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Eyepieces

 

Eyepieces

A: Height of barrel above reference surface
B: Height of 1¼" barrel
C: Height of 2" barrel
D: Diameter of black barrel
E: Depth of 1¼" barrel
F: Approx. location of field stop    (negative number is above reference surface)

    Eyepieces


6 mm Delos
  1. This is a 1.25" barrel design with a 72º apparent field of view and 20mm of eye relief.

Dimensions (in)
Design Focal Length (mm) Apparent Field (°) Eye Rel. (mm) Barrel Size Mag. (x) Exit Pupil (mm) True Field (°) A B C D E F
Delos 6 6 72 20 1¼" 491.1 0.75 0.15 4.1 1.1
2.2
0.25

12 mm Nagler Type 4
  1. The Televue 12mm Nagler Type 4 eyepiece is a 6-element design with more true field than the Type 2 and better imaging and contrast enhancement.
  2. This is a 2/1.25" barrel design with an 82º apparent field of view and 17mm of eye relief.
  3. The Televue 12mm Nagler Type 4 has blackened lens edges, anti-reflection threads and rubber eyeguards deliver maximum contrast.
  4. 100% full field visual inspection with TeleVue flat-field test instruments guarantees performance.

Dimensions (in)
Design Focal Length (mm) Apparent Field (°) Eye Rel. (mm) Barrel Size Mag. (x) Exit Pupil (mm) True Field (°) A B C D E F
Nagler 4 12 82 17 2" & 1¼" 245.5 1.5 0.33 2.3 1.8 1 2.4 1.2 0.78

17 mm Nagler Type 4
  1. The Televue 17mm Nagler Type 4 eyepiece is a 6-element design with more true field, better imaging and contrast enhancement.
  2. This is a 2" barrel design with an 82º apparent field of view and 17mm of eye relief.
  3. The Televue 17mm Nagler Type 4 has blackened lens edges, anti-reflection threads and rubber eyeguards deliver maximum contrast.
  4. 100% full field visual inspection with TeleVue flat-field test instruments guarantees performance.

Dimensions (in)
Design Focal Length (mm) Apparent Field (°) Eye Rel. (mm) Barrel Size Mag. (x) Exit Pupil (mm) True Field (°) A B C D E F
Nagler 4 17 82 17 2" 173.3 2.1 0.47 2.6
1.5 2.4
-0.03

21 mm Ethos
  1. The Televue 21mm Ethos Eyepiece provides a 100° apparent field for a true "spacewalk" view of the night sky.
  2. With an effective field stop diameter of 36.2mm, the true field of the 21mm Ethos is close to that of the much loved 35mm Panoptic.
  3. Televue 21mm Ethos Eyepiece provides a generous 15mm of eye relief for comfortable observing.
  4. Accepts DIOPTRX eyesight astigmatism correctors.
  5. Dramatic mid-level magnification views combine with stunning wide field backgrounds.

Dimensions (in)
Design Focal Length (mm) Apparent Field (°) Eye Rel. (mm) Barrel Size Mag. (x) Exit Pupil (mm) True Field (°) A B C D E F
Ethos 21 100 15 2" 140.3 2.6 0.70 4.3
1.62 2.95
-0.38

31 mm Nagler Type 5
  1. The Televue 31mm Nagler Type 5 eyepiece has a 6-element design that opens the door to the largest possible true field in the Nagler eyepiece line.
  2. This is a 2" barrel design with an 82º apparent field of view and 19mm of eye relief.
  3. The Televue 31mm Nagler Type 5 has blackened lens edges, anti-reflection threads and rubber eyeguards deliver maximum contrast.
  4. 100% full field visual inspection with TeleVue flat-field test instruments guarantees performance.

Dimensions (in)
Design Focal Length (mm) Apparent Field (°) Eye Rel. (mm) Barrel Size Mag. (x) Exit Pupil (mm) True Field (°) A B C D E F
Nagler 5 31 82 19 2" 95.0 3.9 0.82 3.9
1.5 3.3
-0.38

55 mm Plossl
  1. The Televue 55mm Plossl Eyepiece features noticeably less astigmatism and lateral color at field's edge.
  2. Delivers sharper images than any other 4 or 5 element Plossl.
  3. The Televue 55mm Plossl Eyepiece has an Apparent Field of View of 50º and Eye Relief of 38mm.
  4. This is a 2" Barrel Size Eyepiece and comes with a Five Year Manufacturer Warranty.

Dimensions (in)
Design Focal Length (mm) Apparent Field (°) Eye Rel. (mm) Barrel Size Mag. (x) Exit Pupil (mm) True Field (°) A B C D E F
Plössl 55 50 38 2" 53.6 6.9 0.89 3
1.4 2.3
1.16

For a 14.5 inch f/8 - courtesy Tele Vue's Eyepiece Calculator Popup

Design Focal Length (mm) Apparent Field (°) Eye Rel. (mm) Barrel Size Mag. (x) Exit Pupil (mm) True Field (°) True Field @ 1000 yards (feet) Mag. w/2x Barlow (2x) Mag. w/2x Big Barlow or Power-mate (2x) Mag. w/2.5x Power-mate (2.5x) Mag. w/3x Barlow (3x) Mag. w/4x Power-mate (4x) Mag. w/5x Power-mate (5x)
Delos 6 72 20 1¼" 491.1 0.75 0.15 7.7 982.1 982.1 1,227.7 1.473.2 1,964.3 2,455.3
Nagler 4 12 82 17 2" & 1¼" 245.5 1.5 0.33 17.4 491.1 491.1 613.8 736.6 982.1 1,227.7
Nagler 4 17 82 17 2" 173.3 2.1 0.47 24.7 -- 346.6 -- -- 693.3 --
Ethos 21 100 15 2" 140.3 2.6 0.70 36.9 -- 280.6 -- -- 561.2 --
Nagler 5 31 82 19 2" 95.0 3.9 0.82 42.8 -- 190.1 -- -- 380.2 --
Plössl 55 50 38 2" 53.6 6.9 0.89 46.8 -- 107.1 -- -- 214.3 --
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