Eyepiece Skywatcher WA-66 9mm 1.25 inch with 66° apparent field

The Skywatcher WA-66 9mm eyepiece is a 1.25" wide-angle ocular engineered for visual astronomy. With a 9 mm focal length and a 66° apparent field of view, this eyepiece delivers higher magnification for detailed observation while preserving a comfortable, broad viewing area. It is compatible with standard 1.25" focusers and is intended for use on a variety of amateur and intermediate telescopes to observe planetary details, lunar surfaces and medium-field deep-sky objects.

Advantages

The WA-66 9mm combines a relatively short focal length with a wide 66° apparent field, offering a balance between magnification and situational awareness in the eyepiece. Its 1.25" barrel fits common telescope focusers, making it a straightforward upgrade or addition to existing eyepiece sets. The optical design reduces edge distortion across the field, giving clear views of the target with good contrast for planetary and lunar detail as well as star fields in medium-power deep-sky observing.

Suitable for

• Planetary observation and resolving surface detail on the Moon
• High-contrast views of planets (Jupiter, Saturn, Mars)
• Medium-field viewing of star clusters and brighter nebulae
• Use as a higher-magnification ocular in a multi-eyepiece set
• Compatibility with 1.25" focusers on refractors, reflectors and compound telescopes

Key specifications

• Focal length: 9 mm
• Apparent field of view: 66°
• Barrel diameter: 1.25 inches
• Optical type: wide-angle eyepiece (multi-element design)
• Typical use: visual astronomy for planetary, lunar and medium deep-sky observation

How to use

Insert the 1.25" barrel securely into the telescope focuser and tighten any thumbscrews or retaining rings to prevent movement. Start with low to medium magnification to locate and center the object, then switch to the WA-66 9mm to increase magnification and examine finer details. Allow the telescope and eyepiece to reach thermal equilibrium for the best image stability. When observing bright objects, use appropriate filters as needed to improve contrast and reduce glare.

Recommendations

For best results on planetary and lunar targets, pair the 9mm WA-66 with a stable mount and good seeing conditions. Use it as part of a set of eyepieces to cover a range of magnifications: the WA-66 serves well as a medium-high power ocular for detail work while retaining a usable field for context. Clean optics with a soft brush and lens cloth; avoid excessive contact with lens coatings.