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This is a used 40mm ES 62-degree eyepiece in excellent condition. It has clean optics and no marks on the barrel. It comes in its original box.
Using advanced computer design, combinations of low dispersion and high refractive index optical glasses, and durable multilayer deposition coatings, Explore Scientific 62° Series Argon-Purged Waterproof wide field eyepieces are optimized to produce high contrast, high resolution, and superior flat field characteristics. The 62° Series eyepieces are near par-focal (meaning they focus at nearly the same point regardless of the focal length you select) and 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.
Explore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 62° Series eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 62 degrees and near par focal design, these eyepieces offer incredible value in a very nice eyepiece.
Another great benefit of these eyepieces is the excellent contrast and 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.
|Description||40mm 62° Series Argon-Purged Waterproof Eyepiece|
|Field Stop Diameter:||42.2mm|