Binorum Planetary Pro 4mm 58° 1.25″ Planetary Eyepiece
Premium Optics for Razor-Sharp Planetary Details
The Binorum Planetary Pro eyepieces represent a significant advancement in planetary observation technology, combining long eye relief with a comfortable wide field of view. These sophisticated eyepieces deliver exceptional sharpness and contrast without lateral chromatic aberration or stray light, providing observing conditions comparable to the finest orthoscopic and Plössl designs - but with significantly improved comfort and versatility.
Featuring a refined 6-element optical design, the Planetary Pro series delivers a generous 58° apparent field of view with outstanding contrast and a razor-sharp view across the entire field. The surprisingly long eye relief makes these eyepieces ideal for extended observing sessions, whether you wear eyeglasses or not. The 4mm focal length provides high magnification perfect for resolving fine planetary details, lunar craters, and the delicate structure of planetary nebulae.
Optimized for High-Resolution Planetary Imaging
The Planetary Pro eyepieces excel at revealing the intricate details of Solar System objects. Whether you're studying the cloud bands of Jupiter, the polar ice caps of Mars, the ring system of Saturn, or the rugged terrain of our Moon, these eyepieces deliver the contrast and sharpness needed to capture every visible detail. They are equally capable when observing deep-sky objects such as nebulae, galaxies, and star clusters, where their high contrast helps reveal subtle structure.
Beyond visual observation, these eyepieces are excellent for projection photography using DSLR cameras or compact digital cameras, making them versatile tools for both traditional observing and astrophotography applications.
Professional-Grade Optical Construction
Every aspect of the Planetary Pro design focuses on maximizing image quality and observing comfort:
- Fully blackened interior - The entire optical tube features comprehensive blackening to eliminate internal reflections
- Advanced anti-reflection system - All internal baffles incorporate micro-dampeners at their edges and full-surface black anodizing to minimize scattered light
- Premium multi-coating - Every air-to-glass surface receives multiple layers of broadband anti-reflection coating, ensuring maximum light transmission and exceptional contrast on the Moon and planets
- Adjustable eyecup - The threaded eyecup can be raised or lowered to match your preferred eye relief distance, with a flexible fold-down rubber cover for added comfort
- 58° apparent field of view - Wide enough for comfortable viewing while maintaining the optical excellence needed for planetary work
- Long eye relief - Comfortable viewing for eyeglass wearers and extended observing sessions
Technical Specifications
- Focal length: 4mm
- Apparent field of view: 58°
- Barrel diameter: 1.25″ (31.7mm)
- Optical design: 6-element construction
- Coatings: Fully multi-coated on all air-to-glass surfaces
- Eye relief: Long (eyeglass compatible)
- Eyecup: Threaded, adjustable height with fold-down rubber cover
- Internal finish: Fully blackened with anti-reflection baffles
Ideal Applications
The 4mm focal length makes this eyepiece particularly well-suited for:
- High-magnification planetary observation
- Detailed lunar studies and crater exploration
- Planetary nebulae observation
- Double star splitting
- Planetary photography through projection
- Daytime terrestrial observation at high magnification
Why Choose Binorum Planetary Pro?
The Planetary Pro series fills the gap between budget eyepieces and ultra-premium designs, offering professional-grade optical performance at an accessible price point. The combination of high contrast, excellent correction, and long eye relief makes these eyepieces suitable for both beginners seeking their first quality planetary eyepiece and experienced observers expanding their eyepiece collection.
The 4mm focal length pairs excellently with medium to long focal ratio telescopes (f/6 and above) to achieve the high magnifications needed for planetary detail, while the 58° field of view prevents the "tunnel vision" effect of narrower field eyepieces. Whether you're a gift-giver looking for a quality upgrade for an astronomy enthusiast or an experienced observer seeking better planetary performance, the Planetary Pro 4mm delivers exceptional value.
Standard 1.25″ barrel diameter ensures compatibility with virtually all modern telescopes, and the robust construction promises years of reliable service under the stars.
