of eye relief, this eyepiece makes it possible to scan the Milky Way's star fields and frame large nebulae in their entirety, all while maintaining complete viewing comfort.\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 72° Spacewalk: Rich-Field Views in a 2\" Barrel\u003c\/h3\u003e\n\u003cp\u003eDesigned as a definitive rich-field eyepiece, the SWAN 40mm transforms your telescope into a wide-angle window on the universe. The 72° apparent field is substantially larger than a standard Plössl, allowing you to fit entire open clusters like the Pleiades (M45) or the sprawling structure of the North American Nebula (NGC 7000) into a single, breathtaking view.\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\u003e28mm of Eye Relief: Unmatched Comfort for All Observers\u003c\/h3\u003e\n\u003cp\u003eThe SWAN 40mm features an extremely long 28mm of eye relief, a critical specification for comfortable observing sessions. This generous distance allows you to see the entire 72° field without pressing your eye against the lens, making it an ideal choice for observers who wear eyeglasses to correct for astigmatism. You can simply relax and take in the full, unobstructed panorama.\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\u003eContrast-Optimized Design: Fully Blackened Internals for 0 Ghosting\u003c\/h3\u003e\n\u003cp\u003eTo ensure the wide field of view is not compromised by stray light, the SWAN 40mm is engineered for maximum contrast. Fully multicoated lenses provide excellent light transmission, while all internal lens edges and spacers are thoroughly blackened. This meticulous attention to detail eliminates internal reflections, preventing ghosting and flaring when observing bright objects like Jupiter or the Moon.\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\u003eSWAN 40mm vs. a 40mm Plössl: A Wider Perspective\u003c\/h3\u003e\n\u003cp\u003eWhile a standard 40mm Plössl is a good low-power eyepiece, its field of view is typically limited to around 43°. The SWAN 40mm eyepiece offers a significant upgrade with its 72° field.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard 40mm Plössl:\u003c\/strong\u003e Offers a narrow, porthole-like view. It's functional for locating objects but can feel restrictive when observing large star fields.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWilliam Optics SWAN 40mm:\u003c\/strong\u003e Delivers a much more immersive, engaging view that feels like you are floating in space. This wider true field makes it easier to find targets and appreciate the context of objects within their stellar neighborhoods.\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 kind of views does the William Optics SWAN 40mm provide in an f\/10 SCT?\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, the SWAN 40mm eyepiece yields 50x magnification and a wide 1.44° true field of view. This is perfect for framing large deep-sky objects like the Andromeda Galaxy (M31) or sweeping through the dense star fields of the Sagittarius Arm of the Milky Way.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 28mm eye relief on the SWAN 40mm eyepiece good for eyeglass wearers?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, absolutely. The \u003cstrong\u003e28mm of eye relief\u003c\/strong\u003e is exceptionally long, allowing eyeglass wearers to see the entire 72° field of view without removing their glasses. This provides a comfortable, unvignetted viewing experience, which is often not possible with shorter eye relief eyepieces.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the SWAN 40mm's 72° field compare to a standard Plössl eyepiece?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA standard 40mm Plössl eyepiece typically has an apparent field of view between 40° and 50°. The William Optics SWAN 40mm's \u003cstrong\u003e72° field\u003c\/strong\u003e provides a significantly wider, more immersive window into space, making it feel less like looking through a tube and more like a \"spacewalk.\"\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan I use 2\" filters with the William Optics SWAN 40mm eyepiece?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The 2\" barrel of the SWAN 40mm eyepiece is threaded to accept all standard 2\" astronomy filters, such as nebula filters (UHC, O-III) or light pollution filters. This allows you to enhance contrast on faint deep-sky objects while still enjoying the wide-field view.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the William Optics SWAN 40mm eyepiece parfocal?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, the SWAN 40mm is designed to be \u003cstrong\u003eparfocal\u003c\/strong\u003e with other eyepieces in the William Optics SWAN series. This means you can switch between them with little to no refocusing required, making your observing sessions more efficient and enjoyable.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat objects are best for the SWAN 40mm, like the Beehive Cluster (M44)?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe SWAN 40mm excels at framing large celestial objects. It's ideal for open clusters like the Beehive Cluster (M44) or the Pleiades (M45), large nebulae like the Orion Nebula (M42) in its entirety, and for simply scanning the star-rich regions of the Milky Way.\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\u003e40mm\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 Size\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEye Relief\u003c\/td\u003e\n\u003ctd\u003e28 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLens Coatings\u003c\/td\u003e\n\u003ctd\u003eFully Multicoated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eParfocal\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFilter Threads\u003c\/td\u003e\n\u003ctd\u003eStandard 2\" (M48x0.75)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInternal Baffling\u003c\/td\u003e\n\u003ctd\u003eFully Blackened Lens Edges \u0026amp; Spacers\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEyecup\u003c\/td\u003e\n\u003ctd\u003eSoft Rubber, Fold-Down\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\"\u003eWilliam Optics SWAN 40mm Eyepiece\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\"\u003eTop Dust Cap\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\"\u003eBottom Dust Cap\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\/william-optics-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eWilliam Optics 2-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":44967225098525,"sku":"WO-E-SWA40","price":215.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/products\/William-Optics-SWAN-40mm-Eyepiece-2-inch-E-SWA40-1__26285.1596133259.1280.1280.jpg?v=1684339475"}],"url":"https:\/\/davidastro.com\/collections\/william-optics-spl-and-swan-eyepieces.oembed","provider":"David Astro","version":"1.0","type":"link"}