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ORION LINEAR BINOVIOEWER - mini-review

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#1 TOMDEY

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Posted 26 January 2020 - 12:26 AM

ORION PREMIUM LINEAR BINOVIEWER

 

Recent discussions motivated me to get one and evaluate it first-hand. I quickly browsed CN history, noted a blend of both spot-on and misunderstanding, all the more reason to start fresh, slate clean, and  simply experience it for myself. Here's what I've discovered!

 

This make and model is produced in Taiwan and marketed under several brands. There are others operating on the same principles. The Orion and TS-Optics sites provide decent qualitative descriptions regarding the principle of operation and advantages. Not much quantitative... which is fine. Marketing, sales and tech blended for user-consumption, without getting prohibitively techno.

 

Here are images of the gizmo and the cartoon I was able to find. That was annotated in Chinese, but I was able to understand what they were explaining --- fascinating! I annotated in English and added my comments. Now for some (back-solved) techno-speak, for you who enjoy such: The light from the telescope comes in from the left, headed toward the input focal plane, which is virtual, because that positive meniscus singlet lens element intercepts the light, before it gets there. This forms a ~60% compressed real image at my annotated fp conjugate. My first knee-jerk response was "Yikes! that must be a terribly-aberrated real image, compressed to 60% with only a singlet". But, not to worry. The other elements take care of that. As long as their aberration contributions cancel at the final image presented to the eyepiece(s)... all is well! The 1st five elements reimage the telescope's pupil (aka the objective mirror or lens) upon the disjoint pupil splitter. I coined that descriptive moniker to indicate its function, and contrast it with the more traditional beamsplitter approach, which does not require said conjugate relationship. The final doublet reimages the pupil back to where it started, and the focal plane to where the eyepiece would expect to find it, in the absence of the binoviewer --- aberration-free, at 1x, and original F# feed. That's really all there is to it! If it seems cryptic, not to worry... the lens designers take care of all that. The generalized optics context is "periscopes", where the designer has to stuff light thru skinny meandering, articulated tubes, without badly compromising performance. Our predecessors got very good at such work during the 1st and 2nd WWs... we are the beneficiaries!

 

One unavoidable consequence of this disjoint pupil-splitting approach is that each eyepiece gets all the light from half the telescope's lens or mirror. In contrast, the traditional approach, where each eyepiece gets half the light from all the telescope's lens or mirror. In each case it's a 50:50 split, but executed quite differently. Each has its advantages and disadvantages.

 

traditional                    disjoint

 

round pupils                half-moon pupils

50% luminance           100% luminance

tb res preserved          tb res preserved

lr res preserved           lr res degraded

net info preserved       net info preserved

50/50% BS coatings   100% mirror coatings

neg relay Barlow         1x positive relay

prisms                          mirrors

 

I'll just quickly mention that Emmy Noether's Invariance Theorem imposes other conditions, that are unavoidable. But resulting in a rather astonishing advantage for the disjoint-pupil binoviewer. Teaser >>> At very low magnification use, the images will be twice as bright and luminous as with the traditional BV. I'll be happy to expound on that, if anyone is interested. Could allow for enjoying e.g. M31 with a big Dobsonian, at "abnormally low mag" and seeing it "twice as bright" as a plain mono eyepiece.

 

REVIEW:

 

I ordered it via Amazon Prime; it arrived a day and a half later, free delivery, but punitive NYS sales tax. Nice carry case and packaging. Heavier and more compact than I had visualized... and looks more precise, sturdy and promising than what I envisioned. Dank rainy day. I opened a window in one of the spare bathrooms and set up the trusty old Televue Genesis F/5 APO Refractor, aimed at tree twigs about 500 feet away. Put in a good Star Diagonal and set focus on the twigs, using the 10mm TV Delos... 50x. OK, that looked good, and reminded me of the residual color (as one should expect) from a decent fast APO... green/magenta blush thru-focus. So far, so good.

 

Expectation:

 

I resurrected my annoying habit from decades working at the Research Labs at work. Just before field-testing, anticipate/guess what is apt to be right and wrong with what will follow. (Then, after the fact, compare actuals with anticipated.) Well, I guessed that, as nice as this thing looked and felt, that its performance would be somewhere between quite and terribly disappointing. I expected that I would indeed find half-moon pupils, but ragged and/or blurred. I expected the chromatic aberration to be terrible, because of the aggressive positive relay. I expected field curvature, bad collimation, vignetting... especially at the aggressive F/5 feed, which most all binoviewers abhor.

 

Actuals:

 

So, I popped it in. Put in a pair of Delos 10mm @ 50x ... and looked at the twigs again! Astonishing was that they were in perfect focus! When they say ~zero focus shift~ they're serious! I finessed the IPD and L/R focus just to make sure, and then further scrutinized the experience. Well, the image-merge felt comfy, good collimation. Both sides balanced for brightness, neutral color, resolution, field flatness, chromatics (only residuals or scope itself)... I was looking thru an open window, and occasional thermals from that wafted by, but nothing to indicate that the binoviewer was in any way deficient. At that point I knew it was a keeper and exceeding my expectations. And reminded myself that native F/5 is a pretty aggressive feed for a binoviewer.

 

Then scooted over to the Eyepiece Vault to extract any pair of premium eyepieces that were at hand. Here's in order the list of all tried:

 

eyep                          AFOV     FS         mag    pupil

 

>Delos 10mm              72deg  12.7mm    50x    2.0mm

>Nagler T6 13mm       82         17.6         38      2.6

>Nagler T6 9mm         82         12.4         56      1.8

>Nagler T6 5mm         82          7.0       100      1.0

>Delite 18.2mm          62         19.1         27      3.6

>Delos 17.3mm          72         21.2         29      3.5

>Night Vision 26mm   50         18.0         19      (na)  --- not tried yet

 

They all performed well. The Delos 17.3 (biggest field stop) had degraded imagery at the left/right edges, but perfectly fine over the rest. I'm guessing that's the combination of field and F# stressing the system. The Nagler 5mm was challenged for resolution, but that was the open window in cold weather, not the scope, binoviewer, or eyepieces. Occasionally the thermals would subside and then both sides looked nice and sharp. My eyes felt strained at 100x. I was still merged OK, but felt like my eye muscles were stressed to maintain image vergence. At lower mags this was not the case. I didn't have time to reseat the eyepieces, etc. ... but short efl eyeps push collimation and seating challenges.

 

Overall, this 1st trial is very encouraging! I haven't yet tried it on the stars, dark-adapted, faster feed, or on the Newtonians, with their centrally-obstructed apertures. This should be a hoot to poke into the focuser on my giant telescope. My 36-incher is F/3.75 (F/4.3 with essential ParaCorr)... Hmmm... ? Also, not tried yet... my pair of Night Vision Eyepieces! With the Zero Focus Shift, I can pop them directly into the receivers, image(s) falling directly onto the GaAs photocathodes... expecting spectacular performance.

 

[Perspective: I know there have been tons of discussions here on binoviewers, but I chose to not bias my 1st light too much with what others have already decided I should think or discover. I appreciate the history and wisdom archived here, but take Richard Feynman's advice to heart... to rediscover what others and no others have learned in the past, in one's own way. What it was, what it should be, will otherwise contaminate our experiments.]

 

Bunch of pictures >>>    Tom

Attached Thumbnails

  • 07 Orion Linear binoviewer.jpg
  • 02 binoviewer inside 150.jpg
  • 01 pupil-sharing approach.jpg

Edited by TOMDEY, 26 January 2020 - 12:40 AM.

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#2 TOMDEY

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Posted 26 January 2020 - 12:27 AM

nother pic    Tom

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#3 TOMDEY

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Posted 26 January 2020 - 12:28 AM

nother pic    Tom

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#4 TOMDEY

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Posted 26 January 2020 - 12:28 AM

nother pic    Tom

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  • 06 low mag test.jpg


#5 TOMDEY

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Posted 26 January 2020 - 12:30 AM

last picture showing actual disjoint "half-moon" pupils    Tom

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#6 greenstars3

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Posted 26 January 2020 - 01:16 AM

Tom 

 

How do these compare to other binoviewers you have used? I own 1 pair of subpar binos that I have never gotten to merge so have not tried any others.

 

Robert 



#7 TOMDEY

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Posted 26 January 2020 - 01:59 AM

Tom 

 

How do these compare to other binoviewers you have used? I own 1 pair of subpar binos that I have never gotten to merge so have not tried any others.

 

Robert 

Hi, Robert!

 

I'm actually not much of a binoviewer guy, so not experienced here. But, that said, I do have a decent Binotron that I intend to duel 1:1 with this thing. The main thing is that they are totally different approaches. I'm not really much into splitting performance hairs, if things are decent right outa the blocks. Leaving that to others who are macro into such evaluations. Ever since childhood, I decided to ~invent~ and follow my "Ninety Percent Theory" as a way of life. That is to intentionally strive for 90% perfection and then call it good enough and proceed to the next task. Depending on the context, that satisfactory # could be 80, 90, 99, 99.9... but always less than perfection. With just a little more testing (under the stars), I believe I'll decide that I love the Orion Linear, and then just enjoy it!    Tom


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#8 greenstars3

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Posted 26 January 2020 - 02:48 AM

Thanks Tom

 

Robert



#9 clivemilne

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Posted 26 January 2020 - 06:38 AM

Excellent and insightful write up Tom..  

 

Thanks   ;)



#10 bcarter1234

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Posted 26 January 2020 - 02:27 PM

Tom,

 

Thanks for sharing this review. I look forward to your results under the stars.

 

As I have learned from my recently acquired pair of binoviewers, my eyes/brain give about 100 arc seconds of horizontal misalignment at 200X. To merge images I need to be able to either A) tilt the eyepieces holders so the eyepieces converge when looking through them or B) adjust the left and right mirrors/prisms to achieve the same result. Does it look like these would allow either approach? 

 

Take care,

Brent



#11 TOMDEY

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Posted 26 January 2020 - 03:52 PM

Tom,

 

Thanks for sharing this review. I look forward to your results under the stars.

 

As I have learned from my recently acquired pair of binoviewers, my eyes/brain give about 100 arc seconds of horizontal misalignment at 200X. To merge images I need to be able to either A) tilt the eyepieces holders so the eyepieces converge when looking through them or B) adjust the left and right mirrors/prisms to achieve the same result. Does it look like these would allow either approach? 

 

Take care,

Brent

Hi, Brent!

 

Because it manifests only at high mag, is sounds like your binoviewer is misaligned, not your eyes. For the layout of this Linear Binoviewer, rotation of one or both of the final fold mirrors or lateral translation of one or both of the final doublets would achieve that. The only thing preventing one from diving inside would be Orion's one year limited warranty.

 

Counsel to all users of binoculars and binoviewers --- prudent to see a local full-service optometrist, and get your eyes checked for differential "prism" (angle and clocking). Any fixed-mag device can then be trimmed to your comfort. That is a personal "conditional collimation" which would render the device uncomfortable for most other users. The binoviewer is multi-mag, so the conditional alignment would also be for just one single magnification... therefore generally not recommended.    Tom



#12 bcarter1234

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Posted 26 January 2020 - 10:28 PM

Tom,

 

Sorry I was not sufficiently clear. The issue is not only at high magnification nor with any specific binocular device. I get the same result using any binocular device at any magnification. The misalignment is definitely somewhere between the front surface of my Mk I eyeballs and the central processing unit between my ears. My optometrist measured twelve diopters of horizontal and two of vertical misalignment. My eyeglasses have two and one respectively which helps with everyday but would be insufficient for observing. I don't wear glasses when observing.

 

If the final fold mirrors or final doublets can be manipulated in this device that would be very attractive. 

 

Take care,

Brent 


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#13 Eddgie

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Posted 27 January 2020 - 08:35 AM

Thank you for the write-up.

 

Some thoughts for your next test.

Please do a star test with an obstructed instrument and see if they modify the spherical aberration. 

 

Next, when you do the star test, would be drift a defocused star from the center to the edge of each field and see if there is any affect on the fully illuminted circle vs a single eyepiece? The question here is if the very small prism in the illustration is receving all of the off axis rays.  Is so, the off axis field illumination should be preserved vs a single eyepiece, and if not then the question is how much vignetting does it impose. 

 

Also, when viewing planets, is there any affect where the edges of the split pupils bisect a planet that is centered in the field.

 

Of course I am curious how they work with a pair of image intensified eyepieces. I don't see myself doing that because of the weight and stack but it is kind of an interesting thought. 



#14 TOMDEY

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Posted 27 January 2020 - 10:56 AM

Thank you for the write-up.

 

Some thoughts for your next test.

Please do a star test with an obstructed instrument and see if they modify the spherical aberration. 

 

Next, when you do the star test, would be drift a defocused star from the center to the edge of each field and see if there is any affect on the fully illuminted circle vs a single eyepiece? The question here is if the very small prism in the illustration is receving all of the off axis rays.  Is so, the off axis field illumination should be preserved vs a single eyepiece, and if not then the question is how much vignetting does it impose. 

 

Also, when viewing planets, is there any affect where the edges of the split pupils bisect a planet that is centered in the field.

 

Of course I am curious how they work with a pair of image intensified eyepieces. I don't see myself doing that because of the weight and stack but it is kind of an interesting thought. 

Hi, Eddgie! 

 

OK, I understand all that... (good!) The 1x + zero focus shift will allow me to get the prime image right onto the GaAs photocathodes, as long as the scope itself does. This is true of both my 4" F/5 Genesis and 36" F/3.75 Dob (sans ParaCorr). I expect the ParaCorr will be essential to slow the feed down... even that F/4.3 may frustrate the binoviewer? The NV used that way (not afocal) are about as light and compact as the regular glass eyepieces!    Tom



#15 Eddgie

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Posted 27 January 2020 - 05:37 PM

The stack would be the filter wheel and I would now need to run the 1.25" eyepiece holder, then the BV, then the devices. I don't even like the long stack of just the eyepiece and device.

I am interested I how it works though but i don't see this as something I would do in my own setup and while there would not me light loss, there would not be any binocular summation either so it woul be a kind of wash. A binocular telescope would be awesome though. I have thought of building one with a pair if 6" imaging Newtonians.

#16 bcarter1234

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Posted 27 January 2020 - 07:09 PM

The stack would be the filter wheel and I would now need to run the 1.25" eyepiece holder, then the BV, then the devices. I don't even like the long stack of just the eyepiece and device.

I am interested I how it works though but i don't see this as something I would do in my own setup and while there would not me light loss, there would not be any binocular summation either so it woul be a kind of wash. A binocular telescope would be awesome though. I have thought of building one with a pair if 6" imaging Newtonians.

Eddgie,

 

DO IT!!! They are so worth it. ;-) I've got three and am in the planning stages of the fourth.

 

You are a man who analyzes things which I and others benefit greatly from. Consider what you want to do most with it. If you want quality to the edge stay with a high enough F ratio to keep the coma to an acceptable level. Two 8" F/6 tubes strapped to the right framework and Bob's your uncle. From 50X and 1.3 degrees to 200X or more of two eyed bliss.

 

The RB-66 reflector, at 150mm F/5 is pretty good to the edge, Mr Bill's Bino Box as a 127mm F/5.5 refractor is slightly better in that regard but as an achromat it does have color on bright objects and only 5" of light grasp per eye.

 

If you just want to have fun and see if it is for you pick up two 80mm Adventure Scopes for about $80 each. You can get some great views as wide as 3.9" at 16X for relatively low money. 

 

Take care,

Brent



#17 TOMDEY

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Posted 27 January 2020 - 07:28 PM

The stack would be the filter wheel and I would now need to run the 1.25" eyepiece holder, then the BV, then the devices. I don't even like the long stack of just the eyepiece and device.

I am interested I how it works though but i don't see this as something I would do in my own setup and while there would not me light loss, there would not be any binocular summation either so it woul be a kind of wash. A binocular telescope would be awesome though. I have thought of building one with a pair if 6" imaging Newtonians.

Yep... all true. But my ~theory~ re' bino summation is that in this unusual context of two NVs downstream is that the uncorrelated scint might benefit, quite possibly a lot, because our head full of mush (right from the two retinas on back) should substantially filter out the L/R uncorrelated scintillation from the object. That seems theoretically sound to me, especially since this particular pupil-splitting is tantamount to using two telescopes looking thru two different disjoint pupils through two different columns of atmosphere (admittedly right next to each other, but nevertheless disjoint)  Hmmm... ?! Worth trying ... I'm all excited about it and hoping to look for that little baby comet cruising by the Double Cluster, using the same 4-inch scope that I looked at the tree twigs with. Yippee!!!    Tom

Attached Thumbnails

  • 53 binoscope binoviewer pupil differences.jpg


#18 TOMDEY

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Posted 27 January 2020 - 07:35 PM

Eddgie,

 

DO IT!!! They are so worth it. ;-) I've got three and am in the planning stages of the fourth.

 

You are a man who analyzes things which I and others benefit greatly from. Consider what you want to do most with it. If you want quality to the edge stay with a high enough F ratio to keep the coma to an acceptable level. Two 8" F/6 tubes strapped to the right framework and Bob's your uncle. From 50X and 1.3 degrees to 200X or more of two eyed bliss.

 

The RB-66 reflector, at 150mm F/5 is pretty good to the edge, Mr Bill's Bino Box as a 127mm F/5.5 refractor is slightly better in that regard but as an achromat it does have color on bright objects and only 5" of light grasp per eye.

 

If you just want to have fun and see if it is for you pick up two 80mm Adventure Scopes for about $80 each. You can get some great views as wide as 3.9" at 16X for relatively low money. 

 

Take care,

Brent

I have the RB-16s with Night Vision on both sides... Lot to be said for that approach!    Tom

 

~ click on ~ >>>

Attached Thumbnails

  • 33 RB-16 night vision parfocalized to glass eyeps.jpg

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#19 Eddgie

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Posted 28 January 2020 - 11:06 AM

Eddgie,

 

DO IT!!! They are so worth it. ;-) I've got three and am in the planning stages of the fourth.

 

You are a man who analyzes things which I and others benefit greatly from. Consider what you want to do most with it. If you want quality to the edge stay with a high enough F ratio to keep the coma to an acceptable level. Two 8" F/6 tubes strapped to the right framework and Bob's your uncle. From 50X and 1.3 degrees to 200X or more of two eyed bliss.

 

The RB-66 reflector, at 150mm F/5 is pretty good to the edge, Mr Bill's Bino Box as a 127mm F/5.5 refractor is slightly better in that regard but as an achromat it does have color on bright objects and only 5" of light grasp per eye.

 

If you just want to have fun and see if it is for you pick up two 80mm Adventure Scopes for about $80 each. You can get some great views as wide as 3.9" at 16X for relatively low money. 

 

Take care,

Brent

It is something I have considered many times but using a pair of 6" f/4 imaging Newts but I am pretty happy using my image intensifed eyepiece in mono mode.

 

Also I think it would be better to just go to a bigger scope and use a PVS-7.  It is hard to find very high performance PVS-7s but even a decent PVS-7 works pretty well in a telescope for stellar obsevations.  Not the best for nebula, but again, I have my monoculars for that and the fully image intensified binocular for low power work..

 

PVS binoviewer - Copy.jpg

 

But the PVS-7 is why I probably would not do a binocular telescope and this to me would be preferable to using two monoculars in a binoviewer.  

 

PVS 7 in dob.jpg


Edited by Eddgie, 28 January 2020 - 11:08 AM.


#20 Eddgie

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Posted 28 January 2020 - 11:10 AM

I have the RB-16s with Night Vision on both sides... Lot to be said for that approach!    Tom

 

~ click on ~ >>>

You know, a couple of MPCCs might work for you.  These would correct the coma (though not bad at f/5) but also would be 1x and would give you 10mm of added back focus..



#21 bcarter1234

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Posted 16 February 2020 - 01:32 PM

Tom,

 

Any updates? I'm curious about your nocturnal experience with the linear binoviewers, especially if you were able to try them on a Dob.

 

Take care,

Brent


Edited by bcarter1234, 16 February 2020 - 01:33 PM.


#22 Jeffmar

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Posted 20 February 2020 - 12:16 PM

The Orion premium binoviewer has been available for a while now and yet I can’t seem to find an objective review that includes actual viewing of things in the night sky. I have a typical 200 dollar binoviewer I used on my big sct’s, which is great for planets and okay for bright dso’s. The issue I have with my inexpensive binoviewer is the sloppy way eyepieces are mounted with little screws and the amount of fiddling I have to do to get collimation. I have read many of the marketing descriptions of the 500 dollar Orion binoviewer. I would like to see even one writeup about using that binoviewer, in the night sky, that is not from a vendor. 




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