Explore Scientific 40mm 62° 2" Waterproof Eyepiece
The Explore Scientific 40mm 62° Series 2" Eyepiece is a superb choice for deep-sky observers and planetary imagers looking to maximize field of view, eye relief, and contrast in one premium package. Designed with a wide 62-degree apparent field, this eyepiece delivers immersive views with edge-to-edge sharpness, excellent correction, and long-term durability thanks to its waterproof and purged design.
This eyepiece is a great option for low-power sweeping of the night sky, especially when paired with larger focal length telescopes like Schmidt-Cassegrains, Dobsonians, or refractors. With its 40mm focal length and wide-angle design, it’s ideal for scanning open clusters, bright nebulae, and rich star fields with a sense of space and depth that’s hard to match.
Wide Field, Comfortable Viewing
The 62° apparent field of view strikes a smart balance between expansive sky coverage and manageable size and weight. It's wide enough to feel immersive but without pushing into the realm of ultra-wide designs that sometimes trade off eye relief or introduce edge distortions. In fast focal ratio scopes, this eyepiece maintains a well-corrected image across the field, delivering pinpoint stars and crisp detail. It’s an especially attractive choice for observers who want a more natural, porthole-like view compared to narrower Plössl or Kellner eyepieces.
Exceptional Eye Relief
One of the key advantages of this eyepiece is its long 28mm of eye relief. That makes it extremely comfortable to use—even for eyeglass wearers—without sacrificing field of view. The twist-up eyecup provides a customizable experience for those who prefer to observe without glasses, while still giving full access to the view.
Waterproof and Argon-Purged for Longevity
Like all of Explore Scientific’s 62° series eyepieces, the 40mm is fully waterproof and filled with inert argon gas. This design prevents internal fogging, protects against fungus growth, and eliminates dust or moisture infiltration over time. Whether you’re observing in humid summer conditions or taking your scope into colder climates, this eyepiece is built to last and perform without compromise.
Optical Design and Coatings
This eyepiece uses a multi-element optical design with fully multi-coated lenses for superior light transmission and contrast. Internal baffling and blackened lens edges reduce internal reflections and scatter, delivering darker backgrounds and cleaner contrast between stars and nebulae. The result is a noticeably rich, high-contrast image that's ideal for low-light deep sky work.
Compatibility
The 40mm 62° eyepiece features a 2" barrel format, making it compatible with any telescope that accepts standard 2" eyepieces. It's also threaded for 2" filters, allowing easy integration of nebula filters, light pollution reduction filters, or broadband contrast filters to enhance your viewing sessions.
This eyepiece performs particularly well in telescopes with longer focal ratios (f/8 and up), but remains a solid performer even in faster optical systems. In large Dobsonian reflectors, it can offer up to a 1.4°–1.7° true field, depending on your scope’s focal length—perfect for capturing the full extent of large objects like the North America Nebula or the Pleiades.
In Summary:
The Explore Scientific 40mm 62° 2" Waterproof Eyepiece is an excellent choice for the serious observer seeking immersive wide-field views, premium build quality, and long-term performance. Its optical clarity, generous eye relief, and rugged construction make it a go-to for low-power observing sessions, whether you're sweeping the Milky Way or framing entire star clusters in one majestic view.
If you're ready to take your visual astronomy to the next level, this eyepiece offers an exceptional balance of performance and value—and it’s backed by Explore Scientific’s lifetime warranty.
