TeleVue Ethos 13mm 100° – Eyepiece

TeleVue Ethos 13mm 100°: Eyepiece: Ethos eyepiece with 100-degree field of view

The Ethos 13mm is the eyepiece with which the entire series began in 2007 and is still the best-selling model. The 22.3mm field stop provides approximately the same true field of view as a 26mm Ploessl, but at double the magnification.

That's the core of the Ethos idea: a darker sky background and more detail, without sacrificing overview.

What a 100-degree field of view does

A classic Ploessl has 50 degrees, a Nagler has 82 degrees. At 100 degrees, your eye can no longer take in the field at once: you’re looking around the image instead of *at* it. That’s 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.

Why this particular focal length

In the series 21, 13, and 8 mm, the 13 mm is the middle step. On most telescopes, it provides a magnification that remains usable under varying conditions, even when the seeing is not cooperating.

At approximately 585 grams, this is a substantial eyepiece. On a Dobsonian with a light shroud, it's wise to check the balance before letting go of the instrument.

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 92x magnification with a true field of view of about 1.06 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 telescope's focal length.

The field stop of this model is 22.3 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

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

• ✓ Deep-sky observations as a reliable workhorse
• ✓ Observers who want to start with a single Ethos eyepiece
• Telescopes with a 1.25 or 2-inch focuser
• ✗ Mountings that can't bear much weight
• ✗ Whoever is looking for the lowest magnification range

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.