Explore Scientific

BT-100 SF Large Binoculars with 62 Degree LER Eyepieces

Regular price $1,999.99 USD
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BT-100 SF Large Binoculars with 62 Degree LER Eyepieces
$1,999.99 USD
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BT-100 SF Large Binoculars with 62 Degree LER Eyepieces


Description

The Explore Scientific BT-100 SF is a premium giant binocular built for serious astronomy enthusiasts and nature observers who demand the very best in optical clarity and comfort. With 100mm objective lenses and a 560mm focal length, it delivers strikingly bright, high-contrast views of the moon, planets, deep-sky objects, distant landscapes, and wildlife. Each eye benefits from its own complete optical system, creating a natural, immersive viewing experience that reduces fatigue even during hours-long sessions.

Included 62° 20mm LER eyepieces produce 28x magnification and a generous 2.3° field of view, while full compatibility with 1.25" interchangeable eyepieces and filters lets you dial in exactly the right setup for any target. The rugged magnesium housing is IPX6 waterproof and nitrogen-purged, making the BT-100 a reliable companion in demanding outdoor conditions - from dewy stargazing nights to foggy coastal mornings.


Key Features

  • 100mm Objective Lenses: Large aperture gathers exceptional amounts of light for bright, detailed views of celestial and terrestrial targets.
  • 560mm Focal Length / f/5.5 Focal Ratio: Delivers sharp, high-contrast images across astronomy and nature viewing applications.
  • 62° 20mm LER Eyepieces (28x Magnification): Two premium long-eye-relief eyepieces included, offering a wide 2.3° apparent field of view and comfortable viewing even with glasses.
  • 1.25" Interchangeable Eyepiece Compatibility: Accepts all standard 1.25" / 31.7mm eyepieces and filters for customized magnification and enhanced contrast.
  • IPX6 Waterproof & Nitrogen-Purged: Magnesium housing is fully sealed against water intrusion and nitrogen-purged to eliminate internal fogging in any weather.
  • Magnesium Housing: Lightweight yet rugged construction stands up to demanding field use while keeping weight manageable.
  • 45° Viewing Angle: Ergonomic angled eyepiece design reduces neck and back strain during extended observation sessions.
  • Extendable Dew Caps: Shield objective lenses from dew and stray light, extending usable observing time in humid or cold conditions.
  • Helical Single Focus: Fine, precise helical focus mechanism allows quick, smooth adjustments for sharp images at any distance.
  • Integrated Carrying Handle & Tripod Mount: Built-in handle makes transport easy, and the mount is compatible with photo tripods or the optional Explore Scientific U-Mount with Field Tripod.

What's Included

  • BT-100 SF Giant Binocular Body
  • Two 62° 20mm LER Eyepieces

Why You'll Love It

The BT-100 SF is the kind of instrument that transforms a night under the stars from a casual glance into a genuinely breathtaking experience. Its massive 100mm aperture and premium Enhanced Multilayer Deposition (EMD) coatings pull in detail and color that smaller binoculars simply cannot match, making it a favorite among dedicated amateur astronomers and serious nature observers alike. The all-weather magnesium build means you can confidently take it to a dark-sky site, a mountain ridge, or a coastal cliff without worrying about the elements. The 45° viewing angle and generous eye relief make long observing sessions genuinely comfortable - no more craning your neck or straining to hold still. For anyone who has wanted a true giant binocular experience without the learning curve of a telescope, the BT-100 SF delivers that and more. It is engineered for years of dependable, awe-inspiring use.


Product Specifications

View Product Specs
Item Number 01-14220
Optical Design Achromatic Refractor Porro
Objective Lens Diameter 100 mm
Focal Length 550 mm
Focal Ratio f/5.5
Apparent Field of View 62 degrees
Field of View 2.3 degrees
Exit Pupil 3.6 mm
Exit Pupil Distance (Eye Relief) 15 mm
Coating Enhanced Multilayer Deposition (EMD)
Waterproof Yes - IPX6
Total Length 520 mm
Total Width 270 mm
Total Height 155 mm
Net Weight 6,800 g
Housing Material Magnesium

FAQ

Do I need a tripod to use the BT-100 SF?

Yes - at 6,800g and 28x magnification, hand-holding the BT-100 SF is not practical. A sturdy photo tripod or the optional Explore Scientific U-Mount with Field Tripod is strongly recommended for stable, comfortable viewing. The binocular features an integrated carrying handle with a standard tripod mounting interface for easy setup.

Can I use my own eyepieces with the BT-100 SF?

Absolutely. The BT-100 SF accepts all standard 1.25" (31.7mm) eyepieces, giving you the freedom to customize your magnification and field of view. You can also use 1.25" filters to enhance contrast on specific targets like the moon or nebulae.

Is the BT-100 SF suitable for daytime terrestrial viewing as well as astronomy?

Yes. The large 100mm objectives and wide field of view make the BT-100 SF excellent for terrestrial use - birdwatching, wildlife observation, scenic viewing, and more. The 45° angled eyepieces are particularly comfortable for scanning landscapes over extended periods.

What does "nitrogen-purged" mean and why does it matter?

Nitrogen-purging means the interior of the binocular has been filled with dry nitrogen gas and sealed. This prevents moisture from entering the optical path, which eliminates internal fogging when moving between temperature extremes - a common problem with non-purged optics. For nighttime or cold-weather use, this is a critical feature for maintaining image clarity.

What warranty comes with the BT-100 SF?

The BT-100 SF comes with a limited warranty from Explore Scientific. To activate full warranty coverage, register your product within 60 days of purchase. Contact us or visit the Explore Scientific warranty page for complete terms and conditions.

Product specifications table
Specification name Specification Value
Color pattern Silver

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