The 70X two eyed Bible. (1 Viewer)

[Cosme]

Who's have never dream of look at 70x with both eyes? ok, neither is portable or cheap, but the experience should be amazing.

http://www.birdforum.net/showthread.php?p=2970962#post2970962

Im gonna try to summarize this thread to see the options, performance, and prices.

1. Binoscope:

http://www.birdforum.net/showthread.php?t=85808

This is the best choice?: Is the one wich allow you not only to have the highs mags, but the lowers too. Its also, if you choose 80/85 scopes, the lightes combo. The bad thing is you need to collimate and mount, i dont think is hard, but has to be done.

Another bad thing is the eyepieces. If you choose spotting scopes wich doesnt allow alternatives to the zoom or only the ones the brand sell, you will missing a great range of mags and fovs, not to say 60x with zoom is not the same than with a fixed one, and only the expensive scopes can reach at most 75x ... i dont know if all the brands offers fixed eyepieces for 70/80x too. Normally are 30x to 40x depend of the size of the scope. Its not possible with 45 dgree 80 mm and above scopes: not enough IPD. Maybe two 45 dgree 60mm or 65mm can reach enough IPD, but i dont know for sure and we are talkin of less "powerfull" binoscopes, but if you are to are satisfied with it, and want the truly most cheap and lighter this is the way to go. Be very carefull on the measuring or find a store to check it; dont you ever buy them like "im gonna have luck"

There's a plan B: astro binoscope. The most complicated part ist to get straight through prism. The only one i know is a bushnell ... quality? seems to be too cheap so i think is correct, and no more ... there's the nikon prism unit, but i guess cant be attached to the 100% of the scopes. So you need to buy or find one to try it. And then is IPD ... my thoughs are it maybe can work on 80mm scopes, above that im afraid its risky to do the experiment with your own money.

2. Binoviewers:

Its hard to find a set that can go lower than 40x, impossible in maks, maybe in some refractors with a reducer ... BV worst thing is, there's no standar. I look at cloudy nights and some people achieve it with barlows, reducers, others with none ... then is the Binoviewers itselfs, depend on the clear aperture, than can go from 20 to 28mm, you can get more or less FOV, beacuse if the field stop of the eyepieces doesnt "fit" you find vignettin issues.

There are normally, if you choose a refractor, heaviers than the binoscopes, but can go almost half the weight compared with chinese big binoculars, and with much, much better perfomance (normally big binos that are no APO are limited to 30/40x) ... with Maks the weight is more competitive. A binoscope made of 100 mm and a 150 bv mak, and a 127 bv mak and 80 mm binoscope, in practicall terms, are the same loads (and the same apperture)

So, lets take two examples that works:

Celestron C6:

My 5" C5 SCT, after subtracting for central obstruction, is the equivalent of an 81mm bincular. So the best possible widest field I can get, even with a higher quality 26mmCA binoviewer/0.8x opnose, is by using my 26mm Meade/60° eyepiece with a 27.3mm field stop. This gives equivalent to 44x81 with 1.4° TFOV. Using the lower quality 20mmCA binoviewer/1.25x (no OCS) the best I can get is 64x81 with a 0.8° TFOV. In both cases I can use a longer focal length eyepiece for slightly lower power, but cannot get any wider FOV.

The new Celestron C6 SCT with diagonal would operate about f/11. With binovewer and the Denkmeier 0.8x optical nose it would have a focal length near 1320mm. With a 30mm eyepiece you could get a lowest power of 44x. Since Denkmeier has a CA (clear aperture) of 26mm, you would be able to get a widest FOV of about 1.2° in this 6" scope. After subtracting the light loss for the central obstruction (50mm dia), the C6 would give a maximum widest field equivalent of a 100mm binocular at 1.2° at 44x. You could lower the power by using a 32mm or 40mm eyepiece, but you cannot get a wider FOV.

http://www.cloudynights.com/ubbarch...=collapsed&sb=5&o=all&fpart=1&vc=1&PHPSESSID=

A member forum who actually has done it:

http://www.birdforum.net/showpost.php?p=1106438&postcount=25
http://www.birdforum.net/showpost.php?p=1111773&postcount=28

Another example:

If these are the usual Sky-Watcher/Synta/Celestron/whatever versions, you CAN reach focus without any barlow or GPC with a Baader Maxbright or Mark V binoviewer, if you replace the focuser with a Kasai Crayford, attached via a Baader adapter, because this focuser is around 40mm shorter than the standard focuser.

With the Maxbright, this gives a max field on the 120 of around 2° and 1.7° on the 150. With the Mark V, the field increases to 2.7° and 2.2°, respectively.

I have replaced the focuser on my Synta/sky-Watcher 150mm f/8 with a Kasai Crayford and can EASILY reach focus with ANY eyepiece in my Maxbrights with over half an inch to spare with even my 25mm Zeiss microscope eyepieces, which require unusually much back focus. I can even use a Baader amici diagonal which gives a RACI image!

The focuser replacement is a five-minute job that requires no modifications and no tools except a couple of screwdrivers.

Im thinking in a skywacther ED 120 :t:

Here's a formula to calculate the result of a BV used in scopes: Its not the half of light, like i always though.

Example: A 120 scope.

120x120= 11440/2= 7200.

Then, take the apperture of a given binoculars, and multiply like this:

85 binos: 85x85=7225

There you have:

120= Like 85 mm binoculars, keeping the resolution of the source.

I take this formula from Edz, from cloudy nights. Trust me, is correct.

3:Binoculars

I say it before: forget those semi apo, half quater apo etc etc ... 40x max. Its no bad, but we are talking to raise the bar more. If you want it on binoculars, prepare 3000 the less for a brand new buy.

My only hope are the vixen BT81 ... however i dont think they can reach 80x in good conditions, im betting 50x with luck. Wich is very good for 1000 euros and 4 kilos, and can go on low mags.

Anythin else, avoid it for terrestrial use.

Resume:

Binoscope:

Pros:

Can be the lighter combo.
Can works with low mags too

Cons:

Not so many models than can accept 1.25, from 80 to 100 mm straight through, for less than 1000. So the eyepieces versality could be limited. This combo could be the more expensive if you buy new. Maybe with luck you already have a straight and can buy another one. Find the same two models at the same time on second hand, its harder, but not imposible. However, do what you do, be way cheaper than a true APO binoculars.
Need to be collimated and mounted. Remember, only straight through models on 80 mm, 60 or 65 mm need to be tested physically togheter

Binoviewer:

Pros:

High mags performance works better on longer focal scopes and astro focuser made them easy. Can use a mirror diagonal.
I think is easy to find one astro scope and all the stuff needed on the second hand market than two equals spotting scopes. So this could be really, really cheaper compared to a docters 40x80. You can get a beast like a C6 BV, even from new, for less than half any other true APO binoculars. Eyepieces of "any shape and colours" can be used

Cons:

You be missing the low mags ... if you already got a binos this is somehow, fixed.
You need to made sure the set up you choose is work. Dont buy any scope, any BV, and join them like "ok here we go" ... im not saying this is what happen with this forum member, you to show you its not easy.

http://www.birdforum.net/showthread.php?t=61124

Binoculars:

Well, no pros and cons, those semi apos on terrestrial shows a fair amount of CA surpased the 40x and if already this binos combos are heavy, this is another dimension. True APOS: Heavy as well, 3000 euros min. Im keeping searching info of the Vixen BT81, my last hope

Stop scrolling down :king:

 

[OPTIC_NUT]

Clever use of the shape!
Love the monster occulars.

 

[brocknroller]

That is a monster! To use those oversized EPs, you must either use eyeglasses or have a Herbert Hoover bulldog face.

You didn't list the ER, but those huge EPs suggest it's probably long. If I stuck my high-bridged proboscis in between those giant orbs, it would get ground into sausage. I'd have to use the binoscope with eyeglasses, which I would need anyway to correct for astigmatism, which is a bigger deal at night than during the day when shrunken entrance pupils minimize the effects from the astigmatism.

I've always liked the idea of using a binoscope for stargazing. Never tried one, but I have used telescopes with binoviewers, the best of which was the long discontinued Televue Bizarro. Markus from APM Telescopes in Germany offers some high end binoscopes, and there was an ATM in Japan who would customize a binoscope for you. It gets expensive quickly. You start out with two Televue 101 scopes or some other brand, I think he used Pentax scopes, too, and he makes the prism arm assemblies to fit the scopes.

However, I'm not sure about the practicality of using a 70x binoscope for birding. The depth of focus is very shallow at high powers, which is okay for stargazing since you are focused at infinity, but for birding, it might be cumbersome. Once you have the bird sighted (and I don't see a 6x finderscope on the binoscope, which you would need for birding, it would also be useful for stargazing), you'd have to use a deft touch to focus on the bird without overshooting or undershooting.

Also, birds usually don't stay very long in one place (neither do stars, in the sense that the earth is moving, but you just have to nudge the scope, the star is not going to fly away). Might work okay for shorebirds.

Then you also have to deal with atmospheric disturbances, which are easily seen at 70x. During this spring transition from cold to warm, even a 10x bin can pick up instabilities in the air near the ground that cause the image to blur. I experienced this the other day with the 10x42 SLC-HD.

And finally, even with a 120mm objective, @70x only gives you a 1.7mm exit pupil. You'd probably be getting blackouts galore during the day. On the night sky when your entrance pupils are dilated, the small exit pupils are less of an issue. But during the day when your entrance pupils are shrunken to 3mm or less, keeping your eyes centered on a 1.7mm exit pupil can be challenging. I tried this a couple days ago with the SLC. I used two different 2.5x "doublers" with it. The cheaper one was hard for me to use w/out blackouts, the more expensive one I could use with some care, but since it was cloudy the image was somewhat dim. To get a 2.85mm exit pupil, which would easier to use and let in more light, your binoscope would need to have a 200mm objective. Imagine carrying around two 200mm scopes for birding? You'd need arms like the Terminator.

For biding, I'd also like a 45* angle prism. Getting high in the trees with a straight through scope would be rough on the neck or the knees, since you'd have to crank up the tripod head and get on your knees to view a bird high in a tree unless it was at a very long distance.

I think binoscopes are better suited for stargazing than biding. A 15x56/60 seems about the practical limit for biding due to all the above mentioned factors.

Brock

 

[Cosme]

No, this is not the best for birdin ... not only by the facts you say, this is not portable at all! But in others generals use in a stationary point, and im talking terrestrial, or even some birdin in certain situations, gettin the best 70x visual possible (long focal lenght, both eyes) ... dont forget with the BV you can go on 45 degree. From what you and i say, a binoscope is better suited for lower mags, still talking about money and weight, a good sustitute for a Docter, Kowas, APMs etc ... thats the idea.

There are some places that you dont need to move a lot, 5kgs can be carried, not all day from one point to another, but you can pick it and walk a mille or two, still heavy but not a traumatic experience.



Its some kind of a fancy stuff ... you know, just in case :king:

 

[NDhunter]

Cosme:

Good of you to post this one, and when looking at some of the links, this
rig was built by a birder or probably astro viewer from Kansas with ties to the aerospace industry.
Just look at the quality of the work, it is done very well.

Those are Nikon 60mm fieldscopes, either the FSIII or the ED III, and that
is the Wide DS Eyepiece. For 60mm, they give a power of 24, 40 and 60X.
There is usually a rubber cover over that so you don't get too close, in
normal use. The wide MC eyepiece has a twist up eyecup, and is preferred
as it works better with or without eyeglasses. I have had examples of both.
With the Nikon ED82, you could go to 75X.

They should be mounted securely, and all you have to do is focus each one
individually. That gives you the freedom for any diopter correction you may
need.

I have heard that Steve, Mooreorless, is working on this same type of viewer,
as he is halfway there, he is a skilled mechanic, with a machine shop.

Jerry

 

[Rui_Caratão]

70x as your only one mag/eyepiece is not suitable for birding whatever you use your spotting scope or binoscope, they are only used to come close certain bird carachteristics or to klinch an ID that is too far away, most of times you are good with20x or 30x.
Whatever the instrument used it is allways a complement to your low mag bins if your final goal is birding or hunting. Shorebird observation, birding from hides are the exception to the rule and you may get good results with a sturdy tripod and fork, even with flying subjects it is possible to achieve good results, I realized that last summer at Sagres Raptor counts when using the 45x hudge FOV and depth of field of a Zeiss Photoscope....it was unbeliveble the ease that you follow and focused raptors and storks flying just over you at no more than 150mt :clap: Now imagine yourself using both eyes !!! and 2 12.5mm Docter UWA............:eek!:

 

[Cosme]

Happy to see more people are interested in this exotic project

 

[Rui_Caratão]

Binoculars:

Well, no pros and cons, those semi apos on terrestrial shows a fair amount of CA surpased the 40x and if already this binos combos are heavy, this is another dimension. True APOS: Heavy as well, 3000 euros min. Im keeping searching info of the Vixen BT81, my last hope

How much diferent is the another dimension? So far there are still few users that could get their hands to the new 2650euro APM 100mm Apo Binoculars

28x and 25x from cloudynights http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Board/binoculars/Number/6424007/page/1/view/collapsed/sb/5/o/o/fpart/all

"Ok, I received the binoculars today and I was able to use 20mm EPs in both. I gave the Pentax XW20s to the APM Semi-APO and used my WO 20mm SWAN in the new Lunt Engr APO. I figured I would give the EP advantage to the Semi-APO.
Here is a result I snapped using my iPhone's camera. I might have blurred the Semi-APO image a little, but it certainly illustrates the improvement of the APO."

I still have I hopes for APM or Vixen Astro-binoculars!! If only I could get info how they usually star test

 

[Cosme]

Rui, to me that CA at 25x is to be worried -in fact is to be worried in the APO too- look at the bricks distorsion, i repeat, only at 25x ... noticed the semi apo has the Pentax on it while the APO has the william optics ... though the pentax are better, if you put the WO on the semi apo and the pentax on the APO, well, what can i say ... and finally, the APO is FK61 glass, not a typical FPL53 we find in almost APO scopes. So the gap is even closer.

This is taken with the BT81 at 27x (hyperion 17mm) compare one with another

http://www.davidesigillo.eu/test_vixen81.html

Also, i finally get reply for the BT81 owner who confirms it can reach 50x without any loss (except some bright of course) compared with smaller mags. No one of the four or five APM owners i ask give me that performance chance by a long way, that said, he was very explicit that always with very good ep's ... the expensive ones forget about the 50 euros ep's ... so put it on your budget ....

So maybe with some filters you can push it a little more, or maybe without it getting some acceptable CA.

Cost the same, weight half, perfomance better ... my bet for terrestrial, would be the vixen.

 

[Rui_Caratão]

Before we make judgements we must have sure what those images represent. They could be cropped versions from the original image, certainly from outer portion of the field of view where CA is more noticeble....on that Vixen BT link you posted, there is a second cropped image showing exactly this at 27x http://www.davidesigillo.eu/images/tele/bordi.jpg.
Second, the target chosen maybe on the origin of diferent levels of CA, since high contrast on black and white subjects induce more CA like in both APM images, the Vixen image on those roof tiles is not so good the induce CA.

Like I said before I still have high hopes for Vixen BT81 or APM semi and full Apo, but perhaps is better to ask directly to owners how those instruments star test, or how they perform in daylight with quantifiable resolution data, otherwise opinions may differ substancially. Another quote from CN on an older APM semi-Apo thread. http://www.cloudynights.com/ubbthre...ge/0/view/collapsed/sb/5/o/all/fpart/all/vc/1

"Almost forgot to mention.....
Since I was at Yellowstone, I also used the binocs for daytime wildlife viewing and found NO, ZERO, NADA, color fringing at 23X.
Images were razor-sharp and wonderfully 'contrasty'. Set up next to a top-of-the-line KOWA spotting scope (I think it was 82mm), the views with the APM 100's were noticeably more detailed (and being able to use both eyes was, of course, vastly superior).

This was also a pleasant surprise. "

 

[Cosme]

The last review ... if at 23x a 100mm 1000 euros binos are not good ... turn off and leave! (spanish expression :king

CA its more noticeable but its at the edge of the field, and still to me is better than the APM. Look at the bricks, that doesnt have any excuse

About the owners, i said few times, i ask APM and they all tell me the same, 30x ok ... the BT81 50x ok ... remember, for that both need premium ep's ... they dont come cheap and you need two of them so $$$ x2 ... in binoviewers you can use a regular ones ... you already got a tripod? because for the APM you would need a sturdy one, and i mean real sturdy, they dont come cheap neither. Do numbers and you will find yourself very close of BV/binoscope filed

Im still think Rui, dont be afraid and go for BV or binoscope, get a true ED, and dont worry about 30x or 50x, be about 100x :king:

Rui, see, that im truly been searching, asking, googling for months, in english, italian, german, spanish language ... and trust me, APM or any no APO binoculars, no way for more than 50x ... despite what you read, i dont think none of them have anything of APO, not half, not even a quarter, they are just achromatic, a good ones the vixens ... even the very best astro achromatic scopes of the market are limited to 40x with regular ep's before CA begins to get amplify exponentially at each mags. Someone evil would be giving you hope, like "hey yea, they are great = buy it, spend your money and save mine to check see if they works" ... know what i mean? i dont win anything warning you, in fact if using the "evil way" im losing :king:

 

[Rui_Caratão]

Hi Cosme, what do you mean by brick distorsion? Both pictures seem soft to me, I dont know wich Iphone was used, but the owner said he may have blurred the semi-Apo photo (handheld everything could happen), however he states that they show the improvment controlling CA and better sharpness and contrast of the Apo. Comparing photos from APM with the Vixen ones is like comparing apples to oranges in my opinion, diferent cameras, diferent settings, diferent targets, diferent light..... I am not saying that I think one is better than the other, simply we dont have anything concrete that shows that, and without a controlled and proper review side by side this time.... photos doesnt worth a 1000 words!

I love the Vixen, to my eyes its a better looking bino than the semi-Apo plus its ligther, but for the same price, something is wrong if they are diferent beasts when its come to performance and not many have realized that!!! wouldnt that be strange?


Dont get me wrong I value all the time you spent on the web asking for opinions, but this same opinions when not supported by quantifiable data are just flavors of a bigger picture and people have diferent expectations, who have spend time on this forum have realized that people dont experience the same and that the same doesnt suit everyone equally.
Of course you should be concern with CA, that is one kind of aberrration that could wreck a view for many, but you shouldnt misregard resolution, specially if you want high mags .Not so well corrected optics showing astigmatism, coma, spherical aberration... will not resolve so well above 40x.

 

[Cosme]

All i know, Rui, is that everyone owner of the APM tell me 40x is the very limit for terrestrial, 30x is ideal.

The vixen owner told me 50x is totally ok.

Lets say both performance the same, still you have the same price and half the weight.

Both binos need premium ep's.

For 70x i dindt go for any on them.

Take the best achro scope and ask of many mags using normal ep's before CA appears, look the price then multiply by 2 and add the bino made factor. Nobody sells something that can go even true semi apo for less than that.



If you want it a i send you by mp what they told me :t:

 

[Cosme]

I love the Vixen, to my eyes its a better looking bino than the semi-Apo plus its ligther, but for the same price, something is wrong if they are diferent beasts when its come to performance and not many have realized that!!! wouldnt that be strange?

Oh i forgot this ... because they are astro binos, Rui, and 20 mm more in astro have more wow factor than 81mm, both marketing and real perfomance. At daylight as we know, this is less important. This is not in the quote but you talk about it; nobody says the APM has bad resolution etc, but the CA kills everything else at high mags. And i use that word because one of the owners use it few times when we trade pm's. The members i talk with are from cloudy nights (most are posting on that thread you link) to binomania, astrofili.it and anothers italian forums. But i also ask about the BT80, previous model of the BT81, with 900 f/l!!! ... the oberwerks BT100 ... i even remember read reviews on binomania of 125mm binos! guess what? 40x dead end on terrestrial ... about the APM's i dont want you to spend 1000 euros on a bino, 500 on ep's, and who knows how much on a tripod for something limited to 40x and you cant take it nowhere without a wheelbarrow

 

[Rui_Caratão]

Soory Cosme I am just making sure I have something more quantifiable than opinions without comparison. Have you tried a non HD Swarovsky scope? Are those unsuitable for terrestrial viewing above 40x?

Meanwhille, and this is like making a puzzle...I found another thread where a star test and resolution is mentioned about the new APM 100 Apo http://www.cloudynights.com/ubbthre...6132247/page/0/view/collapsed/sb/5/o/all/vc/1

"Comparing Kowa with 20 x against APM 100 with 23 x power...the Kowa offers a kind of non dimensions flat image ( like Swarovski new swarovision binocular) , while the APM offers a kind of 3D view ( like Leica new HD binoculars )...on night sky I like for shure more the 3D view.

Sharpness: I performed a startest with the APM and old 4.8 mm Naglers = 114 power .....nice concentric diffraction rings and excellent spherical correction, like in a good astronomical doublet apo.
"

 

[Cosme]

Soory Cosme I am just making sure I have something more quantifiable than opinions without comparison. Have you tried a non HD Swarovsky scope? Are those unsuitable for terrestrial viewing above 40x?

Meanwhille, and this is like making a puzzle...I found another thread where a star test and resolution is mentioned about the new APM 100 Apo http://www.cloudynights.com/ubbthre...6132247/page/0/view/collapsed/sb/5/o/all/vc/1

"Comparing Kowa with 20 x against APM 100 with 23 x power...the Kowa offers a kind of non dimensions flat image ( like Swarovski new swarovision binocular) , while the APM offers a kind of 3D view ( like Leica new HD binoculars )...on night sky I like for shure more the 3D view.

Sharpness: I performed a startest with the APM and old 4.8 mm Naglers = 114 power .....nice concentric diffraction rings and excellent spherical correction, like in a good astronomical doublet apo.
"

Rui, dont compare a Swarovski optics against the APM. Again, most of the test you bring are at 23x, in startest. Dont expect to do the same at 60x in daytime.

There's something you might need aside more quantifiable test, realistic facts. When i begin to look info about the APM happens the same to me, everything looks cool but some figures doesnt really balance for a short focal, achro binos ...

Look, i send you my mps of cloudy nights and then you have more stuff to think about it.

My final advice: If you want to stay on medium powers, ok, go for it and a very good pair of ep's ... if your plan was doing up 50x with any of these binos, just forget about it.

 

[Rui_Caratão]

Rui, dont compare a Swarovski optics against the APM. Again, most of the test you bring are at 23x, in startest. Dont expect to do the same at 60x in daytime.

Cosme, we also have diferent expectations, I want a grab and go optics capable of delivering good views with both eyes that I will use mainly at 30x or even 40x....and sometimes when atmospheric conditions let me .....I use 60 or 70x, and you are searching for a lightweight intrument capable of giving you magnifications above 70x, that you still be depending on atmospheric conditions.
1st, a lightwieght optic is not necessarily a grab and go.
2nd, whatever the optics brand, their capability of taking high mags depend on their correction, both APM, Swarovski or other spotters are short focal intruments. Both need low aberration optics and binoculars also need good alignment to acomplish it...
3rd, non HD spotting scopes like the Swarovki show a lot of CA and most astronomers are not used to how all medium and high end spotters perform. On the pm you sent an ATX95 was used to make 1/2 of a comparison , but the owner never mentioned resolution and said the APM showed 3 times more CA.
4th, CA is a problem in BT´s and we all have understand that. No way a semi-Apo doublet will perform like todays best high end spotting scope, the ATX 95 regarding transmission or color correction.

But that is the answer I am after....if the APM semi-Apo has as good resolution at 50x or 60x and suffers from the same amount of CA than an non HD medium or High end spotter, their are still a good value. Their QC and collimation issues is what concerns me more...

I will be back to this as soon as I have more substancial news and facts, I dont whant to monopolize the all thread with high magnification binoculars (BT), we must let others give their opinion

 

[Cosme]

Im afraid we have spend such a lot of time then!!!

On the first post of the other thread you mention 70x and thats what i keep in mind all the time ...

For 30x and 40x is ok, i hope you got already a nice set of ep's. This is something all the owners, vixen and apm told me.

So if you finally want to go for big binos, my bet are the vixens rui, mainly the weight ... and i think the better optics.

Buy what you buy, good luck, and personally i've waiting for a truly terrestrial review.