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This is the big one: a used 20mm Explore Scientific with a ONE HUNDRED DEGREE apparent field of view. It is in excellent condition, with clean optics and a relatively unmarked barrel. Comes in its original box with both dust caps. At almost half off, this one won't last!
Explore Ultra-Wide Eyepieces - Comfort, Quality, Value. The Explore Scientific 100° Series eyepieces are hyper-wide class oculars that can transform your visual astronomy experience. You may be startled at the amazingly wide expanse of inky black sky you behold the first time you bring your eye to a 100° Series eyepiece, and after awhile, you may even forget that you have an eyepiece between you and the universe! With an apparent field of view that is close to the maximum for hyper-wide eyepiece design, objects are not only easier to locate, but for non-driven telescopes the object will stay in the field of view for a very long time before any adjustments need to be made.
Another great benefit of hyper-wide eyepieces is the ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.
Explore Ultra-Wide Eyepieces - Comfort, Quality, Value. Explore Scientific 100° Series eyepieces, with their 100° apparent field of view, immerses you in a very comfortable hyper-wide field that naturally promotes relaxation at the eyepiece. When you relax your eyes and take in the scene presented before you, it is much easier to observe for longer periods of time, and details begin to materialize that may not have become apparent to you at first glance.
Using advanced computer design, combinations of low dispersion and high refractive index optical glasses, and durable multilayer deposition coatings, Explore Scientific 100° Series Argon-Purged Waterproof hyper-wide field eyepieces are optimized to produce high contrast, high resolution, and superior flat field characteristics. The 100° Series eyepieces come with a removable and foldable soft silicone rubber eyecup for the comfort of the observer, and as experienced astronomers know, eye comfort is critical when trying to observe at the visual limits of the telescope.
Protection from the Outdoors - By making the 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 of heat 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 insure a perfect seal we test every eyepiece in one meter of water for 30 minutes.
|Description||20mm 100° Series Nitrogen-Purged Waterproof Eyepiece|
|Field Stop Diameter:||34.8mm|