This 2” 30mm Explore Scientific is an excellent low power eyepiece with an ultra-wide 82° field of view, one so wide you have to move your head from side to side to see it all. It is particularly suited to get the maximum image brightness and field of view out of big Dobsonian scopes, but will work well with any scope that can use 2" eyepieces, even an f/15 Maksutov. Viewing through this 30mm Explore Scientific makes you feel like you’re floating above the Earth, taking a space walk, rather than looking through a telescope eyepiece. If you want a truly relaxed and unconfined “picture window” view of the Universe, this is the eyepiece for you.
With an f/4.5 Dobsonian reflector, this 30mm eyepiece has a very large 6.7mm exit pupil larger than some observers’ eyes can dilate. That can effectively waste some of the Dob’s light gathering capacity for those observers, as some of the full light cone will fall on their iris, rather than entering his or her eye. Even so, many observers are willing to trade a little light gathering for the jaw-dropping fully-immersive view through this 82° apparent field eyepiece. If you want to see the big picture, this is an eyepiece you will treasure for years to come.
In addition to its wide field, the 30mm Explore Scientific has an extra benefit for you. 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.
The latest computer design programs have been used to optimize its performance. Its six element/four group design uses low dispersion and high refractive index lenses and full multicoatings for high contrast, high resolution, and flat field images across its very wide 82° field of view. The lens edges have been blackened to improve contrast.
A 12" f/4.5 Dobsonian reflector gives you a full 1.79° field at 45.7x with this eyepiece, well over three lunar diameters, and easily able to encompass all of the Pleiades or Orion in one field. You get over seven minutes of uninterrupted observing with such a scope while an object drifts from one side of the sharp and flat eyepiece 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. Even an 8” f/10 catadioptric has a 1.23° field that’s almost two and a half lunar diameters across, for thrilling views of the larger nebulas, like the Omega and Orion. Use the calculator in the "formula" tab above to see just how wide a field you’ll get with your particular telescope.
With 21mm of eye relief, this 30mm Explore Scientific eyepiece provides unvignetted views for eyeglass wearers, although the 82° field of view is so wide that even non-eyeglass wearers can’t see the whole field at once. All observers have to move their eye from side to side to see out to the field stop.
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. This link will give you full details on this unique transferable lifetime warranty.