It was natural to take lessons learned from the tremendously successful Ethos project and apply it going forward. In the fall of 2008, Paul Dellechiaie was tasked to investigate a long eye-relief eyepiece design in the 70° AFOV range, retaining the key performance goals met with Ethos.
My father named Paul’s design, “Delos.” Delos is a beautiful Greek island which happens to be the mythical birthplace of Apollo, god of light. More importantly the name was chosen to give recognition to Paul, principal designer of both Delos and Ethos. — David Nagler.
Tele Vue’s Delos 17.3mm is the longest focal length in the Delos series. Still with a generous 20mm eye-relief and wide 72° apparent field of view you will enjoy an emmersive viewing experience that is hard to match. The optimized combination of field size and eye-relief makes Delos an eyeglass wearers dream!
There is a good chance the TeleVue Delos will be seen as the ultimate combination of performance, viewing comfort and price. If you’ve been keeping a spot in your case for an affordable, premium eyepiece, you should consider a Delos 17.3mm – it won’t disappoint! Lessons learned from the tremendously successful Ethos series were applied to develop this long eye-relief, 72° apparent field of view eyepiece line.
The Delos 17.3mm has a standard 1.25″ barrel making it suitable for almost any telescope. An excellent choice for low power viewing in bino-viewers!
Tele Vue Delos 17.3mm – Specifications
- Model # EDL-17.3
- Focal Length 17.3mm
- Barrel Size 1.25″
- Apparent Field of View 72°
- Eye Relief 20mm
- Weight 408g
- Field Stop 21.2mm
Tele Vue introduced the Delos In 2011. The series includes mid-to-short focal lengths with all providing 20mm eye-relief and 72° apparent field of view. Tele Vue designer Paul Dellechiaie rethought every optical, mechanical, and ergonomic aspect to achieve reference-standard performance for any visual application.
The Delos was conceived as a narrower field Ethos. Eye-relief was increased while still controlling pupil aberrations by reducing the field to 72°. This was achieved without making the eyepiece too large. With Ethos performance standards as benchmarks, the Delos design achieves full field sharpness, virtually perfect f θ (theta) distortion mapping, and colour neutrality. Image fidelity is maximized utilizing glass matched multicoatings and anti-reflection surfaces throughout the eyepiece.
Contrast is further enhanced with a new, continuously adjustable height eyeguard system that can be locked in any position. Since the Delos eye-lens measures a quite large 35mm in diameter, preventing stray light from reflecting off the first surface and extraneous light from entering your eye pays off in a nice increase in perceived contrast. The eyeguard’s sliding action allows for positioning the soft rubber eyeguard at the ideal height to suit the observer’s preference. Indicator marks on the eyepiece body are handy reference guides for setting your perfect position. The eye-guard can also rotate for Dioptrx users.
Delos 6- & 10-mm
Delos Eyepieces Reviews
Quotes from review of 10mm, 4.5mm, & 14mm Delos on Alpha Lyrae website.
- The stunningly flat field and lack of optical aberrations really allow clusters to shine and galaxies and nebulae are resplendent.
- It is rare I use any other eyepiece for deep sky observing anymore.
- Quite simply, the planetary performance matches the very best dedicated planetary eyepieces I have ever used such as the TMB Super Monocentric.
- There is also an indescribable quality which makes them a very easy and relaxing eyepiece to use.
— Hodgson, Matthew. “Televue Delos Eyepiece Review”. Alpha Lyrae (05 May 2014). Full Review.
Excerpt from Delos 17.3mm review in Astronomy Now magazine.
Examining the stars of the Pleiades served up by the 17.3mm Delos, I was immediately struck by the pinpoint star images right to the edge of the field-of-view. Contrast was superb. Nor could I detect any signs of off-axis distortions.
— Neil English. “Tele Vue Delos”. Astronomy Now (April 2013). Read Full Review (Delos 6-,10- & 17.3-mm) now.
Sky & Telescope Hot New Product for 2012 Award
More Than Expected (Delos 6- and 10-mm)
And while the 20 mm of eye relief make them attractive for those who observe wearing eyeglasses, it was the “distinctly pleasurable” observing experience that most impressed our reviewer. When it comes to eyepiece design, The Delos seems to have hit all the sweet spots.
— Editors. “Hot New Products for 2012”. Sky & Telescope (January 2012). p.39.
Excerpt from ATT review of Delos 6- & 10-mm eyepieces:
Wide-Field Eyepieces That Pack a Planetary Punch
With the Delos, the eyepiece simply “disappears” and allows the observer to observe. I could find nothing whatsoever to complain about; the “twist and tighten” eye relief adjustment feature is the best I’ve ever seen in any eyepiece, and the optics are essentially perfect. Tele Vue somehow always finds a way to continuously improve upon their eyepieces and the Delos is certainly no exception. Bottomline: If you’re in the market for a planetary eyepiece, you owe it to yourself to consider the Tele Vue Delos.
— Erik Wilcox. “Tele Vue Delos”. Astronomy Technology Today (Nov-Dec 2011). Full Review.
Review of the 6mm & 10mm Delos Eyepieces from Astronomy Magazine, December 2011
- Contrast was excellent – right up there with some of the best planetary eyepieces I’ve ever used.
- I searched but saw no internal reflections or scattering in either eyepiece.
- The flat field the Delos eyepieces produce really made star fields pop. Open clusters epitomized the old standard “diamonds on velvet”. Stars on and off axis showed no sign of astigmatism.
- Tele Vue has constructed an eyepiece that stands with the best deep-sky and planetary eyepieces on the market.
— Trusock, Tom. “Astronomy tests Tele Vue’s new eyepiece line”. Astronomy Magazine (December 2011). Full Review.
Excerpts from Sky & Telescope, June 2011, review of Delos eyepieces:
- WHAT WE LIKE:
- Essentially perfect optics
“Immersive” observation experience
- WHAT WE DON’T LIKE:
- Trying to nail down why the observing experience is so pleasurable.
I spent several nights viewing the Moon, Saturn, stars and nebulae with a variety of telescopes … .
The Delos eyepieces are “easy to look through … . They have flat fields, delivering absolute pinpoint stars from edge to edge with no hint of color aberration. The view, especially during the daytime, is very pure with no noticeable color tint. And there wasn’t a hint of ghosts or reflections, even with the brightest stars”.
“What caught me a bit off guard, however, was something that’s best described as the observing experience. It was distinctly pleasurable.”
“I have the sensation of looking out of a circular window rather than into an eyepiece.”
— di Cicco, Dennis. “Tele Vue’s New Delos Eyepieces”. Sky & Telescope (June 2011). p. 58, 59.