Ten 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.
The Optics
Seven 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.
1.25" Barrel
Fits 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.
Waterproof
O-ring sealed and waterproof. Prevents internal fogging, dust intrusion, and fungus. The sealed construction extends the optical life of the eyepiece.
What's Included
- Astro-Tech 10mm 82° UWA 1.25" eyepiece
- Lens caps (top and bottom)
Features
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82° apparent field of view — Nearly three times the area of a standard Plossl. Wide enough to be immersive while maintaining high contrast.
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7-element fully multi-coated optics — High contrast, good edge correction, minimal scatter.
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10mm focal length — The bridge between deep-sky and planetary power. 125x in a 1250mm Dob, 71x in a 714mm refractor, 203x in a 2032mm SCT.
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12mm eye relief — Comfortable without glasses. Tight for eyeglass wearers.
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Waterproof, O-ring sealed — Cold-weather ready. Dust and fungus resistant.
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1.25" barrel with safety groove — Universal 1.25" compatibility.
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Lightweight — No balance concerns on any telescope.
Under the Night Sky
In 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.
Planetary 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.
On 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.
In 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.
Community Says
"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. — Cloudy Nights AT UWA 7mm/10mm/13mm review.
"Best deal in EPs...ever." This owner bought the full 4mm–16mm set after testing one. — Cloudy Nights AT UWA discussion.
Observing Tip
The 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).
FAQ
How does this compare to a 10mm Plossl?
The 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.
Is this parfocal with the other 82° UWAs?
Yes — 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.
Will this work well in an SCT?
Yes. 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.
Final Thoughts
The 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.
