Explore Scientific LER Ar 20mm 62° 1.25″ eyepiece
If you are looking for an eyepiece that can handle demanding observing conditions, offers genuine viewing comfort and will not disappoint even an experienced amateur astronomer, the Explore Scientific 62° LER eyepiece is exactly what you need. A focal length of 20mm combined with an apparent field of view of 62° delivers an excellent balance between magnification and overview - ideal for observing extended deep-sky objects as well as for detailed views of planets and the Moon, depending on the telescope used.
Optical design and coatings
The Explore Scientific 62° LER wide-angle eyepiece uses an SWA (Super Wide Angle) optical design, which ensures sharp imaging not only at the centre of the field of view but also at its edges - even when used with fast optics (low f/ratio). The lenses feature a patented EMD (Enhanced Multi-coating Deposition) multi-layer coating that maximises light transmission and significantly increases contrast. The lens edges are carefully blackened to eliminate unwanted reflections and light scatter that would otherwise reduce image quality. The result is a sharp, high-contrast image with accurate colours across the entire field of view.
Argon purging and waterproof sealing
One of the key advantages of this eyepiece is its argon gas purging. The inert argon atmosphere inside the optical system effectively prevents internal fogging of the lenses, eliminates the risk of fungal growth and prevents dust from reaching the internal optical surfaces. The eyepiece also features a waterproof seal, so it handles dew, light rain and condensation during sudden temperature changes with ease. For an amateur astronomer spending nights outdoors in varying conditions, this means a truly reliable companion for many years to come.
Long eye relief and adjustable eyecup
The LER (Long Eye Relief) designation in the name says it all: the eye relief reaches 15mm, a value at which even observers who wear prescription glasses can view comfortably without needing to remove them. The fold-down rubber eyecup allows you to easily set the optimal eye position and adapt the eyepiece to your needs - whether you wear glasses or not. The result is natural, relaxed viewing without the neck and eye fatigue that often accompanies long observing sessions at the telescope.
Build quality and compatibility
The eyepiece barrel is fitted with a stainless steel collar with a conical safety groove that ensures firm and secure clamping in a 1.25″ focuser. With a weight of just 135g and a length of 60mm, this eyepiece is suited for use with the vast majority of portable and stationary telescopes.
| Parameter |
Value |
| Focal length |
20mm |
| Apparent field of view (AFOV) |
62° |
| Eye relief |
15mm |
| Barrel diameter |
1.25″ |
| Optical design |
SWA (Super Wide Angle) |
| Lens coating |
EMD multi-layer coating |
| Gas purging |
Argon |
| Waterproof sealing |
Yes |
| Eyecup |
Fold-down rubber, adjustable |
| Barrel material |
Stainless steel collar with safety groove |
| Weight |
135g |
| Length |
60mm |
Why choose the Explore Scientific 62° LER series?
Explore Scientific is among the most respected manufacturers of astronomical optics, with a strong emphasis on making genuinely high-quality products accessible to amateur astronomers. The 62° LER series combines a proven optical design with modern coating technologies and practical engineering features such as argon purging and waterproof sealing - qualities that were previously found only in significantly more expensive eyepieces. If you are looking for an eyepiece that will faithfully serve you when observing star clusters, nebulae and planets without putting a serious strain on your budget, the Explore Scientific LER Ar 20mm 62° is an outstanding choice for any enthusiast of the night sky.
