Tele Vue Ethos Eyepiece User Manual

10mm ETHOS EYEPIECE INSTRUCTIONS

Warning: Do not unscrew any sections of the eyepiece, as the lenses
may fall out, thereby voiding the warranty.

Tele Vue 10mm ETHOS Specifications:

Apparent Field: 100º
Focal length: 10mm
Effective Field Stop: 17.7mm
Eye Relief: 15mm (accepts Tele Vue’s Dioptrx astigmatism corrector)
Barrel Size: 2" / 1¼"
Weight: 1.1 lbs.

Thank you for purchasing the Tele Vue 10mm ETHOS, which nicely fills the focal length gap between
8mm and 13mm models. It also becomes the centerpiece of a great 6mm, 10mm and 17mm ETHOS
set.

The 10mm ETHOS fits both 2" and 1¼" focusers or diagonals. Typically, in a 2" focuser, you will
focus “out” a bit (about 3/8" further than a 26mm Nagler Type 5), and in a 1¼" focuser, you’ll focus
“in” about ½" inch further than a 25mm Plössl.

The 10mm is parfocal with the 13mm ETHOS.

Note: the in-travel may prevent focusing in some refractors when using the Tele Vue 60º Everbrite
diagonal, which has an unusually long optical path.

Since it is designed as a 1¼" eyepiece, there is NO optical benefit by using a 2" holder. The 2"
barrel is included just for convenience, but it is also threaded to accept our EBX-2120 2" extension
tube, which allows the use of 48mm filters.

Its 59mm rubber grip diameter makes this model usable in binocular viewers -- for most people.

For 1¼" holders:

1) Back off the lock screw in the 2" barrel section of the eyepiece so it can be fully inserted into the
holder.

2) If the holder has a lock screw, rotate the eyepiece so that the screw slips into the slot in the 2"
section of the eyepiece barrel. Your holder lock screw clamps to the 1¼" barrel of the eyepiece,
while the eyepiece lock screw clamps (if desired) to the outside of your holder for maximum safety.

3) If your holder doesn’t have a lock screw, be sure to clamp the eyepiece lock screw onto the
outside of the holder. Please note that this eyepiece is heavy, and can fall out of holders with a “slip
fit” unless the lock screw is used!

For 2" holders:

1) Remove the eyepiece lock screw (Don’t lose it!)

2) Use the lock screw on your 2" holder, being careful not to let it slip into the slot in the 2" barrel of
the eyepiece.

3) The eyepiece will not “bottom” on Tele Vue 2" diagonals. Be careful if using diagonals by other
manufacturers.

For Newtonians/Dobsonians, we recommend our Paracorr coma corrector to eliminate the mirror
coma in f/5.5 or faster scopes. This permits the same kind of full field sharpness routinely seen in
Tele Vue’s NP-Series refractors. You can use the 10mm ETHOS 2" barrel in the Paracorr with the
tunable top raised to its maximum, mark 1 on Paracorr slot. However, you can get closer to ideal
coma correction by using the 10mm ETHOS in a high-hat 2" to 1¼" adapter (part ACR-2125 or satin
finish ASF-8125) and setting the Paracorr to its full down position, mark 5 on Paracorr slot.

Tele Vue Optics, Inc., 32 Elkay Drive, Chester, NY 10918 845-469-4551

V4/20/2009

Note: when using a 1¼" filter in ETHOS, be careful not to accidentally set the Paracorr’s tunable top
to its lowest setting, as the bottom of the filter might contact the Paracorr’s upper lens. It’s best to
thread a 2" filter onto the front of the Paracorr, or add our EBX-2120 2" extension tube to the 2"
barrel of ETHOS, for general use. For higher magnifications with a 100º field, use Tele Vue Barlows
and Powermates. When using ETHOS in 2" Powermates, use its 2" barrel.

Note: As with the Paracorr, do not use a 1¼" filter when using a 2X Powermate, as it will contact the
upper lens in the 2X Powermate. Again, the best solution is to use 2" filters in front of the
Powermate.

If you have eyesight astigmatism, you can add Tele Vue’s Dioptrx Astigmatism Corrector to ETHOS,
instead of using eyeglasses, to get the sharpest view possible (check dioptrx.com for more details).

We wish you years of exciting viewing with ETHOS, and we welcome comments on your personal
experiences.

Telescope Magnification (x) True Field (°) Exit pupil (mm)

TV-60, TV-60is 36.0 2.82 1.67

TV-76 48.0 2.11 1.59

NP-101, NP-101is 54.0 1.88 1.85

TV-85 60.0 1.69 1.43

NP-127is 66.0 1.54 1.92

TV-102, TV-102iis 88.0 1.15 1.16

Approximate dimensions of 10mm ETHOS

A. Length of barrel above reference surface (3.8")
B. Overall length below reference surface (1.6")
C. Length of 2" barrel (1.1")
D. Diameter of black barrel (2.3")
E. Depth of 1¼" barrel (1.1")
F. Approx. location of field stop (0.27")

Reference surface is location of 2" barrel seat

Tele Vue Optics, Inc., 32 Elkay Drive, Chester, NY 10918 845-469-4551

V4/20/2009