Getting a feel for Binoviewing

[John]

I've managed to get hold of some binoviewers to try. I've glimpsed through some at the SGL star party but did not really get a chance to get a feel for them really.

Having read a lot about their inward focus requirements I was a little concerned that I'd not get them to come to focus in any of my scopes and that was in fact the case with both my refractors, even with the supplied 1.6x barlow nose piece in place. Fortunately Orion Optics newtonians have a point of focus well outside the tube walls and my 12" is fitted with a low profile focuser. I normally use a 35mm extension tube when viewing in cyclops mode but with this removed the binoviewers, with the 1.6x barlow nose piece fitted, came to focus with a couple of cm inward focuser travel to spare. Bingo - I was in business

The binoviewers I've got are the Williams Optics ones which seem a decent entry level for the purposes of seeing if I like them. As well as the 1.6x barlow nose piece they come with a pair of 20mm 66 degree AFoV eyepieces. Assuming the barlow is doing what it says then I'm getting the equivalent of 12.5mm which is 127x in my 12" dob. Quite useful for a range of targets as it happens.

With the scope barely cooled, rather blustery winds and clouds scudding across the sky frequently the conditions were not ideal but I was determined to at least see if I could use these things, as an appetizer, if nothing else.

I managed to get reasonable views of M57, M13, Saturn, M81, M82, M51 and M97. I also had a quick look at a few double stars.

Pretty impressive

For a start objects looked brighter than I thought they would. I know you loose the equivalent of around 40% of the light in the beam splitting process but maybe using both eyes makes up for this loss ?

Resolution was very good too. Features on Saturn, it's fainter moons and some fairly close binaries (eg: Delta Cygni) looked pretty much as good as they did in mono mode with premium eyepieces. There was a little more light scatter around Saturn than I'm used to but it was really not distracting and surprisingly good considering all the extra prisms and lenses that I'd added to the optical system.

The supplied eyepieces and 1.6x barlow seemed pretty decent quality and stars seemed well defined both in the centre of the FoV (expected) and out towards the field stop (not really expected in an F/5.3 scope) although the barlow had effectively turned the scope into an F/8.5 I guess, which would help with controlling astigmatism.

Messier's 57 and 13 looked a real treat in the clear gaps - the latter resolved right to the core and there did seem to be a touch of extra depth to the view, perhaps ?

M82 looked striking too with the dark rifts and some brighter knots standing out across the elongated face of this odd galaxy.

I also tried the optical element of the Baader Q-Turret 2.25x barlow in place of the supplied 1.6x barlow. This had the effect of pushing the point of focus out further so I needed the 35mm extension back in the drawtube. It also delivered much more amplification – my estimate, from Saturn’s apparent diameter in the eyepieces was that I was getting around 300x so around 5mm eyepieces with the Baader barlow lens set acting as something like a 4x barlow parked on the end of the nose piece like that.

This was a touch too much power for the conditions really but I still had some fun with Saturn and then a nice close view of Epsilon Lyrae, the “double double” with both pairs showing lots of black space between them and well resolved airey disks and again I was impressed with the quality of the view, given the extra glass in the optical system.

While far from a thorough evaluation, this taster session has certainly whetted my appetite for viewing with two eyes so I’ll certainly be coming back for more. The Moon is going to be somewhat impressive I feel

Is it any cheaper to buy Pentax XW's / Delos's in pairs ?

[Matthew]

I have the same bino viewers as you John and i must say they are superb value for the money.The C11 and WO bino viewers make a superb combination and i have found planetary / lunar observations are taken to another level.I have a pair of 12.5 mm Hutech Ortho's which im itching to try out but i have been hampered by poor weather and work.

[John]

I'm just thinking of the next eyepieces I'd like to try with the binoviewer Matthew. Something around 10mm - 12mm seems right I think. I don't think I can get much wider than the 20mm 66 AFoV ones supplied due to the 20mm max aperture of the binoviewers.

[Matthew]

Im pretty sure you can get away with 25mm, i have the 20mm and 12.5mm so when combined with the 1.6x barlow you get a decent range of magnification.I do intend to buy some 8-24 zoom eyepieces at least then your not constantly faffing around change eyepieces.

[Space Dragon]

John

Good to hear you enjoyed the binos, you should get more out of them when you get a really decent night. I find the ability to relax with both eyes open reveals more detail and gives you more of a chance of catching those moments when the seeing is clearest.

It's a shame that there aren't more bino friendly refractors around, there was the Stellarvue and I think TS did one, where the tube could be shortened, rather than taking a hacksaw to the tube.

I was able to reach focus with the Baader Maxvisions in a 90mm F/8 with no barlow by using the T2 prism diagonal and keeping the light path as short as possible.

But the clear aperture of the Maxbrights is only 21mm which limits the EP choice and the Baader MkV, which is 28mm and also uses the T2 system, is eye-wateringly expensive.

I did read that ES were planning on releasing a bino, which, if their EPs are anything to go by, could be quality at a good price.

[Avocette]

Very interesting post - many thanks for the detail. I have a feeling your point about the apparent brightness with two eyes is a critical issue here. It's not just the complementary coherent images but also the lack of a confusing contradictory one (even if pure black). That reminds me, I must buy an eyepatch!

[Hairycamel]

I completely agree about the C11; the planetary views are outstanding and the week before last I managed a quick look at the moon down the terminator and you could have reached into the craters - fantastic. I too had focus problems when I tried my WO binoviewers on a Megrez 110 that I used to own, but now it's sold. Apparently, if you go to Siebert Optics, you can buy an optical corrector that will allow binoviewer focus with any scope for $149. Not tried it myself but an interesting thought nontheless......

[Mark at Beaufort]

John I am pleased that you have enjoyed your first outing with the binoviewers. I initially thought that adding a 1.6x barlow would simply increase the focal length of the scope by that factor. My experience is that it creates a much longer FL because of the binoviewers and hence much greater magnification. You may recall at SGL8 that I could not gain focus with my William Optics SD66 but when I used your Baader Q-Turret barlow I could. Have you tried this barlow on your Vixen and Skywatcher 120mm frac - you might gain focus.

On my 4" Astro Tech I can obtain focus and my favourite EPs are a pair of 25mm Antares Plossls, 15mm ultra wide Skywatcher and the best is the William Optics 12.5mm Planetary EPs. I find the 9mm Plossls that I obtained with the binoviwers a bit too much.

Mark

[John]

Thanks for the feedback folks - I'm clearly not alone in enjoying the view with both eyes

Mark - I will try with the Baader barlow in the refractors. Last night I got a bit carried away with the fact that they worked with the dob so I was not as thorough with trying them as extensively with my other scopes.

[Mr Bond]

John, I tried a pair of XW 20mm pentaxes in one of my BVs. Be aware that if your eyes are too close together you might struggle to get the inter pupil didance right. They're a big diameter.

And bl@@dy heavy too, especially when hung on the end of your binoviewer too!

Wait till you see the Lunar surface and the terminator. It's AWESOME!!

[John]

Thanks Mr Bond. I have Pentax XW's for use in mono mode but I'm not sure I can run to pairs of them just yet !

I'm really looking forward to lunar viewing with both eyes open

[Mr Bond]

Just took this with a phone camera on one side of my Denk BV.

What an amazing terminator, talk about rugged terrain!

Imagine this, sharp, and hitting both eyes. Wow!

[Dunkster]

Thanks for the starter John, look forward to the main course

Sounds like it's an eye opening experience (sorry couldn't help it )

[Telescope40]

Hi. Do I see the Lunar X on that shot ??? Think so ??? Yet to see myself with Mark 1 Eyeball

John

[Mr Bond]

Thanks to just having a pleasant conversation with John above (Telescope40), I can now see that I have accidentally caught the Lunar X!

Before tonight I honestly didn't even know what he meant in the post above!

[Damo636]

Nice report John! I've often thought about a binoviewer but never taken the plunge. Your report has stoked the fire again though :-)

[cplee42]

I also have the WO binos matched with my Nexstar 8SE. A really nice combination. No problems with focusing with the SCT! As a sketcher I particularly like the relaxed eye experience, especially with lunar viewing. The weight is certainly obvious and I learned very quickly not to leave the bino in place when slewing on my EQT mount as I was constantly concerned to see my lenses turn in various directions during the rotations! My eyesight is not great in one eye and the dioptre rotation is not quiet sufficent. I have tried to raise this eyepiece a touch in its case but not very elegant!

[cotterless45]

Superb bit of gear for the money. Beautifully engineered.

The viewing experience really relaxes the eye and definitely gives a contrasty three dimensional view. I've used a pair of 40mm eps in them as well as the supplied pair .

Very nice for terrestrial viewing, we were watching folk jogging around the decks on cruisers in the Minch on holiday.

Nick.

[Mark at Beaufort]

John have you been able to test the Baader Q-Turret barlow on your fracs yet? The reason I ask is my Binoviewers have a larger screw thread than the standard 1.25" so its difficult to screw in my 1.6x barlow. I was thinking of buying and then using the whole Baader barlow including the tube to see what difference it makes. Are you able to test the 1.3x barlow and then add the tube to see the effect on the focusing situation.

If anyone else has the Baader Q-Turret barlow and have binoviewers then the same question above applies.

Mark

[PaulC-I]

welcome to the BV club John. The WO versions are bang for buck I had these before going to an intermediate brand (will disclose in a privets email if required) before going for the Baader Mkv and another mortgage! Both these units gave great quality balanced views, yes, with a pair of XW 20's, as well as lighter eps such as Brandons etc. The trick is to magnify before the binos then you can use long FL eps for high power viewing with great comfort. Another bonus is that you do not magnify the aberrations of the BV prisms by using high power eps. I'm a convert and when occasionally view in Cyclops mode do not see planet features as clearly defined as with BV's. Also, think about it.....if we were to be able to have critical sight with just one eye then we would never have evolved with stereo vision! ENJOY!

[spaceboy]

I'm happy I came across this thread as I was just on the verge of doubling up my set of plossl's and getting a binoviewer for use in my refractor. If there are possible issues regards focusing in refractors I may give this idea a swerve as I have also come across talk that there is an increase of CA and distortion in achros due to the use of prisms in the binos  

[avtaram]

I have the WO binoviewer which I use in my Evostar 120ed ds pro.

For the binoviewer to come to focus I have to place the 1.6 barlow between the focuser and the diagonal.

You also need a 1.25" diagonal as focus cannot be achieved in a 2" diagonal.

So far I've looked at the moon, jupiter and the Orion nebular. The views are absolutely mind blowing, viewing with one eye just does not compare. Looking through the binoviewer is just so relaxing that it gives the sensation that you are actualy there in space.

I'm definately a convert.

Avtar