100° & 110° Apparent Field Eyepieces
|TeleVue.com: Eyepieces > Ethos > 13mm|
|Focal Length (mm)||13|
|Barrel Size (in.)||2" & 1¼"|
|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|
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.