This Explore Scientific 16mm argon-purged eyepiece is a truly fine medium power eyepiece with a substantial 68° field of view that can provide a comfortable "picture window onto space" viewing experience with virtually any telescope type.
This new 68° 16mm Explore Scientific is an excellent medium power wide field eyepiece with an unusual benefit. It is O-ring sealed and argon-purged to be 100% waterproof. This prevents internal fogging in the eyepiece; keeps the interior dust-and fungus-free; and makes it easier to clean, as there is no risk of excess cleaning solution getting trapped between the lenses.
Many observers feel that a 68° field eyepiece like this Explore Scientific hits the "sweet spot" between the affordable, but "looking down a tube" view of 45°-50° field eyepieces, and the full-immersion, but very expensive, observing experience of an ultra-wide field 82° or 100° eyepiece.
The 16mm 68° Explore Scientific works with any telescope from a fast focal ratio reflector to a long focal length refractor. It's particularly good with Dobsonians and fast focal ratio refractors, providing high magnification with a very wide field of view for observing globular clusters and compact nebulas. It provides a substantial 0.95° field of view (nearly twice the diameter of the full Moon) and a bright 3.55mm exit pupil with a 10" f/4.5 Dobsonian at 71x.
The eye relief of this six lens/fully multicoated optical system is an acceptable 12mm. The field is vignetted somewhat for those with severe astigmatism who must wear eyeglasses while observing, but markedly less so than with many competitive eyepieces. The eyepiece has a soft fold-down rubber eyecup and comes with dust covers for both ends of the eyepiece.
This individually serial numbered Explore Scientific eyepiece is backed by a limited one year warranty, which will be extended to an Explore Scientific transferable lifetime limited warranty when its warranty card is registered with Explore Scientific within 60 days of purchase. Here's a link to the full details on this unique transferable lifetime warranty
