ED80 binoulars.

[BinocularSky]

On 10/06/2017 at 13:12, Stu said:

I guess the issue is whether the 76 dew shield is too wide to fit in, great thought though!

My memory (and recent looking at images of the binocualr on t'interweb) is that the objective tubes are very widely spaced and that wouldn't be a an issue. Certainly worth checking, though

On 10/06/2017 at 14:15, Peter Drew said:

... glowing reports of the optical performance, the posters, in the main, wished for angled eyepieces and alternative magnifications.  

The "straight through" configuration was something that influenced my decision at the time.

Quote

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.     

I agree that your ED80 setup is a very attractive proposition, especially for those who want high magnification. Are the collimation knobs, in Paul's top image, the LHS horizontal one and what looks like a portion of the RHS vertical one in the ally channel? If so, I like the function-determined simplicity!

[Peter Drew]

6 minutes ago, BinocularSky said:

My memory (and recent looking at images of the binocualr on t'interweb) is that the objective tubes are very widely spaced and that wouldn't be a an issue. Certainly worth checking, though

The "straight through" configuration was something that influenced my decision at the time.

I agree that your ED80 setup is a very attractive proposition, especially for those who want high magnification. Are the collimation knobs, in Paul's top image, the LHS horizontal one and what looks like a portion of the RHS vertical one in the ally channel? If so, I like the function-determined simplicity!

I've made binocular telescopes on the Tak Astronomer principle of using a binocular body as the erector/focusing system, it's the simplest way to do this. The largest aperture that you can produce is determined by the separation of the objectives that the binocular body would have contained when set to your IPD, usually around 125mm. I have made 120mm units by this method but because of the weight and length of the OTA's they have to be fixed for the user IPD, the eyepieces are straight through orientation and not interchangeable.

On my ED80 version, as you suspected, each barrel is independently mounted on spring loaded channel operated by adjusting knobs in a X-Y axis. No previous experience or sophisticated equipment needed to collimate them.   

[BinocularSky]

2 hours ago, Peter Drew said:

No previous experience or sophisticated equipment needed to collimate them.   

One clear advantage of not having the IPD dependent on some species of central hinge!

[Peter Drew]

27 minutes ago, BinocularSky said:

One clear advantage of not having the IPD dependent on some species of central hinge!

Very true.  No matter how well the binocular telescope is made it's impossible to guarantee perfect collimation if high powers are available. Even swapping eyepiece pairs can make a difference or even the same pair swapped from left to right. Change of IPD to suit other users can be another source of miscollimation.   

[MarkRadice]

Peter,

What a fantastic project.  Your approach is elegant and I imagine the views are stupendous.  As you allude, you now have the best of both worlds: wide fields of view for sweeping the milky way and then the ability to switch to high power for lunar and planetary observing.  This isn't something you can achieve with conventional binos or a binoviewer.

Your project has certainly got me thinking ... a second hand 14" skywatcher ... joined diagonals .... dob frame with collimation controls ...

Best regards,

Mark

 

[Peter Drew]

4 hours ago, MarkRadice said:

Peter,

What a fantastic project.  Your approach is elegant and I imagine the views are stupendous.  As you allude, you now have the best of both worlds: wide fields of view for sweeping the milky way and then the ability to switch to high power for lunar and planetary observing.  This isn't something you can achieve with conventional binos or a binoviewer.

Your project has certainly got me thinking ... a second hand 14" skywatcher ... joined diagonals .... dob frame with collimation controls ...

Best regards,

Mark

 

Just as easily done in principle, I have a 12" version. 

[MarkRadice]

Peter,

That sounds fantastic. A 12" binoscope, goodness me! Would you mind posting some more details and pictures? I appreciate that this is wandering off your original post but it is somewhat aligned. 

Thanks in advance!