Explore Scientific BT-120 SF Large Binoculars with 62 Degree LER Eyepieces

EXPLORE SCIENTIFIC BT Series Giant Binoculars – A New Dimension in Stargazing and Nature Observation

Step into a world of unparalleled clarity and detail with the EXPLORE SCIENTIFIC BT Series Giant Binoculars, designed for stargazing, nature observation, and breathtaking landscape views. These versatile binoculars bring celestial wonders like globular clusters, glowing nebulae, and lunar craters to life at night, while offering stunning daytime views of ships, airplanes, and distant landscapes.

Bright, Brilliant Views Anytime
Featuring large, light-gathering lenses and professional multi-layer coatings on all optical surfaces, the BT binoculars produce vibrant, sharp, and detailed images even in low-light conditions. The 45-degree viewing angle ensures fatigue-free use, even when observing overhead objects for extended periods.

Dual Refractor Design for Relaxed, Enhanced Observation
Experience the benefits of observing with both eyes using the BT series' dual refractor setup. This design provides a full-aperture telescope for each eye, offering vivid, lifelike images with improved depth perception and minimal eye strain.

Rugged, Weather-Resistant Construction
Built for tough outdoor conditions, these binoculars feature a lightweight magnesium housing, nitrogen-purged waterproof design (IPX6 rated), and extendable dew caps to prevent lens fogging in humid or cold environments.

Included Premium Eyepieces for Exceptional Clarity
Each BT binocular comes with two high-quality 20mm eyepieces from EXPLORE SCIENTIFIC’s 62-degree LER series, delivering a 33x magnification with a wide 1.8-degree field of view. These eyepieces offer long eye relief (15mm), soft silicone eyecups, and a flat, sharp image ideal for astronomy and daytime use.

Customizable Viewing Options
The interchangeable eyepiece system (1.25-inch/31.7mm diameter) allows you to adjust magnification and field of view to suit your preferences. Pair with EXPLORE SCIENTIFIC eyepieces from the 62- or 82-degree series for a range of magnifications (25x to 75x). Enhance your astronomy experience further by adding compatible color or nebula filters for improved contrast.

Optimized Comfort and Stability

• 45-degree viewing angle: Relaxed observation, even when tilted upward.
• Helical single-focus adjustment: Effortless precision focusing.
• Adjustable interpupillary distance: Perfect for users with varying eye spacings.
• Integrated carrying handle: Easy transport and secure tripod assembly.

Tripod Compatibility for Stable Observation
For the best results, pair these binoculars with a sturdy tripod or the optional EXPLORE SCIENTIFIC U-Mount with a field tripod. Designed specifically for BT series binoculars, this mount offers adjustable friction, vibration damping, and secure positioning for high-magnification observations.

• Professional optics with large, light-gathering lenses
• Waterproof magnesium housing with nitrogen-purging (IPX6)
• Included 20mm wide-angle eyepieces with 33x magnification
• Interchangeable eyepieces for customizable magnification
• Compatible with color and nebula filters for astronomy

Rediscover the beauty of the universe and distant landscapes with the EXPLORE SCIENTIFIC BT Series Giant Binoculars—a must-have for astronomy enthusiasts and nature lovers alike.

FEATURES

• Powerful large binoculars with a 120 mm objective diameter and 660 mm focal length.
• Observe the moon, the planets and bright deep sky objects in the night sky as well as terrestrial targets
• Extremely robust binoculars, sealed and filled with nitrogen
• Convenient 45-degree view and individual focusing
• Carrying handle makes it easier to transport the binocular and ensures a secure hold during tripod assembly
• Includes two premium waterproof Explore Scientific 62 degree 20mm LER eyepieces
• Eyepiece holder 1.25 inch / 31.7mm, interchangeable eyepieces
• Extendable dew caps minimize condensation on the lenses
• Tripod connection: 2 x 1/4 inch and 1 x 3/8 inch photo thread
• Optional accessories: Item 01-14300 U-mount with field tripod

SPECS

• Item Number 01-14230
• Optical design Achromatic refractor Porro
• Mirror / lens diameter 120 mm
• Focal length 660 mm
• Focal ratio 5.5
• Apparent Facial field 62 degrees
• Type of remuneration Enhanced Multilayer Desposition (EMD)
• Exit pupil min. 3.6 mm
• Field of view 1.8 degrees
• Waterproof Yes
• Water resistance protection level IPX6
• Exit pupil distance 15 mm
• Total length 654 mm
• Total width 290 mm
• Total height 156 mm
• Total net weight 8300 g
• Housing material Magnesium

CA Residents: Prop 65 WARNING(S)

MANUAL

Download Manual Here

Explore Scientific offers free collimation service for the Giant Binoculars for the lifetime of the product. The customer is responsible for shipping both ways. Explore Scientific Giant Binoculars come with a 1-year warranty when registered within 60 days of purchase.

The Explore Alliance membership program offers Extended Care for all Explore Scientific products with a paid membership. For more information on the Explore Alliance Click Here 

TESTIMONIALS

My View on the Explore Scientific BT-120 SF Large Binoculars
- Andrew Corkill 10-15-22

I never thought I would be a big binocular user. That includes a binocular of any size. But as I live in a very light polluted area of Southern California, I realized that binoculars greatly help my ability to see the stars.

I’ve launched into a full-on exercise of using binoculars every day from 10x25 all the way to 25x100 in my backyard. The Explore Scientific BT-120 SF Large Binoculars are the largest bino’s I’ve used to date, and I bought them for a specific reason.

I found myself working through the Astronomical League Observing programs using binoculars to observe double stars, variable stars, open clusters, Messier objects, as well as the Moon and Planets. I worked through all these programs using binoculars of many different sizes, all the way up to 20x100’s. After enjoying so much observing with binoculars, I honed in on variable star observations as my nightly passion. I observe, estimate visual magnitude, and submit these observations to the American Association of Variable Star Observers (AAVSO).

As you can imagine, many variable stars are easily seen and can be visually estimated using the naked eye or binoculars. But there are many variable stars that can go from being very bright, greater than 2nd or 3rd magnitude at maximum, then fade all the way to 10th or 12th magnitude at minimum. In my light polluted backyard, when a star goes beyond 10th magnitude, it disappears in my 20x100 binoculars. At this point, I have to move to a larger telescope, or just stop observing that star. This shouldn’t be a problem, just stick to brighter variable stars. But, there are some variable stars that are just too interesting to pass up.

T Coronae Borealis (T CrB) is a variable star that is faint and out of sight. At least it’s out of sight from my backyard binoculars. I can “glimpse” it on a clear, transparent night with my 25x100 binoculars, but it needs to be at least 30 to 40 degrees above the horizon. T CrB is a Recurrent Nova, a star that goes through an incredible outburst of energy and light every 20 years or so. It can brighten from 10th magnitude all the way up to 2nd magnitude when it goes Nova. The next outburst should take place within the next 2 years (sometime in 2023 to 2024). Well, it’s time to measure and prep for this rare event, and I need more accurate ways to measure and see this star when it is fainter than 10th magnitude. The goal is to catch this star when it goes into “outburst” and increases in brightness in less than one night all the way up to 2nd magnitude. It’s time to go deeper and deeper into variable star observations. It’s time for the Explore Scientific BT-120 SF Large Binoculars.

The 120mm objectives of these binoculars, should give me the extra aperture I need to see this faint 10.0 to 11.0 faint magnitude star, T CrB. So after admiring these binoculars on the Explore Scientific website for a few weeks, I finally gathered the courage to ask my wife for a Holiday gift. And although this was the month of August, it seemed just right to me. I purchased the bino’s and they had their first light on Arcturus to get a sharp focus, and the next stop was T CrB.

The Binoculars are big, but lighter than they look. At 8300 grams (that’s 18.3 pounds to you and me) they are quite easy carry and lift onto the tripod. The binoculars came with the U-Mount with field tripod which were designed to work together. The motion is fluid and the binoculars are very easy to balance. They don’t lose their position when pointed at a distant object. Poetry in motion.

T CrB was shockingly easy to see in these binoculars (around 10.2 magnitude), and that is due to their large 120mm objectives. But remember that these binoculars come with 20mm eyepieces with a 62 degree FOV. This renders the sky into a beautiful observable circle of almost 2 degrees. What! This is awesome! With the 20mm eyepieces we are seeing these stars at 31x. Now you can imagine scanning the sky with a big 2 degree (1.96) Field of View and seeing everything magnified 31 times. T CrB and the impending Nova will be no match for these binoculars. I’ve found my trusted companion to watch nightly as we get closer to a very rare event of seeing this star go Nova.

I Highly recommend these binoculars and would not hesitate to encourage others to use both eyes while observing Planets, Star Clusters, Galaxies and other Deep Sky Objects. We have two eyes, and two halves of our brain deserve to get all the visual “stimulation” we can possibly give. You will have deepening experiences with Large Binoculars like these.

Just a note: I zoomed over to look at Jupiter, and found the Galilean Moons and Bands clearly visible. The bands were revealing their secret colors to these 120mm monsters while my brain devoured the details. Quickly to Saturn and WOW! The rings are incredible!

And now its time for the binoculars to go back in the box, they are a holiday gift remember, and my wife doesn't forget. So this is my experience and my update for now. Still so much more to see with these amazing binoculars. I highly recommend them for anyone seeking to enjoy the universe from their backyard.