ED80 binoulars.

[Peter Drew]

Despite making many binoculars/binocular telescopes in recent years it is a long time since I built one with better optics than standard achromats. Recently a s/h SW ED80 was advertsed at a very reasonable price and as I already had another to hand I couldn't resist. . Essentially it is two OTA's on a common base with adjustments for collimation. The attraction was to have a manageable instrument with good low power wide angle performance but also capable of high power when necessary. It has not disappointed! The initial build comprised an astronomically orientated view produced by each OTA having a pair of 1.25" diagonal prisms arranged as a rhomboid to enable an adjustable IPD. The views were so good that it seemed a pity not to be able to use it terrestrially so by sawing 3" off each OTA it allowed me to not only introduce erecting prisms but also to arrange them to give a desirable 90 degree angled viewing position. Performancewise, a pair of Meade 24.5mm Superwides provide a field of around 2.8 degrees, a pair of Hyperion 8-24 zooms give a range of around 25x - 75x. I offered up a 3 - 6mm Nagler zoom individually to the OTA's as I have only one and the max mag of 200x was easily supported by either. The Moon and Jupiter were both excellent at 75x, star fields later on with the Superwides were very promising but the sky wasn't dark enough to do the instrument justice as yet. The only downside at present is that the standard sloppy fit of the diagonals makes the collimation unreliable, once I've addressed that it should be a fine addition to our equipment. Photos to follow.   

[Stu]

Sounds fabulous Peter, looking forward to the photos  

[Moonshane]

Sounds an amazing scope Peter.

Is there a big difference between this and BVs with a single ED 80?

[Chris]

I've always been impressed by the ED80's even on planets, so one for each eye sounds wonderful. Looking forward to seeing pics!

[spaceboy]

I'm waiting on Jules to have a go at a 120ED bino scope. I know he's a big fan

 

On a serious note though I had considered this myself with a pair of 120's but I think mounting them would be the big issue. My guess is even with 80ED it pays to have a nice obsy to keep them in

Can't wait to see the pics. How have you overcome diopter?

[Racey]

21 minutes ago, spaceboy said:

I'm waiting on Jules to have a go at a 120ED bino scope. I know he's a big fan

Nooo.... Don't mention the @nightfisher ED120 in an unrelated thread... That's not the done thing I'm told ?

[paulastro]

I was lucky enough to be up at TAC on Saturday and was able to try them out on daylight targets with Peter.  As Peter says they performed extremely well up to x75, can't wait to try them out at night time. Below are  a few photos I took.

Just edited this, I forgot to point out that in the first three pics the Meade 24.5 SWs are in place, while the last two pics show the Baader Mk111s in use.

 

      

  

 

[Chris]

They look great. I wonder how those diagonals are put together to form the rhomboid portion, do they screw together, Peter? Can you literally do this with 6 diagonals, two shortened ota's, and some kind of adjustable dual mounting bar? Is that all it takes to get a basic binoscope up and running? 

[paulastro]

28 minutes ago, Lockie said:

They look great. I wonder how those diagonals are put together to form the rhomboid portion, do they screw together, Peter? Can you literally do this with 6 diagonals, two shortened ota's, and some kind of adjustable dual mounting bar? Is that all it takes to get a basic binoscope up and running? 

I think Peter told me he glued them together, but I'm sure he'll post a reply later to confirm - or not!

[Peter Drew]

Many thanks for posting the excellent photos Paul, a picture is worth at least a thousand of my words!

Further notes in reply to questions.

Yes, it really is all you have to do to make a no frills refracting binoscope, the main challenge being the adjustment and maintenance of collimation. The "rhomboids" are made by removing a couple of the 1.25" fittings, laying the diagonals on a flat surface to make sure that they are orthogonal and then bonding them together with Araldite. A thin stepped ring between the mating faces ensures concentricity. The rhomboid sections swivel to adjust the IPD, focusing is independent using the original focusers. Both OTA's are mounted on separate portions of aluminium channel which are spring spring loaded for adjustment, one for the horizontal and the other for the vertical, collimation with this system is easy and instant. The slightly longer than usual focal length of the ED80's makes it possible to just fit the prism assemblies into the light path without vignetting the objective. The view with two objectives is definitely better than binoviewers and one objective, specially with a relatively small aperture. The mount is Dobsonian style, smooth and responsive. A much prettier construction could be used but the view would be the same.  

[paulastro]

 You're most welcome Peter, I was pleased to have the opportunity to try them out.  I had to smile to myself how modest you are when you say  'Yes, it really is all you have to do to make a no frills refracting binoscope'   -   you make it sound very easy .  Of course having some good practical skills help (unlike me ) and so do a zillion years practical experience and knowledge (like you) . 

[nightfisher]

2 hours ago, spaceboy said:

I'm waiting on Jules to have a go at a 120ED bino scope. I know he's a big fan

 

 

How strange, why would I want to attempt this

[spaceboy]

2 hours ago, nightfisher said:

How strange, why would I want to attempt this

Just a bit of tongue and cheek mate

[mikeDnight]

2 hours ago, nightfisher said:

How strange, why would I want to attempt this

The seed has been planted, and Peter is always on the look out for willing victims! I'd steer clear of the AC for a while Jules!! 

Mike

[mikeDnight]

How pleased I am that Takahashi price increases have put the breaks on my stupidity/gullibility. 

Mike

[Stu]

13 minutes ago, mikeDnight said:

How pleased I am that Takahashi price increases have put the breaks on my stupidity/gullibility. 

Mike

I was thinking the other day, a nice pair of Tak FC76 Objective upgrades would not even need shortening! Add 6 Zeiss T2 prisms and a couple of Feathertouch focusers and away you (and your bank balance) go!!

Much better off going the 120ED route 

@Peter Drew, that's a lovely looking mount, home built I assume?

[nightfisher]

Peter, that Ed80 bino scope is a work of art, superb mount looking at the pics,a job very well done

[michael.h.f.wilkinson]

That 80 ED binoscope looks great!

[Peter Drew]

Larger non ED version for sale on AB & S at the moment, not me selling. 

[Alan White]

Peter, that is a great idea, you make it sound so simple.

The view through this must be good, the ed is a great scope in my view.

Now if I tried this one objective would point forward and the other backwards at best.

 

[BinocularSky]

On 06/06/2017 at 14:41, Stu said:

@Peter Drew a nice pair of Tak FC76 Objective upgrades

I wonder if they could be made to work with a Tak Astronomer 22x60 (which, I think, uses FS60CB objective tubes. (That is one bino I now regret not getting when I had the chance; used ones are now much more expensive than new ones were!)

[Stu]

11 minutes ago, BinocularSky said:

I wonder if they could be made to work with a Tak Astronomer 22x60 (which, I think, uses FS60CB objective tubes. (That is one bino I now regret not getting when I had the chance; used ones are now much more expensive than new ones were!)

I always fancied some of those, they get fabulous reviews don't they?

Didnt know they used FS60CB tubes, I guess the issue is whether the 76 dew shield is too wide to fit in, great thought though!

[Peter Drew]

1 hour ago, BinocularSky said:

I wonder if they could be made to work with a Tak Astronomer 22x60 (which, I think, uses FS60CB objective tubes. (That is one bino I now regret not getting when I had the chance; used ones are now much more expensive than new ones were!)

I've just had a refresher look at the Tak Astronomer 22x60 on some old CN threads, I'd forgotten that they were essentially a pair of flourite objectives "Tak'ed" on to a regular binocular body! Despite the expected glowing reports of the optical performance, the posters, in the main, wished for angled eyepieces and alternative magnifications. I think this is where an arrangement like I've used on my ED80's would be a better bet, the major part of the exercise was to address any such shortcomings, this has worked out very well. To summarise, larger aperture, magnification range up to 200x, 90 degree eyepiece orientation, individual focusing and instant user collimation facility. If pre-owned components are used, even the cost could be less.       

[Solar B]

I've owned a pair of the Tak Astromomers and they would im sure out preform these for contrast  , colour and correction 

.... but they do indeed cost more and I love this ED 80 pair .... just utterly superb in all respects .... and respect is due ?

 

Brian  

 

 

[Peter Drew]

8 hours ago, Solar B said:

I've owned a pair of the Tak Astromomers and they would im sure out preform these for contrast  , colour and correction 

.... but they do indeed cost more and I love this ED 80 pair .... just utterly superb in all respects .... and respect is due ?

 

Brian  

 

 

I'm sure you could be right Brian, I would love to have a side to side comparison. What I do know is that my DIY effort has provided me with the best and most versatile binocular telescope that I am ever likely to afford. Still early days to fully assess the performance, it's still a work in progress and I've had only one brief astro session but it does look very promising. At 200x each tube presents a textbook star image, something I've not seen in other binocular systems, there is a pale red or blue outer ring slightly out of focus but at focus nothing untoward is noticeable. I look forward to further trials and will report as appropriate.