With its exceptional apparent angle of view, the Tele Vue Ethos-SX 4.7mm Ultra Wide-Angle Eyepiece offers a comfortable eye relief despite the short focal length, with high contrast and excellent on-axis sharpness; and virtually zero astigmatism or field curvature across its expansive 110° field of view. Combining a hyper-wide apparent angle of view with its short focal length, this Ethos delivers high magnification with enhanced details when looking at the moon and planets, while still offering an expansive and immersive observational experience.

A unique design characteristic of the Ethos allows it to be used in the smaller, more common-sized 1.25" drawtubes and accessories; and a simple screw-on installation of the included adapter converts it for use in larger 2" versions. This provides users with an easy and convenient way to expand its functionality and versatility, without limiting its use or relying on eyepiece holder reducer adapters. This model is parfocal with a variety of Tele Vue eyepieces, requiring little or no refocusing when changing between them — greatly decreasing vibration and increasing convenience. A textured collar around the housing provides sure handling in cold weather or while wearing gloves, and a fold-down rubber eyecup allows for comfortable use with or without eyeglasses.