TeleVue Ethos 3.7mm 110° - Eyepiece

TeleVue Ethos 3.7mm 110°: Eyepiece: Ethos eyepiece with 110-degree field of view

The Ethos 3.7mm, along with the 4.7mm, is the only eyepiece in the series with a 110-degree field of view. TeleVue calls these two the Ethos-SX, named after simulator projects founder Al Nagler once worked on.

It's an eyepiece for high magnifications: planets, double stars, and small planetary nebulae. Where most short eyepieces offer a narrow field of view, this one keeps a huge field open.

What a 110-degree field of view does

A classic Ploessl shows 50 degrees, a Nagler 82 degrees. At 110 degrees, your eye can no longer take in the field at once: you look around in the image rather than at it. That is the effect the Ethos series is known for.

Practically, this also means that objects remain in view for longer. On a manually tracked Dobson, this saves constant readjustment.

High magnification without tunnel vision

A short focal length normally corresponds to a small field of view. The Ethos-SX turns that around: 110 degrees at 3.7 mm. On a non-motorized Dobson, that means a planet drifts calmly through the image instead of rushing out of it.

Please keep in mind the usable limit of your telescope. As a rule of thumb, the maximum useful magnification is around twice the aperture in millimeters.

Viewing Comfort and Dioptrx

The eye relief is 15 mm at every focal length in the series. The height of the foldable eyecup is adjustable, so your eye is always in the same position.

If you wear glasses due to astigmatism, you can replace them with Dioptrx on the eyepiece. This corrects your own cylindrical aberration without the eyeglass lenses costing contrast and eye distance.

In your telescope

In a telescope with a focal length of 1200 mm, this eyepiece provides approximately 324x magnification with a true field of view of about 0.33 degrees. You can calculate this for your own telescope using the field stop: true field of view = 57.3 x field stop divided by the focal length of the telescope.

The field stop of this model is 7.0 mm. That number, not just the focal length, determines how much of the sky you actually see.

Included

• Foldable rubber eyecup
• Eyecup protector
• Dust cover for the stitch
• Filter thread abandoned
• Screw-on 2-inch adapter, which also serves as a stand

Featured accessories

Every Ethos eyepiece is compatible with the TeleVue Dioptrx, a corrector for astigmatism that allows you to observe without glasses. If you’re using a fast Newtonian, the Paracorr coma corrector will bring out that last bit of edge sharpness. For a 2-inch focuser, an Everbrite zenith mirror is the logical addition, and an eyepiece case protects your investment while on the go.

For whom yes and for whom no

• ✓ Planets and double stars at high magnification
• ✓ Dobson users observing without a motor
• ✓ Observers with a telescope of 150 mm aperture or larger
• Small telescopes where this magnification can no longer be sharpened
• ✗ Who seeks an overview at low magnification

Specifications

All wide-angle eyepieces are on the page featuring wide-field eyepieces. You can find the complete selection of this merk on the TeleVue merk Page.