Eyepiece Tele Vue Ethos 17 mm 2" 100° apparent field

The Tele Vue Ethos 17 mm eyepiece with a 2" barrel and a 100° apparent field provides a very wide immersive view for visual astronomy. Engineered for comfortable eye relief and edge-to-edge sharpness, this eyepiece is built to deliver expansive views of star fields, nebulae and planetary details when paired with compatible telescopes. Its optical design emphasizes a large apparent field of view while maintaining high contrast and minimal aberrations across the image.

Advantages

This 17 mm Ethos eyepiece offers a 100° apparent field that enables users to see a broad swath of sky without loss of image quality toward the edges. The 2" barrel format supports lower magnifications and wider true fields on telescopes with 2" focusers, while the design preserves sharpness, contrast and comfortable eye relief for extended observing sessions. The eyepiece is optimized for minimal internal reflections and high transmission to maintain fine detail and accurate star images.

Suitable for

• Wide-field visual observation of deep-sky objects such as nebulae, open clusters and the Milky Way
• Immersive star-field sweeping and landscape alignment for astronomical imaging framing
• Planetary and lunar viewing when a wide apparent field and moderate magnification are desired
• Use with 2" focusers on Dobsonians, refractors and large reflectors

Key specifications

• Focal length: 17 mm
• Barrel size: 2 inches
• Apparent field of view: 100°
• Design focus: wide-field, high-contrast visual observing
• Optical performance: edge-to-edge sharpness with minimized aberrations
• Eye relief: comfortable for extended observation (sufficient for eyeglass wearers in many cases)

How to use

Insert the 2" barrel into a compatible 2" focuser and secure with the focuser thumbscrew. Achieve focus by adjusting the focuser inward or outward until the image reaches sharpness. For best results, start with a low-contrast bright star or a well-defined planetary feature and fine-tune the focus. When surveying deep-sky targets, slowly pan the telescope to bring extended objects into the wide apparent field and allow dark-adapted vision to enhance faint details.

Usage recommendations

Use this eyepiece primarily for visual observing sessions where a wide apparent field enhances the experience. Pair it with telescopes that support 2" eyepieces to realize the full true-field advantages, and consider using a field stop or dew shield under moist conditions to protect optics. For eyeglass wearers, adjust eye position to find full field illumination and avoid stray light by using a suitable eyepiece shade.