The 4.8mm XWA is the eyepiece you pull out when the atmosphere cooperates and you want to push your scope to its limits. In a 12-inch f/5 Dobsonian, it delivers 313x — deep into high-power territory where Jupiter's cloud bands show festoons, turbulence, and the swirling oval of the Great Red Spot. In a 10-inch, it runs 260x. In a 4-inch f/7 refractor, 149x. And the 110° apparent field — the widest in the XWA line — means you're not squinting through a pinhole to see it. You're looking through a porthole. One owner put it simply: "I have never had such a huge crisp high mag view like this before."
110° — The Widest in the Line
The 4.8mm and the 3.5mm are the two widest-field eyepieces in the Astro-Tech XWA series. While the 7mm, 9mm, 13mm, and 20mm deliver 100° apparent fields, the 4.8mm and 3.5mm push to 110°. That extra 10° matters at high magnification. The true field is already narrow at 260x+ — the wider apparent field gives you more sky in the eyepiece and more time before the object drifts out of view on an untracked Dobsonian. It's the difference between 30 seconds and 45 seconds of drift time on a planet, and at high power, that difference changes the experience.
The Optics
Eight elements, fully multi-coated with blackened lens edges. Corrected for telescopes as fast as f/4. At 4.8mm, you're demanding a lot from any optical design — the exit pupil is tiny, the magnification is extreme, and optical aberrations that are invisible at longer focal lengths become visible. The 4.8mm XWA handles it well. The field is sharp across the center and middle zones, with some softening in the last 10–15% at fast focal ratios. At f/5 and slower, the correction tightens. The 8-element design keeps contrast high — important when you're trying to detect subtle planetary detail. Cloudy Nights members who have used the 110° XWAs describe them as among the best values in the hyperwide category — the performance gap with premium alternatives narrower than the price gap would suggest.
Eye Relief
Eye relief is 15mm — remarkably generous for a 4.8mm eyepiece. Most eyepieces at this focal length offer 5–10mm of eye relief, which means pressing your eye uncomfortably close to the lens. The 15mm here means comfortable, relaxed viewing even during long planetary observing sessions. Eyeglass wearers can use it, though they'll lose some of the outer 110° field. The soft rolldown eyecup accommodates both use cases.
Dual 1.25"/2" Barrel
Removable 2" collar reveals a 1.25" barrel underneath. Safety grooves on both barrels engage your focuser's thumbscrew. At 19 ounces — the same weight as the 3.5mm XWA — this is a substantial eyepiece at a short focal length. The weight reflects the 8-element optical design needed to deliver a 110° field with 15mm of eye relief.
Waterproof
O-ring sealed and waterproof. Prevents internal fogging during cold-weather planetary sessions, keeps dust out, and protects the internal coatings from humidity and fungus over the life of the eyepiece.
What's Included
- Astro-Tech 4.8mm 110° XWA 1.25"/2" eyepiece
- Removable 2" collar (installed)
- Lens caps (top and bottom)
Features
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110° apparent field of view — The widest field in the XWA line (shared with the 3.5mm). At extreme magnification, the extra 10° over the 100° models gives you noticeably more drift time and a more immersive view.
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8-element fully multi-coated optics — Blackened lens edges, designed for high contrast at focal ratios down to f/4. Maintains sharpness where it matters — across the center and middle zones where planetary detail lives.
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4.8mm focal length — Extreme high-power. 260x in a 1250mm Dob, 313x in a 1500mm 12-inch, 149x in a 714mm refractor. This is the eyepiece for nights of excellent seeing.
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15mm eye relief — Exceptionally generous for a 4.8mm eyepiece. Comfortable for extended planetary sessions. Usable with eyeglasses.
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Dual 1.25"/2" barrel — Removable 2" collar. Safety groove on both barrels.
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Waterproof, O-ring sealed — Cold-weather performance, dust resistance, long-term coating protection.
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19 ounces — Check balance on lightweight scopes. The weight reflects the complex optical design.
Under the Night Sky
This is a planetary eyepiece. In a 12-inch Dob at 313x, Jupiter fills enough of the field to show real weather. The equatorial belts show festoons and barges. The Great Red Spot shows its oval shape, its color, and the turbulence wake trailing behind it. On exceptional nights with steady seeing, you start to pick up subtle banding in the temperate zones — detail that simply doesn't exist at lower magnifications.
Saturn at 313x shows the full ring system in detail. Cassini's Division is a clean gap, not a faint line. The crepe ring is visible against the globe. The shadow of the globe on the rings, and the rings' shadow on the globe, are distinct. Titan shows as a tiny disk, not a point. On the best nights, you can detect the slight color difference between the inner and outer ring.
Mars at opposition is where 313x really delivers. The dark surface features — Syrtis Major, Mare Erythraeum, Solis Lacus — show clearly. The polar cap is a distinct bright spot with a visible edge. On good nights in larger scopes, subtle surface detail emerges that you'd never catch at lower magnification.
The Moon at 313x is a landscape. Crater walls show layered terracing. Central peaks cast long shadows along the terminator. Rilles and graben are resolved as thin dark lines. The Alpine Valley shows its floor. You're not looking at the Moon — you're flying over it.
This eyepiece is not for every night. At 260x+ you need steady seeing — Antoniadi II or better — or the image softens and swims. On those nights, use the 7mm or 9mm XWA instead. But on the nights when the seeing locks in, the 4.8mm XWA shows you what your telescope can really do.
Community Says
"I liked the 4.7mm right away — it was one of my first 100° eyepieces."
— Cloudy Nights XWA Eyepieces discussion. This owner was exploring the XWA line for the first time and found the 110° models immediately compelling at high magnification.
The 110° XWAs are described on Cloudy Nights as among the best value propositions in the hyperwide category. Users note the performance gap with premium alternatives is much narrower than the price gap — a consistent finding across multiple threads and scopes.
Observing Tip
Don't reach for this eyepiece first. Start your planetary session with the 13mm or 9mm XWA to find the target and assess the seeing. If the stars look steady at 140–180x — tight Airy disks with stable diffraction rings — swap to the 4.8mm. If the stars are bloated or shimmering, stay at lower power. The atmosphere sets the ceiling, not the eyepiece. But when the ceiling is high, this is the eyepiece that takes you there.
FAQ
Is this too much magnification for my telescope?
It depends on aperture and seeing. In a 12-inch scope, 313x is useful on steady nights — that's about 26x per inch, well within the theoretical limit. In a 10-inch, 260x is similarly reasonable. In a 6-inch, 210x is pushing the practical limit and will only work well on the steadiest nights. In a 4-inch refractor at 149x, you're at a comfortable power for planets. The rule of thumb: if the image looks soft or mushy, the seeing won't support this magnification tonight. Switch to a longer focal length.
How does this compare to the 3.5mm XWA?
Both are 110° AFOV, 8 elements, 15mm eye relief, 19 oz. The difference is focal length — the 3.5mm delivers even higher magnification (357x in a 1250mm scope vs. 260x for the 4.8mm). The 4.8mm is the more versatile of the two — it hits very high magnification while still being usable on most steady nights. The 3.5mm is for nights of exceptional seeing in larger apertures. Most observers would choose the 4.8mm first unless they already own a 5mm eyepiece.
Can I use this for deep-sky objects?
At 260x+, deep-sky targets are limited to compact, bright objects — planetary nebulae (M57, NGC 7662, NGC 6826), tight globular cores, and close double stars. Large diffuse nebulae and galaxies are too faint and too large for this magnification. The 7mm, 9mm, 13mm, and 20mm XWAs are better choices for deep-sky.
Final Thoughts
The 4.8mm XWA is not an everyday eyepiece — it's the eyepiece for the nights when everything comes together. Steady seeing, a well-collimated scope, and this eyepiece deliver the kind of planetary views that remind you why you bought a telescope in the first place. The 110° field means you don't have to choose between magnification and comfort. The 15mm eye relief means you can observe for an hour without fatigue. And when you drop it into a 12-inch Dob on a night of Antoniadi II seeing and watch Jupiter's cloud bands scroll past, you understand why an owner called it "a must have." It is — for the right nights and the right targets.
