Two Eyepieces at Once - Binoviweing

[joe1950]

Thanks all, very much. I’d say the general consensus by most is that binoviewing has real advantages if you can get past the mechanical challenges of the unit. And, it’s certainly true, they appear to come in two flavors... reasonably priced but not flawless, and very expensive! Nothing in between.

Last evening I was out with the C-80ED refractor. I would honestly have to give the nod to binoviewing. The brightness of the planet appeared to be on par with views using a single eyepiece. The contrast was higher and the visible belt detail was better.

The differences are not huge. But, the differences coupled with the added comfort are a plus in my eyes, at least.

I haven’t used the BVers on anything aside from the moon (where they are excellent) and Jupiter. I may have mentioned that deep sky objects are an exercise in futility from my location, by any means.

With respect to the eyepiece issue, I’ve been using Meade Series 4000 Plossls, that have no undercut at all. They seem to be more manageable as long as you don’t over-tighten them. Plus they are inexpensive yet work well. Since most binoviewers are used with a Barlow/relay lens, longer focal length eyepieces are called for (12mm and above) and Plossls are much more comfortable to use.

Also, with some eyepieces, you can unscrew the barrel, turn it upside down and re attach it. The undercut ends up in a position at the end of the barrel and is not a factor in the tightening process.

I’m so happy many have responded and provided wonderful information and experiences. Binoviewing is certainly not for everyone or every situation. But for someone such as myself who only has access to the moon and planets it appears to be a way of teasing out a little more detail in the view,

Thank you!

[Stu]

Thanks for starting the thread @joe1950It was a good discussion, very useful info.

[nhyone]

I'm fumbling my way with binoviewing on my Mak 127.

I knew magnification would increase due to the longer light path, but I underestimated it. As a result, the image was very dim.

My scope is nominally 1500mm. With binoviewer, it should be ~1700mm, but my crude measurement puts it at 2000mm!

I bought a copy of 8, 10, 12 and 15mm eyepieces. In the end, only the 15mm was really usable. (It is the highest I would use for binoviewing on my scope.)

Edited June 30, 2019 by nhyone

[Louis D]

24 minutes ago, nhyone said:

I'm fumbling my way with binoviewing on my Mak 127.

I knew magnification would increase due to the longer light path, but I underestimated it. As a result, the image was very dim.

My scope is nominally 1500mm. With binoviewer, it should be ~1700mm, but my crude measurement puts it at 2000mm!

I bought a copy of 8, 10, 12 and 15mm eyepieces. In the end, only the 15mm was really usable. (It is the highest I would use for binoviewing on my scope.)

Still, that's only a 1.33x increase in focal length which is much less than the 3x I get using a 2x barlow nosepiece.  Imagine trying to deal with a 4500mm focal length scope!

I use 23mm Aspherics mostly because they yield just about the widest field at a moderately low power, and they're super light.  If I need higher power, I do have pairs of 19mm Konigs (from binoculars) and 15x microscope eyepieces (16.7mm) and the aforementioned 2x (3x) barlow element.

[Rusted]

4 hours ago, nhyone said:

I'm fumbling my way with binoviewing on my Mak 127.

I knew magnification would increase due to the longer light path, but I underestimated it. As a result, the image was very dim.

My scope is nominally 1500mm. With binoviewer, it should be ~1700mm, but my crude measurement puts it at 2000mm!

I bought a copy of 8, 10, 12 and 15mm eyepieces. In the end, only the 15mm was really usable. (It is the highest I would use for binoviewing on my scope.)

For magnification purposes, the Binoviewer usually adds about 100mm, or slightly more to the focal length due to its glass path length.
Which it promptly steals from the usual focal point. Assuming you can reach inward focus, without sawing lumps off the main tube or adding a Barlow, then you are very lucky.
I only rarely use anything shorter than 20mm on my 150/1200 and 180/2160 refractors with the binoviewer. A 2x WO Barlow works wonders with 26mm & 32mm EPs.
Which means 13 & 16mm equivalent EPs without a Barlow but I can still reach focus. So about the same magnification as your 15mm.
The resulting magnifications are fine on the Sun and Moon and I find the longer eye relief, of "longer" EPs, offers much greater comfort when using the binoviewer.

Edited June 30, 2019 by Rusted

[Space Hopper]

On 30/06/2019 at 02:22, nhyone said:

I'm fumbling my way with binoviewing on my Mak 127.

I knew magnification would increase due to the longer light path, but I underestimated it. As a result, the image was very dim.

 

Probably some aperture loss there as well, due to the increase in lightpath.

And with the best part of the primary getting chopped from the outside, the central obstruction by the secondary as a percentage gets bigger.

Hence the dim, over magnified view, and a loss of contrast. SA (Sperical abberation) probably in the mix there as well.

This isn't really a fault you can blame on the BV, its just when you use one with a SCT / Mak you need to optimise everything first to make it work well.

 

 

[nhyone]

Nothing is optimal, for sure. 😀

The scope is 4.7". The binoviewer's clear aperture is just 21mm on the nose side (18mm on the eyepiece side!).

(So no wide views for me. But that's fine, I knew that going in. I find that field stops up to ~23mm are fine.)

One of the things I want to figure out is my effective magnification!

I find it much easier to use on the Moon, because it is bright enough.

Now I just have two (usable) pairs, 15mm and 23mm. Will practise more before deciding whether to get more pairs -- probably not.

[niallk]

I tried BVing with my 250px - Baader maxbrights with a 2.6x GPC and i used two TV 15mm plossls.

It worked for me in that scope, and it became my default way to observe the moon/planets - loved the BV and felt i was seeing more detail.

Unfortunately the BVer doesn't work well in my 15", where i observe mono.  I have to say that the 15" has ultimately delivered the best ever views I've had.

But, i still use the BV with the 250px the odd time I've used it, when i haven't planned the time to really cool the 15" down for a quickie session.

[joe1950]

I'll definitely agree that binoviewing adds a level of difficulty in some set-ups. With my 127mm Mak, I use the lowest power magnification I can go to and that still gives a large image. I did try the Mak without any nosepiece or Barlow and could reach focus in that manner, but I don't know if there is vignetting of the full aperture as a result.  

Last evening I had the 80mm refractor on Jupiter with the binoviewer and what a fantastic image! Detail and contrast galore.

I have a 150mm f/6 DOB that I have to reconstruct. I calculate that if I move the primary forward by 40mm, the binoviewer will work with a nosepiece Barlow. It will still give me nearly 9mm of 100% illumination, which for the planets, and moon, should be fine.

I'll likely arrange two sets of mounting holes for the mirror cell, one for monoviewing and one for binoviewing, as some of the AP crew are known to do!

Nothing comes without some sort of price tag, does it? 😉

[ASSA]

Hi,

 

Let me add my observations from April 16, 2019. As I am a die-hard BV fan, I often compare mono views to bino views. Here are some of the observational notes and conclusions.

TS Individual 102 F11, WO BV, SW 2" dielectric diagonal, pair of Pentax XF 12 mm and 8 mm BST ED.

......................................

19.04.2019

Yesterday, the Moon was a great object for observation, good and stable conditions, sharp edges of craters.
One of the coolest effects was to fill the Gassendi crater with light in just 2 hours !!!
It was great, at the beginning only the peaks and a little interior were lit, and by 22:00 the light was streaming into the interior showing a beautiful relief cut by a network of cracks, craters and hills. I was delighted with this view.

I spent a large part of my time on the Bay of Rainbows where the details of the "half-moon" were wonderfully drawn, I could not decide if I prefer this view in 140x or 90x Every time I changed my eyepieces I was overjoyed and I have no winner. In the south there are countless craters, a lot of different forms. I always try to imagine how they look "from above" and not at a sharp angle seen from Earth where most of them remind me of a potato  

As the conditions were favorable, I decided to play with Plato. I spent a lot of time staring at him and changing the configuration of the eyepieces. Let me share the conclusions:

1. Looking Mono, I could find three craters inside Plato faster and more confidently than I saw with bino. When using bino, I also saw them but as if they were 90% of the time seen in mono. Certainly the result was also due to the fact that the mono was a little brighter and flashed to me with a "more certain" light.

2. At 90x and 140x I saw the same surface details. Both in Pentax 12 XF and 8 mm BST, I caught 3 craters in Plato as well as mini structures that I aimed at in the Bay of Rainbows. Proposal? The resolution capability will not jump with a larger magnification although it was a little easier to separate two tight objects at 140x than at 90x. 

3. Mono can be more effective but it is terribly tiring. While gouging a delicate detail, we focus on 100%, the eye begins to give in, it begins to water. Looking binoviewer we have increased comfort, of course we are also straining to see something on the limit of the equipment capability, but we do it naturally with a pair of eyes, so the effort is smaller, it may take longer.
Hence the conclusion that mono observations will be more effective but only in the hands (eyes) of an experienced observer. It should be easier for the beginner to extract the detail in bino because of the convenience and less eye strain, which distracts attention from the look of the detail.

4. I've remembered the most important conclusion 140x in mono looks like 90x in bino There is such a huge difference in receiving the view that you have the impression of a much larger magnification.

Plato gave me three craters in my eyes, after returning home I checked on the photo which I put below, which it was and on which I will hunt next time.

1. Visible all the time straight ahead.
2. Visible 95% of the time, as it turned out in the picture there are two pieces for me as one. 
3. I had to look at it often, sometimes it disappeared in the waving of the atmosphere. It was a bit more common in mono.
4. I did not know about this rascal, glued to the edge and it seems to be within my range, I will hunt him next time.
5. At this point, it always seemed to me that I saw something. Probably this illusion because the picture looks like it was a brighter area. There are some craters next to each other, which could merge into one but ... well beyond the reach of this lens. What do you think about it?
6. Is this one still within 102 mm of the lens under ideal conditions? I wonder if if I know his place, if he can be seen, he is not much smaller than number 3.

I consider all observations to be very successful, I learned a lot thanks to them.
greetings
Luke

.......................................

 

This is one of many observations comparing bino to mono in detecting small details. I did comparisons on various telescopes and various BV, starting from 100 mm achro or MCT 127 to Newtonian 20". The resolution depends on the size of the telescope, the bino will not improve the view but thanks to the comfort you can focus more and use the time to see small details. I'm not an expert but strongly recommend to everyone try BV

P.S. I forgot to mention, scope is shortened to reach focus with bino without GPC so there was no difference in magnification on both mono and binoviewing.

I apologize for language mistakes  

Edited July 5, 2019 by ASSA

[MarsG76]

Nice report.. I guess mono and bino observing both have their advantages and disadvantages.

 

[joe1950]

Yes, great report ASSA (Luke)!

You really can't change physics and get more resolution or contrast from a given scope with binoviewing. However the eyes and the brain are integral parts of the total system and binoviewing seems to help relax the strain on both to a degree. I certainly can benefit from less strain on the brain!

Excellent planetary observers have trained their eye over time logging a many hours at the eyepiece using monovision and can detect detail the casual or first time observer just can't see. 

In the long run I guess it comes down to what you as an individual feel best with and get the most out of. Over the past few weeks I have seen detail I have not seen before using the binoviewer. But I ask myself, with patience and persistence could I have seen as much or more using monovision? Binoviewers do add more glass and thus more scatter and reflections to the level of which depends on the quality with which they are made, optically and mechanically.

Over the coming weeks I'll do more observing, both binoviewing and monoviewing with Jupiter and Saturn in the evening sky, albeit rather low and not optimal.

Again I thank all for their very informative and interesting contributions!

joe

Edited July 5, 2019 by joe1950
Addition

[joe1950]

The moon this evening is at 1st quarter and the sky clear. Two things that don’t happen often at the same time. It seems from waxing crescent to mid gibbous, the clouds are abundant.

I went out with the Bresser 127 Mak and my Nikon (converted microscope) binoviewer. Compared to the other I have, the Arcturus model, it’s smaller and lighter. It uses microscope eyepieces that fit nicely into the spring pressure tubes and I have a pair of 10x, 16x and 20x (25mm, 16mm and 12.5mm)

The Mak, with a generous 1900mm FL, has to be held down if anything. And with a Mak or SCT, focus can be easily reached with or without the Barlow/transfer lens, if it focuses with a moving primary, which most do.

Seeing was average with some animation of the image. I’d put it at 4-5/10. Nothing to write home about. But the sky transparency was a bit above average for here.

In any event, the moon was spectacular! Endless numbers of craters of all sizes were easy. Features such as rills, cracks and trenches were everywhere. And there was so much detail within larger craters, one could easily spend significant time just on one. I really can’t recall seeing this much detail and stark contrast on the moon in some time. I believe the binoviewing helped quite a lot!

I have observed the lunar surface in all kinds of conditions. Often seeing has been so poor one could get seasick from the image motion. But I believe, and this is just a totally non-scientific observation, that binoviewing somehow mitigates the effect of seeing conditions allowing more detail to, shall we say, show through.

The seeing conditions are made not better by using the binoviewer, but detail that would be otherwise obliterated with monovision, gets through using two eyes as opposed to one.

I know, you think I’ve visited the spirits cabinet, but I’ve noticed this on many occasions and on both the moon and Jupiter. All I can say for sure is that tonight’s session had average seeing conditions yet I saw an immense amount of sharp detail. Sometimes it was moving, but it was there to see.

With this scope, as with most, it has a rather noticeable upper magnification limit. Exceed it and the image quickly loses that amazing sharpness and brightness. Empty magnification, some call it, and with the f/15 Mak it’s easy to reach.

Thanks for reading! All the best to you, my friends!

joe

BTW: In my retirement I’ve been living a rather austere lifestyle. I have deep pockets but they are quite empty. In spite of that I’ve made one more scope purchase; the last hobby related purchase I’m making (had I a nickel for every time I’ve said that, I’d be quite well off).

I got a used, Celestron Omni XLT 102mm f/8.8 OTA. It is an ED type, and uses O’Hara FPL-53 ED glass. These are not sold new any longer and were popular purchases up to about 2010. It’s the big brother of my C80ED as well as the Orion (US) ED-102. They come available now and again at great prices.

These scopes aren’t on the level of TeleVue, Takahashi, Borg or Astro Physics fluorite triplets. Getting one of those, I’d have to live out near the street curb in the carton it was shipped in. But they are excellent scopes for a fraction of the cost.

I reason that a 102mm refractor, is likely the largest refractor I can navigate outside, between the trees and back in the house.

I haven’t received it yet, it’s traveling from the West (they say Best) Coast to me here on the East (they say Least) Coast. I’m looking forward to it. And this is the last hobby related purchase I’m making! Maybe a cheap eyepiece or something will slip through, but this is it for me! 

Cheers!

 

 

 

 

Edited July 9, 2019 by joe1950
Typo

[AdeKing]

1 hour ago, joe1950 said:

I got a used, Celestron Omni XLT 102mm f/8.8 OTA. It is an ED type, and uses O’Hara FPL-53 ED glass. These are not sold new any longer and were popular purchases up to about 2010. It’s the big brother of my C80ED as well as the Orion (US) ED-102. They come available now and again at great prices.

Congratulations, on the XLT102 ED I picked up one of these from Steve (@Saganite) last year and it is a fantastic scope and Steve reckoned that the views were amongst the best he'd seen without spending a silly amount of money more.

I was very lucky as mine was only purchased the year before as new old stock when David Hinds found some unopened ones in their warehouse and sold them on ebay.  The majority of the accessories were still in factory sealed bags when I received it. 

 

[Stu]

Great stuff Joe. I would agree with much of what you have said, and share your enthusiasm for binoviewers.

I reckon that Celestron 102mm will be a lovely scope, relatively slow with good glass, I'm sure you will enjoy it.

[Trikeflyer]

On 28/06/2019 at 19:07, Paz said:

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.

Paz,

I have wo binoviewers. I live near Walsall if you are anywhere near you are welcome to come and try them?

steve

[Space Hopper]

11 hours ago, joe1950 said:

 And this is the last hobby related purchase I’m making! Maybe a cheap eyepiece or something will slip through, but this is it for me! 

 

 

 

 

We don't believe a word of that Joe ! 😉

[joe1950]

Thank you very much AdeKing! Everyone who has one has nothing but nice things to say and the seller assured me this would be no different a sample. It will arrive in a few days.

Yes, Stu, it is f/8.8 but the quoted weight is 8-9 Lbs, so hopefully the mount I have intended for it will do the job. If not, I'll go to the home store and get the essential for a pipe mount. I've been in the hobby since the 1960s and had never built a pipt mount until about 2 years ago. My son has it for his refractor and I must say it is one of the sturdier mounts I've ever used! Heavy though, so I may use the next size down if I end up making one. But I think the mount I have should do nicely. Thank you, Stu!

The William Optics BVers are quite nice from what I hear, Steve. The major differences with the economy models vs the deluxe units seems to be mechanical rather than optical. But the WOs use a good system to hold the eyepieces and rate well! 

Rob, I don't blame you in the least! Even before I retired, I would make the same promise to myself when I would make a substantial purchase. I've often wondered if anyone else would make similar resolutions?

Anyway, I have to try extra hard this time. Retirement seems to be heading in the direction of being a luxury. In my case it was somewhat of a forced issue since the newspaper I worked at for 45 years was being bought by a large group and layoffs were iminate. So if I ever start talking about  a big purchase I ask that someone will step forward and put their foot down.   

I do feel the new scope will complete my kit nicely. Thank you all very much!!!!

[Saganite]

WO binoviewers are the ones I used for several years and are very fine units indeed Joe. The only reason I changed from them was for larger prisms.....

[Rusted]

I would hesitate to build a pipe mount if it relies on standard tapered threads for bearings.
By their very nature two tapers can only ever be slop-free in one situation.
That is when they are screwed tightly together!

I would urge you to consider making a plywood [offset] fork for your lovely [longer] refractor.
Extend the baseboard forwards of the bearing area to carry a counterweight to balance the weight of the OTA.
Lead weights, lead sheet from the church roof  the builder's merchant or a lump of scrap metal. Anything stable will do.

This used to be known as a Richard Berry Offset Fork Mounting because he popularized them rather than inventing them.
An image search will turn up lots of examples.

These mountings rely on buttery smooth PTFE/Teflon against PVC pipe trunnions and PTFE/Formica base bearings.
The side [altitude] bearings are fitted to plywood boards attached to spaced, telescope tube rings.
Much like a Dobsonian reflector but raised on a pier or tripod so you can reach the eyepiece without kneeling.
A star diagonal helps here but don't make your tripod or pier too low.

If you need a stronger equatorial then consider a vintage mounting which are often cheap but stable.
All this assumes that your own mounting can't handle the greater moment of a longer OTA.
It can quickly get expensive if you try to go up in steps until you find a suitable commercial mounting.

 

[joe1950]

That is an important factor for many situations, Steve.

At my location I'm very limited to planetary and lunar observing and thus far the small prism size has not been a factor. In fact, the converted microscope unit I have is a Nikon brand and nothing is antireflection coated! Yet they seem every bit as bright as the fully multi coated Arcturus model!

Some aspects in the use of these are counterintuitive but somehow they work!

 

That is an excellent suggestion, Rusted, and I know exactly the mount you are speaking of! In fact I have plenty of the PTFE pads from an old DOB. 

A little woodworking and you have an excellent mount. Thanks again, a far better option!

Edited July 10, 2019 by joe1950

[bobbyblue]

Most hominids have a dominant eye.  The benefits of binocular vision are primarily to allow judgment of distance  - a marked visual advantage for the predator; perhaps not so much for the passively inclined and visually refined astronomer. Appropriate spectacles might be cheaper.

[Stu]

22 minutes ago, bobbyblue said:

Most hominids have a dominant eye.  The benefits of binocular vision are primarily to allow judgment of distance  - a marked visual advantage for the predator; perhaps not so much for the passively inclined and visually refined astronomer. Appropriate spectacles might be cheaper.

Have you tried them for astro? There is alot more to it than you imply.

[joe1950]

I ventures out again last night with the 80mm refractor, bringing a 4mm Vixen eyepiece to do some monovision and the Nikon binoviewer. Seeing was unsteady.

Starting with the moon, I made an attempt to see any hints of craterlets in Plato, a difficult task from my experience. Plato had just come into daylight and the floor was 90% illuminated.

With the single eyepiece, I may have glimpsed one of the three largest, just about in the center of the crater floor. Results were not buch better with the binoviewer, but there were a few more occasions where I thought I may have seen the central one. In either case, nothing was readily evident. They are often difficult in a 6" reflector for me and a smaller instrument with just average conditions is asking a lot.

The difference with the moon was much more comfort in viewing and a small but noticeable increase in the color dynamic with the binoviewers. The seas, especially appeared to offer more levels of color/grays with the BVers. In one view, I counted 50 shades of gray!  😮  Joshing, couldn't resist. But there were more tones evident with the binoviewer. 

Jupiter was a different story. With the single eyepiece I could see the north and south equatorial belts without problems and shading at the poles. There was a hint of a thin belt in the north temperate area.

With the binoviewer the NEB and SEB showed definite edge detail and some internal structure during moments of good seeing. The polar regions had a darker tone to them and the thin NTB, a thin light colored belt was easier to see. There was just more detail apparent, at least to my view, with the binoviewer.

Different observers have different ways of observing and seeing detail is a personal experience based in part on how your eyes and brain interpret what is offered. Long established planetary viewers have trained their brain to pick out detail others simply cannot see and might have no interest or use for a binoviewer.

Experience counts in planetary observation and results are not the same for everyone. I know some very experienced observers who have used binoviewing for a while and returned to monovision, feeling there was no real advantage. At this point, comparing the two closely, I'd have to give a definite nod to binovision.

Foul weather has arrived today and I have the feeling it will be around for a few days. 

Thanks for reading and the very best to all!

Edited July 11, 2019 by joe1950

[Stu]

Another great post Joe, interesting reading. Thanks!