Binorum Plössl 6.5mm 50° 1.25″ Planetary Eyepiece
Classic Design for High Magnification Observations
Plössl-type eyepieces are classic eyepieces with a wide spectrum of applications in amateur astronomy. These eyepieces are popular not only for their affordable price, but also for their high image quality, particularly in the center of the field of view. The Binorum Plössl 6.5mm is specifically designed for observers who demand high magnification for planetary details, lunar features, and compact deep-sky objects.
Optimized for Planetary and Lunar Observation
Binorum Plössl eyepieces are ideally suited for observing the Moon, planets, deep-sky objects, and compact celestial targets. They are characterized by exceptional sharpness and high color fidelity, ensuring that planetary cloud bands, lunar craters, and delicate surface details appear with natural colors and crisp definition. The 6.5mm focal length delivers the high magnification needed to resolve fine planetary features and split close double stars.
Advanced Optical Features
The Binorum Plössl 6.5mm incorporates several design refinements that enhance observing performance:
- Blackened lens edges suppress internal reflections and glare, which is particularly important when observing bright objects like the Moon, Venus, or Jupiter
- Comfortable eyecup prevents stray light from entering from the sides, maintaining image contrast even in less-than-ideal observing conditions
- 4-element Plössl optical design provides excellent on-axis sharpness with minimal aberrations
- Fully multi-coated optics maximize light transmission and reduce ghosting
- Metal barrel construction ensures precise fit and long-term durability
Exceptional Price-to-Performance Ratio
The price-to-quality ratio of the Plössl series from Binorum provides you with tremendous optical power at minimal cost. This eyepiece delivers performance comparable to much more expensive designs, making high-magnification observation accessible to astronomers at all budget levels.
Technical Specifications
- Focal length: 6.5mm
- Apparent field of view: 50°
- Barrel diameter: 1.25″ (31.7mm)
- Optical design: 4-element Plössl configuration
- Lens coatings: Fully multi-coated
- Eye relief: Approximately 5mm (suitable for most observers without eyeglasses)
- Lens edge treatment: Blackened to reduce stray light
- Filter threads: Standard 1.25″ threads
- Housing: All-metal construction
- Eyecup: Rubber fold-down design
High Magnification for Detailed Views
The short 6.5mm focal length is designed for high-magnification applications. When used with a 650mm focal length telescope, this eyepiece delivers 100x magnification - excellent for detailed lunar crater observation. With a 1000mm telescope, you achieve 154x magnification, perfect for observing the Cassini Division in Saturn's rings, cloud belt details on Jupiter, polar ice caps on Mars, and resolving close double star systems.
Optimal Use Cases
- High-resolution planetary observation - cloud bands, polar regions, surface features
- Detailed lunar crater study and mountain range observation
- Double star separation and close binary systems
- Globular cluster core resolution
- Planetary nebulae observation at high magnification
- Solar system small body observation (when atmospheric conditions allow)
Atmospheric Considerations
The high magnification provided by this 6.5mm eyepiece works best under stable atmospheric conditions. On nights of excellent seeing, you'll be rewarded with stunning planetary details and crisp lunar features. The eyepiece is most effective when your telescope's aperture and atmospheric stability can support the magnification level being used - typically best with telescopes of 4 inches (100mm) aperture or larger.
Comfortable Eye Relief
While the eye relief of approximately 5mm is shorter than longer focal length eyepieces, the rubber eyecup helps you position your eye at the optimal distance for viewing. Most observers without eyeglasses will find the eye relief comfortable for extended observing sessions. The eyecup also serves the important function of blocking ambient light, which is crucial when observing faint details near bright planetary disks.
Compatible with Color and Planetary Filters
The integrated filter threads allow you to enhance planetary observation with standard color filters. Use a #80A blue filter to increase contrast on Jupiter and Saturn, a #21 orange filter to enhance Mars surface features, or variable polarizing filters to reduce glare when observing the Moon. The blackened lens edges work synergistically with filters to maintain maximum contrast.
Why Choose Binorum Eyepieces
Binorum eyepieces represent outstanding value in astronomical optics, delivering performance that rivals premium brands at accessible price points. Each eyepiece is manufactured with precision optical glass and undergoes multi-layer anti-reflection coating to ensure maximum light transmission and image contrast. The blackened lens edge treatment demonstrates attention to optical refinement typically found only in higher-priced eyepieces. Quality control procedures ensure consistent performance across the entire product line, while the robust all-metal construction provides years of reliable service. Binorum has earned recognition in the amateur astronomy community for democratizing access to quality optics, enabling observers at all experience levels to enjoy professional-grade viewing performance without premium pricing.
