Tele Vue Ethos 13mm, 100° apparent field eyepiece
|Focal Length (mm)||13|
|Barrel Size (in.)||2" & 1¼"|
|Apparent Field of View (deg.)||100|
|Eye Relief (mm)||15|
|Weight (lb / oz)||1.30 / 20.8|
|Field Stop (mm)||22.3|
Tele Vue is known for its in-house eyepiece and telescope designs by Al Nagler; our latest eyepiece brings new meaning to the term "in-house." The concept for this eyepiece was first 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 color, angular magnification distortion correction (technical reference), 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 protege 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. At the 2007 Northeast Astronomy Forum, Tele Vue once again broadened the amateur astronomer's perspective on the universe and introduced a new observing experience; 100° of pure Tele Vue quality. With a 13mm focal length evoking the original "Nagler" revolution, the field area of this new eyepiece is more than 50% larger than an 82° field. 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.
This is what Sky & Telescope Magazine has to say about this eyepiece
• Optical Performance ***** (5 Star)
• Sensibly perfect. No meaningful improvements possible.
• Just as the original 13-mm Nagler set a new standard for deep-sky observing in 1981, the Ethos sets a new standard today. Owning one will guarantee long lines at your telescope during any star party.
• f I were dropped on a desert island tomorrow with the 12-inch scope and only one eyepiece, I'd want it to be the Ethos.
• Some of the views were simply stunning. The globular cluster Messier 13 in Hercules appeared as a sprawling sphere with thousands of resolved stars, many sweeping outward in sinuous arcs.
• Even under the most critical examination, bright stars look sharp and round across the entire field.
• The Ethos hasn't sacrificed one bit of on-axis performance in achieving its 100° apparent field.
• he view of a starry sky with the Ethos and TV-NP127is is nothing short of breathtaking.
• Besting the fields of other astronomical eyepieces by more than 20% in diameter and more than 50% in area, Ethos is a stunning optical achievement.