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Miyauchi Fluorite 100mm Binoculars


Having read Mike Barr's comments on SAA regarding his positive experience with his Miyauchi fluorite binoculars, I was intrigued. I already owned several fine, Takahashi refractors, had the AP binoviewer, and was not sure why these (apparently) rather expensive binoculars would provide me with something I already did not have in my existing equipment. This was particularly so since I already had a pair of 16X70 Fujinons. Why pay six times as much for another pair of binoculars? It made no sense to me at the time.

About a month and a half ago, I had the opportunity to look through a pair of Miyauchi fluorite binoculars while taking depositions in England. The view, on an unusually clear night, through the optional, interchangeable 37x eyepieces was more than enough to answer the question I had originally answered before - erroneously. Although I have only had the Miyauchi fluorites for a month now, and my viewing time has been limited because of sky conditions, my answer to the question I asked myself before is now decidedly different - the Miyauchi fluorites are worth every penny I paid for them and can do things that the rest of my ' arsenal' can't do nearly as well!


Just what the Miyauchi fluorites are can be seen from the following material taken from one of the advertising blurbs for these binoculars:

TECHNICAL SPECIFICATIONS: Miyauchi Bj-1001BF Fluorite Apochromatic Binoculars Galaxy 45s

We are pleased to announce the introduction of the world''s first fluorite apochromatic binoculars from Miyauchi.The Galaxy 45's use 100mm f/5, five element fluorite objectives to deliver ultra sharp, high contrast images to the observer. The long eye relief oculars make it easy for eyeglass wearers to view the entire field with their glasses on. The built-in lens shades insure a glare-free dark field.

Each Galaxy 45 will accept all the custom solar, Deep Sky, UHC, OXY III, and solar filters, as well as a finder and fitted waterproof case.

Built out of the same marine grade duraluminum for durability. Each is infinity corrected to produce the sharpest images for astronomical viewing.

The Galaxy 45's present the purchaser with the ultimate viewing experience with the ultimate 100mm binoculars.


Objectives: 100mm five element fluorite f/5 apochromatic objectives Magnification: 20xOculars: Reverse Kellner high eye-point 27mm eye relief. Inclined 45 degreesExit pupil: 5mmField of view: 2.5 degreesCoatings: Multi-coatings on all surfacesWeight: 6kgs - 13.2lbs Standard package: Binoculars, built-in extendable shields, detachable handle, rubber eyecupsOptional accessories: 3x12 illuminatable finder, waterproof ABS case, solar filters, Deep Sky, OXY III and UHC custom filters


These binoculars are a pair of 100 mm f/5 fluorite refractors of the highest optical quality (five elements) that use interchangeable eyepieces. 20x is standard, a set of 37x is optional, and a set of 26x has just been announced. (I have a these on order and should be getting them any day. I'll let you know how they work out as soon as I get the chance to use them.) With this selection of eps, you have what Mike Barr correctly refers to as the " sweet spot" for deep sky viewing. This leaves you with a pair of side - by - side, fast APO refractors that are limited to medium and low power work. Within the range of their magnification, they will meet or beat any 'single' tube of the same aperture - having twice as much room in the objective through which to gather light. Although they weigh 13 pounds, they take less than two minutes to unpack from a carrying case, set up on a tripod, and let you start sweeping the Milky Way. That is setup time that even the easiest telescope to set up cannot match. And, once you are set up and observing, you get a tack - sharp, color - free, wide - field 3-D view that cannot be matched by a telescope even with the finest binoviewer.

As much as I like these binoculars, they will never replace the telescopes in my 'stable' nor will they do so for you. Binoculars are far more "specialized" and less versatile than a telescope. As I have said repeatedly, however, and perhaps have already bored you with stating on SAA, there are ' horses for courses'. For this particular 'course', wide-field, color free, deep sky observing, the Miyauchi fluorite binoculars are without peer. There are, however, many more 'courses.'

The Miyauchi fluorite binoculars are not really binoculars in the sense to that term normally evokes in the mind of the average user. They are not intended to be - and cannot be - used as a pair of 'normal' binoculars. They cannot be handheld or worn around the neck. Even if they could be handheld for a moment, the individual eyepiece focusing, weight, and general design make such use awkward, if not impossible. They are designed to be used for terrestrial or astronomical observation only when mounted on a tripod or other form of similar mounting.


The fluorite element provides for superb, color - free viewing and provides a 3-D effect that has to be experienced rather than something capable of being described adequately. The interchangeable eyepieces provide for what Mike Barr correctly refers to as viewing at the " sweet spot" for deep sky work. The non-fluorite model has the same color-fringing problem noted by Phil Harrington in his review of the 125mm Vixens. The lack of interchangeable eps limits an otherwise superb deep sky instrument. "Straight" eps (such as in some of the large Fujinons or the new Takahashis) makes prolonged use uncomfortable. At the same time, the combination of all these features in the Miyauchis makes deep sky viewing a whole new experience. If you can afford it, do it. If you have the chance to look through a pair of these outstanding binoculars, you will see where the extra cost went, and won't need to ask this question again.


THE MOUNT: Unlike 'normal' binoculars, the Miyauchis require the use of a substantial mount. Although the manufacturer sells a rather expensive fork mount which I have not yet seen, the best possible mounting I am aware of is made by LightSpeed Telescopes. This looks very much like a wide version of a Televue Telepod head, and is beautifully machined. It has the capability of adding DSCs. With this computer capacity, however, the total price of the mount is in excess of a thousand dollars. (This is without the tripod.) The company is in the process of moving from one state to another and production will not begin again until late this spring. However, it still is 'choice #1.

An alternative is the setup I am currently using, a tripod and 'ballhead.' I find that a Bogen "Work Horse" tripod, with a capacity of 26 pounds but a weight of only nine pounds, works just fine. (The tripod costs approximately $175 from various photo supply sources on the Web.) This tripod also lets you extend the binoculars to a height of 81 inches, which will let you view objects at the zenith while standing up. Use of a chair allows the binos to be used without extension. To mate the binos to the tripod, I use the Bogen Proball, quick release head (3435QR) which costs nearly 200 dollars from the same sources. Although you can get away with a simpler and less expensive head, this particular model (rated at 22 pounds) allows you to maintain friction on the binoculars, move them easily, and lock them into place, all with one hand and without losing your concentration. The quick release feature lets you mount the plate to the base of the binoculars and leave that piece attached when you leave them in the case. You then pick up the binos with the plate attached, put the assembly on the ball head and snap the plate into the ball. This presents far less risk of dropping the binoculars then 'screwing' the binos to the head or plate while that plate is attached to the tripod -- and its dark out! Since the quick release feature does not cost any extra and makes the whole affair much easier, it was a "no-brainer" as to selection versus the 'standard' head.SETUP: The binoculars, mounting head, spare eyepieces, and an Orion EZPointer (which I use as a finder and which attaches to the carrying handle that comes with the binoculars) all fit easily in a Pelican 1600 case. (See photo above.) The binoculars themselves are approximately nine inches in width and just over a foot in length. The Orion EZPointer fits easily on the handle and is far better to use (and a whole lot cheaper) than the 'factory' finder scope -an item which I'm not even sure the U.S. importer stocks! If you are willing to pick out the foam yourself, you can buy it from any camera or photo supply house on the Web for about $140. If you want to pay someone else to pick out the foam for you, dealers will sell you a "Miyauchi" case (which I believe is the same) for about 30 dollars more. You can simply carry the tripod or put it in a tripod case, as shown in the photos. The entire setup is easy to carry, and goes from closed case to set up for viewing within two minutes or less.



The views are as sharp and crisp as anything I have seen through my FS 60C, FS 102, or FS 152 Takahashi refractors. The views are also as sharp and crisp as those I have seen looking through other premium refractors made by other outstanding companies. At the same time, the 3-D effect and breadth of view from the side - by -side, twin 100 mm apo tubes cannot be duplicated in the same refractors using a binoviewer even with excellent eyepieces.

Although they are not really intended for lunar or planetary work, the one time I turned them towards the Moon, and the one, quick view of Jupiter and its satellites that I was able to get before the weather closed in, was very pleasing. The binoculars showed everything on the lunar surface as clearly defined, with the 3-D effect quite pronounced as expected.. The same, 3-D effect was obvious in the view of Jupiter, but of course was far less pronounced - again as expected.

Deep sky viewing has to date, unfortunately, been limited to about three, brief sessions before the clouds rolled in. Subsequent evenings have found me either tied up with work or we have been hit with lousy skies here in Chicago. Nonetheless, views of most of the major "highlights" of the deep sky lived up to what I've been told by other users on the Web - absolutely stunning!!!!! A more detailed report will have to wait until skies clear out. Alister and I are planning a "shoot out" in the future between his Vixen 30X125s and my 20X100 Miyauchis. It should be quite a bit of fun, one that we will of course keep you posted on and report to you when it is over.


Although I have not had enough time with these binoculars to give you a detailed observing report, I can tell you that I believe they are well worth their $3500 price tag. They are, of course, a highly specialized item and cannot replace a telescope as a primary observing tool. However, if you can afford a pairof these outstanding binoculars, buy them without hesitation - I promise you will not be sorry.

Addendum (04-17-2000)

I am sorry to report that my initial, highly favorable (if not downright ecstatic) review of the Miyauchi Fluorite 100mm Binoculars (20X100) has been tempered by my subsequent experiences. Like Allister's initial impressions of his 30X125 Vixen's, I too was very impressed with my first usage of these binoculars. Things went downhill when the weather cleared up long enough to give them some extended usage. My first usage was under poor seeing conditions. When I finally got the binos out under clear, steady skies, I noticed some softness in focus, and some difficulty in getting them to "snap in." This ultimately proved to be a collimation problem. My dealer (Astronomics) spoke to me at length and, after discussing this issue with TNR, said they would send out another set.

The second set arrived, and on the first clear night, they snapped into focus like a charm. Stars were perfect, and focus was quick and easy to find. Turned to the Moon, and - the rim was a yellow/green/blue ring - and brighter than the dickens! Had a 22 Panoptic in my TMB 4" mounted next to the Miyauchis, so the magnification was about the same. No ring. Went in and got out the Pronto. Yep, same ring with this non-APO.

Astronomics took this pair back. I don't know if it was a problem with the fluorite, or with the assembly of the optics, but I had NOT had this problem with the first set, which was color free. I assume it was a function of this particular unit.

At this point, I was not able to get a replacement in a reasonable period of time. Astronomics was stand-up and offered to do whatever was necessary to solve the problem. That solution proved to be a pair of 25X150 MT Fujinon Binoculars, the largest binoculars in production today. My brief experience with the 4" Miyauchis left me a firm believer in the concept, but not happy with that particular execution and not willing to spend more to get the 141 versions. I understand that the Fujinon 6" are a "proven" commodity. I will report on those in the near future.

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