Binorum Planetary Pro 2.5mm 58° 1.25″ Eyepiece
Unlock extreme planetary magnification with the Binorum Planetary Pro 2.5mm eyepiece - your gateway to breathtaking close-up views of Mars, Jupiter, and Saturn. This ultra-short focal length eyepiece combines professional-grade optics with exceptional comfort, delivering the razor-sharp, high-contrast views that serious planetary observers demand.
Ultra-High Magnification Made Comfortable
The 2.5mm focal length provides extreme magnification for revealing the finest planetary details. Yet unlike traditional short focal length eyepieces that force you to press your eye uncomfortably close to the lens, the Planetary Pro 2.5mm offers surprisingly long eye relief that makes high-power observing a pleasure, not a struggle - even if you wear eyeglasses.
Professional 6-Element Optical Design
This premium 6-element eyepiece delivers optical performance that rivals eyepieces costing far more:
- Solid 58° apparent field of view - Wide enough for comfortable viewing and easy target tracking at extreme magnifications
- Razor-sharp views - Pinpoint clarity from center to edge with minimal optical aberrations
- Exceptional high contrast - Dark sky backgrounds reveal the subtlest planetary features
- Zero edge color - No chromatic aberration to spoil your views
- Minimal scattered light - Maximum contrast for detecting faint details
What Can You See with 2.5mm?
The 2.5mm focal length delivers extreme magnification that brings you incredibly close to your targets:
Example Magnifications
- 1000mm telescope: 400x magnification
- 1200mm telescope: 480x magnification
- 2000mm telescope: 800x magnification
Perfect for Observing
- Mars - Polar caps, dark albedo features, dust storms, and surface details during favorable oppositions
- Jupiter - Fine details in cloud bands, the Great Red Spot's internal structure, festoons, and moon shadow transits
- Saturn - Ring divisions beyond Cassini, subtle cloud bands, polar features, and atmospheric details
- Moon - Extreme close-ups of craters, rilles, domes, and the smallest visible features
- Venus & Mercury - Sharp phase definition and atmospheric phenomena
- Double stars - Splitting extremely close pairs under excellent seeing conditions
Eyeglass Wearers Welcome
Here's what makes this eyepiece truly special: despite its ultra-short 2.5mm focal length, it offers surprisingly long eye relief for virtually unrestricted use with eyeglasses. This is exceptionally rare in extreme magnification eyepieces and makes the Planetary Pro 2.5mm a game-changer for observers who wear corrective lenses.
No more uncomfortable squinting or removing your glasses to achieve focus. Enjoy relaxed, comfortable viewing even at the highest magnifications.
When to Use the 2.5mm
Ideal Conditions
- Excellent atmospheric seeing - Wait for those steady nights when the atmosphere cooperates
- Large aperture telescopes - 8 inches (200mm) or larger to gather sufficient light
- Planetary oppositions - When Mars, Jupiter, or Saturn are closest to Earth
- Superior collimation - Your telescope must be perfectly aligned for best results
- Cooled optics - Allow your telescope to reach thermal equilibrium
Not Recommended For
- Small telescopes under 6 inches - insufficient light gathering and resolution
- Poor seeing conditions - atmospheric turbulence will blur the image
- Deep-sky objects - they need lower magnifications and wider fields
Premium Anti-Reflection Engineering
Every detail has been optimized for maximum performance:
Fully Blackened Interior
The entire interior is completely blackened to absorb stray light. Internal baffles feature edge-blackened micro-absorbers and comprehensive black anodization that reduces reflections. This ensures maximum contrast and the darkest possible sky background - critical at extreme magnifications.
Fully Multi-Coated Optics
Every air-to-glass surface receives multiple layers of broadband anti-reflection coatings. This means maximum light transmission and beautifully contrasty views where fine planetary details stand out clearly against dark backgrounds.
Perfect for Projection Photography
The Planetary Pro 2.5mm is also excellent for eyepiece projection astrophotography using DSLR cameras or compact digital cameras. The high magnification and superior optics make it ideal for capturing extreme close-up planetary images.
Technical Specifications
- Focal Length: 2.5mm
- Apparent Field of View: 58°
- Eye Relief: Long (comfortable even for eyeglass wearers)
- Optical Design: 6 elements in multiple groups
- Coatings: Fully Multi-Coated (FMC) on all air-to-glass surfaces
- Barrel Diameter: 1.25″ (31.7mm)
- Filter Thread: Standard 1.25″ (M28.5×0.6)
- Housing: Aluminum, black anodized
The Planetary Pro Advantage
What sets the Planetary Pro 2.5mm apart from other ultra-short focal length eyepieces:
- ✓ Exceptional eye relief - comfortable even at 2.5mm focal length
- ✓ Works with eyeglasses - no need to remove corrective lenses
- ✓ Wide 58° field - easier to use than narrow-field high-power eyepieces
- ✓ Professional 6-element optics - superior aberration correction
- ✓ Fully multi-coated - maximum light transmission
- ✓ Comprehensive blackening - maximum contrast
- ✓ Premium build quality - precision machined aluminum
- ✓ Versatile - planetary observation and projection photography
Tips for Maximum Performance
Atmospheric Seeing
The 2.5mm eyepiece reveals atmospheric turbulence ruthlessly. Use it on nights when the stars appear as steady points rather than twinkling. The best seeing often occurs after midnight or just before dawn.
Telescope Preparation
- Allow your telescope to cool to ambient temperature (1-2 hours)
- Ensure perfect collimation - even slight misalignment degrades the image
- Use a stable mount - vibrations are magnified at high power
Observing Technique
- Start with a lower power eyepiece to locate and center your target
- Switch to the 2.5mm only when seeing conditions permit
- Use averted vision for the faintest details
- Be patient - your eyes need time to adapt and perceive fine details
Who Should Choose the 2.5mm?
- Serious planetary observers with 8-inch or larger telescopes
- Mars enthusiasts seeking maximum detail during oppositions
- Jupiter and Saturn specialists hunting subtle atmospheric features
- Lunar observers wanting extreme close-ups of surface details
- Double star observers working with very close pairs
- Astrophotographers using eyepiece projection for high-resolution planetary imaging
- Eyeglass wearers who need long eye relief even at extreme magnifications
Complete Your Eyepiece Collection
The 2.5mm is the ultimate high-power specialist in the Planetary Pro series. Pair it with longer focal lengths from the same series for a complete observing solution:
- 20-25mm - Low power, wide field scanning
- 12-15mm - Medium power, general observing
- 7-9mm - Medium-high power, planetary and lunar details
- 5mm - High power planetary specialist
- 2.5mm - Ultra-high power for exceptional seeing
See What Others Miss
On those rare nights of exceptional seeing, the Planetary Pro 2.5mm reveals details that remain invisible through ordinary eyepieces. Subtle color variations in Jupiter's zones. Fine structure in Saturn's rings. Intricate details on the Martian surface. And you'll see it all in complete comfort, whether you wear glasses or not.
Experience extreme magnification without the traditional discomfort. Discover the Binorum Planetary Pro 2.5mm - where ultimate power meets exceptional comfort.
