Tele Vue 4.7mm Ethos Eyepiece - Manual (Page 2)

Tele Vue Optics, Inc., 32 Elkay Drive, Chester, NY 10918 845-469-4551
Tele Vue 4.7mm Ethos-SX 110°
(Simulator eXperience)
A 60% Greater True Field Area Over the Groundbreaking 3.7mm Ethos-SX 110°
Al Nagler eagerly pushed Ethos designer Paul Dellechiaie to extend the new 3.7mm
focal length to reach 110°, the same field as the LEM Simulator optics Al designed 45-years
ago to train NASA astronauts for lunar landings (see below). Years after the LEM program, the
memory of the 110° view of the simulated lunar surface moving through the triangular cabin
window of the LEM inspired Al to develop an “Ultra Wide Angle” (his patent title) telescope
eyepiece to approach that “simulator experience.” When the 82° Nagler eyepiece hit the
observing fields, it changed how amateur astronomers viewed the heavens. An early customer
dubbed it a “spacewalk” view.
Essentially, “the experience” is about creating an image as natural as one sees with the
unaided eye. With Paul's help, Al's initial dream for amateur astronomers is now fully realized.
The new 4.7mm Ethos-SX, like its 3.7mm progenitor, is designed and crafted to combine its
exceedingly wide field of view with all the contrast, color-rendition, distortion correction and
center-to-edge sharpness needed to achieve that natural view.
Beyond the desire to simply achieve 110° for an extended deep sky field (21% more
AFOV area than 100°) the 4.7mm, like the 3.7mm is a superb planetary eyepiece. Its power
rests midway between the 3.7mm and 6mm focal lengths. Compared to the 3.7mm, its lower
power and 60% greater field area extends the SX-110° technology to more telescope
applications than ever before.
We don't think we can aptly describe Al’s original experience of “flying over the moon,”
but YOU can now experience what the astronauts saw four decades ago in a new dimension:
4.7mm!
Apollo Lunar Excursion Module (LEM) Simulator
Seen at left is one of the Infinity Display Projectors
that fit over the LEM simulator. A separate unit
was required for each window of the spacecraft.
You can imagine why the astronauts affectionately
dubbed the full collection of simulators for the
Apollo mission “The Great Train Wreck!”
The optical design consisted of a series of six-foot
mirrors, beam splitters, and a three-foot lens. It
took a televised image of the lunar surface along
with a separate background star field and projected
the combined image to infinity. With the triangular
compressor lens (seen at left) placed against the
triangular window of the simulated LEM cabin, the
astronauts saw star fields or the Moon filling the
LEM window. The Infinity Display Projectors
essentially acted as giant 110º eyepieces, each
with a 12” exit pupil and 12” eye-relief. So, at one-
foot from the window, the astronauts saw a 110º
field of view.
And, you thought Ethos-SX eyepieces were big.
Imagine that hanging off your telescope!