100° & 110° Apparent Field Eyepieces Eyepieces > Ethos > 13mm
Model #ETH-13.0
Focal Length (mm)13
Barrel Size (in.)2" & 1"
Apparent Field of View (deg.)100
Eye Relief (mm)15
Weight (lb / oz)1.30 / 20.8
Field Stop (mm)22.3
Compare to similar focal lengths
“Absolutely amazing contrast. This eyepiece takes visual observing to the next dimension.”
—G.S., ON

We have not specifically endorsed the 13mm Ethos for Bino-Vue use because of the large diameter barrel. Even so, we were advised by Mike Harvey at the Winter Star Party (February 2008) that only 1-person in 25 had interpupilary limits with the bino'd Ethos (63.5-mm for the initial production 13mm).

However, since many of our customers have been thrilled with the experience, we have maximized the potential use by narrowing the barrel from 63.5-mm to 62-mm diameter for eyepieces delivered beginning mid-March 2008. While the difference is only 1.5-mm, (or 0.75-mm for pairing a first production unit with current production) we decided to make this small change public, in case you want to give it a try.

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