Description Introduced at the 2007 Northeast Astronomy Forum (NEAF), Tele Vue once again broadened the amateur astronomer's perspective on the universe with: 100° of pure TeleVue quality. The field area of this eyepiece is more than 50% larger than the 82° field of the Nagler eyepiece design. The Tele Vue 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. 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. Specifications 17-mm Model # ETH-17.0 Focal Length (mm) 17 Barrel Size (in.) 2" Apparent Field of View (deg.) 100 Eye Relief (mm) 15 Weight (lb / oz) 1.55 / 24.8 Field Stop (mm) 29.6
