William Optics Binoviewers – A Class Act

I like using binoculars… and I like using a telescope. So what happens when you combine both? For savvy telescope users, the result is called a binoviewer – but using one can sometimes introduce problems. Dark images, fast focal ratio telescopes, problems with focusing and outright expense… But can these problems be overcome in a binoviewer that’s easy to afford, works with all telescopes, doesn’t cost an arm and a leg and is high quality? The answer is yes…

Say hello to the William Optics Binoviewer.

At first I really wasn’t very interested in working with a binoviewer because the 3D effect definitely throws my mind a curve when studying at the telescope. Oh, yes. I had all kinds of excuses. More difficulty focusing with one eye than another, my favorite scope has a fast focal ratio, I use reflectors… You name it. But William Optics changed my mind.

When I opened the well-made little carton with it’s pretty embossed logo, I was stunned at the craftsmanship. Pictures do not do it justice. The William Optics Binoviewers are very precision in appearance with sterile white powder coat paint, heavy – but not too heavy, big, easy-to-grip thumbscrews and brass compression ring fittings for the eyepieces. Instead of needing to purchase two additional eyepieces, it comes already equipped with twin William Optics Wide Angle (66ร‚ยบ) 20mm occulars. Just to state a case in point here, I know for a fact these two eyepieces alone are worth more than half of what the binoviewers cost! But, back to the task in hand…

The William Optics Binoviewers spread easily to accommodate interpupillary distance and each eyepiece holder has its own separate helical focuser. What’s more – and this is a feature that sets them apart – they come already equipped with a 1.6X barlow nosepiece. What’s inside? According to the manufacturer specs, we’re talking about a true BaK4 prism with a genuine 20.2mm of clear aperture. So what does terms like that mean to just the average Joe? It means we aren’t talking about a pair of binoviewers that are going to lay around in your eyepiece case because they deliver cruddy images… We’re talking about a class act.

I’m not exactly sure what makes the William Optics Binoviewers work so well, maybe it’s the 4″ optical path, but whatever it is, they are unlike any inexpensive binoviewers I’ve ever used. Combine it with a h-alpha solar telescope and once you’re in tune you’ll get an image that will blow your mind. Put it in a refractor telescope and go for Jupiter… the effect of sheer dimensionality and being able to tell distance in the galiean moons will make you a planetary observer. Use it in your workhorse reflector and study the Moon. You’ll feel like you’re there, dude. Drop the binoviewer into a big dob and check out something familiar – like the M27. Holy guacamole… It looks like something you’d see in an IMAX theatre! Put it in a little rich field telescope and look at a star cluster… You can see the light years between the stars. Put it in an observatory telescope and look at a galaxy?

And you’ll become a believer.

How do I feel about the William Optics Binoviewer now? While it may never surpass the Denkmeier or Bino Vue in some folks opinion, it’s not going to take part of your life savings to afford and you won’t regret the purchase. As far as compatibility goes, it worked with every telescope I happen to own and provided sharp clarity, bright images and an absolutely stunning three-dimensional effect on every object I chose. For $199 you get the complete package and no surprises. You won’t need to buy eyepieces, adapters or a special nosepiece – it works with any 1.25″ focuser and probably any telescope you choose to put it in. Small wonder I’ve never heard anyone say anything bad about William Optics Binoviewers…

They’re a real class act.

We would like to thank Oceanside Photo and Telescope for providing the William Optics Binoviewers for this product review. If you’re interested in purchasing a pair of William Optics Binoviewers from OPT, please remember to put “Universe Today Astronomers” in the club affiliation box when you check out to receive your special UT discount on your final bill!

17 Replies to “William Optics Binoviewers – A Class Act”

  1. I’ll have to look for them at the next star party. 90% of the ones I’ve looked through, I didn’t like: most of the time, I couldn’t merge the image.

    One of the few times I’ve seen some setup properly and gave an amazing image was a pair of Seibert’s and they were sitting behind a PST. I think part of it was that these actually belong to Harry Siebert and he had them perfectly setup. The sun in H-Alpha with a properly setup pair of bino viewers really is an amazing site!!!

  2. I don’t question any of the superlatives about the view through a bino-viewer but I have to be a bit of a skeptic when it comes to what you are getting for $200. If you were to buy a top of the line Denk II with 21MM eyepieces it will cost about $1,800 and if you were to buy the stripped down model “the Big Easy” with eyepieces it would be about $1,050. I know manufacturers can charge what they want to, but are there really that kind of margins in these products?

    It may be more useful for a side by side comparison of several brands rather than being blown away with the view from one maker and one retailer’s pushed product.

    Still, it was an interesting review and does cause some hesitation and thinking about spending the $1,800 for a top of the line system.

  3. This binoviewer sounds very interesting. Does anyone know how it is compared to the Stellarvue BV3 Binoviewer?

  4. Hi Tammy. Another great article from you.

    I have a Williams Optics 2″ 90 degree star diagnol because I couldn’t get enough light to pass to my eyes in the standard 1 and a quarter inch system.

    I am extremely happy with Williams Optics. I could only use my 10mm eyepiec thru the 1 and a quarter system only on nights of perfect seeing. With the WO 2″ system, I can use it on an average night.

    Let the light be there.

  5. Like RapidEye, I wasn’t very kicked on working with binoviewers. At every star party, there’s someone who has a pair of this kind or that kind and they all want my opinion. While I’ve always been nice, more often than not I have difficulty focusing them, getting the right interpupillary distance and eye relief. Let’s just say there are many more unpleasant pairs than pleasant ones…

    However, there has been more than one opportunity when I’ve used extraordinary binoviewers and the absolute top of the line is Denkmeier – seconded by Bino Vue. The first time I used a set of Denks I wanted to go hide somewhere and quietly throw up. Why? Because it felt like someone had tossed me into space, that’s why!! There’s a big difference between a hologram and a Viewmaster. When I could finally settle my stomach down enough to really enjoy the experience, I realized that not all of these things are created equal. As for Stellarvue? I cannot say enough good things about Vic Maris and his company, so I can say that the BV3s are most assuredly quality as well.

    Ricardo? Please realize that no manufacturer, nor retailer makes the choice of what products I decide to review. I do. In these economic times we are very, very grateful for the good folks at OPT who send me what I choose at their own expense and also pay to have it returned. Links to the product are provided as a courtesy. For that favor, I simply list who supplied the product and they return the favor again by offering our readers a discount. Why would I not choose the Denks over the WOs? It’s easy… I can’t afford the Denks. Can you? In all things I try very hard to take the perspective of what real people can afford… and brother… you don’t get anymore real than me. But no offense! If I had ten times the money to spend, I’d choose the higher priced model just because there is a difference between a seeming three-dimensional effect and a visual experience that makes you physically ill because your brain can’t quite wrap around it.

    Are the WOs perfect? Actually, for what they cost – they are. The supplied eyepieces give an excellent field of view with nice enough eye relief for even old eyes. The twin helical focusers have enough focus travel that even mis-matched eyesight stands a chance. You can spread them apart even while they’re connected to the scope with no problems. And, for the most part, if you focus them in with your glasses on, they work for almost everyone else without refocusing. However, don’t drop them. My guess is that one good rap on the concrete would be “game over”. Before you pick up a unbrand pair of binoviewers, stop and think about the WOs, ok? They are very well made and you won’t be disappointed.

  6. Hi Tammy,

    Thanks for the story behind the story (to paraphrase Paul Harvey), it has really cleared up my thinking.

    I may not be able to afford the Denk II but I will buy it, it just means more beans and hotdogs, which has been the routine for well over a year after I ordered a Steve Kennedy 24″ f3.6 mirror when Corning stopped making Pyrex. One just has to choose what is important in life and make do with the rest.

    I hope I’m not behind the barn throwing up every night, but that might be a small price to pay.

    I will even give OPT a shot at the order even though their ads are what want to make me throw up.

    Thanks for your efforts, they are appreciated

  7. LOL! Ricardo? You are a man after my own heart. The hotdogs and beans would be enough. (ramen noodles also work…)

    Talk to the folks at OPT and make sure to get the right set of Denks for the scope you plan on using them in. I’m not exactly crazy about ads either, but everybody has to make a livin’ and I know they will bend over backwards to help.

    If I hear you out back behind the barn, I’ll know I’ve done my job. ๐Ÿ˜‰

  8. I’d eat Franks and Beans for a looooong time if I could talk my wife into letting me buy a 24″ f3.6 mirror… =-)

    I forgot to add the other big reason I don’t see a binoviewer in my EP case anytime soon. My preferred EP’s are Pentax XW’s. I have the 5, 7, 10, 14, 20, & 30mm. That collection took several years to pull together in onesies and twosies – I’d hate to have to buy them all again so that I could have a mated pair for my binoviewer 8-0

  9. RapidEye, I’m widowed so I don’t have to get permission but I don’t recommend that as a choice.

    Anyhow, you would only really want to duplicate your 20mm, possibly the 14mm but it is rather close.


  10. The biggest problem you run into with binoviewers is not enough focus distance in most telescopes (with reflectors being especially bad), so you are forced to use the screw-on barlow that’s built for the binoviewer (and included with most binos).

    This means to use them at all you have to have at least 1.6x magnification (so the 20mm eyepieces you mention become 12.5mm)! And with many binoviewers the magnification is 2x!

    I found out that the barlow MUST be used AFTER I bought my pair!

    Seibert Optics makes an Optical Corrector so you can bring it to focus on most any telescope and only increase magnification by 1.25x or less (which is 16mm for 20mm eyepieces). Check them out at:


    Binoviewing isn’t for everyone, just as any other aspect of this hobby is open to tastes!

  11. Hi Tammy. Great review! I went ahead and ordered one from OPT, but I didn’t see any discount after I entered “Universe Today Astronomers” into the only space I saw for entering it. What was the discount supposed to be? Thanks again for the review and keep up the good work! Mike

  12. hi, mike!

    the discount doesn’t show until your final bill – the one you receive with your order and what shows on your charge card. i know they don’t reveal it on-line so their competitors can’t undercut their prices and i can understand that. (i’m curious, too… because i just ordered a pair of binoculars that i sent to a friend as a gift! she gets to keep them after i review them. ) ๐Ÿ˜‰

  13. Tammy, can I be your friend next time you review a pair of Canon IS binoculars or one of those new carbon fiber short tube 80’s?!?! =-)

  14. (psssst… rapideye… come on over… the next thing comin’ on the wells fargo wagon is a vixen 100ED refractor! between that and the binos we ought to have us a fine star party!)

  15. I have Orion’s binoviewer and was pleased until I compared it to a club member’s Denk. I almost fell through his telescope.

    My Orion bino has an interpupillary distances from 53 mm to 74 mm.. It just wasn’t constructed all that well since the casing has come loose and it is diffucult to adjust. It still is neat to use at public star parties. I’ll keep it for those occasions but in the future it will be a Denk when the funds show up.

  16. Can’t say I was too impressed with these. Maybe it is me, I keep getting double images and a headache to boot. Don’t get me wrong cos I’m a great WO fan, with 2 scopes in the collection. But I’ve never tried another brand viewer. Could it be the collimation ??? Make sure you buy from a good dealer in case your results are as painful as mine. You might be better off with a new eyepiece. Besides duplicating your EP’s might be a little expensive. Buyer beware….!!!!!!

  17. Tammy, just for clarification: So with the barlow, the bino’s have the eqiuivalent of two ep’s, one set of 20mm and one set of 12.5mm. Is this correct?

    You have me itching to spend some money.

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