{"id":107536,"date":"2026-04-28T11:58:58","date_gmt":"2026-04-28T09:58:58","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&p=107536"},"modified":"2026-08-23T15:07:12","modified_gmt":"2026-08-23T13:07:12","slug":"televue-ethos-37mm-110-eyepiece","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/televue-ethos-37mm-110-oculair\/","title":{"rendered":"TeleVue Ethos 3.7mm 110\u00b0 - Eyepiece"},"content":{"rendered":"

TeleVue Ethos 3.7mm 110\u00b0: Eyepiece: Ethos eyepiece with 110-degree field of view<\/strong><\/h2>\n\n\n\n

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.<\/p>\n\n\n\n

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.<\/p>\n\n\n\n

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What a 110-degree field of view does<\/h4>\n\n\n\n

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.<\/p>\n\n\n\n

Practically, this also means that objects remain in view for longer. On a manually tracked Dobson, this saves constant readjustment.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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High magnification without tunnel vision<\/h4>\n\n\n\n

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.<\/p>\n\n\n\n

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.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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Viewing Comfort and Dioptrx<\/h4>\n\n\n\n

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.<\/p>\n\n\n\n

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.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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In your telescope<\/h4>\n\n\n\n

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.<\/p>\n\n\n\n

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.<\/p>\n<\/div>\n<\/div>\n\n\n\n

Included<\/h3>\n\n\n\n