Ethos eyepieces are currently on long back order
Tele Vue is known for its in-house eyepiece and telescope designs by Al Nagler; the development of the Ethos series brings new meaning to the term “in-house.” The concept for this eyepiece series was proposed by Tele Vue President David Nagler, with performance parameters giving it the fundamental characteristics (the ethos) of a Tele Vue eyepiece: high contrast, comfortable eye relief and full field sharpness. Control of astigmatism, field curvature, lateral colour, angular magnification distortion correction, and low pupil sensitivity for daytime use were specified criteria.
Following Tele Vue’s philosophy of pushing the state of the art, long-time Tele Vue employee and optical design protégé Paul Dellechiaie took up the challenge and designed the basic eyepiece form. Under Al’s guidance, Paul tweaked his design to fulfill the original goals.
While sharpness is inherent to the optical design, contrast is maximized through the intelligent use of flat finished baffles and ultra low reflectance, high efficiency coatings tuned to the composition of each element.
Introduced at the 2007 Northeast Astronomy Forum, Tele Vue once again broadened the amateur astronomer’s perspective on the universe with: 100° of pure Tele Vue quality. The field area of this new eyepiece is more than 50% larger than an 82° field. The Tele Vue Ethos 17mm is essentially multiple eyepieces, delivering the true field size of a longer focal length, narrower apparent field eyepiece with the benefits of higher power and darker sky background.
We invited NEAF attendees to take a look and see the universe the way we think it was meant to be experienced, with a field of view incredibly wide and sharp! We were very pleased indeed by the response and validation of our design goals.
The Tele Vue ETHOS 17mm is an ideal complement to the 31mm Nagler Type-5. They are parfocal (both have focus locations about 10mm above shoulder) and the 31mm Nagler Type-5 has exactly twice the true field area.
Tele Vue Ethos 17mm Specifications
|Effective Field Stop Diameter
Technical reference on rectilinear and angular magnification distortion.
Compare eyepieces by quantifying contrast, power, and apparent field.