Eyepiece Skywatcher SWA-58 2.5 mm 1.25 inch — high-power astronomical eyepiece

Skywatcher SWA-58 2.5 mm 1.25" is a high-power astronomical eyepiece designed for use with telescopes that accept 1.25-inch eyepieces. With a 2.5 mm focal length it delivers strong magnification suitable for detailed visual observation of planets, the Moon and other small, bright objects. The eyepiece is compact and lightweight, allowing quick interchange during observing sessions and compatibility with standard 1.25" focusers.

Advantages

The short focal length provides high angular magnification for observing fine surface details on planets and lunar features. Its 1.25" barrel diameter ensures wide compatibility with most amateur telescopes and standard eyepiece holders. The compact design makes storage and swapping simple during an observing run, and the optical layout is intended to deliver clear, high-contrast images at high magnifications when used with suitable telescopes and stable atmospheric conditions.

Suitable for

• High-magnification planetary observation
• Detailed lunar surface studies
• Splitting close double stars under good seeing
• Use with telescopes that accept 1.25" eyepieces

Key specifications

• Focal length: 2.5 mm
• Barrel diameter: 1.25 inches (standard)
• Optical type: high-power eyepiece designed for visual use
• Form factor: compact, lightweight

How to use

Insert the eyepiece into the telescope’s 1.25" focuser and secure it with the focuser’s thumbscrew or clamp. Use with a telescope of appropriate aperture — larger apertures yield higher useful magnification while small apertures may reach the practical limit sooner. Start with a lower-power eyepiece to locate the target, then switch to the SWA-58 2.5 mm eyepiece for high-power examination. Achieve critical focus slowly and allow the telescope to reach thermal equilibrium for the best image quality.

Recommendations

For optimal results, use this eyepiece under steady atmospheric seeing and with a telescope whose aperture supports high magnification. Employ precise focusing and, if available, a tracking mount to keep targets centered. Avoid using excessive magnification beyond the telescope’s practical limit, and store the eyepiece in a dry, dust-free case when not in use.