The 20mm focal length is widely considered the sweet spot in any serious eyepiece lineup. Offering a balanced mix of magnification and field of view, this eyepiece is ideal for observing a broad range of celestial objects—from galaxies and nebulae to star fields and open clusters. When paired with an ED127 f/7.5 refractor, the 20mm eyepiece yields a 1° true field of view, making it an excellent choice for Messier Marathons or deep-sky catalog hunts like the Herschel list.
Part of the high-value Explore Scientific 52° Series, this eyepiece features flat-field optics, argon-purged waterproofing, and fully multi-coated EMD optics—delivering crisp, contrast-rich performance that competes with pricier models. Its compact footprint and 15mm eye relief also make it ideal for binoviewers and portable setups.
Perfect for use with averted vision techniques, this eyepiece enhances your ability to detect faint objects by shifting the image to a more light-sensitive part of your eye—unlocking subtle nebulae and galaxies under dark skies.
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🌟 Features & Benefits
- 20mm focal length provides a versatile mid-power view ideal for deep sky, planetary, and star field observation
- 52° apparent field of view delivers immersive, sharp-edge visuals
- 15mm eye relief ensures comfort for eyeglass wearers and extended sessions
- 5-element, 3-group flat-field optical design maintains edge-to-edge clarity
- EMD (Enhanced Multi-Layer Deposition) coatings for high contrast and brightness
- Edge-blackened lenses minimize stray light and maximize detail
- Argon-purged, waterproof housing resists fogging, dust, and moisture
- Optimized for averted vision, aiding in faint object detection
- Compact and binoviewer-friendly for flexible configurations
- Standard 1.25" barrel with double taper ensures a secure fit
- Flip-down silicone rubber eyecup for personalized comfort and light control
🎯 Who It’s For
- Deep sky observers needing a reliable workhorse eyepiece
- Astronomers seeking a sweet spot between magnification and FOV
- Binoviewer users looking for a lightweight, high-performing match
- Stargazers running Messier or Herschel observing programs
🔭 What You’ll Be Able to See
- Wide views of open clusters, globulars, and galaxies
- Bright nebulae with enhanced contrast
- Great context around planetary targets and the Moon
- Fainter deep sky objects using averted vision under dark skies
🎒 What’s Included
- Explore Scientific 20mm 52° Series Waterproof Eyepiece
- Top and bottom dust caps
- Flip-down silicone rubber eyecup
- Soft storage pouch
Specs
| Item Number | EPWP5220–01 |
|---|---|
| Focal Length | 20mm |
| Apparent Field of View | 52° |
| Eye Relief | 15mm |
| Field Stop Diameter | 18.2mm |
| Optical Elements / Groups | 5 Elements in 3 Groups |
| Lens Coatings | EMD (Enhanced Multi-Layer Deposition) |
| Barrel Size / Type | 1.25" O.D. / Double Taper |
| Filter Thread | Standard 1.25" (1.125" x 42 TPI) |
| Waterproofing | Argon Purged; O-Ring Sealed |
| Test Rating | Submersible to 1 Meter for 30 Minutes |
| Eyecup | Removable Flip-Down Silicone Rubber |
| Size (L x W) | 71mm x 43mm |
| Weight | 181.4g (6.4 oz.) |
| Materials | Optical Glass, Aluminum, Steel, Rubber |
| Markings | Laser Engraved: Focal Length, Series, Serial Number, Brand |
Warranty Information
This product is covered by a Limited One-Year USA Warranty, valid when registered within 60 days of purchase. To activate your warranty, please visit the Explore Scientific website and complete the registration form at: