This new 68° 24mm Explore Scientific is an excellent low to 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 conventional 45°-50° field eyepieces, and the full-immersion, but very expensive, observing experience of an ultra-wide field 82° or 100° eyepiece.
While the 24mm Explore Scientific is particularly well-suited to observing with Dobsonian reflectors and fast focal ratio refractors (it provides a big 5.3mm exit pupil for rich field observing on an f/4.5 Dobsonian, for example), it provides “picture window onto space” images with any telescope type and is a superb eyepiece to replace the so-so 25mm or 26mm that is usually supplied as standard equipment with many new scopes.
You can use the calculator in the "formula" tab above to see just how wide the field will be with your particular telescope. For example, it will give you a 1.43° field at 48x with a 10” f/4.5 Dobsonian, more than enough to take in all of the Pleiades at one time. This gives you over five and a half minutes of uninterrupted observing with such a scope while an object drifts from one side of the eyepiece’s flat field to the other. That’s plenty of time for multiple observers to look at the same object, or for you to absorb as much detail as possible, before having to reposition the scope.
The eye relief of this six lens/fully multicoated optical system is 18mm, foe essentially unvignetted views for those with severe astigmatism who must wear eyeglasses while observing. The eyepiece has a soft fold-down rubber eyecup and comes with dust covers for both ends of the eyepiece.
This is an excellent eyepiece for observing galaxy clusters, framing emission nebulas with the black of space, observing the nebulosity around the Pleiades, etc. The 24mm Explore Scientific waterproof would be a welcome addition to any serious deep space observer’s eyepiece collection.
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