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Explore Scientific 52° Series 40mm Waterproof Eyepiece

SKU EPWP5240-01
Original price $0.00 - Original price $0.00
Original price $0.00
$179.99 - $179.99
Current price $179.99
In stock

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Explore Scientific 52 Degree Series 40mm Waterproof Eyepiece - EPWP5240-01

Discover the Explore Scientific 52° Series 40mm Waterproof Eyepiece, the longest focal length and eye relief in this series, and the only one with a 2.0-inch O.D.

Explore Scientific proudly offers three 40mm eyepieces, including the 40mm 62° Series and the 40mm 68° Series.

This particular focal length caters to dedicated deep sky observers, who seek to push the boundaries of what their telescopes can reveal.

The expansive true field of view is especially well-suited for capturing the likes of the Andromeda Galaxy, the Rosette Nebula, as well as sizable star clusters and comets.

The Explore Scientific 52° Series 40mm Waterproof Eyepiece redefines visual astronomy with its blend of comfort, quality, and exceptional value.

These multi-element optics with a flat field are designed to enrich your stargazing encounters.

Featuring an apparent field of view at 52 degrees, this eyepiece offer remarkable quality and represent a superb investment when compared to similarly priced Plossls.

One of the outstanding advantages of these eyepieces is their ability to provide excellent contrast and effortless observation, achieved by gazing slightly off-center rather than directly at the object.

This technique, known as averted vision, proves particularly invaluable when observing faint celestial objects, as it directs the image to a more light-sensitive area of your eye, allowing you to discern even the faintest details.



  • 52° Apparent Field of View: Immerse yourself in a sweeping celestial vista, encompassing an expansive 52-degree apparent field of view. This immersive perspective elevates the observation of celestial objects, offering a comprehensive and visually stimulating experience.
  • 40mm Focal Length: Striking a harmonious balance between versatility and precision, the 40mm focal length provides an optimal level of magnification for a wide range of astronomical observations. It offers a comfortable view of extended celestial objects like star clusters and galaxies, while also revealing intricate details of planets and lunar features.
  • 2.0-inch O.D. / Double Taper Eyepiece: This eyepiece boasts a 2.0-inch Outer Diameter (O.D.) and features a Double Taper design. This unique construction ensures a secure and stable fit in compatible telescope eyepiece holders, minimizing wobbling or slippage during observation sessions. The larger O.D. contributes to improved light transmission and a wider field of view.
  • EMD (Enhanced Multi-Layer Deposition): Strengthened with EMD coatings, representing Enhanced Multi-Layer Deposition. This specialized coating process heightens light transmission and minimizes internal reflections, resulting in images that are crisper, with heightened contrast and enhanced color accuracy.
  • Waterproof - O-Ring Sealed Argon Gas Purged: Engineered to withstand the elements, this eyepiece features a robust waterproof design. It is fortified with O-ring seals, creating a secure, moisture-resistant barrier against water, dust, and debris. Moreover, it is infused with argon gas, further reinforcing its resistance to internal fogging and moisture-related damage.
  • Rigorous Water Testing: Subjected to meticulous evaluation for waterproof proficiency, this eyepiece endured a 30-minute submersion under one meter of water without any compromise in performance. This certification attests to its suitability for various weather conditions, including damp or rainy environments.
  • Removable Flip-Down Style Soft Silicone Rubber Eyecup: Equipped with a detachable flip-down style soft silicone rubber eyecup, this eyepiece ensures comfort and effectively shields against stray light, enhancing the overall viewing experience. Additionally, its removable design allows for customization based on the observer's preferences.
  • Edge Blackened: Showcasing edge-blackened optics, this eyepiece undergoes a process that darkens the edges of the lens to reduce internal reflections and intensify contrast. This refinement minimizes stray light, resulting in superior image quality, especially in scenarios with pronounced contrasts between bright and dark areas.
  • High-Quality Optics: Meticulously crafted with precision, this eyepiece hosts top-tier optics engineered to deliver exceptional views of celestial objects. The lenses adhere to stringent standards, with their optical surfaces meticulously polished to minimize aberrations and maximize light transmission.
  • Durable Construction: Engineered for resilience, this eyepiece embodies robust construction capable of withstanding the rigors of outdoor use. Its sturdiness ensures it can endure transportation, handling, and exposure to diverse environmental conditions, all without compromising its optical performance.
  • Threaded Barrels for Filters: Equipped with threaded barrels, this eyepiece empowers users to attach standard astronomical filters. This functionality allows for the customization of the viewing experience, enabling the enhancement of specific colors or the reduction of light pollution in accordance with the observer's preferences and target object.
  • Comfortable Eye Relief: Providing ample eye relief, this eyepiece facilitates extended periods of observation without inducing eye strain. This feature is particularly valuable for eyeglass wearers, ensuring they can maintain a full field of view without the need to remove their glasses.
  • Included Accessories: The accessory ensemble accompanying the Explore Scientific 52° Series 40mm Waterproof Eyepiece includes protective eyepiece caps, comfortable soft silicone rubber eyecups, a secure eyepiece pouch/case for storage, and is complemented by a limited 1-year warranty, ensuring heightened peace of mind for users.


                                                                            Explore Scientific 52° Series Eyepieces Highlight Video:

                                                                            Explore Scientific Eyepiece Guide Video:


                                                                            What's Included:

                                                                            ✓ Explore Scientific 52° Series 40mm Waterproof Eyepiece

                                                                            ✓ Eyepiece Caps

                                                                            ✓ Soft Silicone Rubber Eyecups

                                                                            ✓ Eyepiece Pouch/Case

                                                                            ✓ Limited 1 year warranty



                                                                            Item Number  EPWP5240–01
                                                                            Focal Length  40mm
                                                                            Length  96.6mm
                                                                            Width  61.8mm
                                                                            Weight  385.5 grams; 13.6 oz.
                                                                            Barrel Size/Type  2.0” O.D. / Double Taper
                                                                            Eye Relief  27.1mm
                                                                            Field Stop Diameter  36.3mm
                                                                            Coatings  EMD (Enhanced Multi-Layer Deposition) on all lens-to-air surfaces
                                                                            Lens Elements/ Groups  4 Elements in 2 Groups; Edge Blackened
                                                                            Filter Thread  Fits Standard 2.0-inch Dia. Thread in Filters (48mm x 0.75mm)
                                                                            Waterproof  O-Ring Sealed Argon Gas Purged; Tested Under 1 Meter of Water for 30 Minutes
                                                                            Eyecup  Removable Flip-Down Style Soft Silicone Rubber
                                                                            Lens Caps  Slide-on Top and Bottom
                                                                            Materials  Optical Glass; Aluminum; Steel; Silicone Rubber
                                                                            Markings  Laser Engraved: Focal Length; Series; Serial Number; Brand

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