|
Calculator
Eyepiece Calculator
|
TeleVue.com: Article > Calculator |
Input Box
Follow the steps below to see the eyepiece table.
Initial Conditions
| Focal Length: | 600.0mm |
| Aperture: | 85.0mm |
| Focal Ratio: | 7.1 |
| Include 2-inch data: | True |
| Table corrected for Paracorr: | False |
| List only DIOPTRX eyepieces: | False |
| Max recommended mag. for aperture: | 201x |
Tele Vue-85
| 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) |
| Panoptic | 41 | 68 | 27 | 2" | 14.6 | 5.8 | 4.4 | 230.0 | -- | 29.3 | -- | -- | 58.5 | -- |
| Plössl | 55 | 50 | 38 | 2" | 10.9 | 7.8* | 4.4 | 230.0 | -- | 21.8 | -- | -- | 43.6 | -- |
| Nagler 5 | 31 | 82 | 19 | 2" | 19.4 | 4.4 | 4.0 | 210.0 | -- | 38.7 | -- | -- | 77.4 | -- |
| Panoptic | 35 | 68 | 24 | 2" | 17.1 | 5.0 | 3.7 | 193.5 | -- | 34.3 | -- | -- | 68.6 | -- |
| Ethos | 21 | 100 | 15 | 2" | 28.6 | 3.0 | 3.5 | 181.0 | -- | 57.1 | -- | -- | 114.3 | -- |
| Nagler 4 | 22 | 82 | 19 | 2" | 27.3 | 3.1 | 3.0 | 155.5 | -- | 54.5 | -- | -- | 109.1 | -- |
| Panoptic | 27 | 68 | 19 | 2" | 22.2 | 3.8 | 2.9 | 152.5 | -- | 44.4 | -- | -- | 88.9 | -- |
| Ethos | 17 | 100 | 15 | 2" | 35.3 | 2.4 | 2.8 | 148.0 | -- | 70.6 | -- | -- | 141.2 | -- |
| Panoptic | 24 | 68 | 15 | 1¼" | 25.0 | 3.4 | 2.6 | 135.0 | 50.0 | 50.0 | 62.5 | 75.0 | 100.0 | 125.0 |
| Plössl | 32 | 50 | 22 | 1¼" | 18.8 | 4.5 | 2.6 | 135.0 | 37.5 | 37.5 | 46.9 | 56.3 | 75.0 | 93.8 |
| Plössl | 40 | 43 | 28 | 1¼" | 15.0 | 5.7 | 2.6 | 135.0 | 30.0 | 30.0 | 37.5 | 45.0 | 60.0 | 75.0 |
| Nagler 4 | 17 | 82 | 17 | 2" | 35.3 | 2.4 | 2.3 | 121.5 | -- | 70.6 | -- | -- | 141.2 | -- |
| Ethos | 13 | 100 | 15 | 2" & 1¼" | 46.2 | 1.8 | 2.1 | 111.5 | 92.3 | 92.3 | 115.4 | 138.5 | 184.6 | 230.8† |
| Nagler 5 | 16 | 82 | 10 | 1¼" | 37.5 | 2.3 | 2.1 | 110.5 | 75.0 | 75.0 | 93.8 | 112.5 | 150.0 | 187.5 |
| Panoptic | 19 | 68 | 13 | 1¼" | 31.6 | 2.7 | 2.0 | 106.5 | 63.2 | 63.2 | 78.9 | 94.7 | 126.3 | 157.9 |
| Delos | 17.3 | 72 | 20 | 1¼" | 34.7 | 2.5 | 2.0 | 106.0 | 69.4 | 69.4 | 86.7 | 104.0 | 138.7 | 173.4 |
| Plössl | 25 | 50 | 17 | 1¼" | 24.0 | 3.5 | 2.0 | 106.0 | 48.0 | 48.0 | 60.0 | 72.0 | 96.0 | 120.0 |
| DeLite | 18.2 | 62 | 20 | 1¼" | 33.0 | 2.6 | 1.8 | 95.5 | 65.9 | 65.9 | 82.4 | 98.9 | 131.9 | 164.8 |
| Ethos | 10 | 100 | 15 | 2" & 1¼" | 60.0 | 1.4 | 1.7 | 88.5 | 120.0 | 120.0 | 150.0 | 180.0 | 240.0† | 300.0† |
| Nagler 6 | 13 | 82 | 12 | 1¼" | 46.2 | 1.8 | 1.7 | 88.0 | 92.3 | 92.3 | 115.4 | 138.5 | 184.6 | 230.8† |
| Delos | 14 | 72 | 20 | 1¼" | 42.9 | 2.0 | 1.7 | 86.5 | 85.7 | 85.7 | 107.1 | 128.6 | 171.4 | 214.3† |
| Plössl | 20 | 50 | 14 | 1¼" | 30.0 | 2.8 | 1.6 | 85.5 | 60.0 | 60.0 | 75.0 | 90.0 | 120.0 | 150.0 |
| Apollo | 11 | 85 | 18 | 2" & 1¼" | 54.5 | 1.6 | 1.5 | 81.0 | 109.1 | 109.1 | 136.4 | 163.6 | 218.2† | 272.7† |
| DeLite | 15 | 62 | 20 | 1¼" | 40.0 | 2.1 | 1.5 | 80.0 | 80.0 | 80.0 | 100.0 | 120.0 | 160.0 | 200.0 |
| Delos | 12 | 72 | 20 | 1¼" | 50.0 | 1.7 | 1.4 | 75.0 | 100.0 | 100.0 | 125.0 | 150.0 | 200.0 | 250.0† |
| Ethos | 8 | 100 | 15 | 2" & 1¼" | 75.0 | 1.1 | 1.3 | 69.5 | 150.0 | 150.0 | 187.5 | 225.0† | 300.0† | 375.0† |
| DeLite | 13 | 62 | 20 | 1¼" | 46.2 | 1.8 | 1.3 | 69.0 | 92.3 | 92.3 | 115.4 | 138.5 | 184.6 | 230.8† |
| Delos | 10 | 72 | 20 | 1¼" | 60.0 | 1.4 | 1.2 | 63.5 | 120.0 | 120.0 | 150.0 | 180.0 | 240.0† | 300.0† |
| Plössl | 15 | 50 | 10 | 1¼" | 40.0 | 2.1 | 1.2 | 63.0 | 80.0 | 80.0 | 100.0 | 120.0 | 160.0 | 200.0 |
| Nagler 6 | 9 | 82 | 12 | 1¼" | 66.7 | 1.3 | 1.2 | 62.0 | 133.3 | 133.3 | 166.7 | 200.0 | 266.7† | 333.3† |
| DeLite | 11 | 62 | 20 | 1¼" | 54.5 | 1.6 | 1.1 | 58.5 | 109.1 | 109.1 | 136.4 | 163.6 | 218.2† | 272.7† |
| Ethos | 6 | 100 | 15 | 2" & 1¼" | 100.0 | 0.85 | 0.99 | 52.0 | 200.0 | 200.0 | 250.0† | 300.0† | 400.0† | 500.0† |
| Delos | 8 | 72 | 20 | 1¼" | 75.0 | 1.1 | 0.95 | 49.5 | 150.0 | 150.0 | 187.5 | 225.0† | 300.0† | 375.0† |
| Nagler 6 | 7 | 82 | 12 | 1¼" | 85.7 | 0.99 | 0.93 | 48.5 | 171.4 | 171.4 | 214.3† | 257.1† | 342.9† | 428.6† |
| DeLite | 9 | 62 | 20 | 1¼" | 66.7 | 1.3 | 0.92 | 48.0 | 133.3 | 133.3 | 166.7 | 200.0 | 266.7† | 333.3† |
| Plössl | 11 | 50 | 8 | 1¼" | 54.5 | 1.6 | 0.87 | 45.5 | 109.1 | 109.1 | 136.4 | 163.6 | 218.2† | 272.7† |
| Ethos SX | 4.7 | 110 | 15 | 2" & 1¼" | 127.7 | 0.67 | 0.85 | 44.7 | 255.3† | 255.3† | 319.1† | 383.0† | 510.6† | 638.3† |
| Delos | 6 | 72 | 20 | 1¼" | 100.0 | 0.85 | 0.73 | 38.0 | 200.0 | 200.0 | 250.0† | 300.0† | 400.0† | 500.0† |
| DeLite | 7 | 62 | 20 | 1¼" | 85.7 | 0.99 | 0.72 | 37.5 | 171.4 | 171.4 | 214.3† | 257.1† | 342.9† | 428.6† |
| Ethos SX | 3.7 | 110 | 15 | 2" & 1¼" | 162.2 | 0.52 | 0.67 | 35.2 | 324.3† | 324.3† | 405.4† | 486.5† | 648.6† | 810.8† |
| Nagler 6 | 5 | 82 | 12 | 1¼" | 120.0 | 0.71 | 0.67 | 35.0 | 240.0† | 240.0† | 300.0† | 360.0† | 480.0† | 600.0† |
| Plössl | 8 | 50 | 6 | 1¼" | 75.0 | 1.1 | 0.62 | 32.5 | 150.0 | 150.0 | 187.5 | 225.0† | 300.0† | 375.0† |
| Delos | 4.5 | 72 | 20 | 1¼" | 133.3 | 0.64 | 0.53 | 28.0 | 266.7† | 266.7† | 333.3† | 400.0† | 533.3† | 666.7† |
| DeLite | 5 | 62 | 20 | 1¼" | 120.0 | 0.71 | 0.51 | 26.5 | 240.0† | 240.0† | 300.0† | 360.0† | 480.0† | 600.0† |
| Nagler Zoom | 6 - 3 | 50 | 10 | 1¼" | 100.0 - 200.0 | 0.85 - 0.43 | 0.49 - 0.25 | 25.5 - 13.0 | 200.0 - 400.0† | 200.0 - 400.0† | 250.0† - 500.0† | 300.0† - 600.0† | 400.0† - 800.0† | 500.0† - 1,000.0† |
| Nagler 6 | 3.5 | 82 | 12 | 1¼" | 171.4 | 0.50 | 0.46 | 24.0 | 342.9† | 342.9† | 428.6† | 514.3† | 685.7† | 857.1† |
| Delos | 3.5 | 72 | 20 | 1¼" | 171.4 | 0.50 | 0.42 | 22.0 | 342.9† | 342.9† | 428.6† | 514.3† | 685.7† | 857.1† |
| DeLite | 4 | 62 | 20 | 1¼" | 150.0 | 0.57 | 0.41 | 21.5 | 300.0† | 300.0† | 375.0† | 450.0† | 600.0† | 750.0† |
| DeLite | 3 | 62 | 20 | 1¼" | 200.0 | 0.43 | 0.31 | 16.0 | 400.0† | 400.0† | 500.0† | 600.0† | 800.0† | 1,000.0† |
| 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) |
Table Notes
For further reading, see Eyepieces Advice.
†Tele Vue recommends maximum magnification of 60x / inch (2.5x / mm) of telescope aperture and 350x maximum regardless of aperture.
*An exit pupil greater than 7.5-mm may be too big for a telescope with central obstruction (most reflectors). Conversely, small exit pupils may reveal eyesight defects such as floaters. Consider binocular viewing to diminish the effect of an eye having floaters.