At a Glance
3.5mm
Focal Length
72°
Apparent FOV
20mm
Eye Relief
1.25"
Barrel Size
Score Breakdown
Overview
The Tele Vue Delos 3.5mm is a serious high-magnification eyepiece built for observers who spend long nights studying the Moon, planets, and double stars. At 3.5mm focal length, it pushes high power on most telescopes, which means surface detail on Jupiter, Saturn's ring divisions, and lunar craters become genuinely rewarding targets rather than blurry disappointments. What separates this from cheaper high-magnification options is the 20mm eye relief.
Most eyepieces this short make you press your eye uncomfortably close to the lens; this one lets you observe relaxed, with or without glasses. The 72-degree apparent field of view is also unusually generous for a planetary eyepiece, giving you enough sky to track objects without constant nudging. Fully multi-coated optics keep contrast high and minimize light scatter, which matters most when you are trying to pull subtle color bands or shadow detail out of a bright planetary disk.
Worth noting: at $438, this is a premium investment. It rewards a quality telescope with good optics. On a lower-grade instrument, the eyepiece will not compensate for the scope's limitations, though it will never be the weak link in your setup.
Key Features
- 20mm eye relief makes high-power viewing comfortable, including for eyeglass wearers
- 72-degree apparent field of view is wider than most planetary eyepieces, reducing the need to re-center objects constantly
- Fully multi-coated optics improve contrast and color accuracy, which is critical for planetary detail
- Adjustable rubber eyecup blocks stray light, preserving image contrast during outdoor sessions
- 3.5mm focal length delivers high magnification suited to lunar craters, planetary surfaces, and close double stars
- Fits standard 1.25-inch focusers found on most telescopes
- Tele Vue's build quality and optical standards make this a durable long-term addition to any eyepiece collection
Specifications
| Focal Length | 3.5mm |
| Apparent FOV | 72° |
| Eye Relief | 20mm |
| Barrel Size | 1.25" |
| Design | Modified Nagler |
| Elements/Groups | 8/4 |
| Series | Delos |
| Coating | Fully Multi-Coated |
| Waterproof | No |
Popular Telescopes for This Eyepiece
ZWO Seestar S50
71x / 0.7mm exit pupil / Apochromat Refractor
ZWO Seestar S30
43x / 0.7mm exit pupil / Apochromat Refractor
Unistellar eVscope Equinox
129x / 0.9mm exit pupil
Celestron NexStar 130SLT
186x / 0.7mm exit pupil / Newtonian
Amazon Reviews
Just as clear and crisp as you'd expect a TeleVue eyepiece to be... easily discern detailed albedo features (4" refractor) during Mar's recent perigee. (and delivery was so fast that I think Agena Astro ships while I am still looking...)
Nicely built, high-quality Televue eyepiece, no argument there. With such a high power, very hard to find a night with nice steady air to where this eyepiece is actually usable. I have several other TeleVue eyepieces and will be keeping them, but this one will most likely be sold on Ebay or somethin...
This is a great piece of glass, but it should be for the price. I usually use it in the 100 to 150x, have gone to 300 which really gets the planets moving.
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