Binorum Advanced 15mm 66° FMC 1.25″ Eyepiece
Wide-Angle Survey Eyepiece of the Advanced Series
The Binorum Advanced 15mm eyepiece with the longest 17mm eye relief in the entire line represents the ideal choice for wide-angle surveys of the night sky. With its 15mm focal length providing medium magnification, it perfectly suits observation of extended objects - from panoramic Moon views to large star clusters and expansive nebulae. The super wide-angle 66° field combined with medium power creates the most immersive observing experience in the Advanced series.
Best Price-to-Performance Ratio on the Market
The Binorum Advanced series offers unbeatable value - professional wide-angle parameters at accessible prices. While competing 66° eyepieces often cost two to three times as much, Advanced provides comparable performance with five-element optical construction, complete FMC coatings, and robust metal housing. This series thus enables astronomers at all experience levels to acquire quality wide-angle eyepieces without substantial investment.
Maximum Comfort with 17mm Eye Relief
With exceptional 17mm eye relief - the longest in the entire Advanced line - the 15mm eyepiece provides ultimate viewing comfort. This generous distance allows completely relaxed eye positioning with ample clearance, practically eliminating fatigue during extended observing sessions. For eyeglass wearers, this is the ideal choice - comfortable viewing even while wearing glasses. Even without glasses, you'll appreciate the freedom of head movement without losing the image, particularly valuable during extended sky surveys.
Super Wide-Angle 66° Field for Panoramic Views
The 66° apparent field provides truly panoramic views that dramatically exceed standard eyepieces. At medium magnification, this wide field means you can see genuinely extensive sky areas - the entire lunar disk with room to track its motion, large star clusters in their full glory, or expansive nebulae in context. The wide field also significantly facilitates finding objects and navigating the sky, particularly valuable for beginning observers.
Advanced 5-Element Optics with FMC Coatings
Every Advanced eyepiece utilizes sophisticated five-element optical design with glass lenses and multiple anti-reflection FMC coatings on all surfaces. This advanced optical assembly ensures excellent sharpness, high contrast, and faithful color rendition across the entire field of view. The design optimized for wide-angle applications provides good aberration correction right to the edges - quality typically available only in significantly more expensive eyepieces.
Technical Specifications
- Focal length: 15mm
- Apparent field of view: 66°
- Eye relief: 17mm (longest in the series)
- Barrel diameter: 1.25″ (31.7mm)
- Optical design: 5-element with FMC coatings
- Optical material: Quality optical glass
- Housing: All-metal construction
- Eyecup: Rubber fold-down design
- Filter threads: Standard 1.25″ threads
Ideal Medium Magnification for Surveys
With a 15mm focal length, the eyepiece provides universal medium magnification suitable for the widest range of telescopes. With a 750mm telescope, you achieve 50x - perfect for the entire Moon or large star clusters. With a 1200mm instrument, you reach 80x - excellent for lunar region surveys and brighter nebulae. Longer telescopes around 1500mm provide 100x for more detailed views while maintaining the wide field.
Wide Spectrum of Applications
The 15mm Advanced eyepiece excels on extended objects. For lunar observation, it displays the entire disk with margin, allowing you to track the terminator and study extensive mare and highland regions. On star clusters like the Pleiades or Hyades, it captures the entire group in one view. Large nebulae like M42 or M8 appear in full context with surrounding stars. The wide field also enables scanning rich Milky Way regions and discovering objects that would escape notice in narrow fields.
Quality Metal Construction and Practical Eyecup
Robust all-metal construction ensures long lifespan and precise fit in the focuser. The rubber fold-down eyecup shields against ambient light and folds down for eyeglass wearers. Standard 1.25″ filter threads enable use of moon, UHC, or other astronomical filters.
Complete Advanced Range
The Binorum Advanced series offers three strategically chosen focal lengths:
- 6mm - high magnification for planetary details
- 9mm - universal medium-high magnification
- 15mm - wide-angle surveys for extended objects
Who is the 15mm Advanced For
- Observers seeking a wide-angle survey eyepiece
- Astronomers appreciating maximum comfort with 17mm eye relief
- Eyeglass users needing generous eye relief
- Beginners for whom the wide field facilitates sky navigation
- Anyone seeking the best price-to-performance ratio
Why Choose Binorum Advanced
Binorum Advanced combines advanced optical properties - expansive 66° field of view, five-element construction, FMC coatings, longest 17mm eye relief - with price accessibility. Careful optical design minimizes aberrations, quality metal construction guarantees reliability, and generous eye relief provides unbeatable comfort. For astronomers seeking maximum value, the Advanced series represents authentically the best price-to-performance ratio on the astronomical eyepiece market.
