Two Eyepieces at Once - Binoviweing

[joe1950]

I hope this fits well here in ‘Eyepieces.’

About two months ago I got a binoviewer. Not a high end unit, but one to give it a go. Never tried it before but have heard some high praises from others.

At first, I thought it was great and couldn’t imagine going back to mono-viewing. Almost sold my eyepiece kit. From what I can gather, there seems to be a core group of highly devoted binoviewers who use it exclusively, especially on the moon and planets.

The idea is that although the light is split in half by the bino viewer, the brain combines the two images and compensates by adding them in a way that returns some of the lost brightness, and allows for finer detail to be seen via an increase in contrast.

It did seem to work that way for me, but now, I’m not so sure. After using the binoviewer on Jupiter, in particular, with an 80mm ED refractor and a 127mm Mak, I’m not certain I am seeing more detail. The views don’t appear as vivid as they would with one good eyepiece.

I must say binoviewing is more comfortable, but it adds a layer of complexity in terms of weight, back focus and needing/focusing two eyepieces. I suppose for those reasons and others it hasn’t completely taken over the hobby as one might expect. Probably many, many more use monovision than binovision.

 

Just for curiosity sake, I wonder if any in the reading audience have tried binoviewing and either stayed committed to it, or returned to using one eye at a time... or do both? As I said, I’m on the fence right now. Next clear night I’m taking out the single eyepiece kit, the binoviewer kit and a full bottle of mosquito spray and try to reach some conclusions.

 

Thanking you in advance!

joe

 

As you can imagine, our friend Gort (my avatar) insists on monovision. Who am I to argue?

Edited June 26, 2019 by joe1950
Addition

[Demonperformer]

Interesting question, to which I cannot provide an answer. But it's got me wondering if there are any papers out there that apply objective math to the question rather than just a subjective "I can see more"?

[Vondragonnoggin]

17 minutes ago, Demonperformer said:

Interesting question, to which I cannot provide an answer. But it's got me wondering if there are any papers out there that apply objective math to the question rather than just a subjective "I can see more"?

A couple research papers

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5122960/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1191920/

https://iovs.arvojournals.org/article.aspx?articleid=2182682

https://en.m.wikipedia.org/wiki/Binocular_summation

https://www.sciencedirect.com/science/article/pii/0042698978902067

 

There is a lot of material on the web regarding binocular summation and increased visual acuity. Some interesting reading.

[Stu]

Good question Joe.

I suffer from floaters in my observing eye, and started to consider binoviewers as a way of alleviating the effects when viewing at high power through my 4" scope. At small exit pupils eg down to around 0.5mm, floaters can be a real nuisance.

It has taken me literally years to find pairs which suit me and to train my brain to work in the best way to see the detail properly.

I actually started using them for solar white light viewing and now use binoviewers exclusively for this. The views I get are astounding at times and I find it a much more relaxing way of observing.

Lunar was the next one which I cracked, it seems to be easier with larger brighter targets to merge images and pull out the detail.

Like you, I struggled with planetary views, and for a long time found the cyclops view better; through binoviewers the detail was just smoothed out, it wasn't an unpleasant view I just didn't see the level of detail I wanted to. Over the years I have kept at it, largely because of my floaters gradually worsening (I'm approaching 50), and now am at a stage where I generally binoview on planetary too. I still think there may be times when I could get more detail using a single eyepiece so do check this view aswell to be sure, so it is still not totally resolved in my head for planetary, but the benefits outweigh the negatives now.

I tend to use longer focal length eyepieces with Barlows to get to the powers necessary. This works better for me than short focal length eyepieces for some reason.

For all others observing at lower powers and even for high power doubles I use a single eyepiece and prefer this view as I think stars look better and I simply prefer the view.

So, it's a complex issue and also a very personal one, we are all different, but I can totally relate to what you are saying!

[Trikeflyer]

Like Stu I have horrible floaters and I use a binoviewer for solar, lunar and planetary as the views for me are better. On solar and lunar I now only use monoviewing if there was no other option i.e I don’t have the binoviewer to hand. On planetary I’m on the fence. I suspect it comes down to comfort - definitely better for me with binoviewing and might also depend on the quality of eyepieces used in binoviewer.

Steve 

 

 

[John]

I've tried binoviewing a few times over the past few years but I just have not taken to it. I can combine the images OK but, when I've tried it, I've not seen improvements in the views for me at least. I've tried binoviewers with my 12 inch dobsonian and a couple of my refractors. I'd like to like using them, if you see what I mean, because of the positive reports from others, but they just don't do anything for my observing experience. I still have a set of the William Optics binoviewers, eypieces etc on loan from FLO - I might give then (yet) another go at some point to see if I "get it" this time around

I'm just one "data pont" though. Others do love their BV's.

 

[Paul73]

I’ve tried it a few times and have found eye placement problematic. Probably just down to practice, but I’m not going to risk it! One set of eyepieces is quite expensive enough....

[Peter Drew]

Extra expense I agree, but still the biggest upgrade to a telescope for the amount of outlay. Worth persevering with provided one doesn't have any individual eye problem.   😀 

[Saganite]

Hi Joe,

I guess I have been fortunate in that binoviewing, from the very start, seemed perfectly natural and so much more enjoyable. I have spent a lot of  'down time' experimenting with bino types  and eyepieces, across my three scopes until I found everything to be as perfect as I could achieve. I have two binoviewers and eight pairs of eyepieces, and I use them on all types of observation. I gave up looking at the Moon and planets in mono, a good few years ago, and would never go back. The only time I revert to mono, is when Galaxy hunting with my 12" dob  for which I use a Nagler 26mm T5 , and for double stars.

I wish you good observing, with whichever form you decide upon....

Edited June 26, 2019 by Saganite

[Stu]

37 minutes ago, Paul73 said:

I’ve tried it a few times and have found eye placement problematic. Probably just down to practice, but I’m not going to risk it! One set of eyepieces is quite expensive enough....

Eye placement can be a little fussy, as can getting the inter pupil distance correct, that makes a big difference.

In the past I made some extended eyeguards from hobby foam which made eye placement much easier and also reduced glare and reflections. I sold them on and have yet to make any replacements, must get round to it.

I am probably unusual (or just plain odd!) but rather than multiple eyepiece sets, I only use one pair which are some lovely 25mm Zeiss orthos (converted microscope eyepieces) with good eye relief, nice big exit lenses and minimal scatter. I get to high powers with a combination of a x1.7 GPC which is always used, plus an AP barcon. I can basically choose from x100, x150 and x200 by adding extension tubes. It gets a little long at highest powers but I have yet to find anything which works better. I prefer the extensions over using a x2.6 GPC, it seems to give sharper results.

As said, I'm a little weird so don't think this is an approach to be copied necessarily but it works very well for me. I have read, and can confirm in my experience that barlowing lower powered eyepieces is easier to view with than short focal length eyepieces.

[Rusted]

For Lunar and Solar I wouldn't be without my [dealer replaced] TS binoviewers. The first was badly misaligned.
The absence of floaters and relaxed viewing is like flying over the surface rather than staring through a narrow pipe at it.
I use a WO 2x Barlow [much better than TS GPCs] and secondhand pairs of Meade 4000 EPs.
Mostly 32, 26 & 20mm. The 40mm aren't so binov friendly IME due to excessive eye relief and very small field of view.

The Sun in H-alpha shows even texture right across the disk in the binoviewers while providing suitably high powers.
It requires a conscious effort with a single EP to see any detail [at all] in the center of the sun in H-a.

I was afraid of these high powers before experience proved it was easily possible. Thank you, St. Peter.
Proms are much more fun and intricately detailed in the binoviewer. Mere secondary artifacts with one eye.
Every detail is laid bare in the binoviewer. I'm too far north to see any planets from here.

A decent focuser and sturdy mounting are essential for binoviewing. My big Feather Touch made it a real pleasure.
My previous 2" focuser always wanted to hurl the binoviewers down the observatory ladder and spit on their grave! 

[Ricochet]

9 hours ago, joe1950 said:

After using the binoviewer on Jupiter, in particular, with an 80mm ED refractor and a 127mm Mak, I’m not certain I am seeing more detail. The views don’t appear as vivid as they would with one good eyepiece.

If you are not comparing mono and binoviewing in the same session then I suspect that what you are seeing is the atmospheric conditions scrubbing detail from the planet and comparing that to memories from when the planet was better placed and conditions were better. When I have compared mono and binoviewing of planets in the same session I have felt that binoviewing gives better results, even though one of my eyes is weaker than the other. If my weaker eye continues to get worse whilst the stronger eye stays as it is, I suppose that I will reach the point where the weaker eye adds so little that I will be better reverting to monoviewing of planets.

[Tomatobro]

I was looking at Jupiter through my  20/40 x 100 bins the other night and with the 40x all I could see was a disc. Just occasionally the surface detail would snap into focus for a fraction of a second and then be gone so it depends on the conditions.

[Paul73]

One eye or two. Bright planets seem to be all about the conditions..... although, to get the most out of the conditions, playing around with the magnification can be the key. That, for me, is too much hassle with binocular viewing. Does anyone use a pair of zooms?

Paul

[joe1950]

Wow! I thank all for taking the time to comment, and I certainly respect and value everyone’s opinion on this topic!

It’s very true that the benefits noted in papers and experience using binovision are greatly influenced by personal preference and vision ability. I’ve noted that my normal eye for monovision (right side) seems to focus better and easier when I use the binoviewer. Placement and angle of view are critical and I must be seated in a comfortable position to have the BV work properly.

Very interesting and valued replies!

It just so happened that last evening at about 11PM, local time, the skies cleared nicely and Jupiter was available. I gathered my Bresser 127mm Mak and both my collection of mono eyepieces and my bino kit, which is a converted Nikon microscope viewer.

I did a complete alignment of the scope, finally getting the Airy disk bullseye centered in the diffraction ring pattern. Plus it gave the scope time to adjust, although inside/outside temps were close.

I found, as Tomatobro points out, seeing conditions throughout observing were average at best, with detail popping in and out.

I used magnifications in the 150x vicinity, varied by the eyepieces and nosepiece Barlow (binoviewer) available.

In this session I must say the view with the binoviewer was nearly as bright as with individual eyepieces. In fact, I really couldn’t tell if there was a difference. That surprised me.

And, overall, the contrast I noted and belt detail at times was notably better with the binoviewer. Not a night and day type better, but visibly better. So, I’d have to give this round to the binoviewer, with more challenges and different targets to come.

That being said, I believe results will certainly vary from person to person and in the long term, the quality of view will depend on what you find most comfortable and train your eyes to respond to.

As Paul mentions, detail on the planets is very dependent on hitting the magnification ‘sweet spot’ and binoviewers add a level of complexity to that. They can be what some refer to as a PITA.

 

Asking this, I know there is really no definitive answer. Myself, I intend to try both modes with different objects and scopes. I won’t be selling off my individual eyepiece collection, modest as it is, anytime soon.

 

Thank you all so very much again!  Any further findings I’ll certainly report and look forward to added comments and opinions.

joe

 

 

[Ricochet]

9 minutes ago, Paul73 said:

Does anyone use a pair of zooms

I think quite a few people do. I remember @Louis D has a pair of Celestron Regals but I think most people choose the Baader MKIII / IV. With my binoviewers the dioptre adjustment twists up and down and can't be locked so a zoom that I need to twist doesn't really appeal. 

[Ricochet]

2 minutes ago, joe1950 said:

I won’t be selling off my individual eyepiece collection, modest as it is, anytime soon.

I think your individual eyepieces are safe as monoviewing is still superior for stars and DSOs where you want to keep brightness as high as possible (IMO). Also BVs tend to restrict you to narrow FoVs which you often don't want. 

[joe1950]

Very good point, Richochet! Thank you.

[Louis D]

14 hours ago, Ricochet said:

I think quite a few people do. I remember @Louis D has a pair of Celestron Regals but I think most people choose the Baader MKIII / IV. With my binoviewers the dioptre adjustment twists up and down and can't be locked so a zoom that I need to twist doesn't really appeal. 

I crank my diopter adjusters down snug so they don't rotate with zooming.  Luckily, there isn't enough difference in power between my eyes than I ever need to adjust diopter settings on them or on binoculars.

I couldn't afford two BHZs for the infrequency that I use them.  If you're on the US side of the pond, MASILMW sells the Olivon version of the Celestron Regal Zoom with the zoom numbers reversed on CN classifieds for $65 shipped to CONUS.  MASILMW is Sheldon Faworski of Apogee, Inc fame.  The CR or Olivon zoom is optically about 90% of the BHZ with a couple of distinct physical advantages over it.  One, the top doesn't rotate during zooming, unlike the BHZ, so winged eyeguards can be used; and two, the zoom action is much lighter than the BHZ, so they can be zoomed with fingertip pressure.

I find myself using monovision at the eyepiece more than binoviewers lately due to the simplicity of setup and greater range of possible magnifications.

Edited June 27, 2019 by Louis D

[Vondragonnoggin]

I prefer binoviewing but started astronomy with 12x50 binoculars. I later bought 25x100’s, 10x50’s, 12x60’s, 8x42’s, then two Binocular telescopes that take regular 1.25” eyepieces - a 70mm with 90° oculars and a 100mm with 45° oculars. I started collecting eyepiece pairs to use in the Binocular Telescopes. Later bought a Williams Optics Binoviewer and some of my best planetary and lunar views to date are with the binoviewers. 

One thing I noticed about the WO BV I bought used - clear aperture is only 22mm so limits low power eyepieces to those with field stops that don’t exceed the clear aperture and that they are functional but can get finicky with barrels that have undercuts or super high power views getting merging and focusing to be smooth. A trick I learned with the binocular telescopes that also works with binoviewers is to leave loose in the ocular collet and rotate one until easiest alignment is found, then tighten the thumbscrews and none too tight. Just enough to prevent from rotation.

I think my eventual solution will be a much nicer BV with at least 27mm clear aperture. The WO BV is very entry level. Even at entry level they provide me the best lunar and planetary views I’ve had. The 8th of June at 260x on Jupiter was stunning.

Sometimes a wider view with a single eyepiece is nice though. 

The biggest high power complaints I see from others are focusing both sides of a BV and merging. I imagine this gets easier with more precise and better quality binoviewers. The complaints usually come from owners of the entry level systems. Binoviewing is much like any other equipment aspect of amateur astronomy - the higher quality will get less issues and provide a better experience. I had to be sure of binoviewing  first with the used WO BV before committing to a better one. Now I’m sure and hope to upgrade this year sometime. Not in a hurry though because the entry level BV does provide some great views already.

Not all binoviewers are created equal and not all eyepieces work in them well.

My advice would be to save for some quality BV’s from:

Denis Levatić (Denis sells BV’s out of the CN Classifieds and does custom work and very reasonable prices, he is in Croatia) - https://www.cloudynights.com/gallery/album/9553-binoviewers-models-i-superchargemadeadaptmodify/

Denkmeier - https://www.denkmeier.com/

Earthwin - http://www.earthwinoptical.com/index.html

Siebert Optics - https://www.siebertoptics.com/SiebertOptics-blacknightbinoviewers.html

Baader  - https://www.baader-planetarium.com/en/accessories/optical-accessories/bino-viewer/mark-v-großfeld-(giant)-binocular.html

Denis Levatić will also Supercharge your current Williams Optics, TS, or other entry level BV’s for reasonable prices. Just contact him and see if it can be done for yours. 

Im hoping to buy some of his Supercharged Zeiss BV’s. Siebert also does Supercharging service for entry level BV’s. The service consists of increasing clear aperture and collimation plus making sure all functions work well and I believe adding concentric ring to oculars for better hold. Check with Denis or Harry Siebert for specifics 

 

 

Edited June 27, 2019 by Vondragonnoggin

[joe1950]

Thank you Louis! I’ve never had a zoom eyepiece but I should try one at some point. When I started way back in the 1960s, there weren’t many choices and the quality was not there. I’m sure today’s offerings are improved.

 

Good information Vonddragonnoggin. I agree the difference in quality is partly in the ease of focusing and merging.

With the one BVer, an Astromania which appears under several labels, 1.25” eyepieces are used. I’ve found that avoiding eyepieces with undercuts makes life a little easier with this model. And as you say, tightening them in place often causes worse alignment issues.

Another binoviewer I have is a Paul Rini modified Nikon microscope unit. It is lighter and easier to use, and the microscope eyepieces are press fit into their holders. Merging the image is no issue with this unit and it is very sharp and has good light throughput.

A little trick I’ve found useful is to place a Bahtinov focusing mask over the front of the scope. Then using one eye open at a time, center the focusing line for each eye as needed. It won’t work with both eyes open as the brain makes things look better than they are. But doing it with one eye then the other gets the focus of each right on the money. It’s a little extra prep work, but pays off by not having to fuss with the individual focus later.

Thank you both very much!

Edited June 28, 2019 by joe1950

[Vondragonnoggin]

I think we had a long thread years ago in the BV forum at CN on best metal tape to use for taping undercuts. APM used to supply some rubber o-rings that would fill up the undercuts, but straight barrels are best. Even the concentric ring will get caught in the wrong part of the undercut and tilt them sometimes causing alignment issues.

The trick of turning the eyepiece while loose in the collet until you get best alignment, then just barely tighten to keep it from moving was primarily for straight barrels that aren’t perfectly circular. You’d never notice as a single eyepiece in a 1.25” adapter but you definitely notice this in a BV or binocular telescope when trying to align them perfectly.

High powers you really notice things like that. Must be loose tolerances for eyepiece barrels. Probably less an issue with higher priced eyepieces but I have a lot of less expensive Chinese made eyepiece pairs.

[mikeDnight]

For me, a binoviewer has been the best purchase I've ever made. It transforms the resolution detail in my 4" apo refractor to something akin to that of a 5". Obviously, light grasp doesn't increase but the ease with which super-fine detail reveals itself is definitely enhanced. 

The only problems I've encountered are really mechanical in nature. Rotating the diopters can demerge the images and eyepieces with undercuts or tapered barrels can be fractionally pushed out of alignment with a locking screw. Overcoming the mechanics can take time but its well worth the effort.

[Paz]

I've been researching binoviewers for ages but this brand new thread is one of the most helpful I've come across!

I've read so many observation reports from binoviewer users that report consistently better detail than I can see that I think they are worth a go. 

I tried a pair of binoviewers recently ("entry level") but it didn't go well. One side was dimmer than the other, and there were collimation problems sideways and vertically. No amount of checking/tweaking eyepieces, eye placement, or i p d resolved the alignment issue.

They therefore went back but I'm not put off the idea of binoviewers fundamentally. The trouble is that it seems that the options are either entry level or hugely expensive top end level. There is also it seems the issue of needing to practice and test to get the best out if them - it's easy these days to be put off if something that isn't immediately better.

The additional weight/length/set up hassle is also something I realised when trying them, but those challenges can be solved.

I think if there is an opportunity for me to try another pair directly  and know they are straight then I'll be happy to give  binoviewers another go. I'd prefer to avoid the process of buying and returning many units in the search for a good pair.

Edited June 28, 2019 by Paz

[Stu]

25 minutes ago, Paz said:

I think if there is an opportunity for me to try another pair directly  and know they are straight then I'll be happy to give  binoviewers another go. I'd prefer to avoid the process of buying and returning many units in the search for a good pair.

I found that the TS Binoviewers were very good and good value too. Collimation was good and they have self centring eyepiece holders and dioptre adjustment. I have a pair currently and they work well.