Explore Scientific AR 16mm 68° 1.25″ eyepiece
If you are looking for an eyepiece that delivers comfortable, high-contrast and immersive views of the night sky, the 68° Series from Explore Scientific is exactly what you need. The 16mm focal length model with a 68° apparent field of view strikes an excellent balance between magnification and overview - whether you are observing open clusters, nebulae or planetary detail. And thanks to argon purging, your eyepiece will stay in perfect condition even under demanding conditions.
Optical quality - EMD multi-layer coatings
At the heart of the optical performance of the entire 68° Series is a 15-layer Enhanced Multi-layer Deposition (EMD) coating system applied to every glass-to-air surface. These are not basic anti-reflection coatings - they are precision-engineered multi-layer coatings that maximise light transmission and eliminate unwanted reflections. The result is exceptional contrast and accurate colour rendition across the entire field of view. Blackened lens edges further suppress scattered light inside the eyepiece barrel, contributing to the overall image quality.
Argon purging - superior protection against moisture
Waterproofing is achieved by filling the eyepiece with an inert gas - and here Explore Scientific has chosen argon rather than the more commonly used nitrogen. Argon has a larger molecule, which gives it an advantage in resistance to diffusion through the seals. It also retains its protective properties over a wider temperature range, so the eyepiece reliably protects the optics from moisture and condensation even during significant temperature swings - typically when carrying a telescope from a warm room into the cold night air. This is a detail that anyone who takes care of their optics seriously will appreciate.
Optical design and comfortable eye relief
The eyepiece is constructed as an SWA (Super Wide Angle) design with 6 elements in 4 groups, optimised using computer modelling. This shows in practice: the field of view is flat and well corrected from centre to edge - no significant distortion or colour fringing at the edges. The 12mm eye relief allows comfortable viewing even for eyeglass wearers, who retain a full view of the entire field. A fold-down eyecup makes it easy to adjust eye position. The eyepiece is also parfocal within the entire 68° Series, so switching between focal lengths requires minimal refocusing.
Filter thread and practical usability
The eyepiece features a standard 1.25″ filter thread, ready for direct mounting of 1.25″ filters without any additional adapters - a practical advantage when observing nebulae with UHC or OIII filters. The total weight of 151g and a length of 63mm place it among compact and well-balanced accessories that will not overburden even lighter mounts.
Technical specifications
| Parameter |
Value |
| Focal length |
16mm |
| Apparent field of view |
68° |
| Barrel diameter |
1.25″ |
| Optical design |
SWA - 6 elements in 4 groups |
| Coatings |
EMD - 15-layer multi-coating on all surfaces |
| Eye relief |
12mm |
| Eyecup |
Fold-down |
| Filter thread |
1.25″ |
| Purging gas |
Argon |
| Weight |
151g |
| Length |
63mm |
| Parfocal series |
68° Series |
Why choose the Explore Scientific 68° Series?
Explore Scientific is among the most respected manufacturers of astronomical optics, with products popular among advanced amateurs and professional observers alike. The 68° Series is a prime example - combining a thoughtful optical design, premium coatings and robust mechanical construction at a price that fairly reflects genuine quality. If you want an eyepiece that will serve you reliably on every trip under the starry sky and stand up to adverse weather conditions, the AR 16mm 68° is a choice you will not regret.
Ideal for observing
- Open and globular star clusters
- Emission and planetary nebulae - especially with UHC or OIII filters
- Galaxies and extended deep-sky objects
- Planetary detail at medium magnification
- Wide-field Milky Way sweeping
