Explore Scientific 68° Series 28mm Waterproof Eyepiece

The Explore Scientific 68° Series 28mm eyepiece is an Argon-purged, waterproof wide-field eyepiece built for astronomers who want a full-immersion viewing experience without worrying about internal fogging or fungus growth over years of field use. Because Argon atoms are larger and more chemically inert than nitrogen, the gas is less likely to leak through the eyepiece's seals over time, keeping the internal optics pristine long after assembly. Every unit is tested submerged in a meter of water for 30 minutes to confirm the seal before it ships.

• Argon-purged waterproof construction: Argon's larger atomic size and chemical inertness resist leaking through seals better than nitrogen, preventing internal fogging and fungus growth.
• 28mm focal length with long eye relief: Delivers 21.6mm of eye relief and a 31.8mm field stop diameter for a comfortable, wide viewing experience.
• Parfocal design: Focuses at nearly the same point across the series regardless of which focal length eyepiece is in use.
• Removable, foldable silicone eyecup: Adds observer comfort during extended viewing sessions.
• Tested underwater before shipping: Every unit is submerged in one meter of water for 30 minutes to confirm the seal.
• Extended transferable warranty: A 1-year limited warranty converts to Explore Scientific's STAR Transferable Extended Life Warranty upon registration within 60 days.