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12" Binocular Telescope on Refractors

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#1 Rich V.

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Posted 23 January 2013 - 09:52 AM

Just a link to a post on Refractors showing pictures of a new 12" binocular telescope on an equatorial mount. It uses a "rotary clamp" similar to what I've seen on Matsumoto's site to keep the binos level for EQ viewing.

12" BT in Germany

Very cool! :cool:

Rich

#2 Andresin150

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Posted 23 January 2013 - 11:21 AM

Incredible!,
My 40x150's now look portable, aren't they?
amazing project! :bow:

#3 hallelujah

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Posted 23 January 2013 - 11:36 AM

http://www.astromart...ified_id=808439

#4 richsvt

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Posted 23 January 2013 - 05:17 PM

makes anything I have look like a toy.

#5 PhilCo126

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Posted 26 January 2013 - 04:48 AM

Check the vendor topic:
http://www.cloudynig.../Number/5636500

#6 edwincjones

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Posted 26 January 2013 - 05:45 AM

why :question:

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#7 edwincjones

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Posted 26 January 2013 - 05:50 AM

I can understand going up to 150mm (I have one),
but have never understood the logic, reason, usefulness
of the larger BT due to the cost, duplication of optics
Why not just get a larger scope with binoviewer?

Other than uniqueness,
doing it because you have the money and can,
what is the advantage of this binocular over a telescope?

edj

#8 Joad

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Posted 26 January 2013 - 01:55 PM

I have the same questions, but I think I know the answer. There is a certain mystique to binoculars (as opposed to telescopes) that those of us on this forum have personally experienced. It is indeed far more rational to get a big truss dob and use a binoviewer. You can even move the big truss dob to a dark site, while this ton-and-a-half binocular must be permanently placed in a professional quality observatory. And there also seems to be a sort of unofficial law of diminishing returns when it comes to what binoculars can manage relative to magnification and precise collimation.

So I think I this is a harmless indulgence (at $500,000 it is a lot cheaper than I would have expected) on the part of someone with good taste and lots of money. There are a lot worse things to indulge oneself with, and this one will probably be a good investment on top of everything else.

#9 GlennLeDrew

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Posted 26 January 2013 - 02:18 PM

"...unofficial law of diminishing returns..." Unofficial indeed, for it does not apply. :grin:

If a gigantor of a binocular is not relevant, nor is any size bino. Whether big or small, one is using two eyes and hence enjoying the same gain in signal to noise. The improvement realized when going from, say, a 2" to a 4" bino is the same gain found when transitioning from a 6" to a 12" bino. It's all about ratios. And for given exit pupil diameter, the true bino always offers an image twice as bright as that of the BV-equipped mono job. The humongous bino is quite as relevant as any other size.

#10 Joad

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Posted 26 January 2013 - 02:34 PM

Ah, but I'm not referring to the precisions of optical law; I'm referring to the fact that, say, a 100mm binocular telescope (like my BT) simply cannot manage the magnification of a good quality 100mm refractor, and is hugely sensitive to the slightest collimation offsets in a way that the telescope isn't.

I expect that this custom 12 inch binocular will be built with the intention of being so mechanically and optically perfect that it can perform equally with respect to a mid-sized telescope (I count 12" as mid-sized), but I wouldn't be surprised if the final result was not able to achieve such a level of perfection.

Some evidence for my expectations lies in the reviews I've seen of the giant reflector binoculars made by JMI. They are definitely not high magnification instruments, though their aperture is capable of very high magnification in a telescope.

#11 edwincjones

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Posted 26 January 2013 - 02:38 PM

"...unofficial law of diminishing returns..." Unofficial indeed, for it does not apply. :grin:

If a gigantor of a binocular is not relevant, nor is any size bino. Whether big or small, one is using two eyes and hence enjoying the same gain in signal to noise. The improvement realized when going from, say, a 2" to a 4" bino is the same gain found when transitioning from a 6" to a 12" bino. It's all about ratios. And for given exit pupil diameter, the true bino always offers an image twice as bright as that of the BV-equipped mono job. The humongous bino is quite as relevant as any other size.


ok-I can see this

having the 12" binoculars are no more extreme to me
than me having 25x150s are to many others

thanks Glenn for the insight


edj

#12 faackanders2

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Posted 26 January 2013 - 02:40 PM

http://www.astromart...ified_id=808439


WOW, It really is for sale. I thought is was made for someone or some observatory.

#13 faackanders2

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Posted 26 January 2013 - 02:43 PM

I can understand going up to 150mm (I have one),
but have never understood the logic, reason, usefulness
of the larger BT due to the cost, duplication of optics
Why not just get a larger scope with binoviewer?

Other than uniqueness,
doing it because you have the money and can,
what is the advantage of this binocular over a telescope?

edj


Wouldn't it have much wider TFOV for the aperture (than binoviewing with equivalent aperture)?

#14 faackanders2

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Posted 26 January 2013 - 02:49 PM

Ah, but I'm not referring to the precisions of optical law; I'm referring to the fact that, say, a 100mm binocular telescope (like my BT) simply cannot manage the magnification of a good quality 100mm refractor, and is hugely sensitive to the slightest collimation offsets in a way that the telescope isn't.

I expect that this custom 12 inch binocular will be built with the intention of being so mechanically and optically perfect that it can perform equally with respect to a mid-sized telescope (I count 12" as mid-sized), but I wouldn't be surprised if the final result was not able to achieve such a level of perfection.

Some evidence for my expectations lies in the reviews I've seen of the giant reflector binoculars made by JMI. They are definitely not high magnification instruments, though their aperture is capable of very high magnification in a telescope.


Isn't the reason why people choose binos for the wide views (as mentioned binoviewers provide narrow views).

#15 EdZ

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Posted 26 January 2013 - 02:50 PM

depends on the f# of the scope being used to binoview and whether or not it has been designed (shortened as some are) to accomodate a binoviewer witthout the need for an OCS. If you were trying to use a scope/binoviewer to do this you would most certainly design in tose accomodations. In which case, fov then becomes a limitation of the eyepices that can be used. There are binoviewers that will allow use of a 45mm field stop. So, I would say this can easily be accomplished with a scope binoviewer combo. An 18" f/4 scope with a 45mm clear aperure binoviewer would easily accomodate the same field of view, at a fraction of the cost.

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#16 edwincjones

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Posted 26 January 2013 - 04:54 PM

http://www.astromart...ified_id=808439


WOW, It really is for sale. I thought is was made for someone or some observatory.


I am waiting for the "no reserve" auction

edj

#17 Mark9473

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Posted 26 January 2013 - 05:36 PM

WOW, It really is for sale. I thought is was made for someone or some observatory.

The one that's finished now isn't for sale, it's going to China, but they're offering to build you another one by 2015.

#18 edwincjones

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Posted 26 January 2013 - 08:58 PM

it is really not that bad
only 35% down and
time payments over the next 2-3 years
let's see
-$175,000 down
-about $13,000 month x 24 months + any interest


edj

#19 GlennLeDrew

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Posted 27 January 2013 - 12:05 AM

An arbitrarily large bino need not impose any particular difficulty whatsoever as regards similarity of image scale and collimation.

If we allow magnification to differ by 1-2%, as is the case for small binos, the allowable errors on radii of curvature simply scale in proportion, which poses no problem at all in fabrication.

Collimation is never problematic, no matter the magnification, when on-the-fly adjustment is afforded the user. Adherence to basic engineering practice for the avoidance of any significant differential flexure assures reliable performance.

#20 edwincjones

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Posted 27 January 2013 - 06:11 AM

Glenn,

that said,

what would one do with a 12" that could not be done with 4" or 6" binoculars?

when I have gotten larger binoculars,
there has always been a goal
-the Ms I couldnot find with smaller
-the AL H400s

I would guess better reach for comets,
galaxy groups, smaller open clusters
other objects better seen with binoculars than scopes?

:question:

edj

#21 GlennLeDrew

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Posted 27 January 2013 - 12:47 PM

A 12" bino will see stars 4X, or 1.5 magnitudes fainter than could a 6". And at given exit pupil it will reveal twice the resolving power. Just as something like a big Dob is desirable for small, dim objects, so too is a binocular. A bino is not to be considered as merely a 'small' aperture, wide field instrument. When scaled up, benefits accrue just as they do for cyclopean optik tubes.

Mono scopes are, I contend, not natural. Most of us have two eyes, and so a binocular is the 'normal' instrument. It's not that a bino affords a *gain* in signal to noise of a factor of 1.414, but rather the mono scope is a *handicap* which reduces signal to noise to a factor if 0.707.

#22 Joad

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Posted 27 January 2013 - 01:44 PM

I realize, Glenn, that my trying to discuss binoculars with you is like bringing a knife to a gun fight ( :D , but all I know is that I am not alone in my once hoping that a 100mm interchangeable eyepiece BT could be an all-purpose astronomy instrument. It isn't. Not even close. In the very best of circumstances I can crank it up to about 85X, but the image is dim and the collimation tolerances dicey (even with my in-the-field adjustments, which my variety of Oberwerk allows for). Now, since the summation effect of two 100mm objectives is somewhere around 120mm (or, roughly, five inches), a 100mm binocular is roughly the aperture equivalent of a five inch telescope. But a good five inch refractor can easily go to over 200X. The highest any of us here on CN has gone is 150X, and that is with a special Miyauchi, and the person who owns that binocular does not often view at 150X. EdZ, with his 100mm Oberwerk, tends to stick to magnifications under 60X.

I will grant that if everything is absolutely perfect, mechanically and optically, with a binocular, in theory it should perform right up there with a telescope, but I've never seen that actually accomplished. Maybe the half million dollar monster will be the exception. I hope we find out some day.

#23 Tamiji Homma

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Posted 27 January 2013 - 02:09 PM

I am wondering if the giant binoscope goes to this location?

If it were true, it must be one of those life altering experiences in various ways.

Savio Fong's post

5100m observatory

Tammy

#24 Andresin150

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Posted 27 January 2013 - 02:35 PM

I think what Joad wants is not only possible but already exists.. The problem: cost. But for example a Bt out of a couple 102 Taks (or bigger) and a Matsumoto mirror setup will probably take you there.
But I'm not ready to go there, for me, just like the 12" Bt, this is telescope (high mag) realm. Binoculars, regardles of size, are different in their relatively small size for the aperture, big TFov for the magnification, correct image suitable for terrestrial use or simply to make them more user friendly..., the use of two eyes (and its obvious advantages) is a feature, but not exclusive of binoculars, same as portability...
So, if I wanted high magnification images, for example for planetary observation, those 12" could be a great instrument and should be considered by anyone that could afford them, but if those where mine, those would get to be used like a telescope, just like one that happens to be able to be used with both eyes...., but never like a binocular

#25 Mark9473

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Posted 27 January 2013 - 03:22 PM

I think you're right Tammy!






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