Explore Scientific 20 mm - 68° Argon-Purged Waterproof 1.25" Eyepiece - EPWP6820-01

Explore Scientific 20 mm 68º Waterproof Eyepiece - 1.25"

The Explore Scientific 20 mm 68º Series™ eyepiece is an excellent multi-element flat-field eyepiece that will revolutionize your experience with visual astronomy. This ocular is an amazing value and packed with features such as a 68-degree apparent field of view and a close to parfocal design. Enjoy a fully immersive experience with generous eye relief and high-contrast, high-resolution views with this 68º Series eyepiece.

By making this Explore Scientific eyepiece body Argon-purged, the waterproof eyepiece internal elements will remain as pristine as the day they were assembled. Argon atoms are “ larger” than that of Nitrogen and therefore they are less likely to “leak” or diffuse their way through the seals over the life of the eyepiece. The atomic radius of Argon is larger than Nitrogen by 0.13 angstroms and has a larger atomic volume by 11.2 cubic centimeters/molecule. Argon also has superior inertness vs Nitrogen (i.e. forming few or no chemical compounds with other elements) that prevents adverse reactions with eyepiece components and therefore extends the longevity of the internal components, and also prevents chemical reactions with other elemental contaminants that may be introduced through a weakened seal. And, finally, because Argon is less conductive than Nitrogen, Argon cools slower thereby buffering the effects of rapid temperature changes of the optics. The sealed, dry environment is impervious to internal fogging and contaminants such as fungus growing in between the lens elements. Our waterproof eyepiece is easier to clean, and there is no risk of cleaning solution migrating from the top of the lens and seeping around edges to be trapped in between elements. To ensure a perfect seal, Explore tests every eyepiece in one meter of water for 30 minutes.