Tele Vue 8mm Ethos Eyepiece User Manual
8mm ethos eyepiece instructions
Tele Vue Optics, Inc., 32 Elkay Drive, Chester, NY 10918 845-469-4551
V4/3/2009
8mm ETHOS EYEPIECE INSTRUCTIONS
Tele Vue 8mm ETHOS Specifications:
Apparent Field:
100º
Focal length:
8mm
Effective Field Stop:
13.9mm
Eye Relief:
15mm (accepts Tele Vue’s Dioptrx astigmatism corrector)
Barrel Diameter
53.3mm (ideal for binocular viewer applications)
Parfocal
with Tele Vue 1¼" eyepieces
Barrel Size:
2" / 1¼"
Weight:
0.95 lbs.
Thank you for purchasing the Tele Vue 8mm ETHOS, which fits both 2" and 1¼" focusers
or diagonals. Typically, in 2" mode, you will focus “out” about ¾" further than a 26mm
Nagler Type 5, and in 1¼" mode, if you use Tele Vue’s "high-hat" 2"-1¼" adapter, it will be
parfocal with Tele Vue’s Plössls, Radians, Type 6 Naglers, Nagler Zooms and 1¼"
Panoptics.
Since it is designed as an 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 2"
extension tube (EBX-2120), which allows the use of 48mm filters.
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 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. Firmly lock the 8mm ETHOS in the 1¼" Paracorr adapter with the tunable
top set to the 4 setting in the slot.
Note: when using a 1¼" filter in the 8mm 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 2" extension tube (EBX-2120) to the 2" barrel of the 8mm ETHOS.
Warning: Do not unscrew any sections of the eyepiece, as the lenses may fall
out, thereby voiding the warranty.