Eyepiece Tele Vue Nagler Type V 31 mm 2" - wide-field astronomical eyepiece

The Tele Vue Nagler Type V 31 mm 2" eyepiece is a wide-field astronomical eyepiece designed for 2-inch focusers. With a 31 mm focal length it provides comfortable low-to-medium magnification and a broad apparent field of view, making it suitable for visual observing of deep-sky objects, open clusters and wide star fields. The eyepiece is built to deliver edge-to-edge sharpness and a usable field that supports star-hopping and panoramic views through a compatible telescope.

Advantages

The eyepiece combines a large 31 mm focal length with a wide apparent field of view to create immersive views without excessive magnification. Optical design emphasizes contrast and sharpness across the field, reducing coma and off-axis aberrations for a clearer image of nebulae, galaxies and star clusters. The 2" barrel format increases exit pupil and sky coverage on telescopes with suitable focal ratios, while mechanical construction is intended to provide stable mounting and comfortable eye relief for extended observing sessions.

Suitable for

• Visual deep-sky observing of nebulae, galaxies and star clusters
• Wide-field planetary and lunar context views at lower magnification
• Star-hopping and sweeping large areas of sky
• Telescopes with 2" focusers or 2" eyepiece adapters

When it may not be suitable

This 31 mm wide-field eyepiece is not intended for high-power planetary detail where much shorter focal lengths are preferred. On very slow focal ratio telescopes (high f-number) the large exit pupil produced by a 31 mm focal length can lead to overly bright images or vignetting with some optical setups. Also, if your instrument only accepts 1.25" eyepieces without an adapter, this 2"-format eyepiece will not fit directly.

Key specifications

• Focal length: 31 mm
• Barrel size: 2 inch (50.8 mm)
• Designed field of view: wide apparent field suitable for panoramic views
• Intended use: visual observing and star-hopping

How to use

Fit the eyepiece into a telescope focuser or 2" adapter and secure it with the focuser thumbscrews. Begin with low magnification to locate targets and establish framing; the 31 mm focal length and wide field make it useful for initial sweeps and star-hopping. Adjust focus carefully for the sharpest view and use slow, steady movements of the mount to track objects across the field. For best results, pair the eyepiece with telescopes of focal ratios that balance field illumination and exit pupil size.

What to consider before purchase

• Verify your telescope accepts 2" eyepieces or that you have a 2" adapter
• Consider your telescope focal ratio to assess exit pupil and field illumination
• Decide if a wide-field low-to-medium magnification eyepiece matches your observing goals

Usage recommendations

Use the eyepiece for initial locating and wide-field sessions, then switch to higher-power eyepieces for close-up planetary or lunar detail. Allow your eyes to adapt to the dark for improved faint-object visibility and use a stable mount to take advantage of the broad field of view.