Explore Scientific 52° Series 1.25" 20mm Waterproof Eyepiece

The 52° Series 20mm is a go-to general-purpose eyepiece for comfortable views of deep-sky objects. Moderate magnification makes it versatile. It has argon-purged waterproof construction and EMD coatings.

Key Features

• Argon-purged waterproof housing, sealed against moisture and fog. 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 images. The patented coating also suppresses reflections and ghosting.
• 5-element, 3-group optical design with edge-blackened elements to suppress stray light
• Fold-down silicone rubber eyecup with comfortable eye relief for relaxed viewing, 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

• Deep-sky enthusiasts framing nebulae and galaxies
• Messier and Herschel lists. Its mid-range power suits a Messier Marathon or working through the Herschel catalog.
• Binoviewers. Its relatively small size and magnification range suit most binoviewers.

Accessories & Compatibility

• ED127 (952 mm, f/7.5). In the ED127 triplet, through the 1.25" adapter of its 2" diagonal, the 20mm gives 48x, a 2.7 mm exit pupil and a 1.1° true field.
• ED152 (1216 mm, f/8). In the ED152 triplet, also through a 1.25" adapter, it gives 61x, a 2.5 mm exit pupil and a 0.86° true field.