Eyepiece ESET Explore Scientific 25 mm LER 52° apparent field

The ESET Explore Scientific 25 mm LER 52° apparent field eyepiece is an optical accessory for telescopes that delivers medium-power magnification with a 52° apparent field of view. It is designed to provide a balance between magnification and comfortable eye relief, suitable for prolonged visual observation of celestial and terrestrial objects. The eyepiece fits standard telescope focusers and is intended for users seeking stable, familiar framing for star fields, planets and deep-sky targets.

Advantages

This 25 mm LER eyepiece combines a moderate focal length with a 52° apparent field to produce a useful balance of magnification and field width. The long eye relief design reduces eye strain during extended observation sessions and accommodates users who wear glasses. Optical coatings and multi-element construction improve contrast and transmission across the visible range, helping render star fields and planetary details with clarity. The eyepiece’s standard barrel size and mechanical finish ensure secure fitting and smooth insertion into common focusers.

Suitable for

• Visual observation of the Moon and planets at medium magnification
• Wide-field views of star clusters and rich star fields
• Terrestrial viewing with appropriate diagonal or spotting setup
• Amateur astronomers using standard 1.25" or 2" focusers (check adapter requirements)

Key specifications

• Focal length: 25 mm
• Apparent field of view: 52°
• Long eye relief design for comfortable viewing
• Multi-element optical design with anti-reflective coatings
• Standard barrel compatibility for common telescope focusers

How to use

Insert the eyepiece into the telescope focuser or diagonal and secure it using the focuser’s locking mechanism. Start with a low- to medium-power setting to locate the target, then fine-tune focus using the telescope’s focuser knob until the image is sharp. If you wear glasses, adjust your eye position until the full field becomes visible while maintaining the recommended eye relief. For terrestrial viewing, use a right-angle diagonal suited to the eyepiece barrel size to obtain a comfortable viewing posture.

Recommendations

For best results, use the eyepiece under stable seeing conditions and pair it with a telescope whose focal ratio matches medium-power eyepieces to avoid vignetting or excessive field curvature. Clean optical surfaces with appropriate lens-care products and store the eyepiece in a dry, dust-free case when not in use.