BT-100XL-SD Binocular Telescope


BT-100XL-SD Binocular Telescope

(9 customer reviews)


In stock. Usually ships within 2-3 days.

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. 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 Oberwerk 5000 head, Manfrotto 608 Nitrotech head, or the Oberwerk XL-240 Fork Mount.
Fully-automated “go-to” operation is available using the iOptron AZ Pro- details here.

XL Series Accessories

Additional information

Weight 30 lbs
Dimensions 29 × 15 × 12 in
Focal Length



1.75° (40x)

Exit Pupil

2.5mm (40x)

Eye Relief

18mm (40x)

Minimum Focus

25 meters

IPD Range


Product Weight

12.5 lbs.

9 reviews for BT-100XL-SD Binocular Telescope

  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.

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