The 17mm ETHOS is an ideal complement to the 31mm Nagler Type-5. They are parfocal (both have focus locations about 3/8" above shoulder) and the 31mm Nagler Type-5 has exactly twice the true field area. TeleVue is known for its in-house eyepiece and telescope designs by Al Nagler; our latest eyepieces brings new meaning to the term "in-house." The concept for this eyepiece series was proposed by TeleVue President David Nagler, with performance parameters giving it the fundamental characteristics (the ethos) of a TeleVue eyepiece: high contrast, comfortable eye relief and full field sharpness. Control of astigmatism, field curvature, lateral color, angular magnification distortion correction, and low pupil sensitivity for daytime use were specified criteria. Following TeleVue's philosophy of pushing the state of the art, long-time TeleVue 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, TeleVue once again broadened the amateur astronomer's perspective on the universe with: 100° of pure TeleVue quality. The field area of this new eyepiece is more than 50% larger than an 82° field. The TeleVue Ethos 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. Specifications Focal Length 17mm Barrel Size 2" Apparent Field of View 100 degrees Eye Relief 15mm Weight 1.55lbs Field Stop 29.6mm
