Oberwerk BT-100XL-SD Binocular Telescope

Description

Stationed on high-altitude viewing terraces and dark-sky observation fields, the Oberwerk BT-100XL-SD Binocular Telescope delivers stereoscopic optical resolution for deep-space astronomy and ultra-long-range terrestrial surveillance. Equipped with large 100mm objective lenses and supplied 14mm 70-degree wide-field eyepieces that produce 40x magnification, this observation system provides a 91.9-foot field of view at 1000 yards (30.5m at 1000m), an actual angle of view of 1.75 degrees, a 2.5mm exit pupil, and a comfortable 15mm eye relief for identifying lunar craters, deep-sky star clusters, and distant coastal vessels.

The optical train features 100mm apochromatic doublet objectives incorporating Japanese FCD100 super-low dispersion (SD) glass elements, combined with oversized 27mm clear-aperture BaK-4 Porro prisms and broadband fully multi-coated surfaces for sharp color fidelity and photon transmission. Measuring 53.3cm (21 inches) in length and weighing 5.7 kg (12.5 lbs), the chassis is cast from lightweight magnesium alloy finished in protective Luna Pearl enamel. The optical housing is O-ring sealed and nitrogen gas purged for complete waterproof and fogproof protection during humid night sessions. Eyepiece receptacles are inclined at a 45-degree angle to provide relaxed viewing at high altitudes, controlled by individual helical focusers that accept standard 1.25-inch telescope eyepieces, an interpupillary adjustment scale from 50mm to 80mm, retractable dew shields, a built-in Picatinny top rail handle, and a Vixen-style dovetail mounting foot with 1/4-20 and 3/8-16 threaded sockets.

Key Features of Oberwerk BT-100XL-SD Binocular Telescope

Engineered for binocular astronomy and long-range landscape monitoring, this 100mm binocular telescope pairs FCD100 apochromatic doublet glass with comfortable 45-degree angled oculars. Its oversized 27mm BaK-4 Porro prisms and broadband multi-coatings deliver bright, aberration-free views of planetary details and deep-sky nebulae. The nitrogen-purged magnesium alloy frame mounts securely to standard tripods and alt-azimuth fork heads via its integrated dual-threaded dovetail foot.

• 40x magnification using supplied 14mm eyepieces paired with light-gathering 100mm objective lenses
• Porro prism optical architecture incorporating oversized 27mm clear-aperture BaK-4 prisms
• Apochromatic doublet objective lenses incorporating Japanese FCD100 super-low dispersion glass
• Linear field of view of 91.9 feet at 1000 yards (30.5m at 1000m) across a 1.75-degree actual angle of view
• Comfortable 15mm eye relief with soft rubber eyecups on interchangeable 1.25-inch astronomical oculars
• Independent helical focusing collars accommodating standard 1.25-inch astronomical filter accessories
• Airtight nitrogen-purged magnesium alloy chassis providing complete waterproof and fogproof protection
• Integrated Vixen-style dovetail foot featuring 1/4-20 and 3/8-16 threaded tripod mounting sockets

FCD100 SD Doublet Optics & 27mm Clear-Aperture Porro Prisms

The 100mm FCD100 super-low dispersion doublet objective lenses control chromatic aberration across high-contrast borders, presenting bright stellar targets, lunar features, and distant mountain lines with authentic color purity. Massive 27mm clear-aperture BaK-4 Porro prisms provide complete optical throughput across standard 1.25-inch ocular barrels, preventing internal optical vignetting and peripheral light fall-off. Broadband multi-layer coatings applied to every air-to-glass surface optimize light transmission, revealing delicate spiral structure in bright galaxies and subtle planetary cloud bands.

Magnesium Chassis Engineering & 45-Degree Viewing Ergonomics

Weighing 5.7 kg, the magnesium alloy body provides structural rigidity to maintain factory collimation alignment while remaining easily portable for dark-sky field expeditions. The 45-degree angled ocular orientation allows observers to study high-altitude celestial targets and zenith star fields without experiencing neck strain. Retractable aluminum dew shields slide outward to block stray peripheral light and prevent dew formation on the objective glass, while dual independent helical focusers allow precise focal adjustments for each eye.

• Independent helical focus collars delivering micro-fine focus adjustment for individual eye eyesight
• Nitrogen gas purged magnesium alloy housing resistant to outdoor dew, moisture, and temperature drops
• Built-in 45-degree angled eyepiece ports and Picatinny top rail handle for mounting optical reflex finders

Oberwerk 5-Year Limited Warranty & Factory Accessories

The Oberwerk BT-100XL-SD Binocular Telescope is protected by the Oberwerk 5-year limited manufacturer warranty against defects in materials, construction, and optical collimation. The complete factory package contains the Oberwerk BT-100XL-SD binocular telescope optical tube assembly, pair of Oberwerk 14mm 70-degree eyepieces (40x), extendable dew shields, objective covers, eyepiece caps, and wheeled aluminum-frame hard transport case.