Tele Vue 13mm Ethos Eyepiece.

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, 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.

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; 100º 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 82º 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.

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.

Tele Vue 13mm Ethos Specifications:

Apparent Field: 100º
Focal Length: 13mm
Effective Field Stop: 22.3mm
Eye Relief: 15mm (accepts DIOPTRX™ eyesight astigmatism corrector)
Barrel Size: 2”/1¼”
Weight: 1.25lbs.

Price - £421.00 + £7.50 p&p.

Sky &Telescope Ratings:
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.

If 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.
The 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.

See the reviews in the October 2007 issue of Sky & Telescope and ASTRONOMY May 2008.

The Astronomy Shop

1 Tone Hill. Wellington

Somerset TA21 0AU

United Kingdom

Telephone: +44 (0)1823 665510