TeleVue Delos 3.5mm: 72° Wide-Angle Eyepiece: Delos eyepiece with 72-degree field of view
The Delos 3.5mm is the highest magnification in the series. Where most eyepieces with this focal length have a short eye relief, the Delos maintains 20mm. This makes it usable for eyeglass wearers, precisely in the range where that is normally impossible.
This focal length is intended for planetary detail and splitting close double stars, with telescopes of sufficient aperture and on nights with calm seeing.

72 degrees with a long eye relief
The Delos series is designed as a narrower Ethos field of view with more space behind the eyepiece. By keeping the field of view at 72 degrees, TeleVue was able to bring the eye relief to 20mm without the eyepiece becoming unmanageably large.
For eyeglass wearers, that's the difference between seeing the full field of vision and missing a part of it. Even without glasses, you're looking more relaxed because your eye doesn't have to push against the lens.
High magnification, relaxed viewing
With short focal lengths, the eye relief typically becomes shorter as well. This forces you to be right up against the lens and makes long observation sessions tiring. The Delos maintains a consistent eye relief across the entire series.
Calculate beforehand whether your telescope can handle this magnification. As a rule of thumb, the maximum useful magnification is around twice the aperture in millimeters.
Interpupillary distance and adjustable eyecup
The eyecup is steplessly adjustable in height and lockable in any position, with index markings so you can find a previously found position. This ensures your eye's pupil is always in the same position relative to the telescope's exit pupil.
That's more than comfort. A misplaced eye causes edge discoloration and shadows in the image. With a fixed, repeatable eye position, that problem is gone, even during long sessions.
In your telescope
In a telescope with a focal length of 1200 mm, this eyepiece provides approximately 343x with a true field of view of about 0.21 degrees. For your own telescope, you calculate that using the field stop: true field of view = 57.3 x field stop divided by the focal length of the telescope.
The effective field stop of this model is 4.4 mm. That number determines how much sky you actually see, not just the focal length.
Included
- Height-adjustable, lockable eyepiece
- Dust caps for objective and eyepiece lenses
- Filter thread abandoned
Featured accessories
This series accepts TeleVue Dioptrx, which allows you to correct your own astigmatism without glasses. For higher magnifications without sacrificing eye relief, use a Powermate. With a fast parabolic Newtonian, the Paracorr corrects for mirror coma, something no eyepiece alone can solve.
For whom yes and for whom no
- ✓ Planet detail in calm conditions
- ✓ Splitting close binary stars
- ✓ Eyeglass wearers who want high magnification
- Telescopes with a small aperture
- Observing under turbulent seeing conditions
Specifications
| Focal length | 3.5 mm |
| Apparent field of view | 72 degrees |
| Effective field stop | 4.4 mm |
| Eye distance | 20 mm |
| Stitch gauge | 1.25 inches |
| Filter thread | Yes |
| Dioptrx-compatible | Yes |
| Eyecup | Height adjustable and lockable |
| Coating | Fully multi-coated, blackened lens edges |
All wide-angle eyepieces are on the page featuring wide-field eyepieces. You can find the complete selection of this merk on the TeleVue merk Page.





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