The Explore Scientific 40mm is the longest focal length in the 52° Series and the only model with a 2.00-inch barrel, delivering exceptional wide-field performance for deep sky exploration. Whether you're scanning the Milky Way, locating large nebulae, or soaking in the vast structure of the Andromeda Galaxy, this eyepiece offers a sweeping true field of view that’s perfect for spotting faint, extended targets.
Designed with 27.1mm of eye relief, this eyepiece offers all-night comfort, especially for eyeglass wearers. The 36.3mm field stop ensures you capture every bit of the 52° apparent field. Internally, the eyepiece features EMD coatings, edge-blackened lenses, and a flat-field design that produces high-contrast, sharp images from edge to edge—even when using fast telescopes.
The argon-purged, waterproof construction protects against moisture, fog, and contamination, making it ideal for rugged field use. Its flip-down silicone eyecup and standard 2-inch barrel with dual taper provide ergonomic handling and wide compatibility.
CA Residents: Prop 65 WARNING(S)
🌟 Features & Benefits
- 40mm focal length provides expansive, true field views ideal for faint and extended deep sky objects
- 52° apparent field of view with sharp edge-to-edge performance
- Long 27.1mm eye relief delivers unmatched comfort, especially for eyeglass wearers
- 36.3mm field stop diameter for maximizing field capture
- EMD-coated and edge-blackened optics improve contrast and reduce internal reflections
- Waterproof and argon-purged for resistance to fog, moisture, and dust
- Durable metal construction with high-quality aluminum, steel, and optical glass
- Flip-down silicone rubber eyecup for customizable viewing comfort
- 2.00-inch barrel fits all standard 2" focusers and accepts 2" filters
- Ideal for averted vision techniques to detect faint astronomical objects
🎯 Who It’s For
- Deep sky observers and visual astronomers searching for maximum field coverage
- Users who wear eyeglasses and need long eye relief
- Observers interested in comets, open clusters, and large nebulae
- Anyone seeking a premium wide-field eyepiece at a solid value
🔭 What You’ll Be Able to See
- Sweeping star fields in the Milky Way
- The Andromeda Galaxy, Rosette Nebula, and similar extended targets
- Broad, rich regions of open clusters and galactic structure
- Subtle features using averted vision in dark-sky conditions
🎒 What’s Included
- Explore Scientific 40mm 52° Series Waterproof Eyepiece
- Soft pouch
- Dust caps (top and bottom)
Specs
| Item Number | EPWP5240–01 |
|---|---|
| Focal Length | 40mm |
| Apparent Field of View | 52° |
| Eye Relief | 27.1mm |
| Field Stop Diameter | 36.3mm |
| Optical Elements / Groups | 4 Elements in 2 Groups |
| Lens Coatings | EMD (Enhanced Multi-Layer Deposition) |
| Barrel Size / Type | 2.0" O.D. / Double Taper |
| Filter Thread | Standard 2.0" (48mm x 0.75mm) |
| 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) | 96.6mm x 61.8mm |
| Weight | 385.5g (13.6 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: