(17 customer reviews)


In stock.

The BT-100XL-SD is the pinnacle of Oberwerk optical technology: a 100mm binocular telescope, with apochromatic optics, weighing a mere 12.5 lbs! With 100mm FCD100 objectives, 24mm of clear prism aperture, and a lightweight magnesium alloy body (waterproof and nitrogen-filled), this binocular telescope sets a new standard for image quality AND portability. A binocular of this quality deserves great eyepieces, so we include our finest 70° AFOV 14mm (40x) eyepieces. The SD objectives eliminate chromatic aberration up to 80x magnification (7mm eyepieces). With the widest IPD range of any binocular on the market (50-80mm), even small children can view through both eyepieces.
Other features include a Picatinny rail handle (for mounting a wide variety of finders or laser pointers) and extendable glare shields. Not only is the BT-100XL-SD the highest-quality binocular telescope on the market, with its lustrous “Luna Pearl” White finish and gold-anodized trim, it’s also the most attractive! Our exclusive heavy-duty aluminum-frame case is included, and our extra-rugged 100XL weatherproof travel case is available as an upgrade. Every BT-100XL-SD is tested and tuned to perfection prior to shipping, with collimation certified to 140x. 3-year Limited Warranty.

Mounting Options:
Recommended tripods are the Oberwerk TR3 hardwood tripod with carbon-fiber elevator or the Manfrotto 475B with crank-up elevator.
The tripods can be equipped with either the Smallrig DH10, Manfrotto 608 Nitrotech head, or the Oberwerk XL-240 Fork Mount.
Fully-automated “go-to” operation is available using the iOptron HAZ31.

XL Series Accessories

Additional information

Weight 30 lbs
Dimensions 30 × 16 × 12 in

1.75° (40x)

Exit Pupil

2.5mm (40x)

Eye Relief

15.0mm usable (40x)

Minimum Focus

25 meters

IPD Range


Product Weight

12.5 lbs.

17 reviews for BT-100XL-SD

  1. Jorge Garcia (verified owner)

    I got this binocular to explore the city of Los Angeles. They do not disappoint. The optics are amazing! The design and color are spectacular; at 40X magnification out the box was my favorite. I was looking for a higher resolution and I bought the Oberwerk 7mm and I can’t get he whole field of view with 2 eyes so I do not recommend it and I have to use one piece like a telescope. I will try to get Explore Scientific 82° 6.7mm Eyepieces so I can see the whole field of view. I am in love with this piece of equipment. I have seen the moon, Mars and the stars look just amazing. I am exploring the city of Los Angeles and even with the pollution still an amazing city to look at. I will recommend this binoculars to everybody!

    • Kevin Busarow

      Our 7mm eyepieces have been redesigned with a tapered top to make them more comfortable. We’ve exchanged Jorge’s 7mm’s with the new design and I believe he’s happy with them.

  2. Ahmad (verified owner)

    The clarity of this Binocular telescope, far exceeds my other binocular from other companies. I use to get eye fatigue after 30 min of looking at the stars with my other telescopes, but with this awesome Oberwerk telescope, I spend hours looking at the stars and no eye fatigue, its amazing. Also, Kevin and his team provide an immaculate customer service experience.

  3. Dan (verified owner)

    I wanted an ED giant binocular and was looking at many models. In the end I decided to go for the latest BT-100XL-SD for the FCD 100 glass. Before I mention the clarity of view, I will mention the bins fit perfectly on my existing professional mount (Vixen Altazimuth folk and bracket and 130 Tripod) but also on my grab and go Benro A-357 tripod and Manfrotto Micro Fluid Head. Additionally my William Optics 20mm eyepieces for their binoviewer and two AstroTech 7mm eyepieces fill out the binoculars magnification range without additional purchases. So, the bins mesh with my existing equipment quite well. Now on to their ease of use. I am able to quickly set up for nighttime viewing for clear CA free views of planets and globular clusters, etc. But I can set these up and my wifes Meopta Meopro 20-60x fluorite birding scope in less than 5 minutes for great birding. Most surprisingly, to me, the magnification roughly doubles the 60x from the Meopta and is far more detailed. I was looking at a Great Blue herons eyeballs and upper body across a lake. The Meopta loses a good bit of clarity at 60x and you have to back off to 40x or so for clarity. The Oberwerks bins at 80x (560mm/7mm) blew me away. Last, being able to hoist the entire grab and go tripod/head/bins and walk 20 feet to the other side of a small peninsular and switch around 180 degrees without much hassle was priceless. The little red dot sight I mounted on the top rail, makes immediate bird target acquisition an easy chore. During our first outing with the new bins my wife was able to find a new rarity (Pomarine Jaeger) on McGee Lake near Amarillo Texas. Thanks so much for the fine product!

  4. Steve and Jeanna Channel

    Finally! The skies here in the Midwest cleared and my schedule permitted me to do a “first light” evening with the stunning Oberwerk BT-100XL-SD binocular telescope I’d received over a month ago! Honestly, I might have been perfectly happy just looking at this beautiful instrument mounted on the Manfrotto head atop one of Oberwerk’s well crafted Maple Tripods sitting in our living room!! It is beyond well-made….it’s finish and balance are superb. I just knew something that looked that good simply had to function well.
    I was not disappointed! Once set up, I covered it with a dew shield and waited for darkness. Right out of the gate, the crescent moon jumped out from the 14mm eyepieces with clarity and detail. Frankly, it looked better than my 11in dobsonian with a Zambuto mirror….really! I gave my wife a quick tour of the various craters and other features dramatically highlighted at the terminus shadow before the moon fell below the horizon. Then it was time to go check out some old familiar friends. The Double Cluster in Perseus sparkled throughout the amazing field of view that the Oberwerk 14mm eyepieces achieve. Stars were pinpoint across the field, with no drop-off at the field edges. No false coloring or aberration in any of the objects we observed. The Pleiades were equally well defined, taking up the entire FOV. We turned to Andromeda which extended beyond the viewing window!
    Set-up and take down are simple and quick. The release mechanism on the Manfrotto head will take some practice for me. The weight of the binoculars make it a bit awkward to hold whilst simultaneously engaging the two levers required to release the base plate. I’m certain I’ll get better at that with a few more sessions. We did discover that an adjustable viewing chair was quite helpful given the change in angle when viewing several objects especially those closer to zenith. My wife, being rather short, needed some help in finding a comfortable position and a quickly-adjusted chair was a great option there.
    The bottom line: we are delighted with the entire Oberwerk process from purchase, shipment, to customer interaction. This binocular telescope is now our absolute “go to” for viewing. It is readily transported in the well made aluminum case and canvas tripod cover. We bought it as a “take along” instrument in our RV travels across the country. It will serve that role very well….in fact, I sold the dobsonian! This Oberwerk is all we need to enjoy both earth and sky! Thanks Folks!!!

  5. Adien Toledo (verified owner)

    The light gathering power and image quality of these binoculars will blow you away yet they are portable enough for a quick hassle free set up and can easily be repositioned around the yard as necessary. The 5000 tripod and head is suitable for portability. Similar to as another reviewer has mentioned, I bought these to replace my 10” dobsonian and I have no regrets. I live in the heart of light polluted Miami yet I’m amazed at how many background stars I can see when scanning any area of the sky near the Milky Way. Open clusters and even several globulares are a treat right from my backyard. I can’t wait to try these at a dark site! The moon pops right out of the sky in 3D as does the Orion Nebula. I have a red dot finder which allows to just aim and view. The ease of use and reward of quickly finding targets is incredible. Daytime viewing and bird watching is just as enjoyable and relaxing…you’re transported to another world.

    Any 1.25” eyepiece should work as I’ve tried several which I use on my telescope binoviewers and they work interchangeably with these binoculars.

    The BT 100XL-SL are definite road trip companions. I can’t wait to take them on my next trip.

    Overall, I believe this purchase is one which will bring lots of value. It is often said that the best instrument is the one you use most often. This seems to be the case.

  6. Christine Zacharer (verified owner)

    I have wanted to wait a bit before submitting a few words on these. My original order included the walnut TR-3 tripod and Oberwerk 5000 head. Mr Busarow was kind enough to swap that head for the heavier duty (and heavier) Manfrotto head. For me that was a much improved option.

    But really this is about the BT-100XL-SDs…I am no stranger to high quality optics and astronomical gear. However I wanted to include an easy setup/ easy breakdown binocular (binocular telescope) to my visual observing. These meet that requirement and I am happy to say with super easy portability.

    As others have mentioned they are gorgeous to look at just sitting on their walnut tripod in your home. I leave mine in cases as they travel with me for setup and observing. To me they are tools, not objects d’art, but they could be.

    The optics are first class. The field of view is spectacular, flat, wide and color free to the edges. Great contrast through the prisms. They truly are full apochromats. Stars where the most pinpointed I have observed with in decades (through a binoviewer). And while I could detect slight coma, I noticed that it was all in the same direction, indicating that it is my eyes and nott he optics. I do not wear my glasses when observing, and do have astigmatism, Can’t wait to try them out with contacts. I get slight coma in any scope I view through…and Ive used some research grade optics through the years)

    Collimation is dead on, even with 7mm EPs. This truly makes for an enjoyable experience. With respect the EPs (eyepieces) while the BTs have 1.25″ helical focusers and you are free to experiment with your own set ups. I did end up purchasing the entire three sets 22, 14 and 7mm. Yeah, they are high quality wide field EPs. I would put them in the same boat as Baader Morpheus’ at a fraction of the cost. And they are fully threaded for 1.25 filters.
    I guess my only (tiny) complaint is that I cannot fit a double stacked polarizer with any of the EPs. There just isn’t enough room inside the barrel adjusters of the focusers to allow them and reach focus. I prefer variable polarizers over ND filters, but ND filters will work just fine. Indeed any 1.25″ filter should work, except the double stacked polarizers I suspect the Oberwerks are not alone here as double stacking filters takes up a lot of room inside the barrel.

    I guess lastly, Oberwerk customer service is outstanding. Mr Busarow was very attentive to my numerous emails both prior to and post purchasing. Indeed even altering my order after I placed it…

    I now have many hours of observing with the BT-100XL-SDs. I am extremely happy with them. I didn’t compromise to fit a price point, instead I wanted the best, I wanted easy portability (thus not the 127s – I feared they would have been too heavy for me), and I wanted extremely high quality optics (not just really good binoculars) in a binocular telescope.

    Thank you Oberwerk and Mr Busarow. I am enjoying these immensely and haven’t set up my refractor once since first light.

  7. Rob Hutchins (verified owner)

    The BT-100XL Binocular Telescope is a fantastic optical instrument. Twin 100mm objectives collect lots of light for viewing the night sky. Most binoculars have only a single power, but these have removable eyepieces …25X-80X is possible by changing eyepieces. The night time images of bright stars are completely free of color (chromatic aberration ) and dimmer stars are tiny pin pricks of light. The fit and finish is 1st rate. These binoculars need a sturdy tripod and mount as they weigh about 14 lbs with eyepieces installed, even with their light weight magnesium body. I purchased these binoculars for night sky viewing when traveling in my camper. They are an excellent compromise between portability and providing views of dim night sky objects. In summary, these binoculars are 1st rate in every respect!

  8. Howard

    Just tried out a pair of 5mm Nagler type 6 eyepieces with my BT100-XL SD binoculars. I was able to test them on a full moon. First clear night in a while here in Stamford CT. The full moon filled the field of view at 112x. The image was clear across the full field. I found that the interpupillary placement was critical, but once it was set, the eyepieces worked very well. These 5mm eyepieces will work very well for high magnification views and have both a good eye clearance as well as being small enough barrel diameter to allow for a broad range of eyepiece spacing when setting interpupillary clearance for almost anyone. Unlike lower power eyepieces you are also more likely to spot eye floaters – so while this would not my first choice of the primary eyepiece to use with these these binoculars, they do fill in a useful place and the binoculars hold up well under the magnification.

  9. Gary

    I’m very pleased with the purchase of my BT-100XL-SD. The views are stunning and crisp. I also purchased the 7mm and 22mm eyepieces and have been happy with those as well as the included 14mm eyepiece. Additionally, Kevin has been wonderful to work with, answering my beginner’s questions patiently.

  10. Dave Hoagland

    I could list all the technical reasons why I am so satisfied with this telescope but perhaps this incident will illustrate the pure joy of it.

    We have been gathering with friends for viewing sessions for several weeks now at our place in Baja Mexico, viewing all manner of deep space objects and planets to everyone’s delight. It’s hugely popular with everyone and wonderful for us to share these experiences.

    The other night we were observing the first quarter moon when someone spotted a very bright satellite coming down from the north. I was able to quickly intercept it’s path with the reticle sight and begin smoothly and steadily tracking it across the sky. I could actually see not just a point of light but a blazing bright spacecraft with an eccentric geometry of rectangular shapes and angles and I realized immediately that it was the ISS space station. Try that with a standard telescope, there is literally no way!

    We confirmed the sighting with the ISS Detector app on my phone and noted the following evening’s pass would be with an even brighter magnitude of -4.49, this time we were setup and ready and everybody got a viewing turn in an overhead pass that lasted almost 7 minutes. Note that even complete novices are able to quickly learn to aim and operate this telescope.

    We had wanted to learn more about astronomy because we spend almost all our time in our RV in dark sky areas so we got the BT100XL-SD on a Manfrotto tripod with 608 head. This is a most fantastic and usable tool for amateur astronomy, very portable, sets up in minutes, views everything in stereo in correct visual aspect, aims quickly and accurately with a simple reticle sight, pans and scans super smoothly. We have learned more about the stars and deep space objects in 6 months than we could have ever imagined. Our appreciation of the universe is way up!

  11. JC

    Received the BT-100XL-SD quickly and in good order. Product was shipped securely within a well designed aluminum frame case, within a cardboard box, “floating” within a larger heavy duty cardboard box. The Manfrotto 475B ‘workhorse’ tripod and 500 head were similarly well packaged and received without damage.

    After a relatively easy set up I checked the general balance of the tripod and head with the BT-100XL-SD mounted. Adjusted spread, height, drag, and tension – all in good stable working order. Attempted zenith and noted that the BT-100XL-SD was reaching about 82 degrees. The unit was in contact with the top plate of the tripod. I thought about that for a bit them realized if you turn the head around 180 degrees and then mount the BT zenith is easily reached without tripod interference. The guide handles are now attached at the front of the head rather than the customary rear of the head as you would for camera equipment in standard head position. Being very pleased with my workaround thought process I later found out that Kevin produced a 4 minute video on that very subject with the very same correction!

    In use the BT-100XL-SD was easy to maneuver on the tripod and equally easy to set IPD and focus. The included 14MM eyepieces are very adequate and offer a broad 70 degree field of view. I noticed no curvature in the image which seemed to be flat across the entire viewing plane. No refraction, color distortion or fringing noted at various depths of focus.

    Living directly on the Oregon coast the terrestrial and sea views with the BT-100XL-SD are very bright and crisp. It’s very easy spotting crabbing boats and ships miles away, not to mention the bright clear views of the many eagles, sea birds and coastal wildlife. Very impressive for land use.

    Fortunately on the coast I have a near 360 degree view of the night sky. Luckily, on the first night out we had absolutely clear atmosphere with dead black skies and stars that to the naked eye are beyond beautiful. Roaming the sky with the BT-100XL-SD was stunningly, immersive. The Orion constellation, for example, was crisp and clear, with colors I’ve never seen before. Orion’s 3 star belt just popped with a twinkling depth and Rigel glowed a beautiful blue white – beyond words. There is nothing like a binocular view of the heavens. So incredibly deep. You have the feeling of floating through the sky.

    I look forward to trying other eye pieces. I anticipate there will be no problem using them on the BT-100XL -SD.

    Oberwerk customer service is excellent. Kevin is highly technically knowledgeable and is more than willing to spend time speaking with you about the many products and services he offers. All in all a very pleasant experience dealing with Oberwerk.

  12. Kershaw

    I had been an ‘every night possible’ naked eye viewer of the stars for years before I realized I could pull out the binoculars. When I started, I was purchasing binoculars left and right comparing different companies, different options, learning what they could add to my experience. I eventually stumbled onto one of Oberwerk’s ultra line, loved the views and the quality was spectacular, then one of their ED’s (the 8x42ED-another great binocular). I’m a nerd for quality and these really stood out in comparison to what I was experiencing. So, these eventually led me to the Oberwerk BT-100XL-SD that I have mounted on the Oberwerk TR3 tripod in Walnut with a Manfrotto 608 head. I am beyond pleased, and feel lucky to have found this binocular. What it adds to my experience in the night sky is immeasurable. Once again, the quality… I will also say there was a safety in what was a big purchase for me that came from interacting with Kevin and Linda throughout my purchases. This was obviously a great experience for me…

  13. Richard Kunz

    To state the obvious, this is a serious amount of cash to invest in a hobby, especially when coupled with the tripod. I thought about this for a long time before making the purchase. One thing still photography has taught me is that the quality of optics is in direct proportion to the cost. This simply isn’t an area where you should scrimp and try to save a few dollars. Oberwerk hasn’t as the quality of the binoculars is excellent and storage case is suitably stout.

    It was a thrill the first time that I brought Saturn into focus and I will need some time to get accustomed to using the binoculars, but that will be part of the fun. I’m anxious to share the views with my wife, children, and grandchildren.

    In short, no regrets, and I give high marks to Kevin and Linda for their help and communication during the process.

  14. Jim Lynch (verified owner)

    I am 69 and have owned many telescopes, binoculars, eyepieces and more since I was a teenager. I waited a while for these and the tripod, one of the biggest expenses too! These far and away exceed all the other binoculars and many telescopes I’ve owned, I will never sell these! I looked for a long time for a used pair, even Kevin said “I don’t think I’ve ever seen them for sale used”. And they are very easy to take with me anywhere for any purpose. Excellent!

  15. DJ (verified owner)

    I’ve had a decent amount of experience using some excellent telescopes.

    I do understand the logic/math of binocular summation but you have to actually experience it for yourself to get beyond just the intellectual understanding. I compared the view through these with an excellent 90mm Maksutov-cassegrain on the same night on a waxing three-quarters moon with the terminator running from Mare Humorum to Sinus Iridium. The seeing was below average and permitted about 150X magnification in the Mak. Rupes Recta aka the straight wall in Mare Nubium was just visible as a light grey line in the Mak at about 150X. The same feature could be picked out in the Oberwerk binocular at 80X with the 7mm eyepieces. What I cannot capture with numerical information is the 3-dimensional feel of the moon in binocular vision. At 150X in the Mak, you are viewing a section of greys and whites like getting 2 inches away from a B&W photograph. In the binoculars, you can still see the moon as a spherical object with features that appear to recede or protrude from the surface.

    These are very well made objects. You can read the specs but have to experience the smooth satisfying ‘thunk’ of the dew shields sliding out. The interpupillary adjustment is easy to adjust but just stiff enough to avoid shifting accidentally. Focus adjustment is smooth and precise. I would say the only thing that I wish were different is that the lock ring for the eyepieces is positioned just above the focus mechanism and operating it independently of the focus mechanism with gloves is tricky.

    The optics are very good indeed. Crisp images, all aberrations appear well controlled and the excellent contrast that is the raison d’etre of good refractors. There is enough aperture here feeding each eye that DSOs are well within reach. From my location, Orion barely climbs to about 40 degrees above the horizon at best and so never really clears the light pollution dome to the south. Had excellent views of it belying the location. The Trapezium is split at 25X and very obviously so at 40X. I could see knots and tendrils in the nebulosity and even hints of mottling in the Running Man nebula. M36, 37 and 38 look spectacular with the pinwheel and starfish shapes looking almost 3-dimensional. M81/82 were easy to see in direct vision.

    The ergonomics are really good. It is surprisingly easy to throw it around the sky. Getting the collimation correct becomes important with higher powers (at least for me) and these have been collimated superbly. Even at 80X, I had no trouble adjusting them to the point where I could merge the images without any trouble. I would petition them to design a chair with a head rest that could tilt back to about 30-45 degrees to make it supremely comfortable to view the zenith.

    In short, this is a superb bit of kit. If your binocular explorations of the night skies have only involved small aperture of below 50mm and low magnifications of 8x-10x, this could help you rediscover your love for your favorite objects up there and the very act of observing the night sky itself.

  16. Rick Weiss

    I’m an astronomer by hobby and have been for over 25 years. I’ve owned varying numbers, sizes, and types of quality grade telescopes as I’ve enjoyed my adventures with the night sky. However, the instrument I find myself grabbing and using most often is my BT-100 XL SD binocular telescope and my Ioptron HAZ mount.

    The reason why I use these more than any of my other telescopes is that they are just so darn convenient and easy to set up. As with so many states, Ohio weather can often be questionable and I find myself debating the value of setting up a large telescope for what might only be a short period of observing time, if any. I just don’t like to pull out a large telescope, set it up, align it, and hook up all my various support devices such as dew heaters, and cabling just to find myself disassembling all of that within a hour or two due to undesirable sky conditions.

    However, I can set up my HAZ mount and BT-100 XL SDs within a few minutes, including alignment, thus eliminating what might have been 45 minutes to an hour of set up time with one of my other scopes. Oh, and lets not forget the time it takes to break all of that down, especially in the dark.

    It’s just so gratifying to be able to set up and be observing within a few minutes. The ease of set up and tear down makes this my best and most used instrument for observing the night sky. This convenience is well worth the cost, large or small when compared to my other equipment.

  17. Albert Asatryan (verified owner)

    I ordered the BT-100XL-SD mostly for enjoying the beautiful view I have from my house on Quebec City from Levis. The optical quality of these binoculars is just spectacular. I read previous 5 star reviews before ordering and they are justified. Item also comes well packaged and the general feeling out of the box is one of high quality. I am very happy with the purchase.

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