Eyepiece Skywatcher SWA-58 5mm 1.25 inch — high-power 5 mm focal length, 1.25" barrel

The Skywatcher SWA-58 5mm eyepiece is a compact 1.25-inch astronomical eyepiece with a 5 mm focal length, designed to deliver high magnification when used with compatible telescopes. Its short focal length enables detailed views of the Moon and planets, improved resolution for close double stars, and fine-detail inspection of small deep-sky features when seeing conditions permit. The eyepiece fits standard 1.25" focusers and is sized for easy installation and secure holding during observation sessions.

Advantages

The eyepiece provides strong magnification from a small, lightweight design, making it convenient to carry and switch during an observing session. Optical construction is optimized for tight, high-power views with minimal bulk; mechanical dimensions match standard 1.25" telescope focusers to ensure compatibility. The small diameter and short eye relief concentrate the image for precise centering of targets when using high focal-ratio instruments.

Suitable for

• High-magnification planetary and lunar observing
• Splitting close double stars and studying binary systems
• Detail inspection of bright small deep-sky objects
• Use with high focal length or high focal ratio telescopes for maximum resolution

Key specifications

• Focal length: 5 mm
• Barrel size: 1.25 inches (standard)
• Optical type: short focal length eyepiece for high magnification
• Form factor: compact and lightweight

How to use

Insert the eyepiece into the telescope's 1.25" focuser or diagonal and secure the thumbscrews to prevent slippage. Start observing at lower magnification to locate the target, then carefully switch to the 5 mm eyepiece for high-power views. Allow the telescope to reach thermal equilibrium and use fine focuser adjustments to obtain a sharp image. Because of the high magnification, steady mounting and good atmospheric seeing conditions are important for useful detail.

Usage recommendations

Use this 5 mm eyepiece primarily on bright targets such as the Moon and planets, and with a stable mount or tracking to reduce image motion. Consider pairing it with a Barlow lens or using an atmospheric dispersion corrector if operating at high magnifications under marginal seeing. Be mindful of eye relief and take short breaks during extended high-power viewing.