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TeleVue 8mm Ethos Eyepiece | SkiesUnlimited.net


The 8mm Ethos shares the same 100 degree apparent field of its larger 13mm sibling. Actually it looks like a thinner version of the 13mm, making it viable for use in binoviewers.


Item #ProductStock StatusPriceShipping
ETH-08.0TeleVue 8mm Ethos Eyepiece
In Stock - Ships Same Day (business days) This is "live" inventory data. If it says in stock, you can believe it.
$615.00
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Tele Vue 8mm Ethos eyepiece

The 8mm TeleVue Ethos: an ideal high-power eyepiece for big Dobs

April 26, 2008 - TeleVue unveiled what was then the newest member of the Ethos family. OK, so what is our impression of this new Ethos? Don't ask me why, but personally I found myself even more impressed than I did with the original Ethos when it debuted last spring. Perhaps it was the target we observed through the eyepiece, a holiday card with brightly colored crystals embedded in the printed surface. Using a TV60 with a single eyepiece and a TV85 with BinoVue, the Ethos revealed a wealth of detail and color that is simply hard to describe. I walked away wondering what Jupiter would look like this summer using the New Ethos and an apochromatic refractor.

So how dooes the Ethos perform under dark skies? We recently had the opportunity to use this eyepiece in a number of big Dobsonian telescopes in the 16 to 20 inch class, and were simply amazed by the image scale on familiar objects such as the Dumbbell and Swan Nebulae. The incredible 100 degree apparent field allows you to push the magnification on clusters of galaxies while still keeping the grouping comfortably within the field of view.

Tele Vue 8mm Ethos Specifications

  • Apparent field: 100°
  • Focal length: 8mm
  • Effective field stop diameter: 13.9mm
  • Eye relief: 15mm (accepts DIOPTRX eyesight astigmatism corrector)
  • Barrel size: 2"/1¼"
  • Black barrel diameter: 53.4mm
  • Weight: 0.95 lbs (15.2 oz.)

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Optical Specifications: TeleVue 8mm Ethos Eyepiece
Focal Length 8 mm
Apparent Field-of-View 100°
Eye Relief 15 mm
Physical Parameters
Weight 15.2 Ounces
Barrel Diameter 1.25 and 2 Inches
Eyepiece Calculator
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Exit Pupil: <p>Exit pupil represents the diameter of the column of light exiting the eyepiece. Magnification is simply the ratio of telescope aperture to exit pupil. Fox example, using a telescope with 100mm aperture and an exit pupil of 2mm yields a magnification of 50X.</p> <p>There are both upper and lower limits to the useful range of exit pupils. The typical human eye pupil dilates to a maximum of 7mm when fully dark adapted. This figure decreases with age. Using an exit pupil that is larger than this upper limit simply spills the light onto an area of the eye not capable of receiving data. At the opposite end of the range, a smaller exit pupil means less area on the eye is collecting data. Images brightness decreases with decreasing exit pupil. Deep space objects grow dimmer rapidly as the exit pupil falls below 1 mm. The planets also start to become noticeably dimmer when the exit pupil falls much below 0.5 mm.</p> <p>Our eyepiece calculator provides warnings and error messages based upon the value of the exit pupil. These are intended to be guidelines as opposed to hard rules. There is no harm in violating these gidelines, but your enjoyment of the telescope may be diminished if you do. </p>