Explore Scientific 52° Series 1.25" 3mm Waterproof Eyepiece

The 52° Series 3mm delivers the highest magnifications in the lineup, revealing tight double-star splits and fine planetary surface detail on nights of steady seeing. It pairs argon-purged waterproof construction with fully multi-coated optics.

Key Features

• Argon-purged waterproof housing, sealed against moisture and fog-proof inside. O-ring seals keep dirt, fungus and cleaning fluid from getting between the lenses.
• Enhanced Multi-Layer Deposition (EMD) coatings on all air-to-glass surfaces for high contrast. The patented coating also suppresses reflections and ghosting.
• 6-element, 3-group optical design with edge-blackened elements to control stray light
• Fold-down silicone rubber eyecup with comfortable eye relief, including with eyeglasses. Its 15 mm of eye relief is the distance at which your eye takes in the whole field.
• 1.25" barrel. Stainless steel, tapered for a more secure hold.
• Parfocal series. All 52° Series eyepieces focus at about the same point, so swaps need little refocusing.

Ideal For

• Planetary observers chasing fine detail
• Double-star enthusiasts who need the magnification to split tight pairs
• Lunar observers who want high power on the Moon
• Bright, compact deep-sky objects at high power

Accessories & Compatibility

• ED80 (480 mm, f/6). In the Explore Scientific ED80, through the 1.25" adapter of its 2" diagonal, the 3mm gives 160x for nights of good seeing, with a 0.5 mm exit pupil and a 0.32° true field.
• ED152 (1216 mm, f/8). In the ED152 triplet, also through a 1.25" adapter, it reaches 405x with no Barlow, for nights of near-perfect seeing: a 0.4 mm exit pupil and a 0.13° true field.