The 25mm focal length is one of the most universally loved and commonly used eyepiece categories in amateur astronomy. Frequently included with new telescope kits, it delivers the perfect balance between field of view and magnification, making it a top choice for beginners and experienced observers alike. Positioned between mid- and low-power performance, the 25mm is ideal for everything from open clusters to wide star field exploration.
Its compact size and binoviewer-friendly design make it a versatile addition to any observing setup. The 52° apparent field of view offers sharp, edge-to-edge clarity, and the 16.4mm of eye relief ensures a comfortable experience—even for eyeglass wearers.
Built to perform in the field, the eyepiece features a flat-field optical design, fully multi-coated lenses with EMD coatings, and argon-purged waterproof construction to resist fogging and contaminants. The removable flip-down silicone eyecup allows customizable comfort and light shielding.
CA Residents: Prop 65 WARNING(S)
🌟 Features & Benefits
- 25mm focal length for general-purpose viewing with excellent versatility
- 52° apparent field of view delivers a clean, immersive experience
- 16.4mm eye relief offers comfort for long sessions and eyeglass users
- Flat-field design ensures edge-to-edge sharpness
- 4-element design in 2 groups with edge-blackened optics to reduce internal reflections
- EMD multi-coatings maximize contrast and light transmission
- Argon-purged and waterproof to eliminate fogging and block contaminants
- Standard 1.25" barrel with double taper for secure compatibility
- Removable flip-down silicone eyecup supports personalized comfort
- Compact, lightweight design ideal for binoviewer use or grab-and-go setups
🎯 Who It’s For
- Beginners seeking their first premium eyepiece upgrade
- Experienced astronomers who want a reliable workhorse in their kit
- Observers using binoviewers or compact travel scopes
- Visual astronomers targeting star fields, open clusters, and nebulae
🔭 What You’ll Be Able to See
- Stunning sweeps across the Milky Way
- Bright Messier objects like M45 (Pleiades) and M31 (Andromeda Galaxy)
- Large open clusters and wide nebulae with excellent context
- Enhanced faint object visibility using averted vision techniques
🎒 What’s Included
- Explore Scientific 25mm 52° Series Waterproof Eyepiece
- Protective dust caps (top and bottom)
- Flip-down silicone eyecup
- Soft storage pouch
Specs
| Item Number | EPWP5225–01 |
|---|---|
| Focal Length | 25mm |
| Apparent Field of View | 52° |
| Eye Relief | 16.4mm |
| Field Stop Diameter | 18.2mm |
| Optical Elements / Groups | 4 Elements in 2 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) | 67.7mm 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: