TeleVue Ethos 4.7mm 110° - Eyepiece

TeleVue Ethos 4.7mm 110°: Eyepiece: Ethos eyepiece with 110-degree field of view

The Ethos 4.7 mm is the second of the two 110-degree models. Compared to the 3.7 mm, it offers slightly less magnification and a slightly wider field of view, which makes it the more versatile of the two on most telescopes.

For medium-sized apertures, this focal length is often just right for planetary detail: long enough to ensure sharpness, yet short enough to remain usable even in moderate seeing conditions.

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.

The practical side of 110 degrees

The field of view is more than 20 percent larger than that of the 100-degree Ethos models. In practice, you notice this most at the edges: they fall outside your immediate field of view, which largely eliminates the sensation of an edge.

The edge correction remains in order even in fast systems. In an f/4 Newtonian, a coma corrector is still recommended because coma is a property of the mirror, not the eyepiece.

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 255x with a true field of view of about 0.43 degrees. You 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 9.0 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

• ✓ Planet detail at medium to high magnification
• ✓ Observers who want the maximum field of view at short focal lengths
• ✓ Use in combination with a 3.7 mm or 6 mm Ethos
• ✗ Who is mainly looking for a deep-sky overview
• Telescopes with a small aperture

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.