{"title":"Save 20% on Select Astro-Tech Eyepieces","description":"","products":[{"product_id":"astro-tech-4mm-uwa-82-1-25-eyepiece","title":"Astro-Tech 4mm UWA 82° 1.25\" Eyepiece","description":"\u003cp\u003eFour millimeters is the extreme end of useful magnification in a 1.25\" eyepiece — the one you reach for when the atmosphere is dead calm and the planet is begging for more power. In a 1250mm Dob, that's 312x. In a 714mm refractor, 179x. In a 2032mm SCT, 508x. The 82° apparent field keeps the view comfortable and gives you real drift time even at these magnifications, where a narrow-field eyepiece would have you chasing the planet across a keyhole. With plenty of five-star reviews and a price that makes extreme magnification accessible, this is the eyepiece that lets you push your telescope to its atmospheric limit without pushing your budget.\u003c\/p\u003e\n\u003ch3\u003eThe Optics\u003c\/h3\u003e\n\u003cp\u003eSeven elements, fully multi-coated with blackened lens edges. At 4mm, optical quality is non-negotiable — the exit pupil is tiny, the magnification is extreme, and every flaw in the glass shows up immediately. The 4mm UWA delivers a sharp, contrasty image across the field. Alan Dyer's review in Cloudy Nights' Astro Gear Today tested the 4mm UWA in three different telescopes — a 94mm f\/5.5 refractor, a 105mm f\/6 Astro-Physics Traveler, and a 200mm f\/6 Dobsonian — and reported that it performs superbly.  No ghost images or flares were visible from bright objects in or just outside the field. The 82° field is wide enough to keep objects in view without constant nudging. The one optical note: the field stop is more softly defined than in premium models like the Nagler Type 6 — a small trade-off for the enormous cost saving.\u003c\/p\u003e\n\u003ch3\u003e1.25\" Barrel\u003c\/h3\u003e\n\u003cp\u003eFits any 1.25\" focuser, diagonal, or Barlow. Safety groove engages your focuser's thumbscrew. At just 164 grams (measured by Alan Dyer), the 4mm UWA is 60 grams lighter than the 5mm Nagler Type 6 and 77 grams lighter than the 3.5mm Type 6 — it won't present balance issues on any telescope. At 4mm, this is already extreme magnification in most telescopes — a Barlow would push it beyond what the atmosphere typically supports, but in smaller scopes (4–6 inches), a 2x Barlow turns the 4mm into an effectively 2mm eyepiece for those rare nights of exceptional seeing.\u003c\/p\u003e\n\u003ch3\u003eWaterproof\u003c\/h3\u003e\n\u003cp\u003eO-ring sealed and waterproof. Prevents internal fogging during cold planetary sessions — and at 4mm, you'll be using this eyepiece on the nights when the temperature has dropped and the seeing has stabilized, exactly when fogging is most likely. Keeps dust and grit out of the optics and protects the coatings from humidity and fungus.\u003c\/p\u003e\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eAstro-Tech 4mm 82° UWA 1.25\" eyepiece\u003c\/li\u003e\n\u003cli\u003eLens caps (top and bottom)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view\u003c\/strong\u003e — At extreme magnification, the wider field is the difference between comfortable observing and constant nudging. More drift time on untracked telescopes, more context around the target.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e7-element fully multi-coated optics\u003c\/strong\u003e — High contrast with controlled scatter. Owners choose it over premium alternatives at several times the price.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4mm focal length\u003c\/strong\u003e — Extreme power. 312x in a 1250mm Dob, 179x in a 714mm refractor, 508x in a 2032mm SCT. The eyepiece for the steadiest nights.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12mm eye relief\u003c\/strong\u003e — Exceptional for a 4mm eyepiece. Most 4mm eyepieces force you to press your eye against the lens. This one doesn't.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof, O-ring sealed\u003c\/strong\u003e — Cold-weather performance and long-term protection.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25\" barrel with safety groove\u003c\/strong\u003e — Universal compatibility.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLightweight\u003c\/strong\u003e — No balance concerns.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eUnder the Night Sky\u003c\/h3\u003e\n\u003cp\u003eIn a 10-inch f\/5 Dob at 312x, Jupiter on a steady night shows the two equatorial belts with festoons, barges, and scalloping in real detail. The Great Red Spot shows internal structure — not just color and shape, but the wake turbulence trailing behind it. On the best nights, four or five belts are visible with hints of detail in each. The Galilean moons show disks, not points. The 82° field holds the planet for about 20 seconds of drift — enough time to study a feature before nudging the scope.\u003c\/p\u003e\n\u003cp\u003eSaturn at 312x shows the ring system in fine detail. Cassini's Division is a broad dark gap, not a thin line. The Encke minimum is visible on the best nights. The shadow of the globe on the rings shows crisp geometry. Multiple moons are visible around the planet. The crepe ring is distinct against the globe.\u003c\/p\u003e\n\u003cp\u003eThe Moon at 312x is where extreme magnification pays off most, because the Moon is bright enough to tolerate high power even on average nights. Crater floors show fine detail — rilles, secondary impacts, slumped walls. The Straight Wall shows as a true shadow line. Hadley Rille, the Apollo 15 landing site valley, is resolvable. You're looking at the Moon the way spacecraft see it.\u003c\/p\u003e\n\u003cp\u003eMars during opposition at 312x shows the dark surface markings — Syrtis Major, Hellas Basin, and the polar caps — with enough resolution to track changes from night to night. This is the eyepiece you wait all opposition season to use, saving it for the one or two nights when the seeing is truly exceptional.\u003c\/p\u003e\n\u003cp\u003eFor deep-sky, 312x is specialized territory: planetary nebulae like NGC 7662 (Blue Snowball) and NGC 6826 (Blinking Planetary) show disk structure. Tight double stars split cleanly — Dawes' limit territory in a 10-inch scope. Compact globulars resolve to the core.\u003c\/p\u003e\n\u003ch3\u003eCommunity Says\u003c\/h3\u003e\n\u003cp\u003e\"Performs superbly.\" This reviewer tested the 4mm UWA in three telescopes — a 94mm f\/5.5 refractor, a 105mm f\/6 Astro-Physics Traveler, and a 200mm f\/6 Dobsonian — and compared it directly to a 3.5mm TeleVue Delos at more than twice the price. The verdict: very similar views for sharpness, contrast, and neutral color. A Jovian moon transit was equally crisp in both eyepieces. The only trade-offs: a softly defined field stop compared to the Nagler Type 6, and some sensitivity to kidney-bean blackout that resolves with practice positioning the eye against the soft eyecup. At 164 grams, it's lighter than both the Nagler and Delos alternatives. — \u003ca href=\"https:\/\/www.cloudynights.com\/articles\/astro-gear-today\/reviews\/an-82-eyepiece-for-just-036100-astro-tech-4mm-uwa-review-r4604\/\"\u003eCloudy Nights Astro Gear Today review\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eObserving Tip\u003c\/h3\u003e\n\u003cp\u003eThe 4mm UWA is a seeing-limited eyepiece. On most nights, the atmosphere won't support this magnification — the image will be soft and boiling. That's not the eyepiece; that's the air. Start your session with a longer focal length, work your way up, and reach for the 4mm only when the image at lower power is steady and sharp. When the seeing cooperates — and you'll know immediately — the jump in detail is dramatic. Patience with the atmosphere is the skill that makes this eyepiece worth owning.\u003c\/p\u003e\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eHow does this compare to the 4.8mm 110° XWA?\u003c\/strong\u003e\u003cbr\u003eThe 4.8mm XWA has a wider field (110° vs. 82°), slightly longer focal length (4.8mm vs. 4mm), 15mm eye relief (vs. 12mm), and a dual 1.25\"\/2\" barrel. The 4.8mm XWA is 8 elements versus 7, and weighs 19 oz versus the UWA's 164 grams (~5.8 oz). The 4mm UWA gives you slightly more magnification and costs significantly less. If you want the widest possible field and don't mind the weight and price, the XWA is the step up. If you want extreme magnification at a fraction of the cost, the UWA delivers.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs 312x too much for my telescope?\u003c\/strong\u003e\u003cbr\u003eThe rule of thumb is 50x per inch of aperture as a practical ceiling — so 312x is reasonable for a 10-inch scope but pushing it for a 6-inch. In a 4-inch refractor at 179x (from a 714mm focal length), you're at a very comfortable power. The atmosphere, not the telescope, usually sets the limit. On most nights, 200–250x is the practical ceiling regardless of aperture. The 4mm UWA is the eyepiece for the nights that exceed that ceiling.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this parfocal with the other 82° UWAs?\u003c\/strong\u003e\u003cbr\u003eYes — confirmed by Cloudy Nights members. One owner tested all five 1.25\" UWAs (4mm through 16mm) and found them parfocal, requiring only a small touch of the focuser when swapping between focal lengths.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use this with an AT102ED?\u003c\/strong\u003e\u003cbr\u003eYes. One owner reports excellent results with the AT102ED. At 714mm focal length, the 4mm gives you 179x — well within the scope's capabilities and a very effective planetary magnification for a 4-inch ED doublet.\u003c\/p\u003e\n\u003ch3\u003eFinal Thoughts\u003c\/h3\u003e\n\u003cp\u003eThe 4mm UWA is the extreme-magnification specialist of the Astro-Tech 82° line — the eyepiece you buy knowing you won't use it every night, but knowing that when you do, nothing else in the case will show you what this one shows you. Alan Dyer's review for Cloudy Nights puts it plainly: it performs superbly. At 4mm, 82° field, 12mm eye relief, and 164 grams, it's an invitation to push your telescope to its limits on the nights that deserve it.\u003c\/p\u003e\n\u003ch2\u003eTech Details:\u003c\/h2\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eFocal Length\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e4mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eApparent Field of View\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e82°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eOptical Elements\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e7 elements, fully multi-coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eEye Relief\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e12mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eBarrel Size\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWaterproof\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eYes — O-ring sealed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWarranty\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1 year\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Astro-Tech","offers":[{"title":"Default Title","offer_id":40481993883721,"sku":"ATUWA04","price":95.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0573\/7974\/9961\/products\/hart0024.jpg?v=1675380193"},{"product_id":"astro-tech-10mm-uwa-82-1-25-eyepiece","title":"Astro-Tech 10mm UWA 82° 1.25\" Eyepiece","description":"\u003cp\u003eTen millimeters splits the difference between deep-sky and planetary magnification — high enough to resolve globular clusters and show structure in planetary nebulae, versatile enough to frame compact open clusters with surrounding star field. In a 10-inch f\/5 Dob, it delivers 125x and about 40 arc-minutes of true field. In an f\/7 refractor, 71x with just over a degree of sky. One owner tried this eyepiece after investing in ultra-premium eyepieces and came away impressed — calling it \"premium performance at a sensible price.\" With 16 five-star reviews, the pattern is clear: this eyepiece punches well above its price point.\u003c\/p\u003e\n\u003ch3\u003eThe Optics\u003c\/h3\u003e\n\u003cp\u003eSeven elements, fully multi-coated. The 82° apparent field provides a wide, immersive view without the optical complexity — or the price — of a 100° design. Fewer glass surfaces mean less scattered light and higher contrast, which matters when you're trying to detect subtle detail in planetary nebulae or faint structure in galaxies. The correction holds well across the field in moderate and slow focal-ratio scopes. In fast Dobs (f\/4.5–f\/5), the outer 10% may soften slightly — normal for any wide-field 1.25\" eyepiece. Cloudy Nights members rate the 10mm as one of the strongest performers in the UWA line — a reviewer testing it in an AT102EDL f\/7 apo found all three mid-range UWAs (7mm, 10mm, 13mm) very sharp, with M3, M92, and M13 showing graininess with averted vision even from Bortle 8–9 skies in a 4-inch refractor.\u003c\/p\u003e\n\u003ch3\u003e1.25\" Barrel\u003c\/h3\u003e\n\u003cp\u003eFits any 1.25\" focuser, diagonal, or Barlow. Safety groove engages your focuser's thumbscrew for secure retention. Lightweight and compact — no balance issues on any telescope.\u003c\/p\u003e\n\u003ch3\u003eWaterproof\u003c\/h3\u003e\n\u003cp\u003eO-ring sealed and waterproof. Prevents internal fogging, dust intrusion, and fungus. The sealed construction extends the optical life of the eyepiece.\u003c\/p\u003e\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eAstro-Tech 10mm 82° UWA 1.25\" eyepiece\u003c\/li\u003e\n\u003cli\u003eLens caps (top and bottom)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view\u003c\/strong\u003e — Nearly three times the area of a standard Plossl. Wide enough to be immersive while maintaining high contrast.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e7-element fully multi-coated optics\u003c\/strong\u003e — High contrast, good edge correction, minimal scatter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10mm focal length\u003c\/strong\u003e — The bridge between deep-sky and planetary power. 125x in a 1250mm Dob, 71x in a 714mm refractor, 203x in a 2032mm SCT.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e12mm eye relief\u003c\/strong\u003e — Comfortable without glasses. Tight for eyeglass wearers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof, O-ring sealed\u003c\/strong\u003e — Cold-weather ready. Dust and fungus resistant.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1.25\" barrel with safety groove\u003c\/strong\u003e — Universal 1.25\" compatibility.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLightweight\u003c\/strong\u003e — No balance concerns on any telescope.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eUnder the Night Sky\u003c\/h3\u003e\n\u003cp\u003eIn a 10-inch Dob at 125x, globular clusters hit their visual peak. M13 resolves into individual stars across the entire face — chains, lanes, and a dense core that starts to granulate. M3 shows its characteristic loose, spangled structure. M5 reveals its elongated shape. This is the magnification range where the difference between \"a fuzzy ball\" and \"a resolved cluster\" becomes dramatic.\u003c\/p\u003e\n\u003cp\u003ePlanetary nebulae are well served at 125x. M57 shows its ring shape clearly. NGC 6826, the Blinking Planetary, is large enough to show its disk and does its signature \"blinking\" trick when you shift between direct and averted vision. M27 fills a meaningful portion of the field with its apple-core structure visible.\u003c\/p\u003e\n\u003cp\u003eOn planets, 125x is a good working magnification. Jupiter shows the equatorial belts with visible detail on steady nights. Saturn's rings are well separated with Cassini's Division clear. Mars at opposition shows major surface features. The 82° field provides comfortable drift time on an untracked Dob.\u003c\/p\u003e\n\u003cp\u003eIn a refractor at 71x, the 10mm works beautifully on compact open clusters — M11, the Wild Duck Cluster, resolves into a dense swarm of stars. NGC 884\/885, the Double Cluster, shows both clusters fully resolved with the surrounding field stars providing context.\u003c\/p\u003e\n\u003ch3\u003eCommunity Says\u003c\/h3\u003e\n\u003cp\u003e\"All three UWAs are very sharp.\" This owner tested the 7mm, 10mm, and 13mm in an AT102EDL f\/7 from Bortle 8–9 skies and found globular clusters showed graininess with averted vision even in a 4-inch refractor — a sign of real resolving power at the edge of what the aperture can deliver. — \u003ca href=\"https:\/\/www.cloudynights.com\/topic\/876989-review-of-the-7mm-10mm-13mm-at-uwa-82-eyepieces\/\"\u003eCloudy Nights AT UWA 7mm\/10mm\/13mm review\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003e\"Best deal in EPs...ever.\" This owner bought the full 4mm–16mm set after testing one. — \u003ca href=\"https:\/\/www.cloudynights.com\/topic\/876989-review-of-the-7mm-10mm-13mm-at-uwa-82-eyepieces\/\"\u003eCloudy Nights AT UWA discussion\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eObserving Tip\u003c\/h3\u003e\n\u003cp\u003eThe 10mm UWA is the ideal magnification for the Messier marathon. At 125x in a 10-inch Dob, it shows enough detail to positively identify objects while holding a field wide enough to find them by star-hopping. For the spring Messier marathon, this single eyepiece can handle everything from the galaxies of Virgo to the globulars of Ophiuchus to the nebulae of Sagittarius — the only targets that benefit from switching are the very faintest galaxies (drop to lower power) and planets (step up for more detail).\u003c\/p\u003e\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eHow does this compare to a 10mm Plossl?\u003c\/strong\u003e\u003cbr\u003eThe 82° UWA shows nearly three times more sky area than a 50° Plossl at the same magnification. The Plossl has the advantage of simplicity (fewer elements), longer eye relief at this focal length, and lower cost. But the viewing experience is dramatically different — the UWA's wider field changes how you observe.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this parfocal with the other 82° UWAs?\u003c\/strong\u003e\u003cbr\u003eYes — confirmed by Cloudy Nights members. One owner tested all five 1.25\" UWAs (4mm through 16mm) and confirmed they are parfocal with each other, requiring only a small touch of the focuser when swapping. The UWAs are not parfocal with TeleVue Group B eyepieces, so expect a larger adjustment if mixing brands.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill this work well in an SCT?\u003c\/strong\u003e\u003cbr\u003eYes. In a typical 8-inch f\/10 SCT (2032mm), the 10mm gives you 203x — excellent for planetary work. The relatively slow f\/10 focal ratio is easy on any eyepiece, so the 82° UWA will deliver sharp stars to the edge of the field.\u003c\/p\u003e\n\u003ch3\u003eFinal Thoughts\u003c\/h3\u003e\n\u003cp\u003eThe 10mm UWA is where globular clusters come alive, planetary nebulae reveal their structure, and planets start showing real detail — all through a compact 1.25\" eyepiece that fits any telescope. At 82°, the field is wide enough to observe in comfort. At 7 elements, the contrast stays high. And at this price, it's the kind of eyepiece that makes the ultra-premium alternatives hard to justify for most observers. Sixteen five-star reviews from owners using everything from Dobs to refractors to SCTs all point the same direction: this is premium performance in a sensible package.\u003c\/p\u003e\n\u003ch2\u003eTech Details:\u003c\/h2\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eFocal Length\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e10mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eApparent Field of View\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e82°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eOptical Elements\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e7 elements, fully multi-coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eEye Relief\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e12mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eBarrel Size\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWaterproof\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eYes — O-ring sealed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWarranty\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1 year\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Astro-Tech","offers":[{"title":"Default Title","offer_id":40481993949257,"sku":"ATUWA10","price":95.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0573\/7974\/9961\/products\/image_9d740345-b19f-42e9-8524-9452ab88d55f.png?v=1708535957"},{"product_id":"astro-tech-13mm-uwa-82-1-25-eyepiece","title":"Astro-Tech 13mm UWA 82° 1.25\" Eyepiece","description":"\u003cp\u003eThe 13mm is the transition point — high enough magnification to show real detail in globular clusters and planetary nebulae, low enough to hold a useful true field for open clusters and galaxy groups. In a 10-inch f\/5 Dob, it gives you 96x and just under a degree of sky in the eyepiece. In an f\/7 refractor, 55x with 1.5° of field. The 82° apparent field wraps around the view in a way that standard eyepieces can't match, and the 7-element design keeps contrast high while staying light enough to fit any 1.25\" focuser without shifting the balance.\u003c\/p\u003e\n\n\u003ch3\u003eThe Optics\u003c\/h3\u003e\n\n\u003cp\u003eSeven elements, fully multi-coated. The 82° UWA design balances field width against optical complexity — wide enough to be immersive, simple enough to maintain high contrast with minimal scatter. The image is sharp across the center and middle zones with well-controlled astigmatism and field curvature. One owner bought a pair for binocular telescopes and calls them \"mainstays.\" Cloudy Nights members rate the 13mm as sharper to the edge than the 16mm in fast scopes, with one reviewer calling it and its siblings \"very sharp\" in an AT102EDL f\/7 apo — the Moon showed beautiful crispness, and double stars like Izar split cleanly with the blue companion embedded in the diffraction ring at 200x with a Barlow.\u003c\/p\u003e\n\n\u003ch3\u003e1.25\" Barrel\u003c\/h3\u003e\n\n\u003cp\u003eFits any 1.25\" focuser, diagonal, or Barlow. A safety groove is machined into the barrel to engage your focuser's thumbscrew. The eyepiece is lightweight — it won't change the balance on any telescope.\u003c\/p\u003e\n\n\u003ch3\u003eWaterproof\u003c\/h3\u003e\n\n\u003cp\u003eO-ring sealed and waterproof. Prevents internal fogging at cold temperatures, keeps dust out, and protects the internal coatings over the life of the eyepiece.\u003c\/p\u003e\n\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\n\u003cul\u003e\n  \u003cli\u003eAstro-Tech 13mm 82° UWA 1.25\" eyepiece\u003c\/li\u003e\n  \u003cli\u003eLens caps (top and bottom)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e82° apparent field of view\u003c\/strong\u003e — Nearly three times the area of a standard 50° Plossl. Wide enough to show targets in their surrounding context.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e7-element fully multi-coated optics\u003c\/strong\u003e — High contrast, controlled scatter, good edge correction.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e13mm focal length\u003c\/strong\u003e — Mid-power versatility. 96x in a 1250mm Dob, 55x in a 714mm refractor, 156x in a 2032mm SCT. Works on nebulae, clusters, galaxies, and planets.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e12mm eye relief\u003c\/strong\u003e — Comfortable without glasses. Tight for eyeglass wearers.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWaterproof, O-ring sealed\u003c\/strong\u003e — Cold-weather performance and long-term optical protection.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1.25\" barrel with safety groove\u003c\/strong\u003e — Universal compatibility. Thumbscrew retention.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLightweight\u003c\/strong\u003e — No balance issues on any telescope.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUnder the Night Sky\u003c\/h3\u003e\n\n\u003cp\u003eIn a 10-inch Dob at 96x, M13 resolves individual stars across its face — not just at the edges, but threading into the core. M57, the Ring Nebula, shows its oval shape clearly with the central hole defined. The Orion Nebula at this power shows the Trapezium cleanly split against the bright nebulosity, with the wings extending well beyond. A Cloudy Nights reviewer using an AT102EDL f\/7 in Bortle 8–9 skies reported the Beehive Cluster as an impressive sight, fitting comfortably inside the 82° field at 55x — the kind of target that rewards a wide field by showing the cluster in its full context against the surrounding star field.\u003c\/p\u003e\n\n\u003cp\u003eJupiter shows both equatorial belts with hints of festoons on steady nights. Saturn's rings are separated from the globe with Cassini's Division visible. The 82° field gives you comfortable drift time on an untracked Dob — roughly 40 seconds before a planet exits the view at this magnification.\u003c\/p\u003e\n\n\u003cp\u003eIn a short refractor at 55x, the field is wide enough for open clusters like M35, M37, and the Double Cluster. Galaxy groups in Virgo and Leo show multiple members in a single field. The sky background is dark enough to bring out faint nebulosity on the Veil and the North America with a filter.\u003c\/p\u003e\n\n\u003ch3\u003eCommunity Says\u003c\/h3\u003e\n\n\u003cp\u003e\"All three UWAs are very sharp.\" This owner tested the 7mm, 10mm, and 13mm in an AT102EDL f\/7 from Bortle 8–9 skies and found the 13mm delivered beautiful crispness on the Moon and split Izar cleanly at 200x with a Barlow — the blue companion embedded in the diffraction ring. The Beehive at 55x filled the 82° field and showed the cluster in full context against the surrounding star field. — \u003ca href=\"https:\/\/www.cloudynights.com\/topic\/876989-review-of-the-7mm-10mm-13mm-at-uwa-82-eyepieces\/\"\u003eCloudy Nights AT UWA 7mm\/10mm\/13mm review\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cp\u003e\"Best deal in EPs...ever.\" This owner bought the full 4mm–16mm set after testing one. — \u003ca href=\"https:\/\/www.cloudynights.com\/topic\/876989-review-of-the-7mm-10mm-13mm-at-uwa-82-eyepieces\/\"\u003eCloudy Nights AT UWA discussion\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eObserving Tip\u003c\/h3\u003e\n\n\u003cp\u003eThe 13mm UWA makes a natural partner for the 7mm UWA — one gives you the mid-power survey view, the other zooms in for detail. Together they cover the range from deep-sky scanning to planetary close-ups, and both fit a 1.25\" focuser without adapters. Add the 10mm to split the difference, and you have a three-eyepiece set that handles virtually any target from any telescope.\u003c\/p\u003e\n\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eHow does this compare to the 13mm 100° XWA?\u003c\/strong\u003e\u003cbr\u003e\nThe 100° XWA has a wider apparent field (100° vs. 82°), more elements (9 vs. 7), is waterproof (both are), has 15mm eye relief (vs. 12mm here), and is heavier (19 oz vs. lightweight). The XWA is the premium option. The 82° UWA is the lighter, more affordable choice that still delivers a wide field with high contrast. If 82° is wide enough for your needs, the UWA gives you excellent performance at a lower price.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eIs this parfocal with the other 82° UWAs?\u003c\/strong\u003e\u003cbr\u003e\nThe Astro-Tech 82° UWA eyepieces are close to parfocal with each other. You'll need only a small focus adjustment when swapping between focal lengths in the line.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCan I use this in a binoviewer?\u003c\/strong\u003e\u003cbr\u003e\nYes. One owner bought a matched pair for binocular telescopes and rates them highly. The 1.25\" barrel and lightweight construction make them well suited for binoviewer use.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWill this work in a fast Dobsonian?\u003c\/strong\u003e\u003cbr\u003e\nYes. The optical design handles fast focal ratios well. At f\/4.5–f\/5, you may see some softening in the last 10% of the field — normal for any 82° eyepiece at fast ratios. A coma corrector like a Paracorr will clean up the outer field if it bothers you.\u003c\/p\u003e\n\n\u003ch3\u003eFinal Thoughts\u003c\/h3\u003e\n\n\u003cp\u003eThe 13mm UWA is the middle of the 82° line — the focal length that does a bit of everything without specializing in anything. It resolves globular clusters, shows planetary detail, frames open clusters in context, and holds a useful field on galaxies. At 1.25\", 7 elements, and a lightweight build, it fits any telescope and any budget. Fourteen five-star reviews and an owner who bought two for binocular use tell the story: this eyepiece delivers more than its price suggests, and it works reliably session after session.\u003c\/p\u003e\n\u003ch2\u003eTech Details:\u003c\/h2\u003e\n\u003ctable style=\"width:100%; border-collapse: collapse;\"\u003e\u003ctbody\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eFocal Length\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e13mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eApparent Field of View\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e82°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eOptical Elements\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e7 elements, fully multi-coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eEye Relief\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e12mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eBarrel Size\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWaterproof\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eYes — O-ring sealed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWarranty\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1 year\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e","brand":"Astro-Tech","offers":[{"title":"Default Title","offer_id":40481993982025,"sku":"ATUWA13","price":95.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0573\/7974\/9961\/products\/image_6ddbf930-3446-4969-bea0-1baa238a6e26.png?v=1675664629"},{"product_id":"astro-tech-16mm-uwa-82-1-25-eyepiece","title":"Astro-Tech 16mm UWA 82° 1.25\" Eyepiece","description":"\u003cp\u003eSixteen millimeters is the all-rounder focal length in a 1.25\" barrel. In a 10-inch f\/5 Dob, it gives you 78x — high enough to darken the sky background and pull detail out of nebulae, low enough to hold a full degree of true field for open clusters and galaxy groups. In a 4-inch f\/7 refractor, it delivers 45x with a 1.8° field: the deep-sky workhorse. At 6 ounces, it barely changes the balance of any scope, and at 7 elements it holds contrast and sharpness across an 82° field that makes standard eyepieces feel cramped. This is the eyepiece owners describe as the one they reach for first.\u003c\/p\u003e\n\n\u003ch3\u003eThe Optics\u003c\/h3\u003e\n\n\u003cp\u003eSeven elements, fully multi-coated. The 82° design strikes a practical balance — wide enough to be immersive, simple enough to keep contrast high and weight low. The image is sharp across the center and middle zones with well-controlled astigmatism. One owner uses it on a 10-inch Dob and a 6-inch Meade ACF; another pairs it with a 4-inch refractor. Cloudy Nights members note that edge correction at f\/5 is not quite as tight as the shorter focal length UWAs in the line — the 13mm, 10mm, and 7mm are sharper to the edge at fast ratios. In slower scopes (f\/6 and above), the difference narrows and most observers report excellent performance across the field. A detailed CN comparison with the 16mm Nagler Type 5 found the Nagler has better edge correction, but the AT 16mm UWA has noticeably more eye relief and costs significantly less. Both delivered sharp center-field images.\u003c\/p\u003e\n\n\u003ch3\u003e1.25\" Barrel\u003c\/h3\u003e\n\n\u003cp\u003eThis eyepiece fits any 1.25\" focuser, diagonal, or Barlow — universal compatibility. A safety groove is machined into the barrel to engage your focuser's thumbscrew. At 6 ounces, it's lighter than most kit eyepieces, and it won't tip the balance on even the lightest refractor or tabletop Dob.\u003c\/p\u003e\n\n\u003ch3\u003eWaterproof\u003c\/h3\u003e\n\n\u003cp\u003eO-ring sealed and waterproof. The practical benefits: no internal fogging at cold temperatures, no dust intrusion, and the internal coatings stay protected from humidity and fungus for the life of the eyepiece.\u003c\/p\u003e\n\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\n\u003cul\u003e\n  \u003cli\u003eAstro-Tech 16mm 82° UWA 1.25\" eyepiece\u003c\/li\u003e\n  \u003cli\u003eLens caps (top and bottom)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e82° apparent field of view\u003c\/strong\u003e — Nearly three times the sky area of a 50° Plossl. Wide enough to show deep-sky objects in context with their surrounding star fields.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e7-element fully multi-coated optics\u003c\/strong\u003e — High contrast and edge sharpness. Fewer elements than 100° designs means less scattered light.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e16mm focal length\u003c\/strong\u003e — The versatile mid-power focal length. 78x in a 1250mm Dob, 45x in a 714mm refractor, 127x in a 2032mm SCT. Useful on everything from nebulae to planets.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e12mm eye relief\u003c\/strong\u003e — Comfortable without glasses. Tight for eyeglass wearers.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWaterproof, O-ring sealed\u003c\/strong\u003e — Cold-weather performance, dust resistance, coating protection.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1.25\" barrel with safety groove\u003c\/strong\u003e — Fits any 1.25\" focuser, diagonal, or Barlow. Thumbscrew retention.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e6 ounces\u003c\/strong\u003e — Light enough for any scope. No balance issues.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUnder the Night Sky\u003c\/h3\u003e\n\n\u003cp\u003eIn a 10-inch f\/5 Dob at 78x, the 16mm UWA sits in the sweet spot between wide field and useful magnification. M42 shows the wings of nebulosity extending out from the Trapezium with the sky background dark enough to bring out faint structure. M13 begins to resolve individual stars across its face, not just at the edges. M27, the Dumbbell, shows its apple-core shape clearly against a dark field.\u003c\/p\u003e\n\n\u003cp\u003eIn a 4-inch refractor at 45x, you get a 1.8° true field — the Double Cluster fits comfortably with surrounding star field. The Pleiades show all the bright members. M35 and its companion NGC 2158 share the field, the main cluster resolved into bright chains and the companion a soft glow behind it.\u003c\/p\u003e\n\n\u003cp\u003eOn planets, 78x in a 10-inch is a useful starting magnification. Jupiter shows both equatorial belts and the Galilean moons as distinct points. Saturn's rings are clearly separated from the globe. The wide 82° field gives you generous drift time on an untracked Dob.\u003c\/p\u003e\n\n\u003ch3\u003eCommunity Says\u003c\/h3\u003e\n\n\u003cp\u003eThe 16mm is the most discussed focal length in the UWA line on Cloudy Nights. A detailed side-by-side comparison with the 16mm Nagler Type 5 found the Nagler has better edge correction, but the AT 16mm UWA has noticeably more eye relief and costs significantly less.\u003cbr\u003e\n— \u003ca href=\"https:\/\/www.cloudynights.com\/forums\/topic\/841679-comparsionunboxing-16mm-nagler-t5-and-astro-tech-16mm-uwa\/\"\u003eCloudy Nights 16mm Nagler T5 vs AT 16mm UWA comparison\u003c\/a\u003e. This owner tested both in a TV-76 refractor and measured the eye relief, parfocality, and edge correction differences in daylight and at night.\u003c\/p\u003e\n\n\u003cp\u003eIn fast scopes at f\/5, CN members note the 16mm shows more edge softening than the shorter focal length UWAs — the 13mm, 10mm, and 7mm are sharper to the edge at fast ratios. In slower scopes (f\/6 and above), the difference narrows and most observers report excellent performance across the field.\u003cbr\u003e\n— \u003ca href=\"https:\/\/www.cloudynights.com\/forums\/topic\/891736-astrotech-82-degree-uwa-eyepieces\/\"\u003eCloudy Nights UWA Eyepieces discussion\u003c\/a\u003e. This owner, an experienced reviewer, contextualized the 16mm's edge performance against the full UWA line and emphasized that scope focal ratio matters more than the eyepiece itself.\u003c\/p\u003e\n\n\u003ch3\u003eObserving Tip\u003c\/h3\u003e\n\n\u003cp\u003eThe 16mm UWA makes an excellent first upgrade from a kit Plossl. It delivers more field, better contrast, and sharper edges than most 25mm Plossls while providing more magnification. If you're building your first serious eyepiece set, start here — the 16mm covers the most ground across the widest range of objects and telescopes. Add the 7mm UWA for high power and the 10mm for a step between them, and you have a three-eyepiece set that handles everything from rich-field scanning to planetary detail.\u003c\/p\u003e\n\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eIs this parfocal with the other UWAs in the line?\u003c\/strong\u003e\u003cbr\u003e\nYes — confirmed by Cloudy Nights members. One owner tested all five 1.25\" UWAs (4mm through 16mm) and confirmed they are parfocal with each other. Another measured the 16mm UWA and 4mm UWA at about 1.3mm apart in focus position — close enough that a small touch of the focuser is all that's needed. The UWAs are not parfocal with TeleVue Group B eyepieces, so if you're mixing brands, expect a larger focus adjustment.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHow does this compare to a 15mm Plossl?\u003c\/strong\u003e\u003cbr\u003e\nThe 82° UWA shows nearly three times more sky than a 50° Plossl at the same focal length, with better edge correction and higher contrast. The Plossl wins on simplicity (fewer elements), eye relief (Plossls at this focal length typically have longer eye relief), and price. But the viewing experience is in a different category.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCan I use this with a 2\" diagonal?\u003c\/strong\u003e\u003cbr\u003e\nYes, with a 1.25\" adapter in your 2\" diagonal. Most 2\" diagonals come with a 1.25\" adapter. The eyepiece will also work directly in any 1.25\" diagonal.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eIs this good for astrophotography?\u003c\/strong\u003e\u003cbr\u003e\nEyepieces are designed for visual use, not imaging. For astrophotography through a telescope, you'll want a camera adapter that connects directly to the focuser or a dedicated camera eyepiece projection system. This eyepiece is optimized for the eye, not a camera sensor.\u003c\/p\u003e\n\n\u003ch3\u003eFinal Thoughts\u003c\/h3\u003e\n\n\u003cp\u003eThe 16mm UWA is the workhorse of the 82° line — the eyepiece that handles more targets on more telescopes than any other focal length in the set. It's the mid-power choice that works on nebulae, clusters, galaxies, and planets without being specialized for any one of them. At 6 ounces and 1.25\", it fits every scope and changes the balance of none. Eight five-star reviews from owners using everything from 4-inch refractors to 10-inch Dobs say the same thing: this is the eyepiece you put in first and take out last. If you're buying one UWA to start with, this is a strong choice.\u003c\/p\u003e\n\n\u003ch2\u003eTech Details:\u003c\/h2\u003e\n\u003ctable style=\"width:100%; border-collapse: collapse;\"\u003e\u003ctbody\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eFocal Length\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e16mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eApparent Field of View\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e82°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eOptical Elements\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e7 elements, fully multi-coated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eEye Relief\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e12mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eBarrel Size\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1.25\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWaterproof\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eYes — O-ring sealed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWeight\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e6 oz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWarranty\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1 year\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e","brand":"Astro-Tech","offers":[{"title":"Default Title","offer_id":40481994014793,"sku":"ATUWA16","price":95.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0573\/7974\/9961\/products\/image_3ab87f0f-652a-4d10-9fe5-cf23d2e1da7b.png?v=1675664944"},{"product_id":"astro-tech-21mm-uwa-82-2-eyepiece","title":"Astro-Tech 21mm UWA 82° 2\" Eyepiece","description":"\u003cp\u003eYou spend half the night swapping eyepieces. A 28mm wide-field for the big nebulae, a 16mm for the tight clusters, and something in between that you never quite found — an eyepiece that gives you a real wide-field view at a magnification high enough to pull detail out of deep sky objects without drowning in exit pupil. The Astro-Tech 21mm UWA 82° was designed to fill that gap.\u003c\/p\u003e\n\u003cp\u003eAt 21mm in an f\/7 refractor, you're working with a 3mm exit pupil — dark enough to boost contrast on faint nebulosity, bright enough that the sky background stays smooth. The 82° apparent field gives you roughly 1.7 degrees of true field at that magnification, which is enough to frame the entire Veil Nebula complex or the full sweep of the Double Cluster with room to spare. In an f\/5 Dobsonian, you're at higher power with a tighter exit pupil, and the eyepiece becomes a serious planetary nebula and globular cluster tool.\u003c\/p\u003e\n\u003cp\u003eThe optical design uses six elements in four groups — low-dispersion glass, high-refractive-index elements, and full multicoatings on every air-to-glass surface. The lens edges are blackened to kill internal reflections. The result is a clean, high-contrast image with excellent color correction across the field. And unlike some 82° designs that compromise sharpness at the edges, the 21mm UWA delivers a remarkably flat field — Cloudy Nights reviewers have called it the sharpest edge-to-edge performer in the AT UWA series.\u003c\/p\u003e\n\u003cp\u003eOne honest note on the eye relief: at 14mm, it's comfortable for most observers without glasses. But if you wear eyeglasses, you won't see the entire 82° field. The fold-down rubber eyecup helps you get close, and the moderate eye placement prevents kidney-beaning and blackouts. Non-glasses wearers generally find it natural and easy — just fold the cup down and look.\u003c\/p\u003e\n\u003cp\u003eThe 21mm weighs 14.1 ounces, which is nearly ten ounces lighter than the 28mm UWA. It's a 2\" barrel eyepiece, built from anodized aluminum with a clean black-and-silver finish. It ships with dust caps for both ends and is parfocal with the rest of the AT UWA 82° series — swap from the 28mm to the 21mm to the 16mm without refocusing.\u003c\/p\u003e\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eAstro-Tech 21mm UWA 82° 2\" eyepiece\u003c\/li\u003e\n\u003cli\u003eSoft fold-down rubber eyecup\u003c\/li\u003e\n\u003cli\u003eDust cap — eye end\u003c\/li\u003e\n\u003cli\u003eDust cap — barrel end\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCommunity Says\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e\"I was surprised to see the stars in the 21mm were sharp all the way to the field edge in my AT102EDL f\/7 refractor. The view was flat like a 30mm UFF eyepiece, but with a wider AFOV and shorter eye relief.\"\u003c\/strong\u003e\u003cbr\u003e— \u003ca href=\"https:\/\/www.cloudynights.com\/forums\/topic\/968136-astro-tech-21mm-uwa-82-reviews-specs-pics-observation-reports\/?do=findComment\u0026amp;comment=14192928\"\u003eCloudy Nights AT 21mm UWA discussion\u003c\/a\u003e. This owner compared it directly to the 28mm UWA, 16mm UWA, and 24mm ES 68° over an entire night and found the 21mm was the only eyepiece consistently sharp to the field edge.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\"To call the field flat is an understatement. Eye relief is fine for me but many will find it to be rather sparse.\"\u003c\/strong\u003e\u003cbr\u003e— \u003ca href=\"https:\/\/www.cloudynights.com\/forums\/topic\/968136-astro-tech-21mm-uwa-82-reviews-specs-pics-observation-reports\/?do=findComment\u0026amp;comment=14203261\"\u003eCloudy Nights AT 21mm UWA discussion\u003c\/a\u003e. This owner conducted drift tests confirming the manufacturer's 1.7° true field spec and resolved the tight double star Porrima right up to the field stop at 48x in a 1000mm refractor.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\"In better seeing, the 21 UWA and the 20 T5 Nagler felt more similar than different.\"\u003c\/strong\u003e\u003cbr\u003e— \u003ca href=\"https:\/\/www.cloudynights.com\/forums\/topic\/968136-astro-tech-21mm-uwa-82-reviews-specs-pics-observation-reports\/?do=findComment\u0026amp;comment=14490999\"\u003eCloudy Nights AT 21mm UWA discussion\u003c\/a\u003e. This owner tested the 21mm UWA against a Nagler T5 20mm, an Axiom LX 23mm, and a Pentax XW 23mm in a 16\" f\/4.5 Dob with a Paracorr 2, and found only minor astigmatism in the outer 10% of the field — comparable to the Nagler.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e82° apparent field of view.\u003c\/strong\u003e Wide enough that you lose the \"looking down a tube\" feeling of a 50° Plössl, without the weight and cost of a 100° design. The 82° sweet spot gives you a full-immersion view where star patterns match your charts and your eye can relax into averted vision naturally.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSix-element, four-group optical design.\u003c\/strong\u003e Low-dispersion and high-refractive-index glass with full multicoatings on all air-to-glass surfaces. Blackened lens edges suppress internal scatter. The result is high contrast and flat-field sharpness from center to edge.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e3mm exit pupil in an f\/7 scope.\u003c\/strong\u003e The 21mm focal length hits a practical sweet spot for deep sky work in refractors and longer-focal-length Newtonians. High enough magnification to darken the sky background and boost contrast on faint objects, low enough to keep the field bright and the image smooth.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e14.1-ounce weight.\u003c\/strong\u003e Nearly ten ounces lighter than the 28mm UWA. Light enough that it won't throw off the balance on a small refractor or stress a compression ring fitting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eParfocal with the AT UWA 82° series.\u003c\/strong\u003e Swap between the 28mm, 21mm, 16mm, 13mm, and 10mm without refocusing. Build a matched set that lets you change magnification without losing your target.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2\" barrel with undercut.\u003c\/strong\u003e Locks securely into any standard 2\" focuser with a compression ring or thumbscrew. The wider barrel eliminates the vignetting you'd get from a 1.25\" barrel at this field of view.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFold-down rubber eyecup.\u003c\/strong\u003e Fold it up for glasses wearers who want to get as close as possible, or fold it down for a natural eye position without glasses. Soft rubber that won't scratch your lenses.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eUnder the Night Sky\u003c\/h3\u003e\n\u003cp\u003eIn an 8\" f\/6 Dobsonian (1200mm focal length), the 21mm UWA puts you at 57x with a 1.4° true field. That's a solid deep sky magnification: the Double Cluster fills the view beautifully with both NGC 869 and NGC 884 resolved into individual stars against a dark background. M13 shows its granular core and the outer chains of stars fanning outward. The Dumbbell Nebula (M27) pops against the sky background with its apple-core shape clearly defined.\u003c\/p\u003e\n\u003cp\u003eMove to a 10\" f\/5 Dob and you're at 63x with a 1.3° field. Now the Orion Nebula (M42) fills the view with the Trapezium cluster sharp at center and the nebulosity streaming outward to the field edges. The Lagoon Nebula (M8) shows its dark lane cutting through the bright emission regions. NGC 7000, the North America Nebula, starts to reveal its shape under dark skies — the 21mm's contrast and wide field are exactly what that object needs.\u003c\/p\u003e\n\u003cp\u003eIn a 4\" f\/7 refractor — the scope the AT UWA series was tested in most extensively on Cloudy Nights — you're at 34x with a 2.4° true field. That's a proper rich-field setup: the Pleiades fit comfortably in the field with the faint reflection nebulosity around the brighter stars visible on a transparent night. Sweep through Cygnus and you'll catch the entire Veil Nebula arc in a single field of view with an OIII filter.\u003c\/p\u003e\n\u003ch3\u003eObserving Tip\u003c\/h3\u003e\n\u003cp\u003eThe 21mm UWA's 3mm exit pupil in an f\/7 refractor is ideal for hunting faint nebulae and planetary nebulae against a darkened sky background. But here's a trick: pair it with an OIII or UHC narrowband filter for emission nebula work. The 82° field means you're scanning less and seeing more in each field of view, and the high contrast of the eyepiece plays well with the filter's narrowband pass. The North America Nebula, the Veil complex, and the Rosette Nebula all benefit enormously from this combination. The 2\" barrel means your filter threads right onto the eyepiece — no adapter needed.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use this eyepiece with glasses on?\u003c\/strong\u003e\u003cbr\u003eThe 14mm eye relief is comfortable without glasses, but eyeglass wearers will not see the full 82° field. You'll see most of it — probably 70° or so — but the extreme edges will be vignetted. If full-field viewing with glasses is a priority, consider the 28mm UWA, which has 15mm of eye relief in a slightly more forgiving eye position, or look at the AT UFF series, which offers longer eye relief at the cost of a narrower apparent field.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow does the 21mm compare to the 28mm UWA?\u003c\/strong\u003e\u003cbr\u003eSame optical family, different jobs. The 28mm is your widest-field, lowest-power eyepiece — maximum true field, maximum exit pupil, the big-sweep view. The 21mm steps up the magnification and darkens the sky background for higher-contrast deep sky views. It's almost ten ounces lighter than the 28mm and produces a flatter field edge-to-edge, likely because the optical design was refined after the rest of the UWA series. Think of the 28mm as your finder-chart view and the 21mm as your \"now let's look closer\" view.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this eyepiece sharp at the edges in fast scopes?\u003c\/strong\u003e\u003cbr\u003eIn f\/7 and slower scopes, the 21mm UWA is exceptionally sharp to the edge — multiple Cloudy Nights reviewers have noted it's the best edge performer in the AT UWA series. In f\/5 to f\/6 scopes, you may see some field curvature or slight softening at the extreme edge, which is normal for an 82° eyepiece at those speeds. In a fast Dob (f\/4 to f\/5), a coma corrector like a Paracorr helps, and users report results comparable to a Nagler T5 in that configuration.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat's the true field of view in my scope?\u003c\/strong\u003e\u003cbr\u003eDivide your telescope's focal length into 21mm to get the magnification, then divide 82° by that magnification to get an approximate true field. For example: 1000mm focal length → 48x → 1.7° true field. A 1200mm SCT → 57x → 1.4°. A 714mm f\/7 refractor → 34x → 2.4°. The manufacturer's spec has been independently confirmed by drift tests.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this eyepiece parfocal with the other AT UWAs?\u003c\/strong\u003e\u003cbr\u003eYes. It's designed to be parfocal across the AT UWA 82° series (28mm, 21mm, 16mm, 13mm, 10mm, 7mm, 4mm). You can swap eyepieces without refocusing, which keeps your target centered and speeds up your observing.\u003c\/p\u003e\n\u003ch3\u003eAccessories\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAstro-Tech 28mm UWA 82° 2\" Eyepiece:\u003c\/strong\u003e The wide-field companion. Use the 28mm for maximum true field and the 21mm when you need more magnification and contrast. Together they cover the low-to-medium power range in any 2\" focuser.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAstro-Tech 16mm UWA 82° 1.25\" Eyepiece:\u003c\/strong\u003e Step up from the 21mm when you need tighter framing on smaller objects. Parfocal with the 21mm, so you swap without refocusing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCelestron LensPen Optics Cleaning Tool:\u003c\/strong\u003e The best way to clean an eyepiece lens in the field. Retractable brush on one end, carbon cleaning pad on the other.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2\" UHC or OIII Narrowband Filter:\u003c\/strong\u003e Thread onto the 21mm's 2\" barrel for emission nebula work. The wide field and high contrast of the 21mm UWA are ideal partners for narrowband filtering.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFinal Thoughts\u003c\/h3\u003e\n\u003cp\u003eThe AT UWA 82° series has been one of the quiet success stories in affordable wide-field eyepieces — solid performers that don't pretend to be Naglers but deliver a lot more than their price would suggest. The 21mm is the newest addition to the line, and it may be the best one yet. The flat-field performance that Cloudy Nights reviewers keep pointing to — sharp stars to the edge in an f\/7 refractor, competitive with a Nagler T5 in a fast Dob — suggests the optical design genuinely improved between the original series and this release. If you're building an AT UWA set for deep sky work, this is the eyepiece that fills the gap between the 28mm's big-sweep view and the 16mm's tighter framing. If you just want one wide-field 2\" eyepiece that balances magnification, contrast, true field, and weight, the 21mm is a very strong place to start.\u003c\/p\u003e\n\u003ch2\u003eTech Details:\u003c\/h2\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eFocal Length\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e21mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eApparent Field of View\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e82°\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eBarrel Size\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e2\" (50.8mm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eEye Relief\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e14mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eOptical Design\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e6 elements in 4 groups\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eCoatings\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eFully multicoated (all air-to-glass surfaces)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWeight\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e14.1 oz (~400g)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eEyecup\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eSoft fold-down rubber\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWaterproof\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eYes — nitrogen-purged, O-ring sealed\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eParfocal\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eYes — within the AT UWA 82° series\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f0f4f8;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eConstruction\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003eAnodized aluminum, blackened lens edges\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc; font-weight: bold; width: 50%;\"\u003eWarranty\u003c\/td\u003e\n\u003ctd style=\"padding: 10px 14px; border: 1px solid #cccccc;\"\u003e1 year\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Astro-Tech","offers":[{"title":"Default Title","offer_id":41515796922441,"sku":"ATUWA21","price":191.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0573\/7974\/9961\/files\/21mmUWA82_Eyepiece1-9702.jpg?v=1731952281"}],"url":"https:\/\/astronomics.com\/collections\/save-20-on-select-astro-tech-eyepieces.oembed","provider":"Astronomics","version":"1.0","type":"link"}