Explore Scientific 120° Series 2" 9mm Waterproof Eyepiece

The 120° Series 9mm is the flagship of the entire Explore Scientific eyepiece line — a 120° apparent field of view that pushes the boundaries of what is optically possible. No other production eyepiece offers a wider field. At 9mm, it delivers moderate-high magnification while surrounding you with an almost hemispherical view that redefines what eyepiece immersion means.

The optical design behind a 120° field is extraordinarily demanding — maintaining sharp, well-corrected images across such an extreme field width requires precision-engineered multi-element glass groups that few manufacturers even attempt. The result is a viewing experience that observers consistently describe as unlike anything else: planets and deep-sky objects appear within a vast, continuous star field that extends to the very edge of your peripheral vision.

Argon-purged waterproof construction protects this premium optical investment from moisture, fog, and temperature swings. At $899, it represents the highest-performance eyepiece in the ES waterproof lineup and competes in territory where very few alternatives exist.

Key Features

• 120° apparent field of view — the widest field available in any production eyepiece, creating a near-hemispherical immersive view
• Premium multi-element optics — precision-engineered glass groups maintain sharp, corrected images across the extreme 120° field
• 2" barrel for maximum light throughput
• Argon-purged waterproof housing — sealed against moisture, fog, and temperature extremes, protecting a significant investment
• Enhanced Multi-Layer Deposition (EMD) coatings on all air-to-glass surfaces with edge-blackened elements
• Fold-down silicone rubber eyecup for comfortable eye positioning

Ideal For

• Observers seeking the ultimate immersive experience — the 120° field creates a visceral sense of being surrounded by the star field rather than looking through a window
• Experienced visual astronomers who have worked through narrower fields and want to experience the pinnacle of wide-field eyepiece design
• Deep-sky enthusiasts who value the spatial context and depth perception that only an extreme wide-field design can provide
• Collectors and serious observers who want the flagship piece in a premier eyepiece line