TeleVue ETHOS ETH-170 User manual

Tele Vue Optics, Inc., 32 Elkay Drive, Chester, NY 10918 845-469-4551
Thank you for purchasing the Tele Vue 17mm ETHOS, the eyepiece line that
earned a 2009 Hot Product Award from Sky and Telescope magazine.
We wish you years of exciting deep sky viewing with the 17mm ETHOS, and we
welcome comments on your personal experiences.
17mm ETHOS EYEPIECE INSTRUCTIONS
Warning: Do not unscrew any sections of the eyepiece, as the lenses may fall out,
thereby voiding the warranty.
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 17mm ETHOS
2" barrel in the Paracorr with the tunable top at its full
down position, Mark 5 (top mark on Paracorr slot).
Note, the 17mm ETHOS is an ideal complement to
the 31mm Nagler Type-5. They are parfocal (both
have focus locations about 3/8" above shoulder) and
the 31mm Nagler Type-5 has exactly twice the true
field area.
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).
Telescope
Magnification (x)
True Field (°)
Exit pupil (mm)
TV-60is
21.1
4.71
2.83
TV-76
28.2
3.53
2.70
NP-101, NP-101is
31.8
3.14
3.15
TV-85
35.3
2.83
2.43
NP-127is
38.8
2.57
3.27
TV-102, TV-102iis
51.8
1.93
1.98
Tele Vue 17mm ETHOS Specifications
Apparent Field:
100º
Focal length:
17mm
Effective Field Stop:
29.6mm
Eye Relief:
15mm
(accepts Tele Vue’s
Dioptrx astigmatism
corrector)
Barrel Size:
2" (accepts 2" filters)
Weight:
1.55 lbs.
Approximate dimensions of 17mm ETHOS
A. Length of barrel above reference surface (4.5")
C. Length of 2" barrel (1.4")
D. Diameter of black barrel (2.44")
F. Effective location of field stop (-0.39")
(Above Reference surface location of 2" barrel seat)

The Basics
1.
2. Exit Pupil: the circle of light where you
place your eye.
3. True Field of View: angle in sky in
degrees.
4. Apparent field: the angle the field stop
circle appears in your vision, when you
look through the eyepiece.
5. Eye relief: distance from center of eye
lens to exit pupil.
Some General Thoughts
1. Choose a range of eyepieces in
low/mid power in ratios of 1.4 to 1.7
field stops.
2. Limit low powers to exit pupils of 7mm
or less for reflecting telescopes.
3. Limit high power to 200x - 300x (at-
mospheric limits) or to a 0.4mm minimum
exit pupil.
4. If you need to wear eyeglasses to
correct your eyesight astigmatism, select
eyepieces with at least 15mm of eye
relief or consider using DIOPTRX instead
of eyeglasses.
5. In general, large apparent field eye-
pieces are more spectacular and permit
more magnification, darker sky back-
grounds and smaller exit pupils (minimiz-
ing eyesight limitations) than narrow field
eyepieces having similar field stops.
Of course everyone has their own needs
and preferences in eyepieces. Keep those
factors in mind when choosing between
eyepiece types.
For data specific to your telescope visit the
Tele Vue Eyepiece Calculator at Televue.
com.
Eyepiece Reference Data To Assist in Building Your Collection
32 Elkay Dr., Chester, NY 10918 [phone] www.televue.com
Telescope Magnification = Telescope objective F.L.
eyepiece F.L.
Exit Pupil Diameter = eyepiece F.L.
telescope f/#
TFOV =eyepiece field stop dia.
telescope obj. F.L. x 57.3°
Focal
Length
(mm)
Type Product Code Apparent
Field (deg)
Field Stop
Dia. (mm)
Eye Relief
(mm)
Dioptrx
Ready
Pupil size in mm for various f/ratio telescopes
f/4.5 f/5.2 f/7 f/10 f/14
2" Eyepieces for Wide True Fields
55 Plössl EPL-55.0 50 46.0 38 Y 12.2 10.6 7.9 5.5 3.9
41 Panoptic EPO-41.0 68 46.0 27 Y 9.1 7.9 5.9 4.1 2.9
31 Nagler 5 EN5-31.0 82 42.0 19 Y 6.9 6.0 4.4 3.1 2.2
35 Panoptic EPO-35.0 68 38.7 24 Y 7.8 6.7 5.0 3.5 2.5
21 Ethos ETH-21.0 100 36.2 15 Y 4.7 4.0 3.0 2.1 1.5
26 Nagler 5 EN5-26.0 82 35.0 16 Y 5.8 5.0 3.7 2.6 1.9
22 Nagler 4 EN4-22.0 82 31.1 19 Y 4.9 4.2 3.1 2.2 1.6
27 Panoptic EPO-27.0 68 30.5 19 Y 6.0 5.2 3.9 2.7 1.9
17 Ethos ETH-17.0 100 29.6 15 Y 3.8 3.3 2.4 1.7 1.2
20 Nagler 5 EN5-20.0 82 27.4 12 Y* 4.4 3.8 2.9 2.0 1.4
17 Nagler 4 EN4-17.0 82 24.3 17 Y 3.8 3.3 2.4 1.7 1.2
1¼" Eyepieces for Wide True Fields
40 Plössl EPL-40.0 43 27.0 28 Y 8.9 7.7 5.7 4.0 2.9
32 Plössl EPL-32.0 50 27.0 22 Y 7.1 6.2 4.6 3.2 2.3
24 Panoptic EPO-24.0 68 27.0 15 Y* 5.3 4.6 3.4 2.4 1.7
13 Ethos ETH-13.0 100 22.3 15 Y 2.9 2.5 1.9 1.3 0.9
16 Nagler 5 EN5-16.0 82 22.1 10 N 3.6 3.1 2.3 1.6 1.1
19 Panoptic EPO-19.0 68 21.3 13 Y* 4.2 3.7 2.7 1.9 1.4
25 Plössl EAP-25.0 50 21.2 17 N 5.6 4.8 3.6 2.5 1.8
17.3 Delos EDL-17.3 72 21.2 20 Y 3.8 3.3 2.5 1.7 1.2
10 Ethos ETH-10.0 100 17.7 15 Y 2.2 1.9 1.4 1.0 0.7
13 Nagler 6 EN6-13.0 82 17.6 12 Y* 2.9 2.5 1.9 1.3 0.9
14 Delos EDL-14.0 72 17.3 20 Y 3.1 2.7 2.0 1.4 1.0
20 Plössl EAP-20.0 50 17.1 14 N 4.4 3.8 2.9 2.0 1.4
12 Nagler 4 EN4-12.0 82 17.1 17 Y 2.7 2.3 1.7 1.2 0.9
1¼" Eyepieces for Medium Powers
12 Delos EDL-12.0 72 15.0 20 Y 2.7 2.3 1.7 1.2 0.9
11 Nagler 6 EN6-11.0 82 14.9 12 Y* 2.4 2.1 1.6 1.1 0.8
10 Delos EDL-10.0 72 12.7 20 Y 2.2 1.9 1.4 1.0 0.7
15 Plössl EAP-15.0 50 12.6 10 N 3.3 2.9 2.1 1.5 1.1
9 Nagler 6 EN6-09.0 82 12.4 12 Y* 2.0 1.7 1.3 0.9 0.6
11 Plössl EAP-11.0 50 9.1 8 N 2.4 2.1 1.6 1.1 0.8
1¼" Eyepieces for Higher Powers
8 Ethos ETH-08.0 100 13.9 15 Y 1.8 1.5 1.1 0.8 0.6
6 Ethos ETH-06.0 100 10.4 15 Y 1.3 1.2 0.9 0.6 0.4
8 Delos EDL-08.0 72 9.9 20 Y 1.8 1.5 1.1 0.8 0.6
7 Nagler 6 EN6-07.0 82 9.7 12 Y* 1.6 1.3 1.0 0.7 0.5
4.7 Ethos SX ETH-04.7 110 8.9 15 Y 1.0 0.9 0.7 0.5 0.3
6 Delos EDL-06.0 72 7.6 20 Y 1.3 1.2 0.9 0.6 0.4
3.7 Ethos SX ETH-03.7 110 7.0 15 Y 0.8 0.7 0.5 0.4 0.3
5 Nagler 6 EN6-05.0 82 7.0 12 Y* 1.1 1.0 0.7 0.5 0.4
8 Plössl EAP-08.0 50 6.5 6 N 1.8 1.5 1.1 0.8 0.6
4.5 Delos EDL-04.5 72 5.6 20 Y 1.0 0.9 0.6 0.5 0.3
3.5 Nagler 6 EN6-03.5 82 4.8 12 Y* 0.8 0.7 0.5 0.4 0.3
3.5 Delos EDL-03.5 72 4.4 20 Y 0.8 0.7 0.5 0.4 0.3
2.5 Nagler 6 EN6-02.5 82 3.4 12 Y* 0.6 0.5 0.4 0.3 0.2
1¼" Zoom Eyepieces for Medium and Higher Powers
6-3 Nagler
Zoom ENZ-0306 50 5.1-2.6 10 N 1.3-0.7 1.2- 0.6 0.9-0.4 0.6- 0.3 0.4-0.2
4-2 Nagler
Zoom ENZ-0204 50 3.3-1.7 10 N 0.9-0.4 0.8- 0.4 0.6-0.3 0.4- 0.2 0.3-0.1