{"product_id":"explore-scientific-92-ed-9mm-eyepiece","title":"Explore Scientific 92° ED Series 9mm Waterproof Eyepiece (2\")","description":"\u003ch2\u003eHigh power with a 92° window on the sky\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eExplore Scientific 92° ED Series 9mm Waterproof Eyepiece\u003c\/strong\u003e is the high-power member of the series, for planets, globular clusters and small nebulae, with a field wide enough that objects stay in view longer on a mount without tracking. It has a 92° apparent field, a 2\" barrel, 18mm of eye relief and a 13.5mm field stop, and its 9 elements in 6 groups include H-FK61 ED glass to keep color fringing low and contrast high. Explore Scientific builds the series to be waterproof.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey specs:\u003c\/strong\u003e 9mm focal length · 92° apparent field · 2\" barrel · 18mm eye relief · 13.5mm field stop · 9 elements in 6 groups · H-FK61 ED glass · waterproof\u003c\/p\u003e\n\u003ch2\u003eWhat you'll see\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanets:\u003c\/strong\u003e Jupiter's belts and moons and Saturn's rings, with plenty of room before they drift out of view in a Dobsonian.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGlobular clusters:\u003c\/strong\u003e M13, M92 and M5 resolved toward their cores, framed by dark sky.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSmall nebulae:\u003c\/strong\u003e the Ring Nebula, the Cat's Eye Nebula and the Eskimo Nebula.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIn an \u003ca href=\"\/products\/sky-watcher-8-inch-traditional-dobsonian\"\u003e8\" Dobsonian\u003c\/a\u003e (1200mm) the 9mm gives 133x and a 0.64° true field. In an 80mm f\/6 refractor (480mm) it gives 53x and a 1.61° field. For comparison, the full Moon is about 0.5° across.\u003c\/p\u003e\n\u003ch2\u003eWhy the 92° ED series\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eA field you look into, not through:\u003c\/strong\u003e at 92° the edge of the view sits at the edge of your vision, so the eyepiece's field stop seems to disappear. On a Dobsonian or other undriven mount, objects also take longer to drift out of view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eED glass:\u003c\/strong\u003e an H-FK61 fluorophosphate element (Abbe number 81.6) reduces color fringing on bright stars, the Moon and planets. Coatings are multi-layer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e18mm eye relief:\u003c\/strong\u003e comfortable for most eyeglass wearers, which is rare in fields this wide.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof:\u003c\/strong\u003e dew and damp nights are less of a worry, and the eyepiece is easier to keep clean.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhat to add for the best results\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eA 2\" diagonal or focuser (required):\u003c\/strong\u003e refractors and Schmidt-Cassegrains need a 2\" diagonal such as the \u003ca href=\"\/products\/explore_scientific_2in_diagonal\"\u003eExplore Scientific 2\" Diagonal\u003c\/a\u003e or \u003ca href=\"\/products\/celestron-dielectric-star-diagonal-2-wiith-twist-lock\"\u003eCelestron 2\" Dielectric Star Diagonal\u003c\/a\u003e. Most Dobsonians with a 2\" focuser take it directly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA solid focuser:\u003c\/strong\u003e these are large eyepieces (141mm × 58mm), so a 2\" focuser with a compression ring holds them best. Rebalance a Dobsonian or refractor after inserting one.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA nebula filter:\u003c\/strong\u003e a 2\" UHC or OIII filter threads onto the barrel for emission nebulae from suburban skies.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA Barlow:\u003c\/strong\u003e the \u003ca href=\"\/products\/televue-2x-big-barlow-2\"\u003eTele Vue 2x Big Barlow\u003c\/a\u003e doubles the magnification, turning this eyepiece into an effective 4.5mm.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhich 92° ED eyepiece is right for you?\u003c\/h2\u003e\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eFocal length\u003c\/th\u003e\n\u003cth\u003eEye relief\u003c\/th\u003e\n\u003cth\u003eField stop\u003c\/th\u003e\n\u003cth\u003ePower \/ field in an 8\" Dob\u003c\/th\u003e\n\u003cth\u003ePrice\u003c\/th\u003e\n\u003cth\u003eBest for\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e9mm\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e18mm\u003c\/td\u003e\n\u003ctd\u003e13.5mm\u003c\/td\u003e\n\u003ctd\u003e133x \/ 0.64°\u003c\/td\u003e\n\u003ctd\u003e$449.99\u003c\/td\u003e\n\u003ctd\u003ePlanets and globulars, high power\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003ca href=\"\/products\/explore-scientific-92-ed-14mm-eyepiece\"\u003e14mm\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd\u003e18mm\u003c\/td\u003e\n\u003ctd\u003e20.6mm\u003c\/td\u003e\n\u003ctd\u003e86x \/ 0.98°\u003c\/td\u003e\n\u003ctd\u003e$449.99\u003c\/td\u003e\n\u003ctd\u003eAll-round medium power\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003ca href=\"\/products\/explore-scientific-92-ed-20mm-eyepiece\"\u003e20mm\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd\u003e20.2mm\u003c\/td\u003e\n\u003ctd\u003e31.7mm\u003c\/td\u003e\n\u003ctd\u003e60x \/ 1.51°\u003c\/td\u003e\n\u003ctd\u003e$449.99\u003c\/td\u003e\n\u003ctd\u003eDeep-sky wide fields\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003ca href=\"\/products\/explore-scientific-92-ed-25mm-eyepiece\"\u003e25mm\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd\u003e19.6mm\u003c\/td\u003e\n\u003ctd\u003e36.7mm\u003c\/td\u003e\n\u003ctd\u003e48x \/ 1.75°\u003c\/td\u003e\n\u003ctd\u003e$499.99\u003c\/td\u003e\n\u003ctd\u003eWidest field; big objects and star fields\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003cp\u003eWant something smaller and lighter? The \u003ca href=\"\/products\/explore-scientific-72-ed-20mm-eyepiece\"\u003e72° ED series\u003c\/a\u003e uses the same ED glass in a narrower field. See all our \u003ca href=\"\/collections\/eyepieces\"\u003eeyepieces\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eWhat's in the box\u003c\/h2\u003e\u003cul\u003e\u003cli\u003eExplore Scientific 92° ED 9mm eyepiece with dust caps\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003eDiagonals, Barlows and filters are sold separately.\u003c\/p\u003e\n\u003ch2\u003eExplore Scientific 92° ED 9mm FAQ\u003c\/h2\u003e\n\u003ch3\u003eWill it fit my telescope?\u003c\/h3\u003e\u003cp\u003eIt has a 2\" barrel, so it needs a 2\" focuser or diagonal. It won't fit a 1.25\"-only focuser.\u003c\/p\u003e\n\u003ch3\u003eWhat magnification will I get?\u003c\/h3\u003e\u003cp\u003eDivide your telescope's focal length by 9. In an 8\" f\/6 Dobsonian (1200mm) that's 133x; in an 80mm f\/6 refractor (480mm) it's 53x; in a Celestron 8\" SCT (2032mm) it's 226x.\u003c\/p\u003e\n\u003ch3\u003eCan I use it with glasses?\u003c\/h3\u003e\u003cp\u003eYes. 18mm of eye relief is enough for most people who observe with glasses.\u003c\/p\u003e\n\u003ch3\u003e92° or 72°?\u003c\/h3\u003e\u003cp\u003eThe 92° ED shows about 60% more sky at the same magnification and makes objects feel immersive, especially in a Dobsonian. The 72° ED series is smaller, lighter and less expensive, and easier to balance on small telescopes.\u003c\/p\u003e\n\u003ch3\u003eIs it really waterproof?\u003c\/h3\u003e\u003cp\u003eExplore Scientific sells the 92° ED series as waterproof eyepieces, which helps on dewy nights and when cleaning. Dry it before putting the caps back on.\u003c\/p\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\u003cth colspan=\"2\"\u003eOptics\u003c\/th\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal length\u003c\/td\u003e\n\u003ctd\u003e9mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApparent field\u003c\/td\u003e\n\u003ctd\u003e92°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEye relief\u003c\/td\u003e\n\u003ctd\u003e18mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eField stop\u003c\/td\u003e\n\u003ctd\u003e13.5mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eElements\u003c\/td\u003e\n\u003ctd\u003e9 elements in 6 groups\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eED glass\u003c\/td\u003e\n\u003ctd\u003eH-FK61 fluorophosphate crown, Abbe number 81.6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoatings\u003c\/td\u003e\n\u003ctd\u003eMulti-layer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003cth colspan=\"2\"\u003ePhysical\u003c\/th\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBarrel\u003c\/td\u003e\n\u003ctd\u003e2\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSize (L × W)\u003c\/td\u003e\n\u003ctd\u003e141mm × 58mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWaterproof\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWarranty\u003c\/td\u003e\n\u003ctd\u003eLimited lifetime (register with Explore Scientific within 60 days)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eManufacturer model\u003c\/td\u003e\n\u003ctd\u003eEPWP9209ED-01\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e","brand":"Explore Scientific","offers":[{"title":"Default Title","offer_id":50209905737987,"sku":"EPWP9209ED-01","price":449.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1979\/5379\/files\/e7_acee695d-81f0-4b34-87fa-138db20d797b.jpg?v=1794284240","url":"https:\/\/milehighastro.com\/products\/explore-scientific-92-ed-9mm-eyepiece","provider":"Mile High Astronomy","version":"1.0","type":"link"}